Transcript B ERKELEY L AB S.P. Virostek, M.A. Green, D. Li and M.S.

B ERKELEY L AB
S.P. Virostek, M.A. Green,
D. Li and M.S. Zisman
Lawrence Berkeley National Lab
Berkeley, CA 94720, USA
PROGRESS ON THE FABRICATION AND TESTING OF
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THE MICE SPECTROMETER SOLENOIDS
Abstract: The Muon Ionization Cooling Experiment (MICE) is an international collaboration that will demonstrate ionization cooling in a section of a realistic cooling channel
using a muon beam at Rutherford Appleton Laboratory (RAL) in the UK. At each end of the cooling channel a spectrometer solenoid magnet consisting of five superconducting
coils will provide a 4 tesla uniform field region. The scintillating fiber tracker within the magnet bore tubes will measure the emittance of the muon beam as it enters and exits
the cooling channel. The 400 mm diameter warm bore, 3 meter long magnets incorporate a cold mass consisting of two coil sections wound on a single aluminum mandrel: a
three-coil spectrometer magnet and a two-coil section that matches the solenoid uniform field into the MICE cooling channel. The fabrication of the first of two spectrometer
solenoids has been completed, and preliminary testing of the magnet is nearly complete. The key design features of the spectrometer solenoid magnets are presented along with
a summary of the progress on the training and testing of the first magnet.
INTRODUCTION
MICE consists of two spectrometer solenoid systems (the
subject of this poster) and the MICE cooling channel which is
made up of three absorber & focus-coil modules (AFC modules)
and two RF & coupling-coil modules (RFCC modules). Muon
ionization cooling occurs in liquid hydrogen absorbers located
within the AFC modules. The muons are reaccelerated by four
RF cavities contained in each of the two RFCC modules. The
spectrometer solenoid modules couple the muon beam to the
adjacent AFC modules and are used to measure the incoming
and outgoing emittance of the muons. The tracker detectors
within the solenoid bores are five planes of scintillating fibers
that measure the position of the particles within the magnet bore.
Leak check of the magnet cold mass assembly
• Final vacuum leak check of the spectrometer solenoid cold mass
assembly prior to installation into the magnet vacuum vessel
• Cold mass cooled indirectly with cryocoolers (LHe recondenser)
• Cooler condensers located in sleeves welded to top of cryostat
Magnet vacuum vessel w/radiation
shield and cold mass in place
Initial cool down of the completed spectrometer solenoid
• Radiation shield is direct cooled by a separate LN reservoir
MAGNET TRAINING & TESTING
The tracker solenoid magnet consists of five superconducting
coils wound on a common mandrel. All five of the coils are
designed for a nominal current of 275 amps. During training
of the magnet, all five coils are run in series using a single
power supply. During training of the first magnet, all coils
reached a current of 196 amps. However, a problem with the
cold mass cooling circuit prevented the training from
proceeding further. A series of design improvements were
incorporated during assembly of the second magnet. The
training of the second magnet is currently under way…
Additional text TBD
Magnet cold mass and cryostat showing position of
leads, cryocoolers helium pipes and supports
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Magnet leads (left) and the three cryocoolers on the
top of the spectrometer solenoid service tower
This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC02-05CH11231.
Spectrometer solenoid cold mass coil ass’y
Paper ID 3192