March 30, 2004 TJR 1

MICE Upstream Particle Identification

Tom Roberts

Illinois Institute of Technology

March 30, 2004

March 30, 2004 TJR 2

JAN04 MICE Beamline

(3-D view approximately a plan view)

TOF0 TOF1

(MAR04 differs only by changes in magnet positions, primarily ~30% increase between TOF0 and TOF1)

ISISBeam

UpstreamCherenkov(proposed)

Tracker1

March 30, 2004 TJR 3

Why These positions?

• TOF0– Must be after B2– Behind Q4 to reduce singles– As far forward as possible to maximize TOF1-TOF0 distance

• TOF1– Must be after TOF0– As far back as possible to maximize TOF1-TOF0 distance– As far back as possible to let more pi+ decay– Ahead of Q9 for magnetic shielding from Tracker1 solenoid– As far back as possible to minimize singles and pileup

• Cherenkov1– Must be after TOF0– As far back as possible to let more pi+ decay– Needs smaller magnetic field than TOF0/TOF1– Needs more space than TOF0/TOF1– As far back as possible to minimize singles and pileup

March 30, 2004 TJR 4

Can we really intersperse the TOFs and Quads?

• Simulations show that the maximum excursion in the quads corresponds to less Δt than the TOF resolution

• Back of the Envelope:

TOF1-TOF0 distance 9 m

Maximum quad aperture (“diameter”) 0.472 m

Sqrt(92+0.4722) 9.012 m

Typical TOF1-TOF0 time 25 ns

Δt from path length change 34 ps

It seems quite reasonable to intersperse the TOFs and Quads.Besides, we don’t really have space in the hall to do otherwise.

March 30, 2004 TJR 5

JAN04 Beamline TOF1-TOF0 Performance

Includes:• TOF resolution of 50 ps• Momentum measured in Tracker1, with resolution 2-25 MeV/c

depending on P┴

• JAN04 beamline (MAR04 has 30% longer distance)• Events generated to fill the Q4 aperture, with pi/mu=1 (really ~0.02 at TOF1,

~0.002 for good-μ+)

(Red dots are bigger than blue dots)

March 30, 2004 TJR 6

π+ Beam-Related Singles Rates

Normalization Program

Counter LAHET Geant4 MARS

TOF0 5802 7161 8001

TOF1 780 963 1076

Tracker1 474 585 653

Tracker2 312 385 431

TOF2 305 377 421

Good Mu+ (No LH2, No RF) 304 375 419

Rate is kHz during the 1 ms per second of good Target & RF

Other backgrounds are not included.

March 30, 2004 TJR 7

A Note About These Singles Rates

• In Abingdon we decided we need 600 good-mu+/second• JAN04 does not achieve that rate with the target assumptions used• To achieve 600 good-mu+/sec we will need to insert the target

deeper into the ISIS beam (assuming losses permit that)• That will increase all singles rates proportionally• That implies 12-15 MHz at TOF0 is not unlikely

• Note that the JAN04A tune had a factor of 6x more good-mu+/sec than JAN04, with only a few percent increase in TOF0 singles – it did this by keeping more muons in the cooling channel, not by getting more into TOF0

• Note also that these rates are for JAN04 – we need to simulate MAR04 and obtain corresponding rates

March 30, 2004 TJR 8

Quad Apertures in Muon Channel