SREM

Design, performance and calibration documentation

SREM counters

Name	Logic	Particle	Energy ([math]M\!e\!v[/math])
TC1	D1	protons	>20
S12	D1	protons	20 - 550
S13	D1	protons	20 - 120
S14	D1	protons	20 - 27
S15	D1	protons	20 - 34
TC2	D2	protons	>39
S25	D2	ions	150 - 185
C1	D1[math]*[/math]D2	coinc. protons	40 - 50
C2	D1[math]*[/math]D2	coinc. protons	50 - 70
C3	D1[math]*[/math]D2	coinc. protons	70 - 120
C4	D1[math]*[/math]D2	coinc. protons	>130
TC3	D3	electrons	>0.5
S32	D3	electrons	0.55 - 2.3
S33	D3	protons	11 - 90
S34	D3	protons	11 - 30
PL1	D1	Dead Time	NA
PL2	D2	Dead Time	NA
PL3	D3	Dead Time	NA

Description of the product

The SREM data files contain calibrated data for the different energy and particle species channels available in the SREM. Each data file contains 24 hours of data - from midnight to midnight (note this is not an OD) - with the date covered by the file easily identifiable through the file name.

Pipeline

TBW

Input Data

SREM calibrated data was produced from the SREM raw data acquired during the entire mission.

Related Products

Data for the SREM on board Herschel can be retrieved from the Herschel Science Archive.

SREM data from previous missions can be retrieved from the SREM archive at the Paul Scherrer Institut (PSI).

Data format

• Naming convention

The files containing the SREM calibrated data will have a name of the form SREMPlanck_PACC_YYYYMMDD.fits where PACC stands for Processed ACCumulated data and YYYYMMDD is the date the data in the file was acquired.

• Format

Each file contains three binary table extensions named CDFFITS1,CDFFITS2 and CDFFITS3. The first extension contains the accumulated counts data, the second extension the labels to identify the data in the first extension and the third extension the total radiation dosis. The contents of each extension are as follows.

CDFFITS1

Column Name	Contents	Format	Unit
EPOCH	vector containing 1 string with UTC for center of accumulation interval in ISO format (YYYY-MM-DDTHH:MM:SS.MMMZ)	A24	NA
COUNTRATE	vector containing 15 elements (1 for each channel) with counts for accumulation period identified in the EPOCH column	E15.4	[math]s^{-1}[/math]
ORBIT	position (x,y,z) of the SREM in the ECI frame. Distance from center fo the Earth is [math]R=\sqrt(x^2+y^2+z^2)[/math]	E15.4	[math]K\!m[/math]
ATTITUDE	Not in use	E15.4	-
PROT FITQUAL	Not in use	I1	[math]NA[/math]
ODPF	Not in use.	E15.4	-
ODPFERR	Not in use	E15.4	-
ELEC FITQUAL	Not in use	I1	-
ODEF	Not in use	E15.4	-
ODEFERR	Not in use	E15.4	-
ANISOTROPY	Not in use	E15.4	-
TEMPERATURE	2 element vector containing temperature of the two detector heads at each EPOCH	E15.4	[math]^\circ\!C[/math]

CDFFITS2

Column Name	Contents	Format	Unit
EPOCH	this is a keyword	[math]K\!m^2[/math]

CDFFITS3

Column Name	Contents	Format	Unit
RADEPOCH	this is a keyword	A24	[math]K\!m^2[/math]
RADFET	Value proportional to the absorbed dose on a diode mounted on the surface of SREM	E15.4	NA

• N. Of Files

1500 (TBC)

Note: SREM calibrated data files where initially provided in the Common Data Format (cdf) format. This has traditionally been the preferred data format for SREM on board previous ESA missions. However, as cdf is not widely used in the astrophysics community it was later agreed with the provider that fits files should also be provided. This meant taking the original cdf format and converting it to fits. The original cdf files can be retrieved from the SREM site at the PSI.

Header keywords

For data provided in the form of fits files a table containing a description of all the header keywords should be included here. The table should follow this format

Keyword Name	Description	Unit
Keyword1	this is a keyword	[math]K\!m^2[/math]
Keyword2	this is a another keyword	[math]H\!z[/math]

Processed data

The SREM processed data can be downloaded from the PLA interface: "Ancillary data" tab of the "Time-ordered information" section.