Alain Blondel

1
MICE Constraints on the solenoids

• 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

• 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)
• gt STUDY to be made!

• 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

4. WHICH CONFIGURATIONS? Personal thoughts..for
discussion
2
10 cooling of 200 MeV muons requires 20 MV of
RF single particle measurements gt measurement
precision can be as good as D ( e out/e in )
10-3
SC Solenoids Spectrometer, focus pair,
compensation coil
Liquid H2 absorbers or LiH ?
201 MHz RF cavities
T.O.F. I II Pion /muon ID precise timing
Tracking devices He filled TPC-GEM (similar to
TSLA RD) and/or sci-fi Measurement of momentum,
angles and position
T.O.F. III Precise timing
This is FINAL MICE !!
Electron ID Eliminate muons that decay
3
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
4
Step II the first solenoid arrives, the tracker
arrives a few weeks later.
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!)



needed solenoid and all services magnetic
measurement system tracking devices
5
Step III TWO spectrometers
At this step we -- Turn on and map the second
solenoid -- Debug Spectrometer 2 -- Measure
ein, eout and the ratio -- Field reversal is
important for E B effects



-
-
and
THIS IS A VERY IMPORTANT STEP THESE RESULTS
WILL BE PART OF THE FINAL ONES (Systematics on
ein/ eout )
-- can insert a number of materials to
measure e.g. dE/dx vs scattering angle
correlation
6
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


7
Step IV TWO spectrometers and the LH2 absorber
At this step we -- Turn on and map the flip
pair -- Match the system -- Measure ein, eout
and the ratio -- for full AND empty
absorber. -- for AND - configuration
-

or


8
Step V first cooling cell
At this step we -- Turn on and map the flip
pair -- Match the system -- Measure ein, eout
and the ratio -- for full AND empty
absorber. -- for AND - configuration


with flips
or

without flips

9
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.
10
Step VI low beta study


with flips
this has to be completely re-matched. and
re-mapped! Quite an operation
11
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!
12
Step VII The full two-cell MICE ibid.
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)
13
Preliminary conclusions for discussion

• It will be necessary to have enough knobs
• to vary the magnetic configuration to
  adapt to the various avatars of MICE
• 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)