LIGO Document L1600055-v1

VRB Request: approve waiver on qualifying a high QE photodiode

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L - Letters and Memos
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My questions to the VRB are as follows:
1) Do you agree that we can waive the requirement to perform the optical cavity exposure tests to qualify these photodiodes?
2) Do you agree with the proposal to minimally clean (as described in E1600086) and to not bake (air or vacuum) or obtain an RGA scan, for the reasons stated in E1600086?

The adhesives which are used in the Modules are:

  • Eccobond CE3103WLV
  • EPO-TEK H70E-4

Data sheets are included as "other files". Both are rather high temperature epoxies (which generally means low outgassing at room temperature):

1) Henkel/Hysol Eccobond CE3103WLV (electrically conductive):
T glass transition = 114C
T operating = 150C
Not in the NASA outgassing database

2) Epotek H70E-4 (thermally conductive)
T glass transition = 80C
T operating = 200C continuous (300C intermittent)
NASA outgassing database: has data for various cure temperatures and times. Ranges are as follows:
60C to 130C cure
40 to 360 min cure
1.23 to 4.73 %TML (total mass loss)
0.01 to 0.26 %CVCM (collected volatile condensable materials)
0.17 to 0.44 %WVR (water vapor regained)
See the comparison to %CVCM values for other LIGO approved polymer materials in the abstract for this DCC entry: E1200994. Generally .00 to .01 %CVCM

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