Wednesday November 6, 2013

We will meet in TED 2561B on Wednesday November 6 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 “#”

Agenda:

1- New "5 MeV" Dipole update media:new_5Mev_dipole_Oct25.pdf media:new_5Mev_dipole_Oct25.doc

2- Bubble Chamber progress at Argonne

3- Discuss the Bubble Chamber dead time: rates and systematic error. How long does it take to acquire one event?

4- Now we have an Accelerator Operations Logbook, BUBBLELOG: [1]

5- Under Accelerator Task List, ATLis, there is now Project: Bubble Chamber to assign tasks to.

6- There will be an Accelerator Seminar on Thursday December 5, 2013:

 - Title: Measurement of 16O(γ,α)12C with a bubble chamber and a bremsstrahlung beam at Jefferson Lab Injector
 - Abstract: media:Abstract_Acc_Seminar.pdf media:Abstract_Acc_Seminar.docx

---

Notes from this meeting:

• New Dipole Magnet:

 - We are going with Model 3 in Jay's design: with 14.6 cm wide, 10 cm long poles
 - For about $10K one can buy a Hall probe system with claimed accuracy 0.01% and temperature coefficient 10 ppm/C
 - For a 12.5 cm long magnet, the beam scrapes the beamline
 - Do we have the steel on-site?
 - Working with Shaun to complete magnet design and finalize dimensions
 - This new magnet will work fine up to 16 MeV/c (the maximum energy of the new upgraded Injector)

• Bubble Chamber progress:

 - JLab Facility rejected our request for wall power needed for the new Chiller (Two pole, three wire 208V, NEMA 6-15 plug, 8A).
They do not provide this configuration. Their normal procedures are to provide 120 V, 20 A, NEMA 5-20 receptacles or 208/120 V,
30 A, NEMA L21-30 receptacles.
 - Now, what to do about power for the new Chiller?

• Bubble Chamber dead time:

 - There is minimum and maximum rates where within this range the bubble chamber will be able to measure the cross section reliably
 - The minimum rate:
        - Is determined once the background rate is known. The real event rate must be higher than the background rate.
        - At HIGS, the background rate was caused by cosmic rays and was about 1 event/min. This cosmic-ray background is
          expected to be different at JLab tunnel due to earth shielding.