While Betsy and crew were re-installing the lower half of ITMY into BSC8, she was kind enough to shine a flashlight down the beam tube so I could look for signals from the four scattered light PDs associated with the arm cavity baffle, H2 hole.  I clearly saw her flashlight signature as the flashlight was shone on the inner walls of the beam tube.

A first order 70 Hz low pass filter was installed on each of the inputs to the 4 Melles Griot transimpedance amplifiers to cut down on the large high frequency noise.  The filter puts 1k in series with each transimpedance amplifier input (virtual ground node).  This should be fine at the very low light levels associated with the scattered light PDs, but would introduce nonlinearity at photocurrents much higher than 100uA or so.

Each Melles Griot amplifier was left in the 2uA peak transimpedance setting, which corresponds to a transimpedance of 10^6 V/A.  There is also a gain of 10 in the PEM BNC input channels.  The dark noise of each of the four channels as viewed on the data viewer is about 100 counts peak to peak, with small (100s of counts) DC offsets.  The flashlight test caused excursions in the viewed signals of order 1-2 thousand counts.

The PEM channels for each of H2 ITMY scattered light PDs were moved to:
PD1 - software channel 27 (written as "28" on the front of the PEM DAQ chassis)
PD2 - software channel 28 (written as "29" on the front of the PEM DAQ chassis)
PD3 - software channel 29 (written as "30" on the front of the PEM DAQ chassis)
PD4 - software channel 30 (written as "31" on the front of the PEM DAQ chassis)

The last channel of the PEM chassis is dedicated to the duotone input, so it's not