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Entry  Wed Aug 29 19:28:41 2012, Elli King, Update, LSC, Setup for a cavity scan or the input mode cleaner 40m_cavity_scan_diagram.jpg
    Reply  Wed Aug 29 20:43:23 2012, Koji, Update, IOO, Setup for a cavity scan or the input mode cleaner 
Message ID: 7311     Entry time: Wed Aug 29 19:28:41 2012     Reply to this: 7312
Author: Elli King 
Type: Update 
Category: LSC 
Subject: Setup for a cavity scan or the input mode cleaner 

 Riju, Elli

Today we prepared our experimental setup to take a cavity scan of the input mode cleaner, which we want to measure in the next day or so.  Attached is a diagram of our setup.

What we want to do is to inject a set of sidebands into the PSL and sweep their frequency from 32-45 MHz (a range just over one fsr of the mode cleaner- vfsr=11MHz).  We will measure the power transmitted out of the MC using a photo-diode and demodulate this signal with our input signal from the Marconi.  From this we should be able to see the resonant frequencies of the carrier and the higher order modes.

One aspect we spent some time thinking about; whether we would be able to inject a signal into an EOM given the EOM and the Marconi are not perfectly impedance matched.  Based on Kiwamu’s previous e-log entries designing the EOM, we decided that injecting a signal in 32-45 MHz region at 15dBm is similar to injecting the 29.5MHz sideband (at the same power level with very similar input impedance.) Fingers crossed we don’t blow anything up first week on the job.

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