Particle Production in the MICE Beamline

IPAC10

Linda Coney, UC Riverside, Adam Dobbs, Imperial College London, Yordan Karadzhov, Sofia University

The Beam Line

Fig 1. The components of the MICE beam line from the target to the KLOE Light detector

Target

Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9DK sol D2D1

TOF1TOF0GVA1 BPM1

BPM2 TOF2

CKOV-A

CKOV-B

KL

The Muon Ionization Cooling Experiment (MICE) is being built at the Rutherford Appleton Laboratory (RAL) to test ionization cooling of a muon beam. Successful demonstration of cooling is a necessary step along the path toward creating future high intensity muon beams in either a Neutrino Factory or Muon Collider. Production of particles in the MICE beamline begins with a titanium target dipping into the ISIS proton beam. The resulting pions are captured, momentum-selected, and fed into a 5T superconducting decay solenoid which contains the pions and their decay muons. Another dipole then selects the final particles for propagation through the rest of the MICE beamline.

In this poster, the commissioning of the improved MICE beamline and target will be discussed, including the use of Time-of-Flight detectors to understand the content of the MICE beam between 100 and 444 MeV/c.

Introduction

Fig. 2 A schematic of the MICE beamline, up to the start of the cooling channel

Fig. 3 A schematic of the planned MICE cooling channel

The Decay Solenoid

The Target

Detectors

The current MICE target has been in service since September 2009, after replacing the original MICE target. During this time it has performed exceptionally well, being used to run MICE as a stand-alone experiment during ISIS machine physics periods and also parasitically during standard user runs. Methods have been developed to regularly monitor the stability of the target such as monitoring the maximum depth to which the target dips, illustrated below. Target operation studies have also been done to improve beamline performance.

The decay solenoid (DS) is an important part of the MICE beamline designed to capture pions coming from the target and their decay muons. The magnet was fully functional during the MICE data-taking periods in the second half of 2009, though it then suffered difficulties with its cooler which are presently being resolved. The presence of the DS, completing the MICE beamline upstream of the cooling channel, has been shown to significantly increase the particle rate in the beam, and has enabled the start of beam optics optimization and measurements. Fig. 4 A section of the

Decay Solenoid

Fig. 5 The target housing in ISIS and the first MICE quadrupole triplet

0.48 m

10 x 4cm scintillator barsx = 1.15 cmt = 50 ps

TOF00.48 m

7 x 6cm scintillator barsx = 1.73 cmt = 50 ps

TOF1

Fig. 8 Schematics of time-of-flight stations 0 and 1

Fig. 9 Spectra showing TOF station resolution

Fig. 10 A TOF station

Time-Of-Flight

Cherenkovs

Results

Fig. 12 The aerogel Cherenkov detectors

Fig. 13 Sample electron data from the Cherenkovs

e-

--

300 MeV/c e- beame-

--

300 MeV/c e- beam

-

e-

400 MeV/c - 225 MeV/c -

-

e-

400 MeV/c - 225 MeV/c -

e-

-

-

Beam: 337 MeV/c - 250 MeV/c -

e-

-

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Beam: 337 MeV/c - 250 MeV/c -

Fig. 14 Time-of-flight distribution for 300 MeV/c electron beam

Fig. 15 Time-of-flight distribution for 400 MeV/c pion to 225 MeV/c muon beam

Fig. 16 Time-of-flight distribution for 337 MeV/c pion to 250 MeV/c muon beam

The time-of-flight system in MICE consists of three individual detectors (TOF0, TOF1, and TOF2) located along the beamline. The first, TOF0, is just downstream of the second quadrupole triplet, the second (TOF1) is located just after the third quadrupole triplet, and the last (TOF2) will sit downstream of the cooling channel.

After recent calibration runs, TOF0 and TOF1 were found to have timing resolutions of 52 ps and 58 ps respectively.

Particle ID from TOFs

Fig. 17 Data from TOF0 illustrating the effect on the beam of variations in the DS field from the computed nominal

TOF0 y TOF0 xTOF0 2D

Beam Profile

DS field raised 10%

DS field at nominal

DS field lowered 10%

Beam Profile from TOFs

Fig. 18 The upper MICE beamline, including quadrupoles 1-3 and dipole 1 in the synchrotron vault

Analysis continues to fully understand the MICE beam, and the TOF system is proving to be an excellent tool for this process. Not only is it used to identify muons in the beamline, it also provides beam profile information for comparison with simulations, in addition to the dedicated beam profile monitors. The Cherenkovs continue to undergo commissioning, moving toward providing another valuable method of PID for the beamline. Since first beam in the spring of 2008, the MICE Muon Beamline has advanced significantly, and is on course to provide the muon beam needed to allow MICE to demonstrate ionisation cooling.

Fig. 6 Histograms showing the maximum depth of the target dip for a stable target (a) and a failing target (b)

a

b

Fig. 7 Target DAQ display showing ISIS beam intensity (orange), MICE target position (green), and beam loss (purple) during a timing study.

Fig. 11 TOF beam profiles for positive (left plot) and negative particles (right plot). Proton excess motivated switch to negative beamline.{{

TOF1 TOF0 TOF0TOF1

x

x

yy

xy

xy

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