5 May 2009 MICE Analysis - MR 1

The December Shifts:Beam Characterization by the Time of Flight System

Mark Rayner

5 May 2009 MICE Analysis - MR 2

ALL: calibrate

SURVIVORS: characterize

the beam

5 May 2009 MICE Analysis - MR 3

Characterization of the December beam

trace space

momentum spectrum

of the beam

emittancealphabeta

gamma

fit

quantities interesting to beam line people

time of flight

transverse position at TOF0 and TOF1

TOFs measure

momentum

track

calibrated

Problem: Small number of particles means only the central pixels have been calibrated well, but the position measurement is essential to the emittance measurementWe must attempt to calibrate all pixels of TOF0 and TOF1Basic method from Harbin CM (no time-walk, ignores trigger intricacies): today’s dataTime-walk + simplified cable length correction: in development, problems remain

PID

5 May 2009 MICE Analysis - MR 4

TDC cabling of TOF0 and TOF1

Except TOF0 outer slabs

(0 and 9 in both planes)

TDC board 32

0

1N S

0 21

B

T

Beam

PMT number 0

TDC board 0 PMT number 1

TDC board 1

Plane 0 Plane 1

Can compare S and B

andN and T

without worrying about the trigger

5 May 2009 MICE Analysis - MR 5

Simplified Cable Length Calibration

sums over:(TDC S slab i)

– (TDC B slab j) – linear correction nS0

nS6

0

0

nB0

nB6

0

0

nij

nijT

-1

vector ofcable length

corrections

=

Depends only on number of hits per

pixel

Depends only on number of hits per

PMT

Write down everything we know per TDC boardForm a matrix equationMinimize chi-squareOne number per PMTA best-guess calibration for every PMT with a hit

ProblemToo many zero entriesDeterminant = 0Refining method

5 May 2009 MICE Analysis - MR 6

Trace Space Reconstruction

Focusing transfer matrix Defocusing transfer matrix

Effective length l [m]

Central quadrupole gradient [T/m]

300

300

150

150MeV/c

Defocusing

Focusing

Effective phase advance [radians]

Central quadrupole gradient [T/m]

150

200

250

300MeV/c

Effective focusing strength k [m-2]

Central quadrupole gradient [T/m]

150

200

250

300MeV/c

5 May 2009 MICE Analysis - MR 7

5 May 2009 MICE Analysis - MR 8

Emittance measurement

• ???

Horiz TOF0

Vert TOF0

Horiz TOF1

Vert TOF1