Peter, Luis, Rich

A new RFPD has been built by Luis Sanchez at CIT and is ready for installation once the DC transimpedance is set (see below).  Upon arrival, we retested the unit for any parameter shift that may have happened during shipment.  The measured parameters associated with this detector are:

Device Serial Number S1900052
Center Frequency = 6.25MHz
Resonant circuit Q = 27.65
Input Transimpedance (inferred from Q) = 6.5kohms
Shot Noise Equivalent Photocurrent = 10.5uA

We still need to increase the transimpedance of the DC path on this unit, but doing so will limit the use of the portable laser calibrator as the photocurrent from the calibrator is of order 5mA.  This unit is designed to operate at a photocurrent of approximately 10uA.  The present value of the DC transimpedance stage is the nominal 100ohms, which should be increased to either 10kohms, or perhaps even 100kohms.  There is a differential transmitter after this stage that would add an additional gain of two to the resulting transimpedance.