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

2. 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

3. 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 GeV.
Repetition rate 50 Hz
Pulse duration ms.
Pulse intensity /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

4. 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

5. 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

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

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

8. 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

9. 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

10. 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)
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

11. 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

12. 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

13. 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

14. 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

15. 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

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

17. 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

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

19. 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

20. 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

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

22. 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

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

24. 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
PH Mean power dissipation
in horn by current * kW
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

25. 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

26. Continuation of R&D Test the Hg-jet in a 20 T magnetic field
Systematic trough tests in the ISOLDE 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