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

Wed 30th Jun2 Overview MERcury Intense Target Experiment MERcury Intense Target Experiment Purpose of Experiment Purpose of Experiment Experimental location and set-up Experimental location and set-up Data Data –Particle generation / detection –Target stability Summary & Achievements Summary & Achievements

Wed 30th Jun3 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

Wed 30th Jun4 1. Study MHD effects on Hg-jet with normal target size and velocity 2. Study jet disruption by varying the PS spill structure MERIT: 180 J/g (+25°C) protons –1cm diam. Hg-jet –1.2  1.2 mm 2 beam size rms

Wed 30th Jun5 Target 1-cm diameter Hg jet, jet velocity  20m/s 1-cm diameter Hg jet, jet velocity  20m/s Hg jet/proton beam configuration: 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 I ) Proton beam 24 (14) GeV/c extracted from PS 24 (14) GeV/c extracted from PS –Max. intensity 3  protons/pulse (30TP) –Beam spot r  1.2 mm rms –Variable pulse length  700  sec –~100 high-intensity pulses –3  protons on target in total (radiation limit)

Wed 30th Jun6 Target chamberSolenoid Hg container Hg-jet hydraulic system Proton Beam Viewports: Left – 30cm – 15cm – magnetic centre – 15 cm - Right

Wed 30th Jun7 TT2/TT2A: MERIT PS ring Solenoid Beam Dump

Wed 30th Jun8 IR is enclosed in solenoid to capture pions 15 T, liquid N 2 cooled, copper Interaction length optimised to reduce re-interaction Cooling Stresses: 50MPa / 200MPa

Wed 30th Jun9 Simulation Position HadronsNeutrons

Wed 30th Jun10 Simulation: MARS Particle Detection: pCVD PIN Diode ACEM

Wed 30th Jun11 80 μsec/frame

Wed 30th Jun12 Disruption Length increases rapidly in no field Disrupted material moves faster with no field

Wed 30th Jun13 Disruption 24 GeV is about 20cm for 10-15T field Disruption 24 GeV is about 20cm for 10-15T field For a 20m/s jet, 28cm (  I ) can be renewed in 14ms For a 20m/s jet, 28cm (  I ) can be renewed in 14ms –rep rate of 70 Hz possible –equivalent to 8 MW of beam power –neutrino factory baseline = 1 MW 14 GeV 24 GeV

Wed 30th Jun14 Summary 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 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 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 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 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 longitudinal Hg jet velocity was not affected by the magnetic field.

Wed 30th Jun15 The MERIT experiment took beam as scheduled for three weeks in autumn 2007 at CERN PS 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 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 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 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 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. The MERIT experiment represents a big step forward in the targetry R&D for high power targets.

Wed 30th Jun16 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 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 References: