COSPIN/LET Contact:
Dr. R.G. Marsden
Research and Scientific Support Department of ESA, ESTEC
Postbus 299
2200 AG Noordwijk
The Netherlands
Phone: (31) 71 565 3583
Telefax: (31) 71 565 4697
E-mail: richard.marsden@esa.int
RECORD FORMAT:
IMPLICIT REAL(L)
DIMENSION L4_11(8),L13_20(8),L34_38(5)
C FREE FORMAT
READ(1,*)IYEAR,IDOY,IHOUR,IMIN,ISEC,
. L1,L2,L3,L4_11,L12,L13_20,L21,
. L22,L23,L24,L25,
. L26,L27,L28,L29,L30,L31,L32,L33,L34_38
C FIXED FORMAT
READ(1,100)IYEAR,IDOY,IHOUR,IMIN,ISEC,
. L1,L2,L3,L4_11,L12,L13_20,L21,
. L22,L23,L24,L25,
. L26,L27,L28,L29,L30,L31,L32,L33,L34_38
100 FORMAT(I5,X,I3,3(X,I2),38(X,G9.3))
PARAMETER LIST:
IYEAR: year
IDOY: day of year
IHOUR: hour
IMIN: minute
ISEC: second
L1: protons (0.9-1.2 MeV)
L2: " (1.2-3.0 MeV)
L3: " (1.8-3.8 MeV)
L4_11: " " sectors 1 to 8
L12: " (3.8-8.0 MeV)
L13_20: " " sectors 1 to 8
L21: " (8.0-19.0 MeV)
L22: alphas (1.0-5.0 MeV/n)
L23: " (1.9-3.7 MeV/n)
L24: " (3.7-8.4 MeV/n)
L25: " (8.4-19.0 MeV/n)
L26 Li,Be,B (1.9-4.9 MeV/n)
L27 " (4.9-26 MeV/n)
L28 C,N,O (2.6-7.1 MeV/n)
L29 " (7.1-39.0 MeV/n)
L30 Z>=10 (3.0-9.0 MeV/n)
L31 10<=Z<=20 (9.0-50 MeV/n)
L32 Z>=20 (12.0-75.0 MeV/n)
L33 electrons (0.3-1.0 MeV)
L34_38 single detector counting rates
FLUX UNITS: (/cm2/s/sr/MeV/nucleon)
TIME RESOLUTION: 10 minutes (date/time given at start of averaging period)
NOTES:
1. Rate channel L1 (which nominally responds to protons in the energy range
0.9-1.2 MeV) is derived from a single-detector measurement, and as such is
sensitive to penetrating particles which lose part of their energy in the
detector. The background contribution depends on the energy spectrum of the
incident particle population, being negligible for (differential) energy
spectral slopes of -3.5 or steeper, increasing to 80% of the total counts
for a slope of -1.0 or harder.
2. Rate channel L2 is derived from a single detector measurement, and the nominal
energy response to protons (1.2-3.0 MeV) is approximate.
3. Please note that a software error in the LET data reduction algorithm
means that data in sectored channel L4 should be ignored, and will be
corrected at a later date.
3. Rate channel L21 (which nominally responds to protons in the energy
range 9-19 MeV) is also sensitive to higher-energy particles which lose
part of their energy in the telescope structure. As in the case of L1, the
background contribution depends on the energy spectrum of the incident
particle population, being negligible for (differential) energy spectral
slopes of -2.0 or steeper, increasing to 80% of the total counts for a
slope of +0.75 or harder.
4. Rate channel L22 is derived from a single detector measurement, and the nominal
energy response to alpha particles (1.0-5.0 MeV/n) is approximate.
5. Rate channel L25 (which nominally responds to alpha particles in the energy range
8.4-19.0 MeV/n) is also sensitive to higher energy particles that lose part of their
energy in the telescope structure. As in the case of L21, the background contribution
depends on the energy spectrum of the incident particle population (negligible for
differential energy spectral slopes of -2.0 or steeper).
6. Rate channel L26 suffers from background due to pulse pile-up for proton fluxes in L2
greater than 10 protons/cm^2/s/sr/MeV.
7. Rate channel L27 suffers from background due to pulse pile-up for proton fluxes in L2
greater than 30 protons/cm^2/s/sr/MeV.
8. The energy for rate channel L28 is approximate (species dependent).
9. The energy for rate channel L29 is approximate (species dependent).
10. The energy for rate channel L30 is approximate (species dependent).
11. The energy for rate channel L31 is approximate (species dependent).
12. The energy for rate channel L32 is approximate (species dependent).
13. The energy range for rate channel L33 is approximate. L33 suffers from background
from the RTG and GCR.
14. Rate channel L34 includes all particles depositing energy greater than the
minimum discriminator level (D1).
15. Rate channel L35 includes all particles depositing energy greater than the
minimum discriminator level (D2).
16. Rate channel L36 includes all particles depositing energy greater than the
minimum discriminator level (D3).
17. Rate channel L37 includes all particles depositing energy greater than the
minimum discriminator level (D4).
18. Rate channel L38 includes all particles depositing energy greater than the
minimum discriminator level (D5).
(For further information, contact Dr. R.G. Marsden,
richard.marsden@esa.int)
PHA Derived H and He Fluxes
IYEAR: year
IDOY: day of year
IHOUR: hour of day
E1: 2-4 MeV Protons (/cm2/s/sr/MeV)
EE1: Error in E1 "
E2: 4-6 MeV Protons (/cm2/s/sr/MeV)
EE2: Error in E2 "
E3: 6-8 MeV Protons (/cm2/s/sr/MeV)
EE3: Error in E3 "
E4: 8-16 MeV Protons (/cm2/s/sr/MeV)
EE4: Error in E4 "
E5: 16-20 MeV Protons (/cm2/s/sr/MeV)
EE5: Error in E5 "
H1: 4-6 MeV/n Helium (/cm2/s/sr/MeV/n)
EH1: Error in H1 "
H2: 6-9 MeV/n Helium (/cm2/s/sr/MeV/n)
EH2: Error in H2 "
H3: 11-20 Mev/n Helium (/cm2/s/sr/MeV/n)
EH3: Error in H3 "
TIME RESOLUTION: daily (date/time given at mid-point of averaging period)
PHA Derived O, N and Ne Fluxes
IYEAR: year
IDOY: day of year
IHOUR: hour of day
O1: 4-8 MeV/n Oxygen (/cm2/s/sr/MeV/n)
EO1: Error in O1 "
O2: 8-12 MeV/n Oxygen (/cm2/s/sr/MeV/n)
EO2: Error in O2 "
O3: 12-16 MeV/n Oxygen (/cm2/s/sr/MeV/n)
EO3: Error in O3 "
O4: 16-20 MeV/n Oxygen (/cm2/s/sr/MeV/n)
EO4: Error in O4 "
N1: 4-7 MeV/n Nitrogen (/cm2/s/sr/MeV/n)
EN1: Error in N1 "
N2: 8-20 MeV/n Nitrogen (/cm2/s/sr/MeV/n)
EN2: Error in N2 "
Ne1: 4-8 MeV/n Neon (/cm2/s/sr/MeV/n)
ENe1: Error in Ne1 "
Ne2: 9-30 MeV/n Neon (/cm2/s/sr/MeV/n)
ENe2: Error in Ne2 "
TIME RESOLUTION: 20 days (date/time given at mid-point of averaging period)
Yearly PHA Plots
Each plot provides a qualitative representation of pulse height measurements made by the
COSPIN/LET instrument over a complete year, indicating periods of significant heavy ion
fluxes. The plots are constructed using the charge histograms derived from the PHA
analysis of the D1 and D2 detectors of the LET instrument. The number of PHA events in a
charge bin (having a width of 0.01 of a unit of atomic number) is accumulated over a period
of a day, colour coded and plotted as a filled box.
During periods of enhanced particle fluxes, well defined peaks can be seen for typical solar
energetic nuclei. Persistent horizontal banding for certain ions (for example O, N and Ne)
indicates the presence of anomalous cosmic ray (ACR) populations.
Note that the number of PHA events for a given species shown in the plot does not necessarily
reflect its true abundance. This is due to the priority system used by the instrument that
maximizes the collecting efficiency of rarer ions. Further normalization is required to produce
accurate composition ratios (for example, p/He and He/O). Note also that the majority of events
that appear in the region between He and C (i.e., Li, Be, B) are due to background effects in the
instrument.
[ COSPIN LET Index | COSPIN Index ]