Bubble Chamber Meeting Wednesday June 3, 2015

We will meet in TL 2221 on Wednesday June 3 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 progress at Argonne

2- Detection features of new bubble chamber: media:Detection_features_new_bubble_chamber.pdf

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Notes from this meeting:

• Bubble Chamber:

1. Showed bubbles distribution from N₂O with mercury as buffer liquid using PuC neutron source.
2. Plan to measure temperature gradient across the glass cell.
3. Test chamber with C₂F₆ as the super heated liquid.
4. Chamber stand (support structure) for JLab injector beamline.
5. What type of window on chamber high pressure vessel that is used for the camera?

• Supper Heated Liquid:

1. Regarding CO₂: it is possible to suppress the ¹²C(γ,α)2α signal but ¹³C(γ,n)¹²C background is still significant - Not an option.
2. For N₂O: ¹⁵N can be enriched from 0.366% to 98% to help suppress ¹⁴N(γ,p)¹³C background. However, a factor of 50 suppression of ¹⁴N is still tiny when compared to 10⁸ needed; have to rely on chamber efficiency vs temperature.

• Schedule: media:150604_INJ_SAD15.pdf

1. Reconfigure bubble chamber beamline in the first two weeks of July.
2. Chamber arrives JLab in middle of July, move to Injector, install and align.
3. Mercury will be installed in chamber at Argonne.
4. Brad arrives on August 3, 2015. Cool and pressurize with C₂F₆. Complete safety reviews.
5. Beam on chamber in the second week of August. Beam kinetic energy = 4.0 – 5.5 MeV.
6. Remove C₂F₆ and fill with N₂O during the last two weeks of August.
7. Beam on chamber in the first two weeks of September. Beam kinetic energy = 4.0 – 9.5 MeV.

• In June - August: find the highest gradients for the 1/4 cryounit. Do we need to ask for helium processing of the unit? it is not planned.