2011:299 CTU reset EPHIN rates

While in Normal-Sun Mode following the day 2011:299 CTU TLM-processor reset event, the EPHIN detector reached its highest temperature to-date, with a TEPHIN reading of 147.16 degF. At the highest temperatures we observed the E150 coincidence channel rates at levels well above their RadMon safing threshold; the rates, in-fact, hit the ceiling of their encoding (6930432 cts/sample). The data from this interval provide an upper-limit to the temperature that we can expect to allow EPHIN to operate without causing an unnecessary RadMon trigger.

Below are plots of the EPHIN coincidence channel and individual detector rates as a function the sensor temperature for times after the CTU reset until the end of 2011:300. In the E150 plot we can see a sharp rise in the rates once 5EPHINT exceeds 57.5 degC (135.5 degF). We exceeded this temperature during the 2011-July safemode event without seeing such a rise in the E150 rate, so this is "new" behavior.

Also plotted is the observed TEPHIN vs 5EPHINT correlation. While the unit is heating, the TEPHIN reading is hotter than the 5EPHINT reading as expected for the flow of solar heat into the unit. During this warming, when the 5EPHINT reading is ~57.5 degC the TEPHIN reading is ~136 degF.

EPHIN Coincidence Channels

E150

EPHIN E150 rate vs 5EPHINT

E300

EPHIN E300 rate vs 5EPHINT

E1300

EPHIN E1300 rate vs 5EPHINT

E3000

EPHIN E3000 rate vs 5EPHINT

EPHIN Detector Rates

Detector B0

EPHIN detector B0 vs 5EPHINT

Detector C

EPHIN detector C vs 5EPHINT

Detector D

EPHIN detector D vs 5EPHINT

Detector E

EPHIN detector E vs 5EPHINT

Detector F

EPHIN detector F vs 5EPHINT

TEPHIN

TEPHIN vs 5EPHINT

Mike Juda
Last modified: Wed Nov 2 11:42:40 EDT 2011