CFL RFPD 6.25MHz

Document #:

LIGO-S1900052-v6

Document type:

S - Serial numbers

Abstract:

A modified CLF RFPD 6.25MHZ photo-detector circuit using PCB D1101124 and chassis D1101176. This circuit includes a manufactured coil using micro-metals core T25-6 AL=2.7, final inductance 5.976uH. Calculated series resistance 8.75ohms and Photodiode parameters are C=108pF, Fc=6.25MHz, Q=26.824. Measured noise is -128.8dBm/Hz. Calculated noise equivalent photocurrent is 20.8x10-6/Hz

Upon receipt at LHO, this unit was modified slightly (see eTraveler) and the shot noise equivalent photocurrent (SNEP) was remeasured to be 10.5uA (Fc = 6.25MHz, Q = 27.65, Output Noise = -131.5 dBm/Hz, L = 5.98uH)

Files in Document:

• E-Traveler (S1900052.0d4e4e51533d247290a85e5fbd0bffa316042305, file is not accessible)

Topics:

• Basic R&D
• Sensing and Control

Authors:

• Luis Sanchez

Notes and Changes:

CFL RFPD LT6202

This unit was send to LHO on 2-26-19.

This units was modify at LLO, R1 was replaced by a 10Kohms, and L7 was moved and the leads were cut. C26 was added to the circuit to help on the adjustment of resonant frequency. The final current noise was around 10x10-6Amp/Hz 03-05-2019

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