Bubble Chamber Meeting Wednesday October 7, 2015

We will meet in TL 2221 on Wednesday October 7 at 3:30 pm EST.

For those calling in we'll use the Blue Jeans [1] audio conference system.

Phone number: 1-888-240-2560
Meeting ID: 3528502673#
Meeting URL: http://bluejeans.com/3528502673

Agenda:

1- Bubble Chamber removal and shipping back to ANL

2- September beam test summary

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Notes from this meeting:

• Bubble Chamber Removal:

1. Planned on October 20 and 21
2. Crates will be staged by October 19
3. Plan to ship every thing back to Argonne
4. Shipping arrangement will be made once chamber is crated and ready in north tunnel access building

• Beam Test Summary (Ernst):

1. Plus
   1. Chamber operated as expected in Bremsstrahlung beam
   2. Will be able to measure the chamber insensitivity to gammas – we had a high intensity gamma flux on chamber
   3. Measured ¹⁸O(γ,α)¹⁴C cross section at five energies
   4. Found sensitivity as expected to ¹⁴N(γ,p)¹³C when lowering the operational pressure
   5. Cosmic background of about 1 bubble per 8 minutes in JLab tunnel vs 1 – 2 bubbles per minute at Duke or Argonne
2. Minus
   1. Chemistry of mercury – why background rate changed at the end of test
   2. Events distribution shows a cone instead of a cylinder – why?
   3. Ceramic break failed
   4. Beam position on radiator
   5. Better alignment
3. Improvements
   1. Easy
      1. Better light coverage
      2. Improve cooling capacity
      3. Introduce a lens to locate camera farther and for better shielding of gammas (camera was sensitive to gammas)
      4. Improve operational pressure control and regulation
      5. Be able to take data from MCC instead of Injector Service Building
   2. Tough
      1. One fluid system – no more mercury
      2. New collimator in chamber

• Beam Energy:

1. Added steel to cover about 80% of 2D spectrometer line
2. Calibrated ¼ cryounit gradients using 2D line
3. Will check beam energy in 5D line – as of now, beam energies used during September test could be off by few percents
4. Will add steel shielding to 5D line next SAD