Target and Pion Collection System and Support Facility CERN Target and Horn working group CERN 10 May 2001 Http://cern.ch/Helge.Ravn/files/Muon week Talk Helge Ravn CERN Muon week, 08/05/01

CERN Target and Horn working group The E951 Collaboration CERN Target and Horn working group A. AUTIN, A. BALL, A. BERNADON, L. BRUNO, A. FABICH, G. GRAWER, S. GILHARDONI, T. KURTYKA, J. LETTRY, J.-M. MAUGAIN, H. RAVN, M. SILARI, P. SIEVERS, N.VASSILOUPOULOS, V. VLACHOUDIS, H. VINCKE and F. VOELKER Helge Ravn CERN Muon week, 08/05/01

CERN reference scenario In order to produce 1021 neutrinos/year proton beams with a power of 1-4 MW needs to interact with a high Z target. Proton energy 2.2 GeV. Repetition rate 50 Hz Pulse duration 3.3 ms. Pulse intensity 1.5 1014/pulse Average beam power 4 MW Target absorbed power 1 MW Liquid Hg-jet target Diam. 10 mm Pion collection by means of a magnetic horn. Helge Ravn CERN Muon week, 08/05/01

Heat load comparison Radioactivity laboratory and support facility similar to. EURISOL RIA ESS, SNS Nuclear waste transmutation Helge Ravn CERN Muon week, 08/05/01

Thermal expansion waves in ISOLDE targets Splashes threshold (Pb, Sn and La targets 1993): 11013 protons per pulse, 20 bunches (h=5) 0.5  1012 protons per bunch (~60ns, 1GeV) ISOLDE target system Helge Ravn CERN Muon week, 08/05/01

Thermal expansion wave and cavitation Helge Ravn CERN Muon week, 08/05/01

Simulations Surface evolution due to the interaction with proton pulses (R. Samulyak) Helge Ravn CERN Muon week, 08/05/01

Why a Mercury-Jet High pion yield (high Z) High source brightness (high density) Flowing liquid have excellent power handling capabilities No water radiolysis Liquid at ambient temperature (no liquid-to-solid phase change issues) Minimal waste stream (compared to solid alternatives) Passive removal of decay heating No dominant long-lived radiotoxic products No confinement tubing (free flowing jet) No beam windows (differential pumping confinement) Helge Ravn CERN Muon week, 08/05/01

Hg-jet system Power absorbed in Hg-jet 1 MW Operating pressure 100 Bar Flow rate 2 t/m Jet speed 30 m/s Jet diameter 10 mm Temperature - Inlet to target 30° C - Exit from target 100° C Total Hg inventory 10 t Pump power 50 kW Helge Ravn CERN Muon week, 08/05/01

BNL CERN Trough test 0.5-4.01012 protons per bunch, Perpendicular velocities of Hg-”drops” via high speed cameras (8000 frame/s, 25ms aperture and up to 1000 kframe/s, 0.15ms aperture) 0.5-4.01012 protons per bunch, Bunch length 100 ns Proton energy 26 GeV Results (preliminary) 6 to 75 m/s splashes measured (under atm. pressure) Scales with the number of protons in the bunch Questions Response to a multi-bunch pulse (CERN scenario) Response to a bunch length reduced to 3-5 ns Response to other dE/dx Helge Ravn CERN Muon week, 08/05/01

BNL E-951 trough test8 kHz camera 1st P-bunch 1.81012 ppb 150 ns Vsplash ~20-40 m/s Timing : 0.0, 0.5, 1.6, 3.4 ms, shutter 25 ms Helge Ravn CERN Muon week, 08/05/01

Vsplash ~75 m/s BNL E-951 trough test 1MHz camera Timing [ms] 0.0, 0.2, 0.4 0.6, 0.8, 1.0 shutter 150 ns P-bunch 4.01012 ppb 150 ns Vsplash ~75 m/s Helge Ravn CERN Muon week, 08/05/01

BNL Hg-jet chamber P-bunch: 26 Gev, spot size: r=1.6x0.8 mm (rms), intensity <4 10^12 protons per bunch bunch length 150 ns Hg- jet : diameter ~ 1cm jet-velocity ~ 3 m/s prep. velocity ~ 10 m/s Helge Ravn CERN Muon week, 08/05/01

Jet test at BNL E-951 #4 25th April 2001 Pictures timing [ms] 0.000 0.250 0.500 0.175 0.425 0.975 3.000 P-bunch: 3.81012 ppb 100 ns to = ~ 0.45 ms Hg- jet : diameter ~ 1cm jet-velocity ~ 3 m/s prep. velocity ~ 10 m/s Helge Ravn CERN Muon week, 08/05/01

Jet test at BNL E-951 #11 25th April 2001 Pictures timing [ms] 0.00 0.75 4.50 13.00 P-bunch: 2.71012 ppb 150 ns to = ~ 0.45 ms Hg- jet : diameter ~ 1cm jet-velocity ~ 3 m/s prep. velocity ~ 5 m/s Helge Ravn CERN Muon week, 08/05/01

Magnet field injection test 13T Helge Ravn CERN Muon week, 08/05/01

13T Magnet field map Grenoble high magnetic field laboratory: Mirrors vertical Solenoid Bmax=13 T observed maximum gradient dB/dz=49.5 T/m pulsed mercury jet, d=4mm, v=4-15 m/s Measurements in 20 T field planned for Sept. 01 Mirrors Helge Ravn CERN Muon week, 08/05/01

Simulations Surface evolution due to the interaction with magnetic field (R. Samulyak) Helge Ravn CERN Muon week, 08/05/01

Comparison without/with magnetic field - pictures taken with 0,1 ms shutter-speed (at 1000 fps) - all frames 48 ms after trigger of valve without field: 0 T, v = 4.6 m/s with field: 49.5 T/m, v = 4 m/s Helge Ravn CERN Muon week, 08/05/01

CERN Trough test PSB-ISOLDE 1/5 of the Neutrino factory beam power-densities can be obtained in the 1.4 GeV BOOSTER/ISOLDE p-beam PSB-ISOLDE 3.21013 protons per pulse, 20,8,4 bunches (h=5,2,1 ) Pulse length 2.4 ms (-20 ms staggered extraction) Proton energy 1 GeV Trough test at CERN Hg tight sealing ~ 40 pulses. Response to bunch up to 81013 ppB. Response to beam size and beam energy. Disposal of Hg via amalgams ? Helge Ravn CERN Muon week, 08/05/01

CERN/ISOLDE In-Beam Experiment - at ISOLDE Target Area frontend p beam camera Hg container mirror Helge Ravn CERN Muon week, 08/05/01

Nufact PSB-ISOLDE 140 bunches 1.151012 ppB bunch length 5 ns p-energy 2.2 GeV Pulse duration 3.2 ms Pulse intensity 1.61014 ppp “velocities-pressure” benchmarks for simulation PSB-ISOLDE 4 bunches 8.01012 ppB bunch length 200 ns p-energy 1,1.4 GeV Pulse duration 3.2 ms Pulse intensity 3.21013 ppp Helge Ravn CERN Muon week, 08/05/01

Radiation safety of trough test Helge Ravn CERN Muon week, 08/05/01

Magnetic Horn Units H40-400 Type mm 40-400 Waist radius mm 40 Peak current in horn kA 300 Total capacitance for 1 switching section µF 1453 Duty cycle Hz 50 Pulse duration (half period) µs 93 Charging voltage V 6283 Voltage on horn V 4200 r.m.s. current in horn kA 14.5 PH Mean power dissipation in horn by current * kW 39. Water flow needed in l/min with  w= 15°C * l/min 3power dissipation due to beam absorption to be added Helge Ravn CERN Muon week, 08/05/01

Water-cooled granular target P. Sievers/CERN Ta-Spheres, r = 16.8 g/cm R = 1mm Packing density ~60% (~140 spheres/cm3) R = 10g/cm3 Small spheres good for cooling: surface/volume~1.R Water cooling: v = 6m/s through 20% of cross-section V = 11l/s DT =18K (20% of 4MW, S. Gilardoni) DT =36K DP =4-5 Bar Re ~ 104 Helge Ravn CERN Muon week, 08/05/01

Continuation of R&D Test the Hg-jet in a 20 T magnetic field Systematic trough tests in the ISOLDE 1- 1.4 GeV proton beam Development of jet hydrodynamic models Improve the speed and hydrodynamic stability of the Hg-jet Building of a prototype horn and test heat transfer coefficient at the inner conductor and if possible the lifetime. Start preliminary engineering study of the integration of the plumbing of the target and the spent beam absorber in the horn. Design and build a continuos flowing Hg-jet set up for in-beam tests. Continue the study of alternative target concepts like radiation cooled solids and the water cooled granular target. Helge Ravn CERN Muon week, 08/05/01