PDS_VERSION_ID = PDS3
RECORD_TYPE = STREAM
RELEASE_ID = 0001
REVISION_ID = 0000
OBJECT = TEXT
PUBLICATION_DATE = 2005-05-31
NOTE = "Description of the CALIB directory
contents for an ASPERA-3 release."
END_OBJECT = TEXT
END
CALIB Directory Contents
The CALIB directory contains calibration tables for a MEX ASPERA-3
archive volume. The files listed below are found in this directory.
CALINFO.TXT - The file you are reading.
ELSSCIH_CAL.TAB - The ASPERA-3 Electron Spectrometer (ELS) Science High
range data Calibration Table. This table provides the
calibration values per ELS sensor to convert the raw
values (cnts/accum) into scientific units (number flux).
It also provides calibration values to convert deflection
voltages to center energies (eV) for the SCAN values.
ELSSCIH_CAL.LBL - PDS label that describes the ASPERA-3 Electron
Spectrometer (ELS) High range data Calibration Table.
ELSSCIL_CAL.TAB - The ASPERA-3 Electron Spectrometer (ELS) Science Low
range data Calibration Table. This table provides the
calibration values per ELS sensor to convert the raw
values (cnts/accum) into scientific units (number flux).
It also provides calibration values to convert deflection
voltages to center energies (eV) for the SCAN values.
ELSSCIL_CAL.LBL - PDS label that describes the ASPERA-3 Electron
Spectrometer (ELS) Low range data Calibration Table.
Description of calibration table formulations and use:
This is the calibration table formulation for the ELS High range
science data (ELSSCIH) and the ELS Low range science data (ELSSCIL).
These tables provide calibration values (columns) for each anode
(16 rows) with a description of each calibration value and how to
apply the value to the SENSOR data for converting raw [cnts/accum] to
differential number flux [cnts/(cm**2-sr-s-eV)], and to the SCAN data
for converting deflection potential (volts) to center energies (eV).
The formulation and use of the tables are the same for both ELSSCIH
and ELSSCIL, but the actual table values may differ, thus a separate
table for each.
To go from deflection potential (volts) to center energies (eV):
Ec(i) = DV(i) * K_FACTOR
where DV(i) is the deflection voltage for step i (SCAN row data), and
K_FACTOR is the eV/volt for each ELS anode (sector) found
in COLUMN 1 of the calibration tables.
The energy widths are simply the center energies, Ec(i), multiplied by
the sector resolution, Re:
E_Width(i) = Ec(i) * RESOLUTION
where Ec(i) is the center energy (eV) for step i (SCAN row data), and
RESOLUTION is the (delta E)/E for each ELS anode (sector) and is
found in COLUMN 19 of the calibration tables.
The upper and lower bounds for each step i are then calculated by:
E_Min(i) = Ec(i) - E_Width(i)/2
E_Max(i) = Ec(i) + E_Width(i)/2
To calculate cnts/(cm**2-sr-s-eV) from cnts/accum:
The differential number flux per energy channel per anode is:
counts(i) * Sf
j = --------------------------------------------------------
Ec(i) * [Ea/Er(i)] * Gf * Mt * Gt * Aa * Dt * Re
where i is the scan step (energy channel)
counts(i) = data value per energy channel (cnts/accum)
Ec(i) = Energy channel value per scan step (eV)
Er(i) = Relative efficiency per energy channel
(Each anode has a polynomial to be solved per energy channel)
(The polynomials are given below in the column descriptions)
Ea = Absolute efficiency (detector efficiency)
Gf = Geometric factor (cm**2-sr)
Mt = MCP transparency (quoted by manufacturer)
Gt = Grid transparency
Aa = Active anode area ratio (Manufactured / Theory)
Dt = Delta time (data accumulation time in seconds)
Re = Resolution
Sf = Scaling factor
The CSV files contain the counts(i) and DV(i) values. The counts(i)
values are in the SENSOR rows, and the DV(i) values are in the SCAN rows.
The number of energy channels vary from file to file, but are constant
within each CSV data file. In the corresponding LBL files, COLUMN 'VALUES'
has ITEMS = x, where x is the number of energy channels for that file.
The energy channel values (deflection voltages) are the same for each ELS
anode, but can vary between data sweeps. The DV(i) values are included
counts(i) values. The data values (counts(i)) are in the SENSOR rows and
the energy channel values (deflection voltages DV(i)) are in the SCAN rows.
A corresponding SCAN row follows the 16 sector (SENSOR) rows. For example,
the CSV file layout for ELSSCIH is:
Anode 0 SENSOR row: ELS Sector 0 HR, counts(i) in cnts/accum
Anode 1 SENSOR row: ELS Sector 1 HR, counts(i) in cnts/accum
.
.
Anode 15 SENSOR row: ELS Sector 15 HR, counts(i) in cnts/accum
SCAN row: Deflection Potential, DV(i) in volts
Relative Efficiency factors (Er(i)) for ELS are both energy and anode
dependent. For the equations describing the Relative Efficiency factors,
represent the particle energy by the plate voltage needed to detect that
energy particle (remember that the particle energy and ELS deflection
voltage are related by the K-factor).
DV(i) in the equations (polynomials) below represents the ELS Deflection
Voltage in volts of step i (found in SCAN rows of CSV data files). Use the
DV(i) values per step per anode and the K_FACTOR per anode to calculate the
center energies in eV:
Ec(i) = DV(i) * K_FACTOR
COLUMN 1 of CAL TABLE: K_FACTOR per anode (row in CAL TABLE)
K-factors for Anodes 0 - 15 from left to right:
7.167, 7.152, 7.141, 7.165, 7.188, 7.625, 7.262, 7.266,
7.275, 7.254, 7.262, 7.255, 7.255, 7.271, 7.253, 7.188
(Remember each anode has a row of values, anodes
are also referred to as sectors or sensors)
Each DV(i) is different per energy step (i) and per anode.
Use these values in the equations below to calculate the relative
efficiency per energy channel Er(i).
COLUMNS 2 - 12 of CAL TABLE: COEFF_xx, where xx = 00-10
These columns contain the coefficients for the polynomial:
COEFF_00 + COEFF_01 * DV(i) + COEFF_02 * DV(i)**2 +
COEFF_03 * DV(i)**3 + COEFF_04 * DV(i)**4 +
COEFF_05 * DV(i)**5 + COEFF_06 * DV(i)**6 +
COEFF_07 * DV(i)**7 + COEFF_08 * DV(i)**8 +
COEFF_09 * DV(i)**9 + COEFF_10 * DV(i)**10
The equations are:
Relative Efficiency [Er(i)] for ELS Anode 00 =
2141859e-6 + -6024497e-9 * DV(i) + 1794353e-11 * DV(i)**2 +
-2796459e-14 * DV(i)**3 + 2543964e-17 * DV(i)**4 +
-1395010e-20 * DV(i)**5 + 4532808e-24 * DV(i)**6 +
-8024142e-28 * DV(i)**7 + 5954283e-32 * DV(i)**8
Relative Efficiency [Er(i)] for ELS Anode 01 =
1660858e-6 + -6522166e-9 * DV(i) + 3691054e-11 * DV(i)**2 +
-1073737e-13 * DV(i)**3 + 1839852e-16 * DV(i)**4 +
-1977613e-19 * DV(i)**5 + 1369280e-22 * DV(i)**6 +
-6096699e-26 * DV(i)**7 + 1685387e-29 * DV(i)**8 +
-2630885e-33 * DV(i)**9 + 1771363e-37 * DV(i)**10
Relative Efficiency [Er(i)] for ELS Anode 02 =
2021935e-6 + -5955053e-9 * DV(i) + 1878866e-11 * DV(i)**2 +
-3736588e-14 * DV(i)**3 + 5172668e-17 * DV(i)**4 +
-5034701e-20 * DV(i)**5 + 3363807e-23 * DV(i)**6 +
-1488898e-26 * DV(i)**7 + 4137518e-30 * DV(i)**8 +
-6504663e-34 * DV(i)**9 + 4399947e-38 * DV(i)**10
Relative Efficiency [Er(i)] for ELS Anode 03 =
1659460e-6 + -4954925e-9 * DV(i) + 1526991e-11 * DV(i)**2 +
-2516840e-14 * DV(i)**3 + 2433297e-17 * DV(i)**4 +
-1420192e-20 * DV(i)**5 + 4915142e-24 * DV(i)**6 +
-9275283e-28 * DV(i)**7 + 7345382e-32 * DV(i)**8
Relative Efficiency [Er(i)] for ELS Anode 04 =
1731412e-6 + -5380326e-9 * DV(i) + 1709947e-11 * DV(i)**2 +
-2884332e-14 * DV(i)**3 + 2826155e-17 * DV(i)**4 +
-1658431e-20 * DV(i)**5 + 5735419e-24 * DV(i)**6 +
-1076440e-27 * DV(i)**7 + 8447731e-32 * DV(i)**8
Relative Efficiency [Er(i)] for ELS Anode 05 =
1811691e-6 + -5230411e-9 * DV(i) + 1584896e-11 * DV(i)**2 +
-2629686e-14 * DV(i)**3 + 2573125e-17 * DV(i)**4 +
-1519547e-20 * DV(i)**5 + 5306596e-24 * DV(i)**6 +
-1006748e-27 * DV(i)**7 + 7984914e-32 * DV(i)**8
Relative Efficiency [Er(i)] for ELS Anode 06 =
9984187e-7 + 2018039e-10 * DV(i) + -3170439e-12 * DV(i)**2 +
1589455e-14 * DV(i)**3 + -3484247e-17 * DV(i)**4 +
4156025e-20 * DV(i)**5 + -2951669e-23 * DV(i)**6 +
1283619e-26,* DV(i)**7 + -3351854e-30 * DV(i)**8 +
4821632e-34 * DV(i)**9 + -2933104e-38 * DV(i)**10
Relative Efficiency [Er(i)] for ELS Anode 07 =
1593066e-6 + -2964337e-9 * DV(i) + 3217016e-12 * DV(i)**2 +
9241350e-15 * DV(i)**3 + -3138800e-17 * DV(i)**4 +
4137379e-20 * DV(i)**5 + -3044785e-23 * DV(i)**6 +
1346434e-26 * DV(i)**7 + -3552330e-30 * DV(i)**8 +
5151235e-34 * DV(i)**9 + -3156380e-38 * DV(i)**10
Relative Efficiency [Er(i)] for ELS Anode 08 =
2097414e-6 + -3125151e-9 * DV(i) + -4329302e-12 * DV(i)**2 +
4317461e-14 * DV(i)**3 + -9923385e-17 * DV(i)**4 +
1177737e-19 * DV(i)**5 + -8280358e-23 * DV(i)**6 +
3573841e-26 * DV(i)**7 + -9293869e-30 * DV(i)**8 +
1335333e-33 * DV(i)**9 + -8131189e-38 * DV(i)**10
Relative Efficiency [Er(i)] for ELS Anode 09 =
2062909e-6 + -4885969e-9 * DV(i) + 1427184e-11 * DV(i)**2 +
-2260352e-14 * DV(i)**3 + 2111094e-17 * DV(i)**4 +
-1194770e-20 * DV(i)**5 + 4024074e-24 * DV(i)**6 +
-7416131e-28 * DV(i)**7 + 5754756e-32 * DV(i)**8
Relative Efficiency [Er(i)] for ELS Anode 10 =
2180664e-6 + -6296202e-9 * DV(i) + 1891070e-11 * DV(i)**2 +
-3064724e-14 * DV(i)**3 + 2948811e-17 * DV(i)**4 +
-1724577e-20 * DV(i)**5 + 5997964e-24 * DV(i)**6 +
-1138182e-27 * DV(i)**7 + 9060635e-32 * DV(i)**8
Relative Efficiency [Er(i)] for ELS Anode 11 =
1603139e-6 + -8534362e-10 * DV(i) + -8667849e-12 * DV(i)**2 +
4394307e-14 * DV(i)**3 + -8845054e-17 * DV(i)**4 +
9830094e-20 * DV(i)**5 + -6619258e-23 * DV(i)**6 +
2766078e-26 * DV(i)**7 + -7009821e-30 * DV(i)**8 +
9858768e-34 * DV(i)**9 + -5896570e-38 * DV(i)**10
Relative Efficiency [Er(i)] for ELS Anode 12 =
2026128e-6 + -3624418e-9 * DV(i) + 1755093e-12 * DV(i)**2 +
2385497e-14 * DV(i)**3 + -6688306e-17 * DV(i)**4 +
8554336e-20 * DV(i)**5 + -6280654e-23 * DV(i)**6 +
2795381e-26 * DV(i)**7 + -7448619e-30 * DV(i)**8 +
1092352e-33 * DV(i)**9 + -6770721e-38 * DV(i)**10
Relative Efficiency [Er(i)] for ELS Anode 13 =
4264294e-6 + -2121222e-8 * DV(i) + 8360316e-11 * DV(i)**2 +
-1760020e-13 * DV(i)**3 + 2193857e-16 * DV(i)**4 +
-1690439e-19 * DV(i)**5 + 8124086e-23 * DV(i)**6 +
-2368735e-26 * DV(i)**7 + 3831171e-30 * DV(i)**8 +
-2635711e-34 * DV(i)**9
Relative Efficiency [Er(i)] for ELS Anode 14 =
1871975e-6 + -2714091e-9 * DV(i) + -1640371e-12 * DV(i)**2 +
3116431e-14 * DV(i)**3 + -7626180e-17 * DV(i)**4 +
9286905e-20 * DV(i)**5 + -6636238e-23 * DV(i)**6 +
2903883e-26 * DV(i)**7 + -7657761e-30 * DV(i)**8 +
1117466e-33 * DV(i)**9 + -6928145e-38 * DV(i)**10
Relative Efficiency [Er(i)] for ELS Anode 15 =
1714980e-6 + -7089766e-9 * DV(i) + 3259217e-11 * DV(i)**2 +
-8410868e-14 * DV(i)**3 + 1347052e-16 * DV(i)**4 +
-1391524e-19 * DV(i)**5 + 9397261e-23 * DV(i)**6 +
-4114030e-26 * DV(i)**7 + 1123482e-29 * DV(i)**8 +
-1737531e-33 * DV(i)**9 + 1161350e-37 * DV(i)**10
Now, the hard part is done :) -- the relative efficiency per energy
channel [Er(i)] has been determined.
COLUMN 13 of CAL TABLE: ABS_EFF
All anodes have absolute efficiency (Ea) of 0.95
COLUMN 14 of CAL TABLE: GEOM_FACTOR (cm**2-sr)
All anodes have a Geometric Factor (Gf) of 0.000588
COLUMN 15 of CAL TABLE: MCP_TRANS
All anodes have MCP Transparency (Mt) of 0.58 (quoted by manufacturer)
COLUMN 16 of CAL TABLE: GRID_TRANS
All anodes have Grid Transparency (Gt) of 0.81
COLUMN 17 of CAL TABLE: ANODE_RATIO
All anodes have an Active anode area ratio (Aa) of 0.87
COLUMN 18 of CAL TABLE: DELTA_TIME
All anodes have a delta time (Dt) of 0.028125 seconds
COLUMN 19 of CAL TABLE: RESOLUTION
Resolutions (Re) for Anodes 0 - 15 from left to right:
0.08653, 0.08394, 0.08331, 0.08579, 0.08124, 0.08480,
0.08194, 0.07890, 0.07812, 0.08094, 0.08095, 0.08346,
0.08297, 0.07353, 0.07396, 0.08843
COLUMN 20 of CAL TABLE: SCALING_FACTOR
Scaling factors (Sf) for Anodes 0 - 15 from left to right:
2.632867, 1.000000, 0.635386, 0.712443, 0.810931,
0.896400, 1.370552, 0.928571, 0.665921, 1.000000,
0.807453, 1.000000, 0.988789, 1.461922, 0.928571, 2.146711
This completes the set of terms needed to determine the differential
number flux [cnts/(cm**2-sr-s-eV)] per energy channel per anode
using the equation given:
counts(i) * Sf
j = --------------------------------------------------------
Ec(i) * [Ea/Er(i)] * Gf * Mt * Gt * Aa * Dt * Re
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