MICE: Constraints on the solenoids
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Transcript of MICE: Constraints on the solenoids
Alain Blondel
MICE: Constraints on the solenoids
2. Field Homogeneity: 10-2 or 10-3 ?this will be dictated by the detector requirements. TPG will be more demanding (uses the field actively as guide for drift)=> STUDY to be made!
1. Dimensions: we decided in Chicago in February that
the useful spectrometer field region should be 100 cm long and 30 cm diameter. the inner bore should be 40 cm
4. WHICH CONFIGURATIONS?Personal thoughts……..for discussion:
3. Matching: MICE should be magnetically transparent. This requires a matched magnetic system for a certain number of configurations availability of the corresponding KNOBS Movable elements
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T.O.F. IIIT.O.F. IIIPrecise timingPrecise timing
Electron IDElectron IDEliminate muons that decay Eliminate muons that decay
Tracking devices: Tracking devices: He filled TPC-GEM (similar to TSLA R&D)He filled TPC-GEM (similar to TSLA R&D)and/or sci-fiand/or sci-fiMeasurement of momentum, angles and positionMeasurement of momentum, angles and position
T.O.F. I & IIT.O.F. I & IIPion /muon Pion /muon IDIDprecise precise timingtiming
10% cooling of 200 MeV muons requires ~ 20 MV of RF single particle measurements =>
measurement precision can be as good as out/ in ) = 10-3
201 MHz RF cavities
Liquid H2 absorbersor LiH ?
SC Solenoids;Spectrometer, focus pair, compensation coil
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STEP I: we get the muon beam
In this first phase we define the beam tunings, composition, settings for both mu+ and mu- as a function of momentum.
needed: beam (!)
TOF, trigger
some DAQ two SCI FI arrays or beam chambers
PID
10 m
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In this step we 1. turn on and map the first solenoid 2. study the acceptance
and the required thickness of the diffusers 3. debug the Tracker 4. verify the matching of TPG with Sci-fi or beam chamber 5. debug track identification devices 6. (MEASURE BEAM EMITTANCE IN SOLENOID!)
Step II: the first solenoid arrives, the tracker arrives a few weeks later.
needed:solenoid and all servicesmagnetic measurement systemtracking devices
+ -and
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Step III: TWO spectrometers
At this step we:-- Turn on and map the second solenoid -- Debug Spectrometer # 2-- Measure inout and the ratio-- Field reversal is important for E ^ B effects
THIS IS A VERY IMPORTANT STEP : THESE RESULTS WILL BE PART OF THE FINAL ONES
(Systematics on inout )
+ +
and --
do we need + - ?
-- can insert a number of materials to measure e.g.
dE/dx vs scattering angle correlation
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Step III- B: TWO spectrometers
-- can insert a number of materials to measure e.g. dE/dx vs scattering angle correlation
At this point we might want to bring in an absorber and measure its properties in this simpler configuration
++
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Step IV: TWO spectrometers and the LH2 absorber
At this step we:-- Turn on and map the flip pair-- Match the system-- Measure inout and the ratio -- for full AND empty absorber. -- for ++ AND +- configuration
-+
or
+ +
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Step V: first cooling cell
At this step we:-- Turn on and map the flip pair-- Match the system-- Measure inout and the ratio -- for full AND empty absorber. -- for ++ AND +- configuration
+
or
+
+ +
with flips
without flips
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Step VI: low beta study
See; Palmer – Fernow Note – or talk at the October 2001 Workshop at CERN. Limit is: current X 2 in flip coils and zero in coupling coil.
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Step VI: low beta study
+ + with flips
this has to be completely re-matched…. and re-mapped! Quite an operation…
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Other momenta?
MICE could certainly map the acceptance as a function of beam momentum for a given magnetic setting. Off-nominal-momentum performance may be sub-optimal (?). Should we try MICE matched for lower/higher momentum as well? more/less cooling!
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Step VII The full two-cell MICEibid. sensitivity will be better since volts will be higher.
can try various settings of polarities and absorbers (full / empty)and of absorber thicknesses (to match available RF or beam momentum)
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Preliminary conclusions
for discussion
1. It will be necessary to have enough knobs to vary the magnetic configuration to adapt to the various avatars of MICE
2. The various components of the magnetic channel will have to move along the experiment
3. There will be a lot of magnetic measurements to do!
(I must have been a mice (sorry, mouse) in one of my previous lives)