Terminology

4K lines

EMI/EMC influence of the 4K cooler mechanical motion on the bolometer readout electronics.

calibration [HFI meaning]

For a single detector, the absolute calibration is gain factor between the measured signal (watts absorbed by the detector) and the sky signal (in astrophysical units); can vary with time. For a set of detectors, the relative calibration is the difference in the calibration between detector pairs. The latter can be measured very accurately from the observations of the same source by different detectors, and is only slightly affected by the differences in the detector spectral responses, which are similar; the former requires observations of sources with well modeled spectral energy distributions or well known spectra, and requires that the detector's spectral bandpass also be well known.

calibration

[LFI meaning]: absolute calibration refers to the 0th order calibration for each channel, 1 single number, while the relative calibration refers to the component of the calibration that varies pointing period by pointing period.

detector set [HFI meaning]

a detector set (aka detset aka quad) is a combinaison of two pairs of Polarization Sensitive Bolometers pairs at the proper orientations. The lists of detsets is given in here.

effective beam [HFI meaning]

the effective beam at the map level is the overall angular response to the sky in a map pixel, which results from the combined effect of the instrumental response, the scanning strategy and the data processing.

far sidelobe [HFI meaning]

the response to the sky of a detector more than 5 degrees from the beam centroid.

half ring difference 

difference between the map built using the first half of each pointing period (typically 20 minutes of contiguous data) and the one built with the second half. This difference effectively removes the sky signal and most of the correlated noise, leaving only the noise components that have time scales of < ~ 20 min.

HEALPix

(Hierarchical Equal Area isoLatitude Pixelation of a sphere, ) pixelation used to produce Planck sky maps (and HFI HPR).

HPR [HFI meaning]

HEALPix Rings are introduced to avoid any additional binning of the data. We choose a sky pixelization as a basis for this ring making. HPR are therefore partial sky maps produced via a projection onto the sky of each single pointing period separately.

IMO [HFI meaning]

the HFI Instrument MOdel is a central repository containing the models (or a link to them) and sets of fixed parameters used in these models describing for example how photons are gathered and transformed into data. IMO is oriented toward the data reduction and data processing. IMO is also used to monitor the instrument health. IMO represents at any time the official knowledge of the instrument response. It is intended to represent its best current knowledge agreed on by the project and applicable to the data processing. IMO does not represent the knowledge of the instrument. It is a knowledge of its response, (e.g. how photons are gathered and transformed into data). It is a simplified fraction of this knowledge directly useful to reduce the data. The IMO is restricted to the sole parameters used in the DPC. IMO does not contain timelines, nor maps, although it can provide links to calibration timelines (e.g. gain evolution) and calibration maps (e.g. beam maps). Models do not need to be unique (not a single model for a single process). Depending on the purpose for which they are used, they can be more or less sophisticated. (e.g. bolometer models, beam representations, very simplified for first assessment of pointing parameters, ...). IMO does not choose between them : it contains the parameters for each of them at the same time. See HFI RIMO.

jump 

sudden change of the baseline level inside a ring

main beam [HFI meaning]

Response to the sky within 23 arcminutes of the centroid of response.

near sidelobe [HFI meaning]

Response to the sky between 23 arcminutes and 5 degrees from the main beam centroid.

OD 

Operation Day definition is geometric visibility driven as it runs from the start of a DTCP (satellite Acquisition Of Signal) to the start of the next DTCP. Given the different ground stations and spacecraft will takes which station for how long, the OD duration varies but it is basically once a day.

optical beam [HFI meaning]

The response to the sky due to optics alone.

PBR [HFI meaning]

Phase Bin Rings provide a compressed and higher signal-to-noise ratio rendition of the original Time Order Data

polarization leakage [HFI meaning]

in general, systematic effects mix the I,Q,U signals. Given the amplitudes of the sky signals, leakage from temperature to polarisation can be dramatic for polarisation analysis.

ring [HFI meaning]

at the HFI DPC level the ring is the time intervalle between two First Thurster Firings as defined in AHF description document. It thus starts with a satellite slew and thus an unstable pointing period and continue with a satellite dwell and thus stable pointing period.

RIMO [HFI meaning]

The RIMO, or Reduced Instrument Model is a FITS file containing selected instrument characteristics that are needed by users who work with the released data products.

sample [HFI meaning]

scanning beam [HFI meaning]

the scanning is defined as the beam measured from the response to a point source of the full optical and electronic system, after the filtering.

scanning beam [LFI meaning]

the actual beam which couples the optics of the instrument with the scanning movement of the satellite (beam smearing). It can be measured from planet observations.

spectral response (or bandpass)

steady state response of a detector system (i.e., detector and its electronics + horn + filter) as a function of frequency. It does not consider the temporal response and associated transfer function.

survey [HFI meaning]

sky surveys (aka Scan #)are defined in terms of the direction of the satellite's spin axis. Survey periods are given here.

TOD [HFI meaning]

Time-Ordered Data

TOD [LFI meaning]

Time-Ordered Data, refers to calibrated data

TOI [HFI meaning]

Time Ordered Information

TOI [LFI meaning]

Time Ordered Information, refers to uncalibrated data

warm units 

JFET, Bellow, PAU et REU

ACMS 

Attitude Control & Measurement Subsystem (AOCS)

ADC 

analog to digital converter

AHF 

Attitude History File

APID 

Application Program Identifier

APPL  

Augmented Preprogrammed Pointing List

BEM 

LFI warm electronics Back End Module

BEU 

LFI warm electronics Back End Unit

BTB 

Back To Back HFI horns

CDMS 

Command and Data Management System

CDMU 

Command and Data Management Unit

CMB 

Cosmic Microwave background

CoP 

Commissioning Phase

CPV 

Calibration and Performance Verification

CSL 

Centre Spatial de Liège

CTR 

Central Time Reference

CUC 

CCSDS Unsegmented Time Code

DAE 

LFI Data Acquisition Electronics

DCE 

Dilution Cooler Electronics

DDS 

MOC's Data Distribution System

DMC 

Data Management Component, the databases used at the HFI and LFI DPCs

DPC 

Data Processing Center

DPU 

Data Processing Unit

DQR  

Daily Quality Report

DTCP 

Daily Tele-Communication Period

EOL 

End Of Life

ERCSC 

Early Release Compact Source Catalog

ESA 

European Space Agency

ESOC 

European Space Operations Centre (Darmstadt)

ESTEC 

European Space TEchnology and Research Centre

FEM 

LFI cryogenic amplifying stage Front End Module

FEU 

LFI cryogenic amplifying stage Front End Unit

FH 

Feed Horn

FITS  

Flexible Image Transfer Specification

FOG 

Fiber Optic Gyroscope

FOV 

Field-Of-View

FPU 

Focal Plane Unit

FWHM  

Full-Width-at-Half-Maximum

HCM 

Angular momentum Control Mode

HEMT 

High Electron Mobility Transistor

HFI 

(Planck) High Frequency Instrument

HK 

House Keeping

HPFTS 

Herschel/Planck File Transfer System

HPMCS 

Herschel/Planck Mission Control System

HSK 

House-Keeping data

ICD 

Interface Control Document

ILS 

Instrument Line Shape

IOT 

Instrument Operation Team

JFET 

Junction Field Elect Transistor

LEOP 

Launch & Early Orbit Phase

LFER 

low frequency excess response

LFI 

(Planck) Low Frequency Instrument

LOBT 

Local On Board Time

LOS 

Line Of Sight

MOC 

[ESA's] Mission Operation Center [Darmstadt, Germany]

NEP  

Noise Equivalent Power

NET  

Noise Equivalent Temperature

OBT  

On-Board Time

OMT 

LFI Ortho Module Transducer

P/L 

Payload

PAU 

Pre_Amplification Unit

PI 

Principal Investigator

PIA 

Planck Internal Archive

PLA  

Planck Legacy Archive

PLM 

Payload Module

PO 

Physical Optics

POI 

Phase-Ordered Information (DMC group/object)

PPL  

Pre-programmed Pointing List

PPLM 

Planck Payload Module

PSM  

Planck Sky Model

PSO 

Planck Science Office

PTD 

Physical Theory of Diffraction

PUS 

Packet Utilisation Standard

RAA 

LFI Radiometer Array Assembly

RAF 

Raw Attitude history File

RCA 

LFI Radiometer Chain Assembly

REBA 

LFI Radiometer Electronics Box Assembly

REU 

Readout Electronic Unit

RFQM 

Radio Frequency Qualification Model

RIMO 

reduced IMO

ROI 

Ring-Ordered Information (DMC group/object)

rpm 

revolutions per minute

RSSD 

Research Space Science Division of ESA [ESTEC, Netherlands]

RTS 

random telegraphic signal

S/C 

Spacecraft

SAA 

Solar Aspect Angle

SCC 

Sorption Cooler Compressor assembly

SCS 

Sorption Cooler Subsystem (Planck)

SEV  

Sun Earth Vector

SGR  

Small Gap Recovery

SGS  

Science Ground Segment

SIAM  

Spacecraft Instrument Alignment Matrix

SLT 

System Level Test

SOVT  

System Operation and Validation Test

SPPT 

Survey Performance and Planning Tool

SPU 

Signal Processing Unit

SREM 

Space Radiation Environment Monitor

SRP  

Solar Radiation Pressure

SSCE 

Sun-SpaceCraft-Earth angle max= 15°

SSO 

Solar System Object

STR  

Star TRacker

SVM 

Service Module

SZ  

Sunyaev-Zel'dovich

TBC 

To be confirmed

TBD 

To be defined / determined

TC 

Tele-Command

THF 

Telecommand History File

ToS 

Time of Sample

TSA 

hermal Stabilization Assembly

UTC 

Universal Time Coordinate(d)

warm units 

JFET, Bellow, PAU et REU

WG 

LFI Waveguide

WHR 

Weekly Health Report