Voyager LECP Data Analysis Handbook
Calibrations and Channel Definitions
January 24, 1979
TO: Steve Gary
FROM: Tom Armstrong
I need the final, authoritative version of the following Voyager parameters:
- t, "dead time," discriminator output circuit recovery time, or max rate on random pulses.
- T, "resolving time," how close must two incident events occur in order to fire a discriminator as a piled-up pulse.
Nominal values are okay. Give your best estimates of uncertainties. Thanks.
| t | T | |
| A | (A · B coin.) | 70 ns |
| B | 70 ns | |
| δ | 20 ns | |
| δ' | 20 ns | |
| α | 2.4 ms | 1.5 μs |
| β | 2.4 | 1.5 μs |
| β' | 2.4 | 1.5 s |
Response from Steve Gary:
LECP Random Pulser Test
February 5, 1979
SN02
| Input Rate | Output Rate |
| Random Rates: | |
| 855 cps | 852 |
| 6419 | 6290 |
| 9950 | 9656 |
| 31606 | 28335 |
| 54354 | 44595 |
| 94400 | 66100 |
| 156000 | 81800 |
| 217000 | 91800 |
| 341000 | 103000 |
| 508000 | 110000 |
| 20000 | 18700 |
| 42600 | 36500 |
| Fixed Rates: | |
| 148000 | 148000 |
| 173000 | 173000 |
| 193000 | 182000 |
| 205000 | 66000 |
| 225000 | 31700 |
February 22, 1979
D1-D2
| r = R / (1+RT) | 1 + RT = R/r RT = R/r - 1 T = 1/r - 1/R = (R-r) / Rr |
| Live time = | 1 - Rt |
| r = | R(1 - rT) |
| r = | R - rRT |
| R = | r(1 + RT) |
| r = | R / 1 + RT |
r = 100 k
R = 260 k
T = (260k - 100k) / (260k)(100k) = 160k / 260(100)kk = 1.6 / 260k = 1.6 / .26M = 6.15 ms
| R | 1+RT | r(calc) | r(act) |
| 10000 | 1.062 | 9420 | 9.6 |
| 20000 | 1.123 | 17800 | 18.5 |
| 40000 | 1.246 | 32100 | 35 |
| 80000 | 1.492 | 53600 | 58 |
| 150000 | 1.922 | 78100 | 82 |
| 250000 | 2.54 | 98400 | 99 |
| 500000 | 4.08 | 123000 | 110 |
Figure: Feb. 5, 1979, LECP SN02, D1D2 Coincidence Strobe. Output Rate vs. Input Rate, Random Pulser Inputs ~1 MeV into Channels D1 and D2 (Rate Channel 3).
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Updated 8/9/19, Cameron Crane
VOYAGER 1 ELAPSED TIME
*Since official launch
September 5, 1977, 12:56:00:00 UTC
VOYAGER 2 ELAPSED TIME
*Since official launch
August 20, 1977, 14:29:00:00 UTC
QUICK FACTS
Mission Duration: 40+ years have elapsed for both Voyager 1 and Voyager 2 (both are ongoing).
Destination: Their original destinations were Saturn and Jupiter. Their current destination is interstellar space.