jeffrey.bartlett@LIGO.ORG - posted 15:23, Friday 21 February 2020 - last comment - 12:39, Wednesday 10 March 2021(55221)
BOSEM LED Decay Study
Attached below are plots of the past 2 years of operation of the BOSEMs on the BS, ITMs, ETMs, TMSs, HxTS suspensions. These plots have been zoomed to better show changes and trends in the counts. The purpose of this study was to see if there are BOSEMs which need replacing during the post O3 vent.
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Tagging SUS.
I've referenced this new data in a comment to the on-going IIET ticket that tracks this issue: IIET Ticket 10093. If anyone needs a calibration of this data, take any of these "INMON" channels, which are in units of raw ADC counts, which you can convert back to current on the PD (in Amps) with the following inverse response of the sensing PD's electronics chain at "DC" (i.e. at 0 Hz so we can ignore the frequency response of the satellite amp, and approximating the voltage gain of the AA chassis at 1.0 [V_ADC/V_satAmp] and thus dropped from below): 1 [V_ADC] 1 [A_PD] PD current [A] = inmon [ct] * --------------- * -------------- = inmon [ct] * 2.54e-9 [A_PD / ct_ADC] 1638.4 [ct_ADC] 240e3 [V_satAmp] Then, if Stuart Aston (or someone as awesome as Stuart) has the spec on efficiency of the BOSEM PD to get the Watts per Amp, then the spec on the Watts per LED current, then you could map this data directly to "how much has the LED current actually decayed over this time period," to make a sanity check as to whether the calculated estimate matches the expected LED current decay rate.
Adding some more plots showing '2 year trends for BOSEM', which seems to be missing above - TMSX (F2,F3), SRM (LF), SR2 (LF), PRM (LF, RT), ITMY (UL, UR, LL, LR), ITMX (F1,F2,F3, UL, UR, LL, LR).
Note: adding links to Jeff. B's plot which will make it easier to find and look at them: BS , ETMX, ETMY, ITMX, ITMY, MC1, MC2, MC3, PR2, PR3, PRM, SR2, SR3, SRM, TMSX, TMSY,
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Additional plots for ITMX and ITMY. H1:SUS-ITMX_R0_OSEMINF_F1_INMON H1:SUS-ITMX_R0_OSEMINF_F2_INMON H1:SUS-ITMX_R0_OSEMINF_F3_INMON H1:SUS-ITMX_R0_OSEMINF_LF_INMON H1:SUS-ITMX_R0_OSEMINF_RT_INMON H1:SUS-ITMX_R0_OSEMINF_SD_INMON H1:SUS-ITMY_R0_OSEMINF_F1_INMON H1:SUS-ITMY_R0_OSEMINF_F2_INMON H1:SUS-ITMY_R0_OSEMINF_F3_INMON H1:SUS-ITMY_R0_OSEMINF_LF_INMON H1:SUS-ITMY_R0_OSEMINF_RT_INMON H1:SUS-ITMY_R0_OSEMINF_SD_INMON
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