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GALILEO

The Galileo Energetic Particles Detector

 

Galileo EPD Handbook

 

Chapter 2. EPD Software

 

New EPD Format and Implementation (continued)

Source: S. Jaskulek, May 11, 1993

 

CMS Pulse Height Analysis (PHA) Data

 

The CMS rate channels are used to group measured events into categories, such as "low energy protons." This categorization approach is necessary because there is insufficient telemetry, even in the Version 2 software mode, to send down detailed data on each event. While the rate channel data is sufficient for most of our science, detailed data from a few of the measured events must be sent down to help us check the rate channel data and look more closely at selected aspects of the measurements.  The PHA data provides this window into the individual particle measurements.

 

Sectored PHA Event Collection Scheme:

 

Spin Sector

Motor Position

0 1 2 3 4 5 6
A p1 p2 p3 p4 p5 p6 p7
B   p8 p9 p10 p11 p12 p13
C p14 p15 p16 p17 p18 p19
D p20 p21 p22 p23 p24 p25

 

In the Version 3 software, four events will normally be collected in each motor position, one per spin sector. In the calibration position (motor position=0), however, PHA data will be read only in one sector (A). Based on normal EPD motor scanning between motor positions 0 and 6, the PHA collection sequence will be as follows:

 

0A, 1A, 1B, 1C, 1D, 2A, 2B, 2C, 2D, 3A, 3B, 3C, 3D, 4A, 4B, 4C, 4D, 5A, 5B, 5C, 5D, 6A, 6B, 6C, 6D, 5A, 5B, 5C, 5D, 4A, 4B, 4C, 4D, 3A, 3B, 3C, 3D, 2A, 2B, 2C, 2D, 1A, 1B, 1C ,1D, 0A, 1A, 1B, 1C, 1D...

 

The PHA events will be stored in a buffer within the EPD memory.  There will be either 12 or 24 events transmitted in a science record (depending on which telemetry mode the EPD is in). The buffer size (12 or 24) will be determined based upon a variable loaded from the CDS during telemetry mode changes. The PHA events will be loaded into this buffer by the EPD software on a rotating basis.

 

We wish to maximuze the number of events that are sent down via the PHA, even when event rates are very low. Empty slots will be filled with events from other spatial sectors and tagged with a rate channel ID of "F." 

 

TABLE 29. Rate Channel Assignments for EPD LEMMS Sensor; Channel Map 1

 

Energy Range Channel 16 sec.
+Cal
6 sec.
+Cal
Omni 
+Cal
Total
Channels
LEMMS (MeV)
0.022-0.042 keV A0   1   7
0.042-0.065 A1 1     17
0.065-0.120 A2 1     17
0.120-0.280 A3   1   7
0.280-0.515 A4   1   7
0.515-0.825 A5   1   7
0.825-1.68 A6   1   7
1.68-3.20 A7   1   7
3.50-12.4 (Z>=2) A8   1   7
  
0.015-0.029 E0   1   7
0.029-0.042 E1 1     17
0.042-0.055 E2   1   7
0.055-0.093 E3   1   7
 
0.093-0.188 F0   1   7
0.174-0.304 F1   1   7
0.304-0.527 F2 1     17
0.527-0.884 F3   1   7
 
3.20-10.1 (z=1) B0     1 2
1.5-10.5 (e-) B1     1 2
16.0-100 (z=2) B2     1 2
 
14.5-33.5 (z>=1) DC0     1 2
51-59 (z>=1) DC1     1 2
>=2.0 (e-) DC2     1 2
>=11 (e-) DC3     1 2
 
A singles AS     1 2
B singles BS     1 2
C singles CS     1 2
D singles DS     1 2
Background EB1     1 2
Background EB2     1 2
Background FB1     1 2
Background FB2     1 2
 
LEMMS Total   4 13 15 189

 

TABLE 30. Rate Channel Assignments for EPD CMS Sensor; Channel Map 1

 

Energy Range Channel 16 sec.
+Cal
6 sec.
+Cal
Omni 
+Cal
Total
Channels
TOF x E (MeV)
0.08-0.22 (H) TP1 1     17
0.22-0.54 (H) TP2 1     17
0.54-1.25 (H) TP3   1   7
0.027-0.155 (He) TA1   1   7
0.155-1.0 (He) TA2   1   7
0.012-0.026 (CNO) TO1 1     17
0.026-0.051 (CNO) TO2 1     17
0.051-0.112 (CNO) TO3   1   7
0.112-0.562 (CNO) TO4   1   7
0.016-0.030 (S) TS1 1     17
0.030-0.062 (S) TS2   1   7
0.062-0.31 (S) TS3     1 2
0.02-0.20 (Fe) TH1   1   7
TAC Singles TACS   1   7
KT Singles KTS   1   7
Start Singles STARTS 1     17
Delta E x E
0.19-0.49 (He) CA1        
0.49-0.68 (He) CA3        
0.68-1.4 (He) CA4        
0.16-0.55 (CNO) CM1        
0.55-1.1 (CNO) CM3        
1.1-2.9 (CNO) CM4        
2.9-10.7 (CNO) CM5        
1.0-2.2 (Na) CN0        
2.2-11.7 (Na) CN1        
0.22-0.33 (Fe) CH1        
0.33-0.67 (Fe) CH3        
0.67-1.3 (Fe) CH4        
1.3-15.0 (Fe) CH5        
Ja Singles JAS        
Jb Singles JBS        
K Singles KS        
 
CMS Total   6 9 1 167
Total Channels   10 22 16 356

 

 

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Updated 8/23/19, Cameron Crane

QUICK FACTS

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.