Transcript THE MERIT HIGH-POWER TARGET EXPERIMENT AT THE CERN PS (WEPE078, IPAC10) K.T. McDonald*, Princeton University, Princeton, NJ 08544, USA H.G.

THE MERIT HIGH-POWER TARGET EXPERIMENT
AT THE CERN PS
(WEPE078, IPAC10)
K.T. McDonald*, Princeton University, Princeton, NJ 08544, USA
H.G. Kirk, H. Park, T. Tsang, BNL, Upton, NY 11973, USA
I. Efthymiopoulos, A. Fabich, F. Haug, J. Lettry, M. Palm, H. Pereira, CERN, CH-1211 Genéve 23, Switzerland
N. Mokhov, S. Striganov, FNAL, Batavia, IL, 60510, USA
A.J. Carroll, V.B. Graves, P.T. Spampinato, ORNL, Oak Ridge, TN 37831, USA
P.H. Titus, Princeton Plasma Physics Laboratory, Princeton, NJ 08543, USA
J.R.J. Bennett, O. Caretta, P. Loveridge, RAL, Chilton, OX11 0QX, UK
The MERIT Experiment, which ran at CERN in 2007, is a proof-of-principle test for a target system that converts a
4-MW proton beam into a high-intensity muon beam for either a neutrino factory complex or a muon collider. The
target system is based on a free mercury jet that intercepts an intense proton beam inside a 15-T solenoidal magnet.
SC-2 SC-3 SC-4
SC-1
SC-5
Window
Nozzle
Tube
Mercury
Drain
Mercury
Pool
Proton
Beam
Splash
Mitigator Water-cooled
Mercury
Tungsten Shield
Jet
Iron
Plug Resistive
Magnet
Concept of a continuous mercury jet target for an intense proton
beam. The jet and beam are tilted by 100~mrad and 67~mrad,
respectively, with respect to a 20-T solenoid magnet that conducts
low-momentum pions into a decay channel.
Cutaway view of the MERIT experiment. The solenoid/Hg jet
system is tilted by 100~mrad with respect to the beam/floor. The
15-T magnet is cooled by LN2 and can be pulsed every 30 min. The
Hg jet is 1-cm in diameter and has a velocity of 20 m/s, which
presents a new, 2-interaction-length target to the beam every 20 ms.
B=0T, 24GeV
B=5T, 24GeV
B=10T, 24GeV
B=15T, 24GeV
B=5T, 14GeV
B=5T, 14GeV
B=5T, 14GeV
0.4
During:
A 1-cm diameter, 15-m/s Hg jet at 0, 75, 175, and 375 s after
interaction with 10  1012 24-GeV protons in a 10-T solenoid
field. The velocity of the filamentary dispersal was ~ 40 m/s.
Max. Filament velocity (m/s)
180
140
120
100
80
0.3
0.2
0.1
0.0
After:
0
1
2
3
4
5
6
7
8
3
Total energy deposition (10 J)
Above: The disruption of the jet by the beam is confined to the
beam/jet interaction region, and is damped by high magnetic fields.
B=5T,24GeV
B=10T,24GeV
B=15T,24GeV
B=5T,14GeV
B=10T,14GeV
Fit,B=0T
Fit,B=5T
Fit,B=10T
Fit,B=15T
Fit,B=20T
Fit,B=25T
160
Disruption length (m)
Before:
PUMP: 12 bunches,
12 1012 protons
Probe target in -Probe target out
Pump target in -Pump target out
Ratio =
Probe target out
Pump target out
60
PROBE: 4 bunches,
41012 protons
40
20
0
0
25
50
75
100
125
150
Peak energy deposition (J/g)
Above: Observed filament velocities, together
with a global fit, for various proton beam energies
and magnetic field. High magnetic fields damp
the velocity.
Above : Studies with a second set of proton bunches up to 750 s after the
first show negligible reduction in the production of pions.
The MERIT Experiment, has demonstrated the a free mercury jet target could be used in pulsed protons beams of
power up to 8 MW, taking into account that a strong magnetic field reduces the disruption of the jet by the beam.
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