Vladimir Tumakov

1
Production Solenoid Environment
RSVP Simulation Review New York University
January 12 2005

• Vladimir Tumakov
• University of California, Irvine

• Proton beam simulation
• PS and TS coil hitting in beam normal and fail
  conditions
• Validation of energy load simulation

2
The MECO Apparatus
Straw Tracker
Muon Stopping Target
Muon Beam Stop
Superconducting Transport Solenoid
(2.5 T 2.1 T)
Crystal Calorimeter
Superconducting Production Solenoid (5.0
T 2.5 T)
Superconducting Detector Solenoid (2.0 T
1.0 T)
Collimators
Proton Beam
Heat Radiation Shield
Muon Production Target
3
Water Cooled Target

• Simulation and experimental tests for energy load
  heating and cooling
• No simulation or study for target material
  radiation damage
• Needs to be tested in the beam

inlet
outlet
4.5 kW energy load
beam direction

• 0.3 mm water jacket
• 0.5 mm Titanium or stainless steel containment
  shell

4
Beamline Simulation in GEANT3
18 quadrupoles and 1 dipole to make vertical
pitch angle
Beam direction
Beam protons trajectories after the last
dipole effects of solenoid field on spot size
Beam profile on the target sx1.1mm sy0.7mm
Beam direction
5
Event by Event Energy Balance Distributions
Envelope around the target
Envelope around the shield
Beam energy
5 6 7 8
9 Kinetic Energy
GeV
5 6 7 8 9
Kinetic Energy GeV

• For estimation we used 7 MeV binding energy for
  each n, p, D, T, a produced in GEANT simulation
• Energy balance good to 3

6
Energy Removed by Particles Leaving PS Bore

• PS heat shield must be water cooled (16 kW)
• TS heat shield may be water cooled
• Thermal management of SM bores is important

• Load on PS cold mass primarily from neutrons
• Backward energy flow requires some TS shield

7
Production Solenoid Heat Shield

• 50 kW beam incident on gold target (15 kW in the
  shield)
• Superconducting magnet is protected byCu
  (55tons) and W (21tons) heat and radiation shield

• Simulation with Geant3 Gcalor and Mars
• 60 W load on cold mass
• 20 ?W/g instantaneous load
• 20 Mrad integrated dose

2.5T
5T
Cu
W
Superconducting coil
Productiontarget
Heat Shield
8
TS Shield Geometry
8
2
6
2
n,p,p
6
6
4
6
4
?
or Cu
6
All dimensions are in cm
9
Shield optimization

• Average energy deposition in TS coils with
  Tungsten shield is 2.2 W
• For some selected configurations, energy
  deposition is as high as 3 W
• Energy deposition from other sources is 20 W

10
Energy Deposition in PS and TS Coils
9 mW/g
3 mW/g
Azimuthal angle
5 10 15 20 25
TS coil number
2 4 6 8 10
PS coil number
2 4 6 8 10
5 10 15 20 25

• Cylindrical proton beam pipe R4cm
• Azimuthal asymmetry due to targeting angle

11
Transport Solenoid Shield

• Passive protection
• 75 cm Zinc shield outside
• 4 cm Copper shield inside

• Active protection
• Ionization chambers to measure beam losses
• Window frame monitors
• Beam position monitors
• Cryogenic magnets beam abort system

8 cm x 6 cm
18 cm x 14 cm
Simulations of normal and fault beam conditions
show that beam control system response time
should be of order 100ms (expected about 10 ms)
n,p,µ
4 cm Cu
12
TS Outer Shield

• Move beam up 3 cm in X projection
• Muon yield does not decrease
• PS coil radiation load in normal condition does
  not increase

Quadrupole Bore
Rx
Ellipse radius cm
Rx
13
Beam Pipe Optimization

• Look at energy load on TS under fault conditions
  quadrupole failure, last dipole failure
• Compare elliptical tube profile with conical and
  cylindrical tube profiles

Elliptical profile has best performance with
combination of quadrupole and dipole failures
MQ12 field is nominal MQ13 field is zero
14
TS Energy Load vs Beam Deflection in X-Y
Calculate temperature rise in TS coil with 30
mW/g fault load Temperature margin is 1.5 K
gt no problem with quench evenwith 500 ms beam
abort
15
Validation of MC Neutron Production and Transport
Total neutron flux from 20cm Pb target

• MARS and GCALOR agree with data for total neutron
  flux
• Some evidence simulations may underestimate high
  energy neutrons important for PS heating

gt100MeV
gt1MeV
gt20MeV
Neutrons flux from 3.7 GeV protons vs. cos(q)
16
Conclusions

• GEANT3, GEANT4, and MARS simulations all show
  that energy deposition in PS and TS coils should
  not be a problem
• Limited data has been found to validate the
  neutron flux (particularly at high energy), which
  is important for PS coils
• Experimental data from shielding experiments
  would be useful
• We should allow some contingency in design of PS
  magnets ability to handle nuclear heat load