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Fundamental TechnologiesGalileo Spacecraft Pages |
Source: R. McEntire, SDO/PAO-0040, January 20-21,1981
A suggested list of sources that would be placed on the foreground shield for flight calibration is contained in Table 21. Barium 133 would give 70 percent 45 keV electrons, and 10 percent 75 keV, 266 keV, and 319 keV electrons, respectively. To give 10 counts per second after injection at Jupiter, an initial source strength of 2 mc would be required (half life is about 7 1/2 years). Americium 241 could be used to calibrate the A detector by using a foil to lower the energy of the alpha particles in units to 200 keV.
In the CMS in front of Ja', a cocktail source of Americium and Gadolinium will give two distinct energy peaks in the DE by E matrix. An Americium source degraded by a foil to H1.3 MeV will be placed in front of the Jc' detector.
Table 21. EPD Flight Calibration Sources (nominal)
| LEMMS | ||
| Ba-133 (2 microcurie) | 45, 75, 266, 319 keV electrons ~10 cps total at injection | |
| Am-241 (3.4 microcurie) | 5.48 MeV alpha line degraded by foil to 200 keV (FWHM ~ 200 keV) ~10 cps | |
| CMS | ||
| Ja' | Am-241 (0.05 microcurie) | +
Gd-148 (0.05 microcurie) 5.48 + 3.18 MeV alphas ~2 cps/peak |
| Jc' | Am-241 (0.1 microcurie) | degraded by foil to
~1.3 MeV alphas ~4 cps |
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Updated 3/4/04, T. Hunt-Ward
tizby@ftecs.com