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Entry  Wed Feb 24 00:27:14 2010, Dmass, Lab Infrastructure, Doubling, Doubling Crystal Damaged 
    Reply  Thu Feb 25 01:00:31 2010, Dmass, Lab Infrastructure, Doubling, Doubling Experiment Update! 
       Reply  Fri Feb 26 01:50:06 2010, Dmass, Lab Infrastructure, Doubling, Doubling Experiment Update! 
          Reply  Fri Feb 26 16:19:05 2010, Dmass, Lab Infrastructure, Doubling, Doubling Experiment Update! PD1AnaNoise.pdfPD2AnaNoise.pdfPD3AnaNoise.pdfPD4AnaNoise.pdf
Message ID: 621     Entry time: Thu Feb 25 01:00:31 2010     In reply to: 619     Reply to this: 622
Author: Dmass 
Type: Lab Infrastructure 
Category: Doubling 
Subject: Doubling Experiment Update! 

Update on rebuilding:


  • Rana found me a 4 mirror REO package with 2 mirrors in it.
  • One of these is a supermirror.
  • The other is something unknown that looks different, has an engraved barrel, and is most definitely NOT high reflective (maybe a splitter) at 1064.
  • I can't find the 1064 transmission (of 100 mW) of the supermirror on a viewer, or sensitive card. It appears to be very small. This is good.
  • I see bright 532 spots reflected from both surfaces of this mirror. This is less than good.
  • I still have 100 uW transmitted, which is within a factor a 3 of my max power. This will give me around 1V DC with a 50K load resistor on one of the PDs I will use (below).
  • I am using some 90% R 45P (the beam is S) to dump a large fraction of my IR power before my PDs.


  • I took one of the ISS PDs off the 40m PSL table. Siobhan was her name.
  • I had another ISS PD from Stefan's time here.
  • I pulled the 500 ohm SM transimpedance resistor from both of these, and replaced it with a 500 Ohm thin film resistor from the 40m. (I didn't get a good pic, but had no problems soldering, and Koji gave me a tired thumbs up when I asked him if I "did it wrong")
  • I am going to use the ISS PD box to power and readout these.
  • I also have two DET110's  and two nice and old Thorlabs PDs of unknown model number (but known PD type: Hamamatsu S1223).
  • The DET110's have a quoted NEP of 2e-14 W/rtHz and the Hamamatsu's have a quoted NEP of 1e-14.
  • These numbers are way better than the newer thorlabs PDs I was using (which were total shite - like 10 pA/rtHz NEPs of 1e-11 to 1e-12. Terrible.)
  • I will think about the loading tomorrow, and see what I can get away with for each of these. The batteries are 12 and 22.5V, respectively.
  • A 150K load would fill the DAQ with what I have, so maybe this is a good number to shoot for?

Table Layout:

  • I think I have everything fitting!

Beam Dumps:

  • Frank found some of the Si slabs we are using for the low scatter beam dumps, I am planning on fashioning two crude dumps from these (I have only 3 slabs).
  • I have up to 200 mW coming out of my MZ, so I have to dump some so as not to cook the ISS PDs.
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