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The Galileo Energetic Particles Detector


Galileo EPD Handbook


Chapter 1. Instrument Summary



Revised 19 April, 1985, TPA


Energy Range
Species (MeV) Logic
CE1 Electrons 0.050-0.100 (JaP1) (JcP) KE1 (K0) (L0)
CE20   0.100-0.200 (JaP1) (JcP) K0 (KE2) (L0)
CE30   200>0.300 (JaP1) (JcP) KE2 (K1)
CP1 Protons 0.200-0.290 JaP1 (JaP2) (K0)
CP2   0.290-0.500 + JaP2 (Ja0) (K0)
CP3   0.05-1.4 JaP1 (Ja0) K0 (K1) (L0)
CA0 Alphas 0.08-0.19 + Jc0 (Jcl) (K0)
CA1   0.17-0.39 + Ja0 (Ja1) (K0)
CA2**   0.19-0.45 Jc0 (Jc1) K1 (L0) T1 (T2)
CA3**   0.38-0.80 Ja0 (Ja1) K0 (K2) (L0) T1 (T2)
CA4**   0.80-1.8 Ja0 (Ja1) K2 (K5) (L0)
CM0 Medium Nuclei 0.08-0.15 + Jc1 (Jc3) (K0)
CM1   0.16-0.45 + Ja1 (Ja3) (K0)
CM2**   0.14-0.59 Jc1 (Jc3) K0 (K3) (L0) T2 (T3)
CM3**   0.41-1.0 Ja1 (Ja3) K0 (K4) (L0) T2 (T3)
CM4**   1.0-2.7 Ja1 (Ja3) (S1) K4 (K5) (L0)
CM5**   2.7-10.7 Ja0 (S1) K5 (L0)
CN0** Intermediate Nuclei 0.91-2.0 [S1 or Ja3] (Ja4) K4 (K5) (L0)
CN1**   2.0-11.7 S1 (S2) K5 (K6) (L0)
CH0 Heavy Nuclei 0.025-0.035 + Jc3 (Jc4) (K0)  
CH1   0.07-0.10 Ja3 (Ja5) (K0)  
CH2**   0.11-0.37 [Jc3 or {T3 and Jc1}] (Jc4)  K0 (K3) (L0)
CH3**   0.33-0.8 Ja3 (Ja5) K0 (K4) (L0) T3  
CH4**   0.8-1.7 Ja4 (Ja5) K4 (K5) (L0)  
CH5   1.7-13.0 S2 (Ja5) K5 (L0)  
JaS Singles Rates   Ja0 JbS Ja0 JcS Jc0 KS K0 LSL0


+ High energy limit will be greater for the 180 end, when Detector K does not provide a reliable anticoincidence cut-off. Single parameter channels.
** An event in these channels may also be transmitted as a CMS PHA event.


TABLE 15. EPD CMS Discriminator Levels
Measured 7/6/84


Energy (MeV) PHA
Name Address
Ja00 23 0.42 23
Ja0 24 0.635 43
Ja1 25 2.00 97
Ja3 26 9.22 176
Ja4 27 12.5 191
Ja5 28 38.8 251
Ja Thresh 0.52  
Jb Thresh 0.52  
JaP1 21 0.15  
JaP2 22 0.24  
Jc0 21 0.26 22 (+6,-6)
Jc1 22 1.15 106 (+4,-4)
Jc3 23 5.02 198
Jc4 24 10.7 244
K0 31 0.12 44 (+3.-3)
K1 32 1.30 121
K2 33 1.26 119
K3 34 5.80 161
K4 35 7.95 169
K5 36 48.5 216
L   0.085  


S1 and S2 must be readjusted.


(Slope in log space = -0.78 for both discriminators.
S1 through J = 6.7 MeV, K = 48 MeV.
S2 through J = 12.0 MeV, K = 48 MeV.)


TABLE 16. CMS System Commands


PRIME SELECT Controls the four signal-select switches, choosing from either 0 degree or 180 degree end of telescope
T OVERRIDE Removes time-of-flight requirements from rate definitions
HI-LOW BIAS Chooses either of two bias voltages for Ja' and Jc' detectors
A ON Applies power to Ja/Ja' and Ka' linear processing circuitry
B ON Applies power to Jb linear processing circuitry
C ON Applies power to Jc/Jc' and Kc' linear processing circuitry
L ON Applies power to L linear processing circuitry.



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Updated 8/23/19, Cameron Crane


Manufacturer: The Galileo Spacecraft was manufactured by the Jet Propulsion Laboratory, Messerschmitt-Bölkow-Blohm, General Electric, and the Hughes Aircraft Company.

Mission Duration: Galileo was planned to have a mission duration of around 8 years, but was kept in operation for 13 years, 11 months, and 3 days, until it was destroyed in a controlled impact with Jupiter on September 21, 2003.

Destination: Galileo's destination was Jupiter and its moons, which it orbitted for 7 years, 9 months, and 13 days.