Subject: grounding expts
From: [email-masked]
To: "Rob Simcoe" <[email-masked]>
Cc: "Bill Forrest" <[email-masked]>, "Craig McMurtry" <[email-masked]>, "Judy Pipher" <[email-masked]>
Date: Thu, 10 Sep 2009 11:25:25 -0400 (EDT)

Rob

Since we had not other information from TIS yeaterday (9/09) we decided to
try some grounding experiments.  All with gain code 8 (gx4), 4 outputs,
Vrefmain=1.5, Vref1=1.8, Vbiasgate=2.05.  Data in
C:\Data\HXRG\H2RG-ASIC-000-0-000\CDSReference\20090909xxxxxx

Bottom line is that our standard operating mode (dewar, jade, external
power supply sitting on ESD pad; array+asic floating w.r.t. dewar, no
external grounds attached except the jumper connecting digital and analog
ground on the jade, no USB isolator) is best.

Below are results and description of condition

xxxxxx  description                            outputs 1,2,3,4 ADU
******************************************************************
165244  standard operating mode                6.37, 6.83, 7.51, 6.10
145308  pump on, attached, no external grounds 11.3, 9.4, 17.6, 10.3
145844  pump on, attached, ground dewar ext pwr gnd 7.78, 7.65, 10.9, 7.63
150203  disconnect pump, dewar still grounded   7.47, 7.38, 10.5, 7.51
150610  disconnect dear ground - SOM            6.49, 6.33, 7.67, 6.90
152809  USB isolator on, metal boxes, table touch 19.2, 8.3, 29.7, 19.3
153317  USB isolator on, metal boxes table isolated 15.3, 8.3, 23.7, 15.3

Cheers, Judy