3 June 2009J. H. Cobb 1 ANALYSIS SUMMARY CM24 Agenda for Analysis parallel session at CM24...
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Transcript of 3 June 2009J. H. Cobb 1 ANALYSIS SUMMARY CM24 Agenda for Analysis parallel session at CM24...
![Page 1: 3 June 2009J. H. Cobb 1 ANALYSIS SUMMARY CM24 Agenda for Analysis parallel session at CM24 -------------------------------------------- Sunday 31 May 14:00.](https://reader033.fdocuments.us/reader033/viewer/2022051216/5697c01f1a28abf838cd1e04/html5/thumbnails/1.jpg)
3 June 2009 J. H. Cobb1
ANALYSIS SUMMARY CM24
Agenda for Analysis parallel session at CM24
--------------------------------------------
Sunday 31 May 14:00 - 17:30
14:00 - 14:20 R. Tsenov (pp Y. Karadzhov) TOF Calibration
14:20 - 14:40 M. Rayner Emittance Measurements with TOFs
14:40 - 15:00 D. Forrest Statistical Errors
15:00 - 15:20 D. Adey Beam Weighting
16:00 - 16:10 J. Cobb Effect of Absorber displacement
16:10 - 16:30 C. Rogers Eigen emittances (tbd)
=============================================================
16:30 - 17:30 All Field mapping - Discussion
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3 June 2009 J. H. Cobb2
TOF CALIBRATION: R. Tsenov pp Y.K.
Also reported by M. Bonesini in plenary session & a VC
• 51 & 62 pS resolution achieved
• (but not for all pixels due to lack of illumination)
• e//TOF spectrum not yet fully understood
• dE/dX in materials, path length
• Beam simulation recently provided by Marco Apollonio
• TBC
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3 June 2009 J. H. Cobb3
BEAM EMITTANCE: M. Rayner
December 400 MeV/c pion data
TOF position measurements + calculated Xfer matrix for Q789
Optical parameters and emittance of beam between TOFs
Comparison with G4BL simulations of M. Apollonio started -- tbc
Important as:
1. Check of beamline codes
2. Measure emittance of muons upstream of TOF1 in STEP I
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3 June 2009 J. H. Cobb4
STATISTICAL ERRORS: D. Forrest
Question: “Given that up- and downstream measurements on the same set of muons are correlated, what is statistical error on change in emittance?”
Truly heroic effort of many many G4MICE simulations on GRID
Answer: About 10 times fewer muons required than if samples are uncorrelated
This is good news! (But must be pencil & paper route to the answer.)
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3 June 2009 J. H. Cobb5
EVENT WEIGHTING: D. Adey
Developing algorithm using Voronoi cells to weight input beam to desired distribution in (6D) phase space
Weight = Integral of target distribution over cell area
Demonstrated in 2D
Some technical difficulties (memory limitations)
Will be tried on MC data (but also needs beam simulation??)
A statistical question – Which is statistically better, weighted or accepted/rejected events?
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3 June 2009 J. H. Cobb6
FIELD MAPPING: Discussion
Question: “Given the time & expense, is it necessary to map the Coupling (and Focus) coils? Especially as they are unscreened and susceptible to local iron &c. If so how well?”
Lively(ish) discussion
• Shield walls are important. They shift the reference axis but don’t [seem to] change emittance
• Not clear that fine grid detailed mapping of coils is useful ex situ
• Is a large scale, coarse grid, map of field in Hall required? How?
• How else can we know fields are as calculated in situ ? TBC
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3 June 2009 J. H. Cobb7
THE END