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Entry  Fri May 6 01:27:12 2011, Koji, Summary, General, aLIGO BBPD / Green PD investigation PD_response.pdfFFD-100_AP389_MCL.pdf
    Reply  Sat May 7 12:57:54 2011, Koji, Summary, General, aLIGO BBPD / Green PD investigation PD_response.pdf
       Reply  Tue May 10 09:05:49 2011, Koji, Update, General, aLIGO BBPD / Green PD investigation PD_response.pdf
          Reply  Wed Jun 1 21:56:43 2011, Koji, Update, General, aLIGO BBPD / Green PD final result PD_response.pdflinearity_GALI_6.pdf
Message ID: 4676     Entry time: Tue May 10 09:05:49 2011     In reply to: 4658     Reply to this: 4778
Author: Koji 
Type: Update 
Category: General 
Subject: aLIGO BBPD / Green PD investigation 

BBPD update

- The BBPD circuit has been constructed on the aLIGO BBPD board

- It still keeps 200MHz BW with FDD-100 Si PD for the 100V bias.

- The noise spectrum has been cleaned up a lot more. It shows the noise level of the 0.4mA shotnoise between 9-85MHz.
The noise at 160MHz is the noise level of the 1mA shotnoise.

Some of the noise peaks at around 97MHz came from the bias voltage.

What to do next

- Confirmation of the performance with the original aLIGO BB PD configuration.

- Notch filter for 9MHz (for aLIGO).

- Implementation of a power amplifier. (issues: power supply and heat removal)

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