Wednesday October 2, 2013

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We will meet in TED 2561B on Wednesday October 2 at 3:00 pm EST.

For those calling in we'll use the ReadyTalk audio conference system.

1. Dial Toll-Free Number: 866-740-1260 (U.S. & Canada)
2. Enter 7-digit access code 4402297, followed by “#”


1- Bubble Chamber progress at Argonne

2- Computer Center support: mailing list, group disk, wiki page, ...

3- Cost:

 - Indirect General and Administrative (G&A) cost: 55.65% for both labor and procurement (Material and Shop)
 - Indirect Statutory and Fringe for labor: 57.15%
 - Final Bubble Chamber cost media:Bubble_FinalCost.pdf media:Bubble_FinalCost.pptx

4- Error Analysis:

 - Analytical: Statistical, Absolute and Relative Systematic Errors media:Bubble_ErrAna.pdf media:Bubble_ErrAna.pptx
 - Monte Carlo Technique: Statistical, Absolute and Relative Systematic Errors media:Bubble_ErrAnaMC.pdf media:Bubble_ErrAnaMC.pptx
 - Root macro files used in error analysis study (change txt to tar): media:ErrorAna.txt

Notes from this meeting:

  • Bubble Chamber:
- The State of Virginia reporting limit for mercury brought on-site is 5.0 lbs. This is about 2268 grams or 168 mL.
- Distance from the Bremsstrahlung radiator to the center of the bubble chamber must not exceed 50 cm. The Bremsstrahlung
photon beam has a large opening angle at this low electron beam energy and thus the photon flux drops very quickly with distance.
- JLab will high-pressure test to 100 atms a cylindrical fixture (called Phase Separator, will be used to hold mercury).  
  • Submitted a request to JLab Computer Center for a new mailing list and group. Our name is "bubble".
- Mailing List:
- Group: bubble
- Group Disk: /group/bubble
- Work Disk: /work/accel/bubble
- Bubble experiment is set up for farm use with 500GB work storage; please use project bubble for your jobs (Group account: accelerator).
  • Cost:
- The grand total loaded cost is about $360k. 
- Is it possible for our procurement cost to be considered "Capital Equipment"?
  • Error Analysis:
- Bubble Chamber Efficiency Systematic Error: This error accounts for the fact that there will be a threshold on bubble formation
in the superheated fluid. This threshold depends on the pressure and temperature of the fluid and will be used to reject low energy
ions from the reaction 14N(γ,p)13C and from neutron elastic scattering. For the reaction 14N(γ,p)13C, we need at least 108 suppression.
- It is very important to have the systematic errors being relative, i.e., these errors do not change from one energy to another.
Some of the systematic errors are clearly relative like radiator thickness or chamber thickness errors. For others, we have to 
make sure that they are relative. For example, when we do the energy scan, we need to change the beam energy by exactly 0.1 MeV
without changing or introducing any new factor that would affect the beam energy systematic error. Also we do not want to change
the beam position or size on the radiator when changing beam energy.
- Relative systematic errors do not get amplified with Penfold-Leiss unfolding.