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Helge Ravn CERN Muon week, 08/05/01
1
Target and Pion Collection System and Support Facility
CERN Target and Horn working group
Http://cern.ch/Helge.Ravn/files/Muon week Talk
CERN 10 May 2001
Helge Ravn CERN Muon week, 08/05/01
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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
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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 s.
• 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
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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
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Thermal expansion waves in ISOLDE targets
• Splashes threshold (Pb, Sn and La targets 1993):
– 11013 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
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Thermal expansion wave and cavitation
Helge Ravn CERN Muon week, 08/05/01
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Simulations
(R. Samulyak)
Surface evolution due to the interaction with proton pulses
Helge Ravn CERN Muon week, 08/05/01
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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
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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
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BNL CERN Trough test• Perpendicular velocities of Hg-”drops” via high speed cameras
(8000 frame/s, 25s aperture and up to 1000 kframe/s, 0.15s aperture)
– 0.5-4.01012 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
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Timing : 0.0, 0.5, 1.6, 3.4 ms, shutter 25 s
11stst P-bunch1.81012 ppb
150 ns
BNL E-951 trough test8 kHz camera
Vsplash ~20-40 m/s
Helge Ravn CERN Muon week, 08/05/01
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BNL E-951 trough test1MHz camera
Timing [ms]0.0, 0.2, 0.40.6, 0.8, 1.0
shutter 150 ns
P-bunch4.01012 ppb
150 nsVsplash ~75 m/s
Helge Ravn CERN Muon week, 08/05/01
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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/sprep. velocity ~ 10 m/s
Helge Ravn CERN Muon week, 08/05/01
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Jet test at BNL E-951 #4 25th April 2001
P-bunch: 3.81012 ppb100 nsto = ~ 0.45 ms
Hg- jet : diameter ~ 1cm jet-velocity ~ 3 m/sprep. velocity ~ 10 m/s
Picturestiming[ms]0.0000.2500.5000.1750.4250.9753.000
Helge Ravn CERN Muon week, 08/05/01
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Jet test at BNL E-951 #1125th April 2001
P-bunch: 2.71012 ppb150 nsto = ~ 0.45 ms
Hg- jet : diameter ~ 1cm jet-velocity ~ 3 m/sprep. velocity ~ 5 m/s
Picturestiming[ms]0.000.754.50
13.00
Helge Ravn CERN Muon week, 08/05/01
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Magnet field injection test 13T
Helge Ravn CERN Muon week, 08/05/01
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13T Magnet field mapGrenoble high magnetic field laboratory:vertical Solenoid Bmax=13 Tobserved maximum gradient dB/dz=49.5 T/mpulsed mercury jet, d=4mm, v=4-15 m/sMeasurements in 20 T field planned for Sept. 01
Helge Ravn CERN Muon week, 08/05/01
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Simulations
(R. Samulyak)
Surface evolution due to the interaction with magnetic field
Helge Ravn CERN Muon week, 08/05/01
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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
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CERN Trough test1/5 of the Neutrino factory beam power-densities can be obtained in the 1.4
GeV BOOSTER/ISOLDE p-beam
PSB-ISOLDE3.21013 protons per pulse, 20,8,4 bunches (h=5,2,1 )Pulse length 2.4 s (-20 s staggered extraction)Proton energy 1 GeV
Trough test at CERNHg tight sealing ~ 40 pulses. Response to bunch up to 81013 ppB.Response to beam size and beam energy.Disposal of Hg via amalgams ?
Helge Ravn CERN Muon week, 08/05/01
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CERN/ISOLDE In-Beam Experiment
2965
11 68
1208
- at ISOLDE Target Area
p beam
frontend
Hg container
mirror
camera
Helge Ravn CERN Muon week, 08/05/01
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0
1
0 0.6 1 .2 1 .8 2 .4
2.4 s proton pulse h=5
0
1
0 0.6 1.2 1.8 2.4
h=1
Time [s]
tS tS
0
1
0 0.6 1 .2 1 .8 2 .4
protons [a.u.]
h=2
NufactNufact
140 bunches 1.151012 ppBbunch length 5 nsp-energy 2.2 GeVPulse duration 3.2 sPulse intensity 1.61014 ppp
PSB-ISOLDEPSB-ISOLDE
4 bunches 8.01012 ppBbunch length 200 nsp-energy 1,1.4 GeVPulse duration 3.2 sPulse intensity 3.21013 ppp
“velocities-pressure” benchmarks for simulation
Helge Ravn CERN Muon week, 08/05/01
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Nu-fact Trough experiment at ISOLDE q 1.60E-19
protons_per_ C 6.25E+12Goal : Irradiation of 1.3 cm3 Hg (16g) contained in a ssteel box with quarz windows by PSB proton pulses.The ssteel box himself is contained in a vacuum tight box.
Radioactive waste production of the Hg trough vs. an ISOLDE Pb target 1 to 100000
Nu-fact Hg Target thickness 13 g/cm2Z 80
Proton beam Energy 1 and 1.4 GeV
Lead / Hg trough Ratio2 x 3 pulses each at pulse intensities 5.0E+12
8.0E+12 Target thickness : 171.2E+13 Integrated p-beam : 57971.5E+132.0E+13 R-waste or Dose rate : 981052.5E+133.0E+13
average ppp: 1.6E+13number of pulses 42tot N protons 6.9E+14microC 110
Expected contact dose rate (1 month cooling) 0.0003 mS/h
ISOLDE Lead target thickness 220 g/cm2Z 82Proton beam tot N protons 4.00E+18microC 640000
Contact dose rate 1 day after irradiationContact dose rate after 1 month cooling 30 mS/hComparative RIB production (see next worksheets)
Radiation safety of trough test
Helge Ravn CERN Muon week, 08/05/01
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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
L
R
C
CU0L
i
i / m
m
U0 / m
= 20 ms
Figure 1: basic circuit
i
R
Lp Ls
Tc
T/2
IM
U0
Helge Ravn CERN Muon week, 08/05/01
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Water-cooled granular target• P. Sievers/CERN
Ta-Spheres, = 16.8 g/cmR = 1mmPacking density ~60% (~140 spheres/cm3)R = 10g/cm3
Small spheres good for cooling: surface/volume~1.RWater cooling:v = 6m/s through 20% of cross-sectionV = 11l/sT =18K (20% of 4MW, S. Gilardoni)T =36KP =4-5 BarRe ~ 104
Helge Ravn CERN Muon week, 08/05/01
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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.
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