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The MERIT experiment at the CERN PS. MOPC087 WEPP169 WEPP170. Leo Jenner. Overview. MERcury I ntense T arget Experiment Purpose of Experiment Experimental location and set-up Data Particle generation / detection Target stability Summary & Achievements.
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The MERIT experiment at the CERN PS MOPC087 WEPP169 WEPP170 Leo Jenner
Overview • MERcuryIntense Target Experiment • Purpose of Experiment • Experimental location and set-up • Data • Particle generation / detection • Target stability • Summary & Achievements
A proof-of-principle test of a target station suitable for a Neutrino Factory or Muon Collider source using a 24-GeV proton beam incident on a target consisting of a free mercury jet that is inside a 15-T capture solenoid magnet. Proposal submitted to CERN – May 2004 Experiment approved as nTOF11 Participating Institutes • BNL, MIT, ORNL, Princeton University • CERN, RAL
Study MHD effects on Hg-jet with normal target size and velocity • Study jet disruption by varying the PS spill structure MERIT: 180 J/g (+25°C) • 28TP@24GeV protons • 1cm diam. Hg-jet • 1.21.2 mm2 beam size rms
Target • 1-cm diameter Hg jet, jet velocity 20m/s • Hg jet/proton beam configuration: • Hg-jet ↔ solenoid axis = 33 mrad • proton beam ↔ Hg-jet axis = 67 mrad • beam ↔ Hg-jet interaction length = ~30cm (2.1 lI) Proton beam • 24 (14) GeV/c extracted from PS • Max. intensity 3 1013 protons/pulse (30TP) • Beam spot r 1.2 mm rms • Variable pulse length 0.134 700 msec • ~100 high-intensity pulses • 3 1015 protons on target in total (radiation limit)
Solenoid Target chamber Hg-jet hydraulic system Hg container 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 Hadrons Neutrons
Simulation: MARS Particle Detection: pCVD PIN Diode ACEM
Disruption Length increases rapidly in no field Disrupted material moves faster with no field
14 GeV 24 GeV • Disruption length @ 24 GeV is about 20cm for 10-15T field • For a 20m/s jet, 28cm (2lI) can be renewed in 14ms • rep rate of 70 Hz possible • equivalent to 8 MW of beam power • neutrino factory baseline = 1 MW
Summary • The break up of the Hg jet is influenced by the magnetic field. • The splash velocity increases as the beam intensity increases, however, magnetic field reduces the effect • The Hg jet disruption length is suppressed by magnetic field. • The 24 GeV proton beam tends to result in a longer disruption length than the 14 GeV proton beam. • The magnetic field stabilizes the Hg jet flow. • The fluctuations on the jet surface decreases as the magnetic field increases. • The field tends to keep the jet size constant as it moves downstream • The longitudinal Hg jet velocity was not affected by the magnetic field.
The MERIT experiment took beam as scheduled for three weeks in autumn 2007 at CERN PS • All systems performed well, the run with beam was very smooth and the whole scientific program was completed • The experiment was dismantled in winter 2007 with its components put in temporary storage for cool-down at CERN waiting to be shipped back to US • The primary objective to conduct a successful and safe experiment at CERN was amply fulfilled • Important results validating the liquid metal target concept are already available, more to come as the analysis progresses • The MERIT experiment represents a big step forward in the targetry R&D for high power targets.
References: • 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-Hernando • Chapter 9 - Simulation of the worst accident scenario with a test beam