LH2%20Absorber%20Heat%20Load%20and%20Homeostasis

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LH2 Absorber Heat Load and Homeostasis
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What has happened before

• Huge LH2 volumes, low heat deposition Bubble
  chambers
• Small LH2 volumes, low heat deposition FNAL E866
• here density fluctuations are an issue
• Medium volumes, large heat deposition Sample,
  Slac E158

Our challenge
Large heat deposition and beam path is through
entire volume of absorber! 1. Liquid must move
everywhere 2. Need gauge of temperature and
density uniformity
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Sample and E158 Targets

• E158 target 60 liters
  Sample target 25 liters
• Beam size 2mm defines small turbulence scale,
  and is small part of total volume
• Calibration was total s measurement

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Muon Ionization Cooling
q2
x
x
Multiple scattering
P2
q2
P1
q1
q1
P1
q1
accelerator
accelerator
z
z
absorber
absorber
RF cavity
RF cavity
With transverse focussing (solenoid)




Heating term (Mult.Scatt.)
Cooling term

• Need to minimize heating!

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Convection absorber design
Convection is driven by heater and particle
beam.Heat exchange via helium tubes near absorber
wall. Flow is intrinsically transverse.
Internal heat exchange
Output from 2-dim Computational Fluid Dynamics
(CFD) calcs. (K. Cassel, IIT). Lines indicate
greatest flow near beam center.
Qualitatively demonstrated but parameters need to
be measured. Prototyping of this design is being
done by Shigeru Ishimoto et al at KEK.
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Forced-Flow Absorber Design
External Heat Exchange
Mucool 100W (E. Black, IIT) Large and
variable beam width gt large scale
turbulence Establish transverse turbulent flow
with nozzles

• For 8W/cm heat deposition, need to cycle 0.05
  volumes/sec LH2 (e.g. 240W/30cm).
• Nozzle design complicated - needs prototyping
  and testing.

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So far
Three dimensional LH2 flow simulations (W. Lau)
Schlieren testing of convection flow (water)
test at ANL

1. Nozzle arrangement
2. Heat application
3. Cryo tests

Testing 3-dimensional simulations with water
flow test at NIU
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Flow Tests Proposed
Three test modes (E.Black)

• Absorber manifold , two plastic windows
• Absorber filled with water at room temp. the
  pattern of flow will be photographed by
  circulating water from inlet to outlet using a
  luminous die injected at inlet. Hard to get real
  window volume flow picture this way.

• Absorber manifold, one plastic windows, one
  aluminum window
• Absorber subjected to a heat source. Infrared
  pictures taken (for forced-flow and convection
  absorber type). Distortion from heat distribution
  in window.

• Absorber manifold , two thin Al windows,
  cryogenic
• Absorber integrated into a cryo system,
  operating in test mode with extreme temperature
  and pressure variations considered for safety.
• Yet to have a definitive determination of
  adequate probe placement.

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Infrared flow test setup
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Now, the questions

• What computations are helpful?
• Are flow/convection predictions linear?
• What tests will be useful, and how quantitative
  can they be?
• What level of instrumentation will convince us of
  sufficient temperature uniformity?
• 5. How will convection and force-flow models be
  evaluated?

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At this meeting

• Lets decide what activity to pursue that
• Makes sense for the LINAC Cryo program next year
• Contributes substantively to the MICE tech.
  review meeting in Oct.