Galileo Heavy Ion Counter

Science Requirements Document
Section 4 of 4
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PHA Gain and Discrimination Levels

The nominal gain and discriminator values are given below. Actual values should be requested from Thomas L. Garrard.

Table 12 -- Gain and Discriminator Values
detector name normal full scale
normal discriminator
LE1 307 9.6
LE2 307 2.0
LE3 2048 26.
LE4 6144 120.
LE5 6144 120.
LB1 307 0.5
LB2 307 0.4
LB3 2048 4.0
LB4 50* 2.0
* Pre-amp full scale; not connected to an analyzer.
LET E -- Slant SB:
low gain -> LE1 + LE2/2 + LE3/10 + (LE4+LE5)/25 = 9.6 MeV
LET B -- Slant SLB:
LB1 + 0.42*L2 + 0.20*L3 = 9.6 MeV


Both events and rates go though one stage of buffering in the instrument and another in the GAB. Study the cal stim printouts to see the 2 minor frame delay in the readout here. More buffering must be done in the CDS (spacecraft); this is almost certainly one minor frame. This must be understood so that correlation or rate readout and angle from the AACS can be done.

Figure 9 shows accumulation time and readout time of rate data. It also shows two extreme possibilities for event time and event readout; one event readout with minimal buffering delay and one with a maximum delay due to all six event polling buffers being full. The AACS is readout with no delay as shown in the figure.

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