Abstracts Brochure - CERN

MOPCH189
MOPCH190
MOPCH191
26-Jun-06 16:00 - 18:00 MOPCH — Poster Session
Calculating the Muon Cooling within a MICE Liquid Absorber
The key elements of the Muon Ionization
M.A. Green (LBNL) S.Q. Yang (OXFORDphysics)
Cooling Experiment (MICE) cooling channel
are the absorbers that are a part of the MICE
absorber focus coil modules (AFC modules). The boundaries of room temperature solid absorbers are well defined.
The density of most solid absorber materials is also well understood. The properties of solid absorber are most
certainly understood to 0.3 percent. The MICE liquid absorbers are different in that their dimensions are a function
of the absorber temperature and the fluid pressure within the absorber. The second element in the liquid absorber is
the variability of the liquid density with temperature and pressure. While one can determine the absorber boundary
within 0.3 percent, the determination of the liquid density within 0.3 percent is more difficult (particularly with liquid
helium in the absorber). This report presents a method of calculating absorber boundary and the cooling performance
of the MICE absorbers as a function of fluid temperature and pressure.
Cryomodule Development for Superconducting RF Test Facility (STF) at KEK
K. Tsuchiya, H. Hisamatsu, M. Masuzawa, H. Matsumoto, S.
Noguchi, N. Ohuchi, T. Okamura, K. Saito, A. Terashima (KEK)
104
Current status of the cryomodule development
for superconducting RF test facility,
STF, at KEK is presented. The objective of
the STF construction is to have an experience
of 5-m long cryomodule fabrications and to learn an operational method of superconducting RF cavities. The STF
consists of two 5-m long cryomodules, each housing four 9-cell cavities (one for 35 MV/m and the other for 45 MV/
m). In addition to the cavity type, each cavity has variations in its appendices. Thus, two cryomodules must have
different structures for the cavity support and for the port of the RF input coupler. This paper describes the details
of the cryomodule design, the development of the bimetallic joint for connecting the titanium helium vessel to the
stainless steel cooling pipe, and the studies of the magnetic shielding for high quality cavities.
Copper Heat Exchanger for the External Auxiliary Bus-bars Routing Line in the LHC Insertion
Regions
The corrector magnets and the main
C. Garion, A. Poncet (CERN) M. Sitko, B. Skoczen (CUT)
quadrupoles of the LHC dispersion suppressors
are powered by a special superconducting
line (called auxiliary bus-bars line N), external to the cold mass and housed in a 50 mm diameter stainless
steel tube fixed to the cold mass. As the line is periodically connected to the cold mass, the same gaseous and liquid
helium is used for cooling the magnets and the line. The final sub-cooling process (from 4.5 K down to 1.9 K) consists
of the phase transformation from liquid to superfluid helium. It is slightly delayed with respect to the magnets. To
accelerate the process, a special heat exchanger has been designed. Located in the middle of the dispersion suppressor
portion of the line it consists in creating a local sink of heat extraction, providing two additional lambda fronts that
propagate in opposite directions towards the line extremities. Both the numerical model and the sub-cooling analysis
are presented in the paper for different configurations of the line. Design, manufacturing and integration aspects of
the heat exchanger are described. Finally, the results of the qualification tests and the expected performance of the
line are given.