Minutes -- Mucool meeting -- 11 Feb '00
Scribe: Dave Carey
S. Geer
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What are colling needs and how do we meet those
need ? Table of potential cooling channel problems and
corresponding experimental tests discussed last time, and in the
minutes of the meeting last week. Updated table presented this
week. Whre are we with defining the beam tests ? Need to
resolve:
1) Do we need a precise scattering experiment.
2) What parameters is a cooling channel sensitive to
(what do we have to measure and with what precision ?)
Listed current mucool R&D projects. -- What
can be pushed and what can't
1) RF development
2) Absorber development
Push on design studies, plan beam test.
3) Prelim. Engineering design -- Ed Black
plus initial cost estimate.
4) Initial cooling experiment
Must understand what we have to measure --
including scattering and straggling.
Need to know impact of errors on cooling.
Alvin has just produced nice note.
5) Cooling channel beam test
Need cooling design that works --
need to know sensitivities to errors.
Is cooling essential for neutrino factory.
Discussion on the need to determine the precise
absorber dimensions before the test beam is built
and tested.
Greg Penn at LBL
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Simulation activity. Focus on phase rotation in
induction linac. Get .03 muons per proton. Emittance
is pretty close to target emittance. Define target
emittance as hard cut at 3*sigma.
Mary Anne Cummings
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LH2 absorber tests at FNAL. Bob Trendler is setting
up safety review. No hard plan for absorber. Problem
factorizes -- can work on several things simultaneously.
1) Windows and pressure test
2) Absorber assembly
3) Cryo plumbing and refrigeration
4) Pressure and temperature measurements
Presented budget, which was in color and landscaped.
Total cost with magnets $1,382,481
Total cost without magnets 582,481
Absorber assembly includes large window. Showed
picture of absorber. Discussion about cost of
refrigeration.
Ed Black
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Last week active with new FOFO. Put drawings on
web. Showed first stage DFOFO cooling channel lattice.
Flanges on each end of vessel don't fit. Trouble with
disassembly.
Volume of 6 gallons. Assume we we have to move
volume --> 2.5 liters/sec. Need more than one nozzle
to facilitate movement of liquid. Discussion about
heat dissipation.
Showed picture of EFOFO lattice. Gigantic 2.7
meter diameter vacuum chamber.
Chun-Xi Wang
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Cooling formulae. Second moments for cylindrical
symmetric beam. Moments significantly simplified.
Reduces number of variables from ten to four. Derive
moment equations. Parameterize beam moments. Similar
to Twiss parameters. Everything consistent with
well-known parameterization -- e.g. beta*gamma =
1 + alpha**2.
Greg worked with = epsilon_{n}*beta_{perp},
similarity with Twiss parameters. Beta_{perp} is
different with angular momentum. Beta is still for
single particles. Can get equation governing evolution
of envelope.
Derive equations for emittance and angular momentum.
Many ways to solve it. First-order homogenous equation.
Solutions are described. Considers equilibrium emittance
and equilibrium angular momentum. Want to minimize
both.
Shows plots of four curves
1) ICOOL
2) DPGEANT
3) ICOLL without correlation between amplitude and
energy.
4) Analytical formulae (within 10% of simulation)
Showed cases of transverse cooling factor for
different channels using simulations vs. analytical
formulae.
Jim Norem
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Phase II mu-cool experiment: Must make assumptions.
Want to have a high power beam line ASAP. Requirements
for coolings. Showed diagram for high-power facility.
Momentum analyzed beam going into absorber.
Has been using Penn's formalism. Beta functions
between Penn and ICOOL do not agree. Start with
alternating solenoid lattice for p about 120 MeV/c.
Assume rf frequency is 805 MHz. Can get a lot of
numbers with lattice. Described what can we do with
this setup. Listed advantages of lower momentum.