MTA Cryostat

1
MTA Cryostat cooling loop design

• Christine Darve
• Fermilab/Beams Division/ Cryogenic Department/
  Engineering and Design Group
• Preparation of the Mucool/MICE review
• 02/11/03

2
MTA cryo-system - Specifications
Remove up to 150 Watt of energy loss from LH2 P
1.2 atm, T 17 K Dr lt 5 DT 1 K (could be 3 K)

• Safety requirements
• Guidelines for the Design, Fabrication,
  Testing, Installation and Operation of LH2
  Targets20 May 1997, Fermilab by Del Allspach et
  al.
• Fermilab ESH (5032),
• code/standard ASME, NASA,
• NEC (art 500)
• CGA

3
MTA cryo-system - Materials

• Caltech LH2 pump
• Max LH2 mass-flow 450 g/s (0.12 MPa, Tin17 K)
• DP total lt 0.36 psig
• References
• A high power liquid hydrogen target for parity
  violation experiments, E.J. Beise et al.,
  Research instruments methods in physics
  research (1996), 383-391
• MuCool LH2 pump test report, C. Darve and B.
  Norris, (09/02)

• Cryo department refrigeration system
• Max He mass-flow 27 g/s (0.2 MPa , Tin14 K)
• DT3 K for 450 W (17 K, 0.12 MPa)
• Reference
• Results of the MuCool Expander Flow Tests
  Performed at the Meson Cryogeni Test Facility,
  A. Martinez and A. Klebaner, (12/02)

4

Part V A look at the Hydrogen
Proposal Cryo-system design- Pressure drop
calculation
RECALL from Internal review (09/24/02)
If m450g/s and 32 nozzle dia. 0.6 then
Maximum allowable DP 0.364 psi Total DP
calculatedgt 0.203 psi
0.011 psi
0.011 psi
0.036 psi
0.027 psi
0.031 psi
0.011 psi
0.078 psi
Will a velocity at the nozzle equal to 2.5 m/s be
enough for ionization cooling?
5
MTA cryo-system Cryoloop Design
mass flow
Velocity at nozzle
Given geometry, Power and nozzle distribution
DP
Heat transfer coeff.
Flow Simulation by Wing Lau/ Stephanie Yang/
Charles Holding (Oxford)
DT

• Oxford studies
• Simulate the current MTA manifold geometry
• Simulate beam at 150 W (volume, ø10mm (3 sigma
  gaussian))
• Calculate heat transfer coefficients and
  temperature distribution for MTA conditions (DV
  0.5 m/s 4 m/s)

6
MTA cryo-system Cryostat Design

• Cryostat assembly
• Vacuum vessel MAWP25 psig SS, IPS 16 Sch10,
  IPS 50 Sch10
• Dome (SS, 10 mm)
• Plate (SS, 10 mm)
• Thermal shield MLI (Al, Mylar)
• Piping (SS, IPS 1, 2)
• Helium buffer(SS,f 3)
• Vacuum window(Al)
• Safety devices (see internal review)

• Heat exchanger assembly
• Coil (copper, f 0.55in)
• Outer shell (SS, IPS6)
• LH2 pump assembly
• LH2 pump and shaft with foam
• Motor outer shield

7

Part V A look at the Hydrogen Proposal To meet
the standard
RECALL from Internal review (09/24/02)

• Pressure relief valve LH2 II C 4 a (iii)
• Relief pressure (10 psig or 25 psid)
• Sized for max. heat flux produced by air
  condensed on the LH2 loop at 1 atm.
• 2 valves ACGO gt 0.502 in2
• ASME code Redundant
• Capacity 52 g/s
• Pressure relief valve Insulation vacuum II D
  3
• MAWP (15 psig internal)
• Capable of limiting the internal pressure in
  vacuum vessel to less than 15 psig following the
  absorber rupture (deposition of 25 liter in the
  vacuum space)
• Vapor evaluation q 20 W/cm2
• Take into account DP connection piping and
  entrance/exit losses
• 3 parallel plates (FNAL design) gt 2
• ASME code Redundant
• Capacity 197 g/s
• Relief system must be flow tested

8

MTA cryo-system Cryostat Design

• Absorber assembly
• Ed Black/Wing Lau windows and manifold design
• Interface of the systems
• Bimetallic junction
• Indium Doubled-seal
• Supporting system
• G10 spider
• Instrumentation
• P Penning, DP
• T Cernox
• Flowmeter, Heater
• Valve (elec, pneum, manual..)
• Turbomolecular pump (N2 guard)

• Minimum spark energies for ignition of H2 in air
  is 0.017 mJ at 1 atm, 300 K
• Lower pressure for ignition is 1 psia (min abs.
  0.02 psia // 1.4 mbar)

9

MTA cryo-system Conclusions

• Cryostat design Focus
• Final cooling system
• Implementation of the vacuum windows
• Heater implementation (Helium side)
• Supporting system
• Instrumentation implementation

• Cooling loop Focus
• Thermo-hydraulic behavior inside LH2 absorber
  for which DT1 K geometry and nozzle, power
  distribution, mass flow gtDP
• Validation of optimization to DT and DP as
  specified

10

MTA cryo-system Questions

• Sealing for vacuum window Teflon Oring, Indium
  sealing, copper gasket (Radiation hardness)
• Cryopumping (turbo-molecular pump, thermal
  shield)
• Distribution of RFs and magnets around cryostat
  interface atmosphere or vacuum behind cryostat
  vacuum window
• Supporting system and absorber position in magnet
• Who design cryostat support in hall?
• Absorber Instrumentation routing and port
• ..

11

Part V A look at the Hydrogen Proposal Process
and Instrumentation Diagram
RECALL from Internal review (09/24/02)
12

Part IV A look at the Windows and Absorber
Vessel LH2 Manifold absorber (by E. Black)
RECALL from Internal review (09/24/02)