Difference between revisions of "HFI design, qualification, and performance"

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The inversion of HFI data requires that one knows how the instrument selects photons, how these photons are transformed in data transmitted by telemetry and what spurious signals are added in this process.
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This section provides an overview of the High-Frequency Instrument and of its different sub-systems.  
[[Category:Instruments]]
 
  
==HFI high level description and Architecture==
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* [[HFI_cryogenics | Cryogenics]]
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* [[HFI_cold_optics_%26_spectral_response | HFI cold optics and spectral response]]
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* [[HFI_detection_chain | Detection chain]]
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* [[HFI_operations | Operations]]
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* [[HFI_performance_summary | Performance summary]]
 +
* [[HFI_instrument_annexes | Annexes]]
  
<span style="color:red">(Lamarre/Pajot)</span>
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Two papers that include and detail this information are available: {{PlanckPapers|lamarre2010}} and {{PlanckPapers|planck2011-1-5}}. Additional detailed information potentially useful for users of HFI data is included in this section or annexed to it.
Should be short, understandable and point through links to the relevant sections and papers.
 
  
==Cryogenics==
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[[Image:HFI_2_4_1_JML_TheElectronicsAndServiceModule.png|thumb|500px|center|HFI electronics in the satellite]]
<span style="color:red">(F .Pajot)</span>
 
===Dilution===
 
  
The HFI 3He-4He dilution cooler produces temperatures of 0.1 K for the bolometers through
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The HFI instrument is designed around 52 bolometers. Twenty of the bolometers (spider-web bolometers or SWBs) are sensitive to total power, and the remaining 32 units are arranged in pairs of orthogonally-oriented polarisation-sensitive bolometers (PSBs). All bolometers are operated at a temperature of ~0.1 K by means of a space qualified dilution cooler coupled to a high precision temperature control system. A 4He-JT system provides active cooling for 4 K stages using vibration controlled mechanical compressors to prevent excessive warming of the 100 mK stage and minimize microphonic effects in the bolometers. Bolometers and sensitive thermometers are read using an AC-bias scheme through JFET amplifiers operated at ~130 K that provide high sensitivity and low frequency stability. The HFI covers six bands centred at 100, 143, 217, 353, 545, and 857 GHz, thanks to a thermo-optical design consisting of three corrugated horns and a set of compact reflective filters and lenses at cryogenic temperatures.
the dilution of 3He into 4He and 1.4 K through JT expansion of the 3He and 4He mixture. The
 
dilution cooler is described in detail in section 2.3.3 of {{PEarly|2|page=7}}.
 
  
The dilution was operated with flows set to the minimum available values, and provided a total
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[[Image:HFI_horns.jpg|thumb|500px|center|HFI focal plane optics and 4K thermo-mechanical stage.]]
lifetime of 30.5 months, exceeding the nominal lifetime of 16 months by 14.5 months. The
 
dilution stage was stabilized by a PID control with a regulating power between 20 and 30 nW
 
providing a temperature close to 101 mK. The bolometer plate was stabilized at 102.8 mK with a
 
PID regulating power around 5 nW. The cooling power values were in very good agreement with those obtained during the ground tests and calibration.
 
However, the cosmic particles interactions with the 100 mK stages induced temperature fluctuations and glitches on the thermometers measurements.
 
The decorrelation of 100 mK bolometer stage temperatures fluctuations from the bolometers signals is described in section 4.4.2.
 
  
[[File:HFI_2_4_1_100mK_stability.png|500px|100 mK stages temperatures during the mission]]
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The whole satellite is organized to provide thermal transitions between its warm part exposed to radiation from the Sun and Earth, and the focal plane instruments that include the cold receivers (Sections [[HFI_cold_optics]] and [[HFI_detection_chain]]). The various parts of the HFI are distributed among three different stages of the satellite in order to provide each sub-system with an optimal operating temperature. The "warm" parts, including nearly all the electronics and the sources of fluids of the 4K and 0.1K coolers, are attached and thermally linked to the service module of the satellite. The first stage of the preamplifiers is attached to the back of the passively cooled telescope structure. The focal plane unit is attached to the 20K stage cooled by the sorption cooler. This is detailed in Section [[HFI_detection_chain]].
  
(here a few lines of 100 mK boloplate stability)
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The telescope and horns select the geometrical origin of photons. They provide a high transmission efficiency to photons inside the main beam, while photons coming from the intermediate and far-side lobes have very low probability of being detected. The essential characteristics are determined by a complex process mixing ground measurements of components (horns, reflectors), modelling the shape of the far sidelobes, and measuring bright sources in-flight, especially planets.
  
[[File:HFI_2_4_1_1_6K_stability.png|500px|1.6K stage temperatures during the mission]]
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The filters and bolometers define the spectral response and absolute optical efficiency, which are known mostly from ground-based measurements performed at component, sub-system, and system levels, reported in this document. The relationships between spectral response and geometrical response are also addressed.
  
Detailed analysis of the in-flight stability of the
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Photons absorbed by a bolometer include the thermal radiation emitted by the various optical devices: telescope, horns, and filters. They are transformed into heat that propagates to the bolometer thermometer to influence its temperature, which is itself measured by the readout electronics. Temperatures of all these items must be stable enough not to contaminate the scientific signal delivered by the bolometers. How this stability is reached is described in Section [[HFI_cryogenics]].  
dilution cooler can be found in section
 
5.4 of {{PEarly|2|page=23}}.
 
  
=== 4K J-T cooler ===
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The bolometer temperature depends also on the temperature of the bolometer plate, on the intensity of the biasing current, and on any spurious inputs, such as cosmic rays and mechanical vibrations. Such systematics are included in a list discussed in Section [[HFI-Validation]].
  
The HFI 4K J-T cooler produces a temperature of  
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Since the bolometer thermometer is part of an active circuit that also heats it, the response of this system is complex and has to be considered as a whole. In addition, due to the modulation of the bias current and to the sampling of the data, the response signal of the instrument when scanning a point source is more complex still. Item in Sub-Section [[HFI_detection_chain#Time_response|Time_response]] and Annex [[HFI_time_response_model]] are dedicated to the description of this time response.
4K for the HFI 4K stage and optics and the  
 
precooling of the dilution gases. Full
 
description of the 4K cooler can be found in  
 
in section 2.3.2 of {{PEarly|2|page=7}}.
 
  
The 4K cooler was operated without interruption
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[[Image:HFI_2_4_1_JML_SignalFormation.png|thumb|500px|center|HFI signal formation.]]
during all the survey phase of the mission. It is
 
still in operation as it also provides the
 
cooling of the optical reference loads of the
 
LFI. The 4K PID stabilizing the temperature of
 
the HFI optics is regulated at 4.81 K using a
 
power around 1.8 mW.
 
  
[[File:HFI_2_4_1_4K_stability.png|500px|4K stage temperatures during the mission]]
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Logic of the formation of the signal in HFI. This is an idealized description of the physics that takes place in the instrument. The optical power that is absorbed by the bolometers comes from the observed sky and from the instrument itself. The bolometers and readout electronics, acting as a single and complex chain, transform this optical power into data that are compressed and transmitted for science data reduction.
  
(here a few lines of 4K stability, including compressors operation)
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<div style="clear: both"></div>
 +
== References ==
 +
<References />
 +
 +
  
Details on the in-flight performance of the
 
4K J-T cooler can be found in in section
 
5.3 of {{PEarly|2|page=21}}.
 
  
 
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[[Category:HFI design, qualification and performance|000]]
 
 
== Cold optics ==
 
<span style="color:red">(Lamarre)</span>
 
=== Horns,lenses===
 
links to Peter's paper
 
=== filters, band===
 
Includes Locke's very detailed document.
 
 
 
== Detection chain ==
 
<span style="color:red">(Francesco Piacentini)</span>
 
=== Bolometers===
 
 
 
(notes by Alain: take from DOC file (50 Mo) from Francesco, email 15 Oct 2012 17:39:03)
 
 
 
The heart of the HFI - the detectors - are bolometers, solid-state devices in which the
 
incoming radiation dissipates its energy as heat that increases the temperature of a
 
thermometer. The instrument Flight Model total number of bolometers is 52, split into 6
 
channels at central frequencies of 100, 143, 217, 353, 545, and 857GHz.
 
 
 
Thirty two of these bolometers are polarization sensitive allowing a map of the CMB polarisation to be built.
 
 
 
 
 
 
 
Bolometers consist of (i) an absorber that transforms the in-coming radiation into heat; (ii) a thermometer that is thermally linked to the absorber and measures the temperature changes; and (iii) a weak thermal link to a thermal sink, to which the bolometer is attached.
 
 
 
 
 
The detectors are semi-conducting NTD thermistor bolometers. There are two kinds of detector modules:
 
 
 
* SWB, spider web bolometers, are mounted on an absorbing spider-web of metallised silicon nitride
 
* PSB, polarization sensitive bolometers, are mounted or on a parallel absorbing grid of metallised silicon nitride.
 
 
 
 
 
In the spider-web bolometers, or SWBs (Bock et al. 1995; Mauskopf et al. 1997), the absorbers consist of metallic grids
 
deposited on a Si3 N4 substrate in the shape of a spider web.
 
The mesh design and the impedance of the metallic layer are
 
adjusted to match vacuum impedance and maximize the absorption of millimeter waves, while minimizing the cross section to
 
particles. The absorber is designed to offer equal impedance to
 
any linearly polarised radiation. Nevertheless, the thermometer
 
and its electrical leads define a privileged orientation (Fig. SWB) that
 
makes the SWBs slightly sensitive to polarisation, as detailed in
 
(Rosset et al. 2010). The thermometers are
 
made of neutron transmuted doped (NTD) germanium (Haller
 
et al. 1996), chosen to have an impedance of about 10 MΩ at
 
their operating temperature.
 
 
 
 
 
[[File:HFI_2_4_1_FPiacentini_bolo1.png|500px|
 
((Illustration 6)): Picture of a spider web bolometer. This a 143 GHz module, The temperature sensor is at the center of the absorbing grid]]
 
 
 
 
 
 
 
The absorber of PSBs is a rectangular grid (Fig. PSB) with metallization in one direction (Jones et al.
 
2003). Electrical fields parallel to this direction develop currents and then deposit some power in the grid, while perpendicular electrical fields propagate through the grid without significant interaction. A second PSB perpendicular to the first one absorbs the other polarisation. Such a PSB pair measures two polarisations of radiation collected by the same horns and filtered by the same devices, which minimises the systematic effects: differences between polarised
 
beams collected by a given horn are typically less than −30 dB of
 
the peak. The differences in the spectral responses of a PSB pair
 
also proved to be a few percent in the worst case. Each pair
 
of PSBs sharing the same horn is able to measure the intensity
 
Stokes parameter and the Q parameter associated with its local
 
frame. An associated pair of PSBs rotated by 45◦ scans exactly
 
the same line (if the geometrical alignment is perfect), providing
 
the U Stokes parameter.
 
 
 
 
 
[[File:HFI_2_4_1_FPiacentini_bolo2.png|500px|
 
Picture of a polarization sensitive bolometer. This a 217 GHz module, The temperature sensor is at the an edge  of the absorbing grid]]
 
 
 
 
 
 
 
The detectors operate at a temperature close to 100 mK, while the filters are distributed on the 100mK, 1.6 K,
 
and 4 K stages in such a way that the heat load on the coldest stages is minimized to
 
limit the heat load on the detectors and to decrease
 
the heat lift requirement and thus enhance the mission lifetime. The self-emission of the 4K stage is minimised to limit the photon noise contribution on the detectors from the instrument.
 
The HFI Focal Plane Unit accommodates sub-millimiter absorbing
 
material in order to decrease the scattering inside it.
 
 
 
 
 
 
 
Insert here table 1 from HFI-Early paper http://dx.doi.org/10.1051/0004-6361/201116487http://dx.doi.org/10.1051/0004-6361/201116487
 
I report the table as a figure for the moment
 
 
 
[[File:HFI_2_4_1_FPiacentini_table1.png|500px|to be change into a real table]]
 
 
 
===Focal plane layout===
 
 
 
This section may also go somewhere else, like in optics
 
 
 
The layout of the detectors in the focal plane is defined to cope with the
 
scanning strategy. The HFI horns are positioned at the centre of the focal plane, where the optical
 
quality is good enough for the high frequencies. The curvature of
 
rows compensates for the distortion of images by the telescope.
 
A pair of identical SWB will scan the same circle on the sky to
 
provide additional redundancy. Similar horns feeding PSBs are
 
also aligned so that two pairs of PSBs rotated by 45◦ with respect to each other scan the same line. This will provide the Q and U Stokes parameters with minimal correction for the pointing (Rosset et al. 2010). Residual systematics will come from the differences between the beam shapes of the two horns. In all
 
cases except for the 100 GHz horns, a measurement is also done
 
by a pair of similar channels shifted by 1.25 arcminutes in the cross-scan direction, to ensure adequate sampling. In the figures focal plane layout is reported.
 
 
 
[[File:HFI_2_4_1_FPiacentini_FocalPlaneLayout.png|500px|Focal plane layout as seen from outside the celestial sphere. Each spot represents an horn in the focal plane. Coordinates are in pointing direction with respect to the telescope boresight. PSBs detectors are indicated with a cross oriented as the two polarimeters axes. Scan direction is from
 
left to right.]]
 
 
 
[[File:HFI_2_4_1_FPiacentini_FocalPlaneGeo.png|500px|Illustration 4: Focal plane layout as seen from outside the celestial sphere. In this case PSBs orientations are reported. Red rod is for a elements of PSBs, blue rod is for b elements.]]
 
 
 
=== Readout===
 
 
 
 
 
[From HFI pre flight paper]
 
The AC bias readout electronics of the HFI instrument (Gaertner et al. 1997) includes a number of original features proposed by several laboratories (CRTBT in Grenoble, CESR in Toulouse and IAS in Orsay), which were validated on the Diabolo experiment and on the balloon-borne Archeops experiment. It was developed for space by the CESR in Toulouse.
 
 
 
 
 
The particular features of the HFI AC bias readout are mainly
 
 
 
 
 
* i)that the cold load resistors were replaced by capacitors because they have no Johnson noise;
 
* ii)that the detectors are biased by applying a triangular voltage to the load capacitors
 
which produces a square current [Ibias ] in the capacitors, and a square voltage [T bias ] that compensates for the stray capacitance of the wiring (producing a nearly square bias current into the bolometer;
 
* iii)that a square offset com-pensation signal is subtracted to the bolometric signal to minimise the amplitude of the signal that has to be amplified and digitized;
 
* iv)that the electronic scheme is symmetrical and uses a differential amplification scheme to optimize the immunity to electromagnetic interferences;
 
* v)and finally that every parameter of the REU can be set by commands, which
 
is made possible by using digital-to-analog and analog-to-digital converters extensively.
 
 
 
 
 
The readout electronics consist of 72 channels designed to perform low noise measurements of the impedance of 52 bolometers, two blind bolometers, 16 accurate low temperature thermometers, all in the 10 MΩ range, one resistor of 10 MΩ and one capacitor of 100 pF. The semiconductor bolometers and thermometers of Planck-HFI operate at cryogenic temperature around 100 mK on the focal plane, with impedance of about 10 MΩ when biased at the optimal current. The readout electronics on the contrary have to operate at “room” temperature (300 K). The distance between the two extremities of the readout chain is about 10 m and could represent a point of extreme susceptibility to electromagnetic interference. The readout electronic chain was split into three boxes. These are the JFET box, located on the 50 K stage of the satellite at 2.2 m from the focal plane, the pre-amplifier unit (PAU), located 1.8m further at 300 K, and the REU, located on the opposite side of the satellite, 5 m away. Each of the three boxes (JFET, PAU and
 
REU) consists of 12 belts of six channels. The first nine belts are dedicated to the bolometers, and the three last ones to the accurate thermometers, the resistor and the capacitor (see figure Organization of the HFI readout).
 
 
 
[[File:HFI_2_4_1_FPiacentini_HFIreadout.png|500px|
 
Illustration 6: Organization of the HFI readout. Each row represents a belt. Each belt has 6 channels.]]
 
 
 
[[File:HFI_2_4_1_FPiacentini_table2.png|500px|Illustration 5: Organization of the HFI readout. Each row represents a belt. Each belt has 6 channels. (to be change into a real table ?)]]
 
 
 
===Principles of the readout electronics. ===
 
 
 
From HFI pre-flight paper
 
 
 
See figure [Principles of readout electronics]. The bolometer is biased by a square wave AC current obtained by the differentiation of a triangular voltage through a load capacitance, in a completely differential architecture. The presence of the stray capacitance due to losses of charge in the wiring requires a correction of the shape of the square bias current by a transient voltage. Thus the bias voltage generation is controlled by the two parameters I-bias and T-bias that express the amplitude of the triangular and transient voltage. The compensation voltage added to the bolometric signal to optimize the dynamic of the chain is controlled by the V-bal parameter.
 
 
 
Illustration 6: Principles of readout electronics. The three modules of the chain are shown: JFet Box, Pre-Amplifier
 
Unit (PAU) and Readout Electronic Unit (REU).
 
 
 
 
 
Parameters of the Readout Unit can be set to optimize the detectors performance.
 
 
 
The modulation frequency of the AC bias system, fmod of the square bias current
 
can be tuned from 70 Hz to 112 Hz by the telecommand parameters:
 
Nsample, which defines the number of samples per half period of modulated signal,
 
fdiv which determines the sampling frequency of the ADC.
 
 
 
The optimal frequencies are around 90 Hz.
 
 
 
 
 
Each channel has its own settings for the following parameters:
 
I-bias, amplitude of the triangular bias voltage;
 
 
 
T-bias, amplitude of the transient bias voltage;
 
 
 
V-bal, amplitude of the square compensation voltage;
 
 
 
G-amp, value of the programmable gain of the REU [1/3, 1, 3, 7.6];
 
 
 
N-blank, number of blanked samples at the beginning of halfperiod not taken into account during integration of the signal;
 
 
 
S-phase, phase shift when computing the integrated signal.
 
 
 
All these parameters influence the effective response of the
 
detection chains, and were optimized during the calibration
 
campaigns and confirmed during the calibration and performance
 
verification (CPV) phase following the launch of
 
Planck. The scientific signal is provided by the integral of the
 
signal on each half-period, between limits fixed by the S-phase
 
and N-blank parameters.
 
 
 
 
 
The interaction of modulated readout electronics with semiconductor
 
bolometers is rather different from that of a classical
 
DC bias readout (Jones 1953). The differences were seen during
 
the calibration of the HFI, although the readout electronics
 
was designed to mimic the operation
 
of a DC biased bolometric system as far as possible. With the
 
AC readout the maximum of responsivity is lower and is obtained
 
for higher bias current in the bolometer with respect to the DC model.
 
This is caused by the stray capacitance in the
 
wiring which has negligible effects for a DC bias and a major
 
effect for an AC bias. In our case, a stray capacitance of 150 pF
 
induces increases of NEP ranging from 4% (857 GHz bolometers)
 
to 10% (100 GHz bolometers) and also affects the HFI time
 
response. Details of the effect of the HFI AC bias system into
 
the time response of the detectors are discussed in the Time Response Section [link].
 
 
 
[Here I suggest to copy the wiki post with in flight setting of parameters http://wiki.planck.fr/index.php/Proc/HFIstatehttp://wiki.planck.fr/index.php/Proc/HFIstate Or a table with the physical values. I have an excel file prepared by F-X Desert]
 
 
 
=== JFETs===
 
 
 
Taken from pre-flight paper
 
 
 
Given the high impedance of the bolometers and the length of the connecting cables, it it is  essential that the impedance of the signal is lowered as close as possible to the detectors. In our system this is accomplished by means of JFET source followers, located in boxes connected to the 50 K stage. There are two JFETs per channel, since the readout is fully differential, and they provide a current amplification of the signal while keeping the voltage amplification very close to unity.
 
 
 
Inside the box, the JFETs are mounted on a thermally insulated plate with an active temperature control to keep them at the optimal temperature of 110 K. With a dissipated power lower than 240 mW, mainly produced by the JFETs and the source resistors, we obtained a noise power spectral density of less than 3 nV Hz1/2 for the frequency range of interest. This increases the total noise ofall bolometer channels by less than 5%.
 
 
 
 
 
=== Data compression===
 
=== Time response.===
 
 
 
 
 
 
 
The HFI bolometers and readout electronics have a finite response time to changes in incident optical power.  The bolometers are thermal detectors of radiation whose response time is determined by the thermal circuit defined by the heat capacity of the detector and thermal conductivity.
 
 
 
Due to Planck's nearly constant scan rate, the time response is degenerate with the optical beam.  However, because of the long time scale effects present in the time response, the  time response is deconvolved from the data in the processing of the HFI data (see [[TOI processing|TOI processing]]).
 
 
 
The time response of the HFI bolometers and readout electronics is modeled as a Fourier domain transfer function (called the LFER4 model) consisting of the product of an bolometer thermal response <math>F(\omega)</math> and an electronics response <math>H'(\omega)</math>.
 
 
 
<math>\label{LFER4def}TF^{LFER4}(\omega) = F(\omega) H'(\omega)</math>
 
 
 
=== LFER4 model ===
 
 
 
If we write the input signal (power) on a bolometer as <math>\label{bol_in}
 
s_0(t)=e^{i\omega t}
 
</math> the bolometer physical impedance can be written as: <math>\label{bol_out}
 
s(t)=e^{i\omega t}F(\omega)
 
</math> where <math>\omega</math> is the angular frequency of the signal and <math>F(\omega)</math> is the complex intrinsic bolometer transfer function. For HFI the bolometer transfer function is modelled as the sum of 4 single pole low pass filters: <math>\label{bol_tf}
 
F(\omega) = \sum_{i=0,4} \frac{a_i}{1 + i\omega\tau_i}
 
</math> The modulation of the signal is done with a square wave, written here as a composition of sine waves of decreasing amplitude: <math>\label{sigmod}
 
s'(t)=e^{i\omega t}F(\omega)\sum_{k=0}^{\infty} \frac{e^{i\omega_r(2k+1)t}-e^{-i\omega_r(2k+1)t}}{2i(2k+1)}
 
</math> where we have used the Euler relation <math>\sin x=(e^{ix}-e^{-ix})/2i</math> and <math>\omega_r</math> is the angular frequency of the square wave. The modulation frequency is <math>f_{mod} = \omega_r/2\pi</math> and was set to <math>f_{mod} = 90.18759 </math>Hz in flight. This signal is then filtered by the complex electronic transfer function <math>H(\omega)</math>. Setting: <math>\omega_k^+=\omega+(2k+1)\omega_r</math> <math>\omega_k^-=\omega-(2k+1)\omega_r</math> we have: <math>\label{sigele}
 
\Sigma(t)=\sum_{k=0}^\infty\frac{F(\omega)}{2i(2k+1)}\left[H(\omega_k^+)e^{i\omega_k^+t}-H(\omega_k^-)e^{i\omega_k^-t}\right]
 
</math> This signal is then sampled at high frequency (<math>2 f_{mod} NS</math>). <math>NS</math> is one of the parameters of the HFI electronics and corresponds to the number of high frequency samples in each modulation semi-period. In order to obtain an output signal sampled every <math>\pi/\omega_r</math> seconds, we must integrate on a semiperiod, as done in the HFI readout. To also include a time shift <math>\Delta t</math>, the integral is calculated between <math>n\pi/\omega_r+\Delta t</math> and <math>(n+1)\pi/\omega_r+\Delta t</math> (with <math>T=2 \pi/\omega_r</math> period of the modulation). The time shift <math>\Delta t</math> is encoded in the HFI electronics by the parameter <math>S_{phase}</math>, with the relation <math>\Delta t = S_{phase}/NS/f_{mod} </math>.
 
 
 
After integration, the <math>n</math>-sample of a bolometer can be written as <math>\label{eqn:output}
 
Y(t_n) = (-1)^n F(\omega) H'(\omega) e^{i t_n \omega}
 
</math> where <math>\label{tfele}
 
H'(\omega) = \frac 12 \sum_{k=0}^\infty
 
e^{-i(\frac{\pi\omega}{2\omega_r}+\omega\Delta t)} \Bigg[
 
\frac{H(\omega_k^+)e^{i\omega_k^+ \Delta t}}{(2k+1)\omega_k^+}
 
\left(1-e^{\frac{i\omega_k^+\pi}{\omega_r}}\right)
 
\\ - \frac{H(\omega_k^-)e^{i\omega_k^- \Delta t}}{(2k+1)\omega_k^-}  \left(1-e^{\frac{i\omega_k^-\pi}{\omega_r}}\right)
 
\Bigg]
 
</math>
 
 
 
The output signal in equation eqn:output can be demodulated (thus removing the <math>(-1)^n</math>) and compared to the input signal in equation bol_in. The overall transfer function is composed of the bolometer transfer function and the effective electronics transfer function, <math>H'(\omega)</math>: <math>TF(\omega) = F(\omega) H'(\omega)
 
</math>
 
 
 
The shape of <math>H(\omega)</math> is obtained combining low and high-pass filters with Sallen Key topologies (with their respective time constants) and accounting also for the stray capacitance low pass filter given by the bolometer impedance combined with the stray capacitance of the cables. The sequence of filters that define the electronic band-pass function <math>H(\omega) = h_0*h_1*h_2*h_3*h_4*h_{5}</math> are listed in table table:readout_electronics_filters.
 
 
 
=== Parameters of LFER4 model ===
 
 
 
The LFER4 model has are a total of 10 parameters(<math>A_1</math>,<math>A_2</math>,<math>A_3</math>,<math>A_4</math>,<math>\tau_1</math>,<math>\tau_2</math>,<math>\tau_3</math>,<math>\tau_4</math>,<math>S_{phase}</math>,<math>\tau_{stray}</math>) 9 of which are independent, for each bolometer. The free parameters of the LFER4 model are determined using in-flight data in the following ways:
 
 
 
* <math>S_{phase}</math> is fixed at the value of the REU setting.
 
* <math>\tau_{stray}</math> is measured during the QEC test during CPV.
 
* <math>A_1</math>, <math>\tau_1</math>, <math>A_2</math>, <math>\tau_2</math> are fit forcing the compactness of the scanning beam.
 
* <math>A_3</math>, <math>\tau_3</math>, <math>A_{4}</math> <math>\tau_4</math> are fit by forcing agreement of survey 2 and survey 1 maps.
 
* The overall normalization of the LFER4 model is forced to be 1.0 at the signal frequency of the dipole. 
 
 
 
The details of determining the model parameters are given in (reference P03c paper) and the best-fit parameters listed here in table table:LFER4pars.
 
 
 
 
 
===HFI electronics filter sequence ===
 
 
 
{| class="wikitable" style="text-align: left; border-collapse: collapse; border-width: 1px; border-style: solid; border-color: #000"
 
|+HFI electronics filter sequence. We define $s = i \omega$
 
|-
 
! style="border-style: solid; border-width: 1px"|Filter
 
! style="border-style: solid; border-width: 1px"|Parameters
 
! style="border-style: solid; border-width: 1px"|Function
 
|-
 
|style="border-style: solid; border-width: 1px"|0. Stray capacitance low pass filter
 
|style="border-style: solid; border-width: 1px"|<math>\tau_{stray}= R_{bolo} C_{stray}</math>
 
|style="border-style: solid; border-width: 1px"|<math>h_0 = \frac{1}{1.0+\tau_{stray}*s}</math>
 
|-
 
|style="border-style: solid; border-width: 1px"|1. Low pass filter
 
|style="border-style: solid; border-width: 1px"|<math>R_1=1</math>k<math>\Omega</math> <br /> <math>C_1=100</math>nF
 
|style="border-style: solid; border-width: 1px"|<math>h_1 = \frac{2.0+R_1*C_1*s}{2.0*(1.0+R_1*C_1*s)}</math>
 
|-
 
|style="border-style: solid; border-width: 1px"|2. Sallen Key high pass filter
 
|style="border-style: solid; border-width: 1px"|<math>R_2=51</math>k<math>\Omega</math><br /> <math>C_2=1\mu</math>
 
|style="border-style: solid; border-width: 1px"|<math>h_2= \frac{(R_2*C_2*s)^2}{(1.0+R_2*C_2*s)^2}</math>3
 
|-
 
|style="border-style: solid; border-width: 1px"|3. Sign reverse with gain
 
|style="border-style: solid; border-width: 1px"|
 
|style="border-style: solid; border-width: 1px"|<math>h_3=-5.1</math>
 
|-
 
|style="border-style: solid; border-width: 1px"|4. Single pole low pass filter with gain
 
|style="border-style: solid; border-width: 1px"|<math>R_4=10</math>k<math>\Omega</math><br /> <math>C_4=10</math>nF
 
|style="border-style: solid; border-width: 1px"|<math>h_4= \frac{1.5}{1.0+R_4*C_4*s}</math>
 
|-
 
|style="border-style: solid; border-width: 1px"|5. Single pole high pass filter coupled to a Sallen Key low pass filter
 
|style="border-style: solid; border-width: 1px"|<math>R_9=18.7</math>k<math>\Omega</math><br /><math>R_{12}=37.4</math>k<math>\Omega</math><br /> <math>C=10.0</math>nF<br /><math>R_{78}=510</math>k<math>\Omega</math><br /> <math>C_{18}=1.0\mu</math>F<br /><math>K_3 = R_9^2*R_{78}*R_{12}^2*C^2*C_{18}</math><br /> <math>K_2 = R_9*R_{12}^2*R_{78}*C^2+R_{9}^2*R_{12}^2*C^2+R_9*R_{12}^2*R_{78}*C_{18}*C</math><br /> <math>K_1 =R_9*R_{12}^2*C+R_{12}*R_{78}*R_9*C_{18}</math>
 
|style="border-style: solid; border-width: 1px"|<math>h_{5} = \frac{2.0*R_{12}*R_9*R_{78}*C_{18}*s}{s^3*K_3 +
 
      s^2*K_2+
 
      s*K_1 + R_{12}*R_9 } </math>
 
 
 
|}
 
 
 
 
 
 
 
{| class="wikitable" style="text-align: left; align: center; border-collapse: collapse; border-width: 1px; border-style: solid; border-color: #000"
 
|+ Parameters for LFER4 model.
 
|-
 
|style="border-style: solid; border-width: 1px"|Bolometer
 
|style="border-style: solid; border-width: 1px"|<math>A_1</math>
 
|style="border-style: solid; border-width: 1px"|<math>\tau_1</math> (s)
 
|style="border-style: solid; border-width: 1px"|<math>A_2</math>
 
|style="border-style: solid; border-width: 1px"|<math>\tau_2</math> (s)
 
|style="border-style: solid; border-width: 1px"|<math>A_3</math>
 
|style="border-style: solid; border-width: 1px"|<math>\tau_3</math> (s)
 
|style="border-style: solid; border-width: 1px"|<math>A_4</math>
 
|style="border-style: solid; border-width: 1px"|<math>\tau_4</math> (s)
 
|style="border-style: solid; border-width: 1px"|<math>\tau_{stray}</math> (s)
 
|style="border-style: solid; border-width: 1px"|<math>S_{phase}</math>
 
|-
 
|style="border-style: solid; border-width: 1px"|100-1a
 
|style="border-style: solid; border-width: 1px"|0.392
 
|style="border-style: solid; border-width: 1px"|0.01
 
|style="border-style: solid; border-width: 1px"|0.534
 
|style="border-style: solid; border-width: 1px"|0.0209
 
|style="border-style: solid; border-width: 1px"|0.0656
 
|style="border-style: solid; border-width: 1px"|0.0513
 
|style="border-style: solid; border-width: 1px"|0.00833
 
|style="border-style: solid; border-width: 1px"|0.572
 
|style="border-style: solid; border-width: 1px"|0.00159
 
|style="border-style: solid; border-width: 1px"|0.00139
 
|-
 
|style="border-style: solid; border-width: 1px"|100-1b
 
|style="border-style: solid; border-width: 1px"|0.484
 
|style="border-style: solid; border-width: 1px"|0.0103
 
|style="border-style: solid; border-width: 1px"|0.463
 
|style="border-style: solid; border-width: 1px"|0.0192
 
|style="border-style: solid; border-width: 1px"|0.0451
 
|style="border-style: solid; border-width: 1px"|0.0714
 
|style="border-style: solid; border-width: 1px"|0.00808
 
|style="border-style: solid; border-width: 1px"|0.594
 
|style="border-style: solid; border-width: 1px"|0.00149
 
|style="border-style: solid; border-width: 1px"|0.00139
 
|-
 
|style="border-style: solid; border-width: 1px"|100-2a
 
|style="border-style: solid; border-width: 1px"|0.474
 
|style="border-style: solid; border-width: 1px"|0.00684
 
|style="border-style: solid; border-width: 1px"|0.421
 
|style="border-style: solid; border-width: 1px"|0.0136
 
|style="border-style: solid; border-width: 1px"|0.0942
 
|style="border-style: solid; border-width: 1px"|0.0376
 
|style="border-style: solid; border-width: 1px"|0.0106
 
|style="border-style: solid; border-width: 1px"|0.346
 
|style="border-style: solid; border-width: 1px"|0.00132
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|100-2b
 
|style="border-style: solid; border-width: 1px"|0.126
 
|style="border-style: solid; border-width: 1px"|0.00584
 
|style="border-style: solid; border-width: 1px"|0.717
 
|style="border-style: solid; border-width: 1px"|0.0151
 
|style="border-style: solid; border-width: 1px"|0.142
 
|style="border-style: solid; border-width: 1px"|0.0351
 
|style="border-style: solid; border-width: 1px"|0.0145
 
|style="border-style: solid; border-width: 1px"|0.293
 
|style="border-style: solid; border-width: 1px"|0.00138
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|100-3a
 
|style="border-style: solid; border-width: 1px"|0.744
 
|style="border-style: solid; border-width: 1px"|0.00539
 
|style="border-style: solid; border-width: 1px"|0.223
 
|style="border-style: solid; border-width: 1px"|0.0147
 
|style="border-style: solid; border-width: 1px"|0.0262
 
|style="border-style: solid; border-width: 1px"|0.0586
 
|style="border-style: solid; border-width: 1px"|0.00636
 
|style="border-style: solid; border-width: 1px"|0.907
 
|style="border-style: solid; border-width: 1px"|0.00142
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|100-3b
 
|style="border-style: solid; border-width: 1px"|0.608
 
|style="border-style: solid; border-width: 1px"|0.00548
 
|style="border-style: solid; border-width: 1px"|0.352
 
|style="border-style: solid; border-width: 1px"|0.0155
 
|style="border-style: solid; border-width: 1px"|0.0321
 
|style="border-style: solid; border-width: 1px"|0.0636
 
|style="border-style: solid; border-width: 1px"|0.00821
 
|style="border-style: solid; border-width: 1px"|0.504
 
|style="border-style: solid; border-width: 1px"|0.00166
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|100-4a
 
|style="border-style: solid; border-width: 1px"|0.411
 
|style="border-style: solid; border-width: 1px"|0.0082
 
|style="border-style: solid; border-width: 1px"|0.514
 
|style="border-style: solid; border-width: 1px"|0.0178
 
|style="border-style: solid; border-width: 1px"|0.0581
 
|style="border-style: solid; border-width: 1px"|0.0579
 
|style="border-style: solid; border-width: 1px"|0.0168
 
|style="border-style: solid; border-width: 1px"|0.37
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|100-4b
 
|style="border-style: solid; border-width: 1px"|0.687
 
|style="border-style: solid; border-width: 1px"|0.0113
 
|style="border-style: solid; border-width: 1px"|0.282
 
|style="border-style: solid; border-width: 1px"|0.0243
 
|style="border-style: solid; border-width: 1px"|0.0218
 
|style="border-style: solid; border-width: 1px"|0.062
 
|style="border-style: solid; border-width: 1px"|0.00875
 
|style="border-style: solid; border-width: 1px"|0.431
 
|style="border-style: solid; border-width: 1px"|0.00138
 
|style="border-style: solid; border-width: 1px"|0.00139
 
|-
 
|style="border-style: solid; border-width: 1px"|143-1a
 
|style="border-style: solid; border-width: 1px"|0.817
 
|style="border-style: solid; border-width: 1px"|0.00447
 
|style="border-style: solid; border-width: 1px"|0.144
 
|style="border-style: solid; border-width: 1px"|0.0121
 
|style="border-style: solid; border-width: 1px"|0.0293
 
|style="border-style: solid; border-width: 1px"|0.0387
 
|style="border-style: solid; border-width: 1px"|0.0101
 
|style="border-style: solid; border-width: 1px"|0.472
 
|style="border-style: solid; border-width: 1px"|0.00142
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|143-1b
 
|style="border-style: solid; border-width: 1px"|0.49
 
|style="border-style: solid; border-width: 1px"|0.00472
 
|style="border-style: solid; border-width: 1px"|0.333
 
|style="border-style: solid; border-width: 1px"|0.0156
 
|style="border-style: solid; border-width: 1px"|0.134
 
|style="border-style: solid; border-width: 1px"|0.0481
 
|style="border-style: solid; border-width: 1px"|0.0435
 
|style="border-style: solid; border-width: 1px"|0.27
 
|style="border-style: solid; border-width: 1px"|0.00149
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|143-2a
 
|style="border-style: solid; border-width: 1px"|0.909
 
|style="border-style: solid; border-width: 1px"|0.0047
 
|style="border-style: solid; border-width: 1px"|0.0763
 
|style="border-style: solid; border-width: 1px"|0.017
 
|style="border-style: solid; border-width: 1px"|0.00634
 
|style="border-style: solid; border-width: 1px"| 0.1
 
|style="border-style: solid; border-width: 1px"|0.00871
 
|style="border-style: solid; border-width: 1px"|0.363
 
|style="border-style: solid; border-width: 1px"|0.00148
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|143-2b
 
|style="border-style: solid; border-width: 1px"|0.912
 
|style="border-style: solid; border-width: 1px"|0.00524
 
|style="border-style: solid; border-width: 1px"|0.0509
 
|style="border-style: solid; border-width: 1px"|0.0167
 
|style="border-style: solid; border-width: 1px"|0.0244
 
|style="border-style: solid; border-width: 1px"|0.0265
 
|style="border-style: solid; border-width: 1px"|0.0123
 
|style="border-style: solid; border-width: 1px"|0.295
 
|style="border-style: solid; border-width: 1px"|0.00146
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|143-3a
 
|style="border-style: solid; border-width: 1px"|0.681
 
|style="border-style: solid; border-width: 1px"|0.00419
 
|style="border-style: solid; border-width: 1px"|0.273
 
|style="border-style: solid; border-width: 1px"|0.00956
 
|style="border-style: solid; border-width: 1px"|0.0345
 
|style="border-style: solid; border-width: 1px"|0.0348
 
|style="border-style: solid; border-width: 1px"|0.0115
 
|style="border-style: solid; border-width: 1px"|0.317
 
|style="border-style: solid; border-width: 1px"|0.00145
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|143-3b
 
|style="border-style: solid; border-width: 1px"|0.82
 
|style="border-style: solid; border-width: 1px"|0.00448
 
|style="border-style: solid; border-width: 1px"|0.131
 
|style="border-style: solid; border-width: 1px"|0.0132
 
|style="border-style: solid; border-width: 1px"|0.0354
 
|style="border-style: solid; border-width: 1px"|0.0351
 
|style="border-style: solid; border-width: 1px"|0.0133
 
|style="border-style: solid; border-width: 1px"|0.283
 
|style="border-style: solid; border-width: 1px"|0.00161
 
|style="border-style: solid; border-width: 1px"|0.000832
 
|-
 
|style="border-style: solid; border-width: 1px"|143-4a
 
|style="border-style: solid; border-width: 1px"|0.914
 
|style="border-style: solid; border-width: 1px"|0.00569
 
|style="border-style: solid; border-width: 1px"|0.072
 
|style="border-style: solid; border-width: 1px"|0.0189
 
|style="border-style: solid; border-width: 1px"|0.00602
 
|style="border-style: solid; border-width: 1px"|0.0482
 
|style="border-style: solid; border-width: 1px"|0.00756
 
|style="border-style: solid; border-width: 1px"|0.225
 
|style="border-style: solid; border-width: 1px"|0.00159
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|143-4b
 
|style="border-style: solid; border-width: 1px"|0.428
 
|style="border-style: solid; border-width: 1px"|0.00606
 
|style="border-style: solid; border-width: 1px"|0.508
 
|style="border-style: solid; border-width: 1px"|0.00606
 
|style="border-style: solid; border-width: 1px"|0.0554
 
|style="border-style: solid; border-width: 1px"|0.0227
 
|style="border-style: solid; border-width: 1px"|0.00882
 
|style="border-style: solid; border-width: 1px"|0.084
 
|style="border-style: solid; border-width: 1px"|0.00182
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|143-5
 
|style="border-style: solid; border-width: 1px"|0.491
 
|style="border-style: solid; border-width: 1px"|0.00664
 
|style="border-style: solid; border-width: 1px"|0.397
 
|style="border-style: solid; border-width: 1px"|0.00664
 
|style="border-style: solid; border-width: 1px"|0.0962
 
|style="border-style: solid; border-width: 1px"|0.0264
 
|style="border-style: solid; border-width: 1px"|0.0156
 
|style="border-style: solid; border-width: 1px"|0.336
 
|style="border-style: solid; border-width: 1px"|0.00202
 
|style="border-style: solid; border-width: 1px"|0.00139
 
|-
 
|style="border-style: solid; border-width: 1px"|143-6
 
|style="border-style: solid; border-width: 1px"|0.518
 
|style="border-style: solid; border-width: 1px"|0.00551
 
|style="border-style: solid; border-width: 1px"|0.409
 
|style="border-style: solid; border-width: 1px"|0.00551
 
|style="border-style: solid; border-width: 1px"|0.0614
 
|style="border-style: solid; border-width: 1px"|0.0266
 
|style="border-style: solid; border-width: 1px"|0.0116
 
|style="border-style: solid; border-width: 1px"|0.314
 
|style="border-style: solid; border-width: 1px"|0.00153
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|143-7
 
|style="border-style: solid; border-width: 1px"|0.414
 
|style="border-style: solid; border-width: 1px"|0.00543
 
|style="border-style: solid; border-width: 1px"|0.562
 
|style="border-style: solid; border-width: 1px"|0.00543
 
|style="border-style: solid; border-width: 1px"|0.0185
 
|style="border-style: solid; border-width: 1px"|0.0449
 
|style="border-style: solid; border-width: 1px"|0.00545
 
|style="border-style: solid; border-width: 1px"|0.314
 
|style="border-style: solid; border-width: 1px"|0.00186
 
|style="border-style: solid; border-width: 1px"|0.00139
 
|-
 
|style="border-style: solid; border-width: 1px"|217-5a
 
|style="border-style: solid; border-width: 1px"|0.905
 
|style="border-style: solid; border-width: 1px"|0.00669
 
|style="border-style: solid; border-width: 1px"|0.0797
 
|style="border-style: solid; border-width: 1px"|0.0216
 
|style="border-style: solid; border-width: 1px"|0.00585
 
|style="border-style: solid; border-width: 1px"|0.0658
 
|style="border-style: solid; border-width: 1px"|0.00986
 
|style="border-style: solid; border-width: 1px"|0.342
 
|style="border-style: solid; border-width: 1px"|0.00157
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|217-5b
 
|style="border-style: solid; border-width: 1px"|0.925
 
|style="border-style: solid; border-width: 1px"|0.00576
 
|style="border-style: solid; border-width: 1px"|0.061
 
|style="border-style: solid; border-width: 1px"|0.018
 
|style="border-style: solid; border-width: 1px"|0.00513
 
|style="border-style: solid; border-width: 1px"|0.0656
 
|style="border-style: solid; border-width: 1px"|0.0094
 
|style="border-style: solid; border-width: 1px"|0.287
 
|style="border-style: solid; border-width: 1px"|0.00187
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|217-6a
 
|style="border-style: solid; border-width: 1px"|0.844
 
|style="border-style: solid; border-width: 1px"|0.00645
 
|style="border-style: solid; border-width: 1px"|0.0675
 
|style="border-style: solid; border-width: 1px"|0.0197
 
|style="border-style: solid; border-width: 1px"|0.0737
 
|style="border-style: solid; border-width: 1px"|0.0316
 
|style="border-style: solid; border-width: 1px"|0.0147
 
|style="border-style: solid; border-width: 1px"|0.297
 
|style="border-style: solid; border-width: 1px"|0.00154
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|217-6b
 
|style="border-style: solid; border-width: 1px"|0.284
 
|style="border-style: solid; border-width: 1px"|0.00623
 
|style="border-style: solid; border-width: 1px"|0.666
 
|style="border-style: solid; border-width: 1px"|0.00623
 
|style="border-style: solid; border-width: 1px"|0.0384
 
|style="border-style: solid; border-width: 1px"|0.024
 
|style="border-style: solid; border-width: 1px"|0.0117
 
|style="border-style: solid; border-width: 1px"|0.15
 
|style="border-style: solid; border-width: 1px"|0.00146
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|217-7a
 
|style="border-style: solid; border-width: 1px"|0.343
 
|style="border-style: solid; border-width: 1px"|0.00548
 
|style="border-style: solid; border-width: 1px"|0.574
 
|style="border-style: solid; border-width: 1px"|0.00548
 
|style="border-style: solid; border-width: 1px"|0.0717
 
|style="border-style: solid; border-width: 1px"|0.023
 
|style="border-style: solid; border-width: 1px"|0.0107
 
|style="border-style: solid; border-width: 1px"|0.32
 
|style="border-style: solid; border-width: 1px"|0.00152
 
|style="border-style: solid; border-width: 1px"|0.00139
 
|-
 
|style="border-style: solid; border-width: 1px"|217-7b
 
|style="border-style: solid; border-width: 1px"|0.846
 
|style="border-style: solid; border-width: 1px"|0.00507
 
|style="border-style: solid; border-width: 1px"|0.127
 
|style="border-style: solid; border-width: 1px"|0.0144
 
|style="border-style: solid; border-width: 1px"|0.0131
 
|style="border-style: solid; border-width: 1px"|0.0479
 
|style="border-style: solid; border-width: 1px"|0.0133
 
|style="border-style: solid; border-width: 1px"|0.311
 
|style="border-style: solid; border-width: 1px"|0.00151
 
|style="border-style: solid; border-width: 1px"|0.00139
 
|-
 
|style="border-style: solid; border-width: 1px"|217-8a
 
|style="border-style: solid; border-width: 1px"|0.496
 
|style="border-style: solid; border-width: 1px"|0.00722
 
|style="border-style: solid; border-width: 1px"|0.439
 
|style="border-style: solid; border-width: 1px"|0.00722
 
|style="border-style: solid; border-width: 1px"|0.0521
 
|style="border-style: solid; border-width: 1px"|0.0325
 
|style="border-style: solid; border-width: 1px"|0.0128
 
|style="border-style: solid; border-width: 1px"|0.382
 
|style="border-style: solid; border-width: 1px"|0.00179
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|217-8b
 
|style="border-style: solid; border-width: 1px"|0.512
 
|style="border-style: solid; border-width: 1px"|0.00703
 
|style="border-style: solid; border-width: 1px"|0.41
 
|style="border-style: solid; border-width: 1px"|0.00703
 
|style="border-style: solid; border-width: 1px"|0.0639
 
|style="border-style: solid; border-width: 1px"|0.0272
 
|style="border-style: solid; border-width: 1px"|0.0139
 
|style="border-style: solid; border-width: 1px"|0.232
 
|style="border-style: solid; border-width: 1px"|0.00173
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|217-1
 
|style="border-style: solid; border-width: 1px"|0.0136
 
|style="border-style: solid; border-width: 1px"|0.00346
 
|style="border-style: solid; border-width: 1px"|0.956
 
|style="border-style: solid; border-width: 1px"|0.00346
 
|style="border-style: solid; border-width: 1px"|0.0271
 
|style="border-style: solid; border-width: 1px"|0.0233
 
|style="border-style: solid; border-width: 1px"|0.00359
 
|style="border-style: solid; border-width: 1px"|1.98
 
|style="border-style: solid; border-width: 1px"|0.00159
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|217-2
 
|style="border-style: solid; border-width: 1px"|0.978
 
|style="border-style: solid; border-width: 1px"|0.00352
 
|style="border-style: solid; border-width: 1px"|0.014
 
|style="border-style: solid; border-width: 1px"|0.0261
 
|style="border-style: solid; border-width: 1px"|0.00614
 
|style="border-style: solid; border-width: 1px"|0.042
 
|style="border-style: solid; border-width: 1px"|0.00194
 
|style="border-style: solid; border-width: 1px"|0.686
 
|style="border-style: solid; border-width: 1px"|0.0016
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|217-3
 
|style="border-style: solid; border-width: 1px"|0.932
 
|style="border-style: solid; border-width: 1px"|0.00355
 
|style="border-style: solid; border-width: 1px"|0.0336
 
|style="border-style: solid; border-width: 1px"|0.00355
 
|style="border-style: solid; border-width: 1px"|0.0292
 
|style="border-style: solid; border-width: 1px"|0.0324
 
|style="border-style: solid; border-width: 1px"|0.00491
 
|style="border-style: solid; border-width: 1px"|0.279
 
|style="border-style: solid; border-width: 1px"|0.00174
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|217-4
 
|style="border-style: solid; border-width: 1px"|0.658
 
|style="border-style: solid; border-width: 1px"|0.00135
 
|style="border-style: solid; border-width: 1px"|0.32
 
|style="border-style: solid; border-width: 1px"|0.00555
 
|style="border-style: solid; border-width: 1px"|0.0174
 
|style="border-style: solid; border-width: 1px"|0.0268
 
|style="border-style: solid; border-width: 1px"|0.00424
 
|style="border-style: solid; border-width: 1px"|0.473
 
|style="border-style: solid; border-width: 1px"|0.00171
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|353-3a
 
|style="border-style: solid; border-width: 1px"|0.554
 
|style="border-style: solid; border-width: 1px"|0.00704
 
|style="border-style: solid; border-width: 1px"|0.36
 
|style="border-style: solid; border-width: 1px"|0.00704
 
|style="border-style: solid; border-width: 1px"|0.0699
 
|style="border-style: solid; border-width: 1px"|0.0305
 
|style="border-style: solid; border-width: 1px"|0.0163
 
|style="border-style: solid; border-width: 1px"|0.344
 
|style="border-style: solid; border-width: 1px"|0.0017
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|353-3b
 
|style="border-style: solid; border-width: 1px"|0.219
 
|style="border-style: solid; border-width: 1px"|0.00268
 
|style="border-style: solid; border-width: 1px"|0.671
 
|style="border-style: solid; border-width: 1px"|0.00695
 
|style="border-style: solid; border-width: 1px"|0.0977
 
|style="border-style: solid; border-width: 1px"|0.0238
 
|style="border-style: solid; border-width: 1px"|0.0119
 
|style="border-style: solid; border-width: 1px"|0.289
 
|style="border-style: solid; border-width: 1px"|0.00157
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|353-4a
 
|style="border-style: solid; border-width: 1px"|0.768
 
|style="border-style: solid; border-width: 1px"|0.00473
 
|style="border-style: solid; border-width: 1px"|0.198
 
|style="border-style: solid; border-width: 1px"|0.00993
 
|style="border-style: solid; border-width: 1px"|0.0283
 
|style="border-style: solid; border-width: 1px"|0.0505
 
|style="border-style: solid; border-width: 1px"|0.00628
 
|style="border-style: solid; border-width: 1px"|0.536
 
|style="border-style: solid; border-width: 1px"|0.00181
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|353-4b
 
|style="border-style: solid; border-width: 1px"|0.684
 
|style="border-style: solid; border-width: 1px"|0.00454
 
|style="border-style: solid; border-width: 1px"|0.224
 
|style="border-style: solid; border-width: 1px"|0.0108
 
|style="border-style: solid; border-width: 1px"|0.0774
 
|style="border-style: solid; border-width: 1px"|0.08
 
|style="border-style: solid; border-width: 1px"|0.0149
 
|style="border-style: solid; border-width: 1px"|0.267
 
|style="border-style: solid; border-width: 1px"|0.00166
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|353-5a
 
|style="border-style: solid; border-width: 1px"|0.767
 
|style="border-style: solid; border-width: 1px"|0.00596
 
|style="border-style: solid; border-width: 1px"|0.159
 
|style="border-style: solid; border-width: 1px"|0.0124
 
|style="border-style: solid; border-width: 1px"|0.0628
 
|style="border-style: solid; border-width: 1px"|0.0303
 
|style="border-style: solid; border-width: 1px"|0.0109
 
|style="border-style: solid; border-width: 1px"|0.357
 
|style="border-style: solid; border-width: 1px"|0.00156
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|353-5b
 
|style="border-style: solid; border-width: 1px"|0.832
 
|style="border-style: solid; border-width: 1px"|0.00619
 
|style="border-style: solid; border-width: 1px"|0.126
 
|style="border-style: solid; border-width: 1px"|0.0111
 
|style="border-style: solid; border-width: 1px"|0.0324
 
|style="border-style: solid; border-width: 1px"|0.035
 
|style="border-style: solid; border-width: 1px"|0.0096
 
|style="border-style: solid; border-width: 1px"|0.397
 
|style="border-style: solid; border-width: 1px"|0.00166
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|353-6a
 
|style="border-style: solid; border-width: 1px"|0.0487
 
|style="border-style: solid; border-width: 1px"|0.00176
 
|style="border-style: solid; border-width: 1px"|0.855
 
|style="border-style: solid; border-width: 1px"|0.006
 
|style="border-style: solid; border-width: 1px"|0.0856
 
|style="border-style: solid; border-width: 1px"|0.0216
 
|style="border-style: solid; border-width: 1px"|0.0105
 
|style="border-style: solid; border-width: 1px"|0.222
 
|style="border-style: solid; border-width: 1px"|0.00199
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|353-6b
 
|style="border-style: solid; border-width: 1px"|0.829
 
|style="border-style: solid; border-width: 1px"|0.00561
 
|style="border-style: solid; border-width: 1px"|0.127
 
|style="border-style: solid; border-width: 1px"|0.00561
 
|style="border-style: solid; border-width: 1px"|0.0373
 
|style="border-style: solid; border-width: 1px"|0.0252
 
|style="border-style: solid; border-width: 1px"|0.00696
 
|style="border-style: solid; border-width: 1px"|0.36
 
|style="border-style: solid; border-width: 1px"|0.00228
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|353-1
 
|style="border-style: solid; border-width: 1px"|0.41
 
|style="border-style: solid; border-width: 1px"|0.000743
 
|style="border-style: solid; border-width: 1px"|0.502
 
|style="border-style: solid; border-width: 1px"|0.00422
 
|style="border-style: solid; border-width: 1px"|0.0811
 
|style="border-style: solid; border-width: 1px"|0.0177
 
|style="border-style: solid; border-width: 1px"|0.0063
 
|style="border-style: solid; border-width: 1px"|0.329
 
|style="border-style: solid; border-width: 1px"|0.00132
 
|style="border-style: solid; border-width: 1px"|0.00097
 
|-
 
|style="border-style: solid; border-width: 1px"|353-2
 
|style="border-style: solid; border-width: 1px"|0.747
 
|style="border-style: solid; border-width: 1px"|0.00309
 
|style="border-style: solid; border-width: 1px"|0.225
 
|style="border-style: solid; border-width: 1px"|0.00726
 
|style="border-style: solid; border-width: 1px"|0.0252
 
|style="border-style: solid; border-width: 1px"|0.0447
 
|style="border-style: solid; border-width: 1px"|0.00267
 
|style="border-style: solid; border-width: 1px"|0.513
 
|style="border-style: solid; border-width: 1px"|0.00154
 
|style="border-style: solid; border-width: 1px"|0.00097
 
|-
 
|style="border-style: solid; border-width: 1px"|353-7
 
|style="border-style: solid; border-width: 1px"|0.448
 
|style="border-style: solid; border-width: 1px"|0.0009
 
|style="border-style: solid; border-width: 1px"|0.537
 
|style="border-style: solid; border-width: 1px"|0.0041
 
|style="border-style: solid; border-width: 1px"|0.0122
 
|style="border-style: solid; border-width: 1px"|0.0273
 
|style="border-style: solid; border-width: 1px"|0.00346
 
|style="border-style: solid; border-width: 1px"|0.433
 
|style="border-style: solid; border-width: 1px"|0.00178
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|353-8
 
|style="border-style: solid; border-width: 1px"|0.718
 
|style="border-style: solid; border-width: 1px"|0.00223
 
|style="border-style: solid; border-width: 1px"|0.261
 
|style="border-style: solid; border-width: 1px"|0.00608
 
|style="border-style: solid; border-width: 1px"|0.0165
 
|style="border-style: solid; border-width: 1px"|0.038
 
|style="border-style: solid; border-width: 1px"|0.00408
 
|style="border-style: solid; border-width: 1px"|0.268
 
|style="border-style: solid; border-width: 1px"|0.00177
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|545-1
 
|style="border-style: solid; border-width: 1px"|0.991
 
|style="border-style: solid; border-width: 1px"|0.00293
 
|style="border-style: solid; border-width: 1px"|0.00743
 
|style="border-style: solid; border-width: 1px"|0.026
 
|style="border-style: solid; border-width: 1px"|0.00139
 
|style="border-style: solid; border-width: 1px"| 2.6
 
|style="border-style: solid; border-width: 1px"|  0
 
|style="border-style: solid; border-width: 1px"|  0
 
|style="border-style: solid; border-width: 1px"|0.00216
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|545-2
 
|style="border-style: solid; border-width: 1px"|0.985
 
|style="border-style: solid; border-width: 1px"|0.00277
 
|style="border-style: solid; border-width: 1px"|0.0128
 
|style="border-style: solid; border-width: 1px"|0.024
 
|style="border-style: solid; border-width: 1px"|0.00246
 
|style="border-style: solid; border-width: 1px"| 2.8
 
|style="border-style: solid; border-width: 1px"|  0
 
|style="border-style: solid; border-width: 1px"|  0
 
|style="border-style: solid; border-width: 1px"|0.00187
 
|style="border-style: solid; border-width: 1px"|0.00097
 
|-
 
|style="border-style: solid; border-width: 1px"|545-4
 
|style="border-style: solid; border-width: 1px"|0.972
 
|style="border-style: solid; border-width: 1px"|0.003
 
|style="border-style: solid; border-width: 1px"|0.0277
 
|style="border-style: solid; border-width: 1px"|0.025
 
|style="border-style: solid; border-width: 1px"|0.000777
 
|style="border-style: solid; border-width: 1px"| 2.5
 
|style="border-style: solid; border-width: 1px"|  0
 
|style="border-style: solid; border-width: 1px"|  0
 
|style="border-style: solid; border-width: 1px"|0.00222
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|857-1
 
|style="border-style: solid; border-width: 1px"|0.974
 
|style="border-style: solid; border-width: 1px"|0.00338
 
|style="border-style: solid; border-width: 1px"|0.0229
 
|style="border-style: solid; border-width: 1px"|0.025
 
|style="border-style: solid; border-width: 1px"|0.00349
 
|style="border-style: solid; border-width: 1px"| 2.2
 
|style="border-style: solid; border-width: 1px"|  0
 
|style="border-style: solid; border-width: 1px"|  0
 
|style="border-style: solid; border-width: 1px"|0.00176
 
|style="border-style: solid; border-width: 1px"|0.00111
 
|-
 
|style="border-style: solid; border-width: 1px"|857-2
 
|style="border-style: solid; border-width: 1px"|0.84
 
|style="border-style: solid; border-width: 1px"|0.00148
 
|style="border-style: solid; border-width: 1px"|0.158
 
|style="border-style: solid; border-width: 1px"|0.00656
 
|style="border-style: solid; border-width: 1px"|0.00249
 
|style="border-style: solid; border-width: 1px"| 3.2
 
|style="border-style: solid; border-width: 1px"|  0
 
|style="border-style: solid; border-width: 1px"|  0
 
|style="border-style: solid; border-width: 1px"|0.0022
 
|style="border-style: solid; border-width: 1px"|0.00125
 
|-
 
|style="border-style: solid; border-width: 1px"|857-3
 
|style="border-style: solid; border-width: 1px"|0.36
 
|style="border-style: solid; border-width: 1px"|4.22e-05
 
|style="border-style: solid; border-width: 1px"|0.627
 
|style="border-style: solid; border-width: 1px"|0.0024
 
|style="border-style: solid; border-width: 1px"|0.0111
 
|style="border-style: solid; border-width: 1px"|0.017
 
|style="border-style: solid; border-width: 1px"|0.002
 
|style="border-style: solid; border-width: 1px"| 1.9
 
|style="border-style: solid; border-width: 1px"|0.00152
 
|style="border-style: solid; border-width: 1px"|0.00126
 
|-
 
|style="border-style: solid; border-width: 1px"|857-4
 
|style="border-style: solid; border-width: 1px"|0.278
 
|style="border-style: solid; border-width: 1px"|0.0004
 
|style="border-style: solid; border-width: 1px"|0.719
 
|style="border-style: solid; border-width: 1px"|0.00392
 
|style="border-style: solid; border-width: 1px"|0.00162
 
|style="border-style: solid; border-width: 1px"|0.09
 
|style="border-style: solid; border-width: 1px"|0.00152
 
|style="border-style: solid; border-width: 1px"| 0.8
 
|style="border-style: solid; border-width: 1px"|0.00149
 
|style="border-style: solid; border-width: 1px"|0.000558
 
|}
 
 
 
 
 
 
 
 
 
== System (Ken) ==
 
===List of systematics===
 
 
 
{{:HFI-bottom_up}}
 
 
 
==Summary==
 
<span style="color:red">(Lamarre)</span>
 
here remind worse sytematics and point to DPC
 
Summary of sucess and limitations. JML. Link to early HFI in flight perf.
 

Latest revision as of 12:12, 12 July 2018

This section provides an overview of the High-Frequency Instrument and of its different sub-systems.

Two papers that include and detail this information are available: Planck-PreLaunch-IX[1] and Planck-Early-IV[2]. Additional detailed information potentially useful for users of HFI data is included in this section or annexed to it.

HFI electronics in the satellite

The HFI instrument is designed around 52 bolometers. Twenty of the bolometers (spider-web bolometers or SWBs) are sensitive to total power, and the remaining 32 units are arranged in pairs of orthogonally-oriented polarisation-sensitive bolometers (PSBs). All bolometers are operated at a temperature of ~0.1 K by means of a space qualified dilution cooler coupled to a high precision temperature control system. A 4He-JT system provides active cooling for 4 K stages using vibration controlled mechanical compressors to prevent excessive warming of the 100 mK stage and minimize microphonic effects in the bolometers. Bolometers and sensitive thermometers are read using an AC-bias scheme through JFET amplifiers operated at ~130 K that provide high sensitivity and low frequency stability. The HFI covers six bands centred at 100, 143, 217, 353, 545, and 857 GHz, thanks to a thermo-optical design consisting of three corrugated horns and a set of compact reflective filters and lenses at cryogenic temperatures.

HFI focal plane optics and 4K thermo-mechanical stage.

The whole satellite is organized to provide thermal transitions between its warm part exposed to radiation from the Sun and Earth, and the focal plane instruments that include the cold receivers (Sections HFI_cold_optics and HFI_detection_chain). The various parts of the HFI are distributed among three different stages of the satellite in order to provide each sub-system with an optimal operating temperature. The "warm" parts, including nearly all the electronics and the sources of fluids of the 4K and 0.1K coolers, are attached and thermally linked to the service module of the satellite. The first stage of the preamplifiers is attached to the back of the passively cooled telescope structure. The focal plane unit is attached to the 20K stage cooled by the sorption cooler. This is detailed in Section HFI_detection_chain.

The telescope and horns select the geometrical origin of photons. They provide a high transmission efficiency to photons inside the main beam, while photons coming from the intermediate and far-side lobes have very low probability of being detected. The essential characteristics are determined by a complex process mixing ground measurements of components (horns, reflectors), modelling the shape of the far sidelobes, and measuring bright sources in-flight, especially planets.

The filters and bolometers define the spectral response and absolute optical efficiency, which are known mostly from ground-based measurements performed at component, sub-system, and system levels, reported in this document. The relationships between spectral response and geometrical response are also addressed.

Photons absorbed by a bolometer include the thermal radiation emitted by the various optical devices: telescope, horns, and filters. They are transformed into heat that propagates to the bolometer thermometer to influence its temperature, which is itself measured by the readout electronics. Temperatures of all these items must be stable enough not to contaminate the scientific signal delivered by the bolometers. How this stability is reached is described in Section HFI_cryogenics.

The bolometer temperature depends also on the temperature of the bolometer plate, on the intensity of the biasing current, and on any spurious inputs, such as cosmic rays and mechanical vibrations. Such systematics are included in a list discussed in Section HFI-Validation.

Since the bolometer thermometer is part of an active circuit that also heats it, the response of this system is complex and has to be considered as a whole. In addition, due to the modulation of the bias current and to the sampling of the data, the response signal of the instrument when scanning a point source is more complex still. Item in Sub-Section Time_response and Annex HFI_time_response_model are dedicated to the description of this time response.

HFI signal formation.

Logic of the formation of the signal in HFI. This is an idealized description of the physics that takes place in the instrument. The optical power that is absorbed by the bolometers comes from the observed sky and from the instrument itself. The bolometers and readout electronics, acting as a single and complex chain, transform this optical power into data that are compressed and transmitted for science data reduction.

References[edit]

(Planck) High Frequency Instrument

Junction Field Elect Transistor