Wednesday December 11, 2013

We will meet in TED 2561B on Wednesday December 11 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_Nov20.pdf

2- The accelerator will fund (as part of running CEBAF (RSR) in FY14):

 - New dipole magnet and a Hall probe system: GMW DTM-151 [1].  The Group3 DTM-151 is the highest performance Hall effect
teslameter commercially available with digital linearity and temperature correction to provide 0.01% accuracy, resolution to 2ppm,
and a temperature stability of 10ppm/°C.
 - New fast valve and its electronics media:275218EC_Manual.pdf media:752_1VFE.pdf. Total closing time <10 ms.

3- Latest drawing of Bubble Chamber beamline: media:Bubble_Chamber_BeamLine_Drawing_top.pdf media:Bubble_Chamber_BeamLine_Drawing_side.pdf (units of the drawing are inches) and side-view elevation:

4- Bubble Chamber progress at Argonne

5- Draft of the Accelerator Seminar talk (on Thursday January 23, 2014): media:Acc_Seminar.pdf media:Acc_Seminar.pptx.

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Notes from this meeting:

• New Dipole Magnet:

- We may build two dipoles depending on the cost of one vs two. We have enough steel for two.
- Magnet faces will be flat and parallel to about 10 μm.
- Magnet drawings are according to ANSI Y14.5, Geometric Dimensioning and Tolerancing (GD&T).
- A spare set of coils will be also made.
- Mapping will be done with the Hall Probe impeded in the magnet.
- Need new fixture to mount the dipole on that allows for alignment adjustments.

• Beamline:

- The design of the beamline should include an Earth-Field correcting coil. For the absolute beam energy measurement, the biggest
systematic error could be the correction for the earth's magnetic field. We should have a coil that spans our beamline to cancel
the earth's field.
- So far, we are unable to locate the radiator chamber used during PEPPo. Maybe it is in the Magnet Lab? The solenoid attached
to the chamber is there for mapping.
- There is a fast valve just before the 0L03 cryo-unit. Is it possible to have the gauge of that valve to close both the
existing valve the new fast valve? i.e., can the new fast valve share electronics with the fast valve on the other side
of the Injector? 
- We will use an excess dipole magnet as a Sweep Magnet (we have this magnet in our cabinet in the Injector Service Building).
We will increase the size of the gap to fit the larger beam pipe expected after the radiator. For this we will use excess steel
from the piece we have on-hand. This dipole was used in the FET Recirculation Experiment in CEBAF Injector in 1993. We have two
dipoles: BNRB06 (dipole #3) and BNRB10 (dipole #1). media:Sereno_91-053.pdf media:Sereno_92-004.pdf

• Bubble Chamber progress:

- Brad expressed concerns about the positioning of the Chamber at JLab. Shaun Gregory will send him a 3D model of the layout. 
- Brad is in contact with JLab Facility electrical engineer (Paul Powers) to formulate a plan to deal with the power requirements
of the Chiller. 

• Next meeting: Wednesday January 15 or 22.