Transcript ISOLDE highlights

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
08/05/01
CERN Muon week,
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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
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CERN Muon week,
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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.
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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.
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Heat load comparison
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Radioactivity laboratory and
support facility similar to.
EURISOL
RIA
ESS, SNS
Nuclear waste transmutation
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Thermal expansion waves
in ISOLDE targets
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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
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Thermal expansion wave and
cavitation
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Simulations
Surface evolution due to the interaction with proton pulses
(R. Samulyak)
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Why a Mercury-Jet
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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)
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CERN Muon week,
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Hg-jet system
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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
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08/05/01
CERN Muon week,
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•
BNL CERN Trough test
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
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Results (preliminary)
– 6 to 75 m/s splashes measured (under
atm. pressure)
– Scales with the number of protons in
the bunch
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Questions
– Response to a multi-bunch pulse
(CERN scenario)
– Response to a bunch length reduced to
3-5 ns
– Response to other dE/dx
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BNL E-951 trough test8 kHz camera
1st P-bunch
1.81012 ppb
150 ns
Timing : 0.0, 0.5, 1.6, 3.4 ms, shutter 25 msVsplash ~20-40 m/s
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08/05/01
CERN Muon week,
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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
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Vsplash ~7512m/s
BNL Hg-jet chamber
• P-bunch:
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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
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CERN Muon week,
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Jet test at BNL E-951 #4
25th April 2001
P-bunch:
Hg- jet :
Helge Ravn
08/05/01
3.81012 ppb
100 ns
to = ~ 0.45 ms
diameter ~ 1cm
jet-velocity ~ 3 m/s
prep. velocity ~ 10 m/s
CERN Muon week,
Pictures
timing
[ms]
0.000
0.250
0.500
0.175
0.425
0.975
3.000
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Jet test at BNL E-951 #11
25th April 2001
P-bunch:
Hg- jet :
Helge Ravn
08/05/01
2.71012 ppb
150 ns
to = ~ 0.45 ms
diameter ~ 1cm
jet-velocity ~ 3 m/s
prep. velocity ~ 5 m/s
CERN Muon week,
Pictures
timing
[ms]
0.00
0.75
4.50
13.00
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Magnet field injection test 13T
Helge Ravn
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CERN Muon week,
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13T Magnet field map
375
8
275
175
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75
-2 5
-2
-1 2 5
-2 2 5
c o nto ur d e l'a im a nt
-7
B c a lc ule
-3 2 5
B d o nne p a r le L C M I
g ra d ie nt d B /d z [T/d m ]
-4 2 5
-5 4 0
-1 2
-4 1 5
-2 9 0
-1 6 5
-4 0
85
210
335
460
585
d is t a n c e [ m m ]
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champ magn [Te sla]
Measurements in 20 T field
planned for Sept. 01
B vs z
distance [mm]
Grenoble high magnetic field
laboratory:
vertical Solenoid Bmax=13 T
observed maximum gradient
dB/dz=49.5 T/m
pulsed mercury jet, d=4mm,
v=4-15 m/s
Simulations
Surface evolution due to the interaction with magnetic field
(R. Samulyak)
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CERN Muon week,
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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
Helge Ravn
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CERN Muon week,
with field:
49.5 T/m, v = 4 m/s
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CERN Trough test
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 ?
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CERN Muon week,
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CERN/ISOLDE In-Beam Experiment
- at ISOLDE Target Area
frontend
p beam
Hg container
camera
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1
1 CERN Muon week,
mirror
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Nufact
2.4 ms proton pulse h=5
1
140 bunches
bunch length
p-energy
Pulse duration
Pulse intensity
1.151012 ppB
5 ns
2.2 GeV
3.2 ms
1.61014 ppp
0
h=2
“velocities-pressure”
benchmarks for simulation
PSB-ISOLDE
4 bunches
bunch length
p-energy
Pulse duration
Pulse
intensity
Helge
Ravn
08/05/01
8.01012
protons [a.u.]
1
0
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ppB
200 ns
1,1.4 GeV
0
3.2 ms
13 ppp
0
3.210CERN
Muon week,
tS
tS
0.6
1.2
Time [ms]
h=1
1.8
2.422
Radiation safety of trough test
Nu-fact Trough experiment at ISOLDE
q 1.60E-19
protons_per_mC 6.25E+12
Goal : 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
Z
Proton beam
Energy
13 g/cm2
80
1 and 1.4 GeV
Lead / Hg trough
2 x 3 pulses each at pulse intensities
average ppp:
number of pulses
tot N protons
microC
5.0E+12
8.0E+12
1.2E+13
1.5E+13
2.0E+13
2.5E+13
3.0E+13
1.6E+13
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6.9E+14
110
Expected contact dose rate (1 month cooling)
ISOLDE Lead target
thickness
Z
Proton beam
tot N protons
microC
R-waste or Dose rate :
17
5797
98105
0.0003 mS/h
220 g/cm2
82
4.00E+18
640000
Contact dose rate 1 day after irradiation
Contact dose rate after 1 month cooling
Comparative RIB production (see next worksheets)
Helge Ravn
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Target thickness :
Integrated p-beam :
Ratio
CERN Muon week,
30 mS/h
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Magnetic Horn
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Units
H40-400
i
U0
Type
mm
40-400
Waist radius
mm
40
Peak current in horn
kA
300
R
i
i/m
Tc = 20 ms
Lp
Total capacitance
U0
for 1 switching section µF
1453
Duty cycle
50
Hz
Pulse duration
IM
L
C
C
m
Ls
L
U0 / m
R
T/2
Figure 1: basic circuit
(half period)
µs
93
Charging voltage
V
6283
Voltage on horn
V
4200
r.m.s. current in horn
kA
14.5
P Mean power dissipation
H
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
Helgeadded
Ravn
08/05/01
CERN Muon week,
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Water-cooled granular
• P. Sievers/CERN target
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
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CERN Muon week,
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Continuation of R&D
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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
08/05/01
CERN Muon week,
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