3 June 2009 J. H. Cobb1

ANALYSIS SUMMARY CM24

Agenda for Analysis parallel session at CM24

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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)

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16:30 - 17:30 All Field mapping - Discussion

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

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

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.)

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?

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

3 June 2009 J. H. Cobb7

THE END