The MERIT experiment at the CERN PS Leo Jenner MOPC087 WEPP169 WEPP170.

The MERIT experiment at The MERIT experiment at the CERN PSthe CERN PS

Leo JennerLeo Jenner

MOPC087

WEPP169

WEPP170

Wed 30th JunWed 30th Jun 22

OverviewOverview

MERcuryMERcury IIntense ntense TTarget Experiment arget Experiment Purpose of ExperimentPurpose of Experiment Experimental location and set-upExperimental location and set-up DataData

– Particle generation / detectionParticle generation / detection– Target stabilityTarget stability

Summary & AchievementsSummary & Achievements


A A proof-of-principle test of a target stationproof-of-principle test of a target station suitable for a suitable for a Neutrino Factory or Muon Collider source using a 24-GeV proton Neutrino Factory or Muon Collider source using a 24-GeV proton beam incident on a target consisting of a beam incident on a target consisting of a free mercury jetfree mercury jet that that

is inside a is inside a 15-T capture solenoid magnet15-T capture solenoid magnet..

Proposal submitted to CERN – May 2004 Proposal submitted to CERN – May 2004

Experiment approved as Experiment approved as nTOF11nTOF11

Participating InstitutesParticipating Institutes BNL, MIT, ORNL, Princeton University CERN, RAL


1.1. Study MHD effects Study MHD effects on Hg-jet with on Hg-jet with normal target size normal target size and velocityand velocity

2.2. Study jet disruption Study jet disruption by varying the PS by varying the PS spill structurespill structureMERIT: 180 J/g

(+25°C)– 28TP@24GeV 28TP@24GeV

protonsprotons– 1cm diam. Hg-jet1cm diam. Hg-jet– 1.21.21.2 mm1.2 mm22 beam beam

size rmssize rms


TargetTarget 1-cm diameter 1-cm diameter Hg jet, Hg jet, jet velocity jet velocity 20m/s 20m/s Hg jet/proton beam configuration:Hg jet/proton beam configuration:

– Hg-jet ↔ solenoid axis = 33 mradHg-jet ↔ solenoid axis = 33 mrad– proton beam ↔ Hg-jet axis = 67 mradproton beam ↔ Hg-jet axis = 67 mrad– beam ↔ Hg-jet interaction length = ~30cm (2.1 beam ↔ Hg-jet interaction length = ~30cm (2.1 II))

Proton beamProton beam 24 (14) GeV/c extracted from PS24 (14) GeV/c extracted from PS

– Max. intensity Max. intensity 3 3 10 101313 protons/pulse (30TP) protons/pulse (30TP)– Beam spot rBeam spot r 1.2 mm rms 1.2 mm rms – Variable pulse length 0.134 Variable pulse length 0.134 700 700 secsec– ~100~100 high-intensity pulses high-intensity pulses – 3 3 10 101515 protons on target in total (radiation limit) protons on target in total (radiation limit)


Target chamberSolenoid

Hg container

Hg-jet hydraulic system

Proton Beam

Viewports:

Left – 30cm – 15cm – magnetic centre – 15 cm - Right


TT2/TT2A: MERIT

PS ring

Solenoid

Beam Dump


IR is enclosed in solenoid to capture pions

15 T, liquid N2 cooled, copper

Interaction length optimised to reduce re-interaction

Cooling Stresses: 50MPa / 200MPa


Simulation

Position

HadronsNeutrons


Simulation: MARS

Particle Detection:

pCVD

PIN Diode

ACEM


80 μsec/frame


Disruption Length increases rapidly in no field

Disrupted material moves faster with no field


0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32

0.000

0.025

0.050

0.075

0.100

0.125

0.150

0.175

0.200

0.225

0.250

0.275

0.300

B=0TB=5TB=10TB=15T

Dis

rup

tio

n le

ng

th, m

Beam intensity, TP

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32

0.000

0.025

0.050

0.075

0.100

0.125

0.150

0.175

0.200

0.225

0.250

0.275

0.300

B=0TB=5TB=10TB=15T

Dis

rup

tio

n le

ng

th, m

Beam intensity, TP

Disruption length @ 24 GeV is Disruption length @ 24 GeV is about 20cm for 10-15T fieldabout 20cm for 10-15T field

For a 20m/s jet, 28cm (For a 20m/s jet, 28cm (II) can be ) can be renewed in 14ms renewed in 14ms – rep rate of 70 Hz possiblerep rate of 70 Hz possible– equivalent to equivalent to 8 MW 8 MW of beam powerof beam power– neutrino factory baseline = 1 MW neutrino factory baseline = 1 MW

14 GeV

24 GeV


SummarySummary

The break up of the Hg jet is influenced by the magnetic field. The break up of the Hg jet is influenced by the magnetic field. – The splash velocity increases as the beam intensity The splash velocity increases as the beam intensity

increases, however, magnetic field reduces the effectincreases, however, magnetic field reduces the effect– The Hg jet disruption length is suppressed by magnetic The Hg jet disruption length is suppressed by magnetic

field. field.

The 24 GeV proton beam tends to result in a longer disruption The 24 GeV proton beam tends to result in a longer disruption length than the 14 GeV proton beam. length than the 14 GeV proton beam.

The magnetic field stabilizes the Hg jet flow. The magnetic field stabilizes the Hg jet flow. – The fluctuations on the jet surface decreases as the The fluctuations on the jet surface decreases as the

magnetic field increases.magnetic field increases.

The field tends to keep the jet size constant as it moves The field tends to keep the jet size constant as it moves downstreamdownstream

The longitudinal Hg jet velocity was not affected by the The longitudinal Hg jet velocity was not affected by the magnetic field.magnetic field.


The MERIT experiment took beam as scheduled for three weeks in The MERIT experiment took beam as scheduled for three weeks in autumn 2007 at CERN PSautumn 2007 at CERN PS

All systems performed well, the run with beam was very smooth All systems performed well, the run with beam was very smooth and the whole scientific program was completed and the whole scientific program was completed

The experiment was dismantled in winter 2007 with its The experiment was dismantled in winter 2007 with its components put in temporary storage for cool-down at CERN components put in temporary storage for cool-down at CERN waiting to be shipped back to USwaiting to be shipped back to US

The primary objective to conduct a successful and safe The primary objective to conduct a successful and safe experiment at CERN was amply fulfilledexperiment at CERN was amply fulfilled

Important results validating the liquid metal target concept are Important results validating the liquid metal target concept are already available, more to come as the analysis progressesalready available, more to come as the analysis progresses

The MERIT experiment represents a big step forward in the The MERIT experiment represents a big step forward in the targetry R&D for high power targets. targetry R&D for high power targets.


Neutrino Beams from Muon Storage Rings: Characteristics and Physics Potential, S. Geer, Fermilab-PUB-97/389

The MERIT High Intensity Liquid Mercury Target Experiment at the CERN PS, I.Efthymiopoulos et al, MOPC087, EPAC 08

The MERIT High-power Target Experiment at the CERN PS, H.G. Kirk et al, WEPP169, EPAC 08

A 15-T Pulsed Solenoid for a High-power Target Experiment, H.G. Kirk et al, WEPP170, EPAC 08

http://proj-hiptarget.web.cern.ch/proj-hiptarget/doc/ACEM_slides.ppt

Thesis: Development of a Beam Condition Monitor System for the Experimental Areas of the LHC Using CVD Diamond, Juan Luis Fernández-HernandoJuan Luis Fernández-Hernando

Chapter 9 - Simulation of the worst accident scenario with a test beam

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The MERIT experiment at the CERN PS Leo Jenner MOPC087 WEPP169 WEPP170.

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