View source for Tuesday, April 14, 2015 11:30am EST

Last meeting: [[Thursday, March 26, 2015 10:00am EST]]

<br><br> 
<big>'''Collimator working group meeting'''</big>
<br><br> 

== Agenda ==
<br><br>
* Engineering
** KK Intro. [https://hallaweb.jlab.org/wiki/images/f/f2/Collimintromoller.pdf slides]
** Jason's summary
** Supports
** Water cooling
** Remote adjustments
* Physics
** power deposited sims
** sensitivity sims

<br><br>

== Minutes ==

Attending: Juliette, Jason, Ernie, Tyler, Seamus, KK, Jim

* Account extended at MIT, waiting for funds from JLAB
* KK's intro
** Slide 4 - downstream of target beampipe needs to be designed
*** definitely metal seals throughout
*** top could maybe be rubber
** Slide 5 - Collimator concept
*** collimator 3 catches lowest angle
*** power divided between 1 and 3
*** 5 does not exist, but other numbers are accurate
*** last green is new 5
** Slide 6 - estimated power still old numbers 
*** new numbers are pretty close
*** beampipe shown as designed in slide 14
** Slide 7 - E158 Concept (won't work exactly)
*** micrometer controls to change orientation of collimator (x, y)
*** we have to support along radial direction in shadow of collimators
*** 1 and 3 have to be precisely placed
**** 1, 2 and 3, 4 could be single units but collimator 3 has slipped further upstream 
**** 2, 4 need to be placed to within 1mm for the acceptance definition 
**** 1, 3 have to be more stringent b/c of the difference in the power deposited (0.5 mm)
**** design for more power than estimated and also precision placement
** Slides 8-14 2-bounce system  
*** Need to block line of sight to detectors
*** slide 4 - encircle beampipe close to target
*** beam pipe to shield photons from edge of 1 and 2 
*** 13 - shows how to block line of sight
*** 14 - realistic geometry
** 15-18 - zoomed "beampipe shields" in hybrid and upstream regions
** 15 bottom 3 mm of W works
** 16, 17 - "beampipe shield" in upstream
** 18 - "beampipe shield" in hybrid
** high Z but non-magnetic (iron free) exact permeability? (Rembar)
* Moving forward
** Questions:
*** How to support all and align (1, 3 in particular) 
*** Materials (W, Cu) cooling vs. shielding vs. weight 
*** water cooling leads that don't interfere with envelope
*** 2, 4 need 40 radiation lengths along z (20, 25 absolute minimum)
*** inner and outer radii for 1, 3 fixed by CAD (length along z, Moliere radius)
** Engineers will provide some feedback
** Physicists will run by CAD and check physics
* Next meeting will be Thursday, April 23rd at 2pm ET



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