Hiroshi Yamaoka

Conceptual design of a thin superconducting solenoid for particle astrophysics

A description is given of the conceptual design of a proposed superconducting magnet system for particle astrophysics in space, using a thin solenoid configuration. The system, called Astromag, provides large acceptance and uniform magnetic field for analyzing cosmic-ray charged particles. Also discussed is the development of a prototype thin solenoid, expected to be used in balloon-borne experiments for high-energy particle astrophysics. >

A thin superconducting solenoid magnet for particle astrophysics

An extremely thin superconducting solenoid magnet is being developed to investigate cosmic-ray antiparticles in the Universe. The uniform solenoidal field is provided in a particle detector system to analyze the particle momentum. The solenoid coil is wound with advanced aluminum stabilized superconductor recently developed by using micro-alloying with Ni, followed by cold-work mechanical hardening. It is designed with a central magnetic field of 1.2 T in a volume of 0.9 m in diameter and 1.4 m in length. The radiation thickness of the coil is to be 0.056 X/sub 0/ with a physical coil thickness of 3.4 mm. This paper describes the conceptual design and progress of basic development work.

Progress of LHC low-/spl beta/ quadrupole magnets at KEK

Development of the LHC low-/spl beta/ insertion quadrupole magnet has been in progress at KEK since 1995 as a cooperative program between CERN and KEK. Five 1-m short model magnets have been fabricated and three of them have been tested. From the various test results of the first two models, the coil configuration was further optimized to reduce the higher magnetic field harmonic coefficients. The cold test of the third model showed satisfactory performances of the field harmonics. After this R&D work, the authors are at a stage for the fabrication of two prototype magnets which have the same scale as the production magnets. The status of the R&D for the LHC low-beta insertion quadrupole magnet at KEK is described.

Analysis of mechanical tolerances of a low-/spl beta/ quadrupole magnet for the LHC

The development of high-gradient superconducting quadrupole magnets for the LHC interaction regions has been carried out. The mechanical design has been optimized with the two-shell coil structure tightly fixed by thin non-magnetic collars and by iron-yoke with keys. The mechanical rigidity is fully achieved at room temperature. The paper describes the mechanical design characteristics and analysis of mechanical tolerances and the influence on the field quality.

Development of an ASTROMAG test coil with aluminum stabilized superconductor

An ASTROMAG test coil with aluminum stabilized superconductor is being developed. The pure aluminum stabilizer will improve stability of the superconducting coil within the limited weight. A test coil that is approximately full size compared to the ASTROMAG main coil was designed. A description is given of the design study and progress in test coil development.

Development of a Superconducting Solenoid Magnet System for the B-Factory Detector (BELLE)

A large superconducting solenoid magnet has been designed and fabricated for the BELLE particle detector, which will be installed in the KEKB colliding beam ring. It provides a central magnetic field of 1.5 T at 4000 A in a cylindrical volume of 3.4 m in diameter and 4.1m in length. The stored energy is calculated to be 42 MJ. The coil is wound with aluminum stabilized superconductor, after which aluminum strips are laminated on the coil for quench protection. The coil cold mass is approximately 7 tons with an estimated thermal load of 22 W at 4.2 K. A refrigerator of 240 W at 4.2 K is attached. The coil is indirectly cooled by forced flow of 2 phase helium through a cooling tube on the coil support cylinder. This method is preferred in order to avoia explosive boiling which may happen if a pool cooling method was used. A line in the solenoid is designed to allow the stored helium in the top buffer tank to circulate gravitationally in case of a suspension of cryogen, producing slow discharge without induced quench. This report presents the design and fabrication of the BELLE superconducting solenoid magnet.

Conceptual design of the ATLAS thin superconducting solenoid magnet

A thin superconducting solenoid has been designed to be installed into one of the major colliding particle detecting facilities, ATLAS, for LHC (Large Hadron Collider) project at CERN. The thin solenoidal coil wound with stiffened aluminum stabilized superconductor is indirectly cooled by forced two-phase helium through one serpentine tube on the outer support cylinder. The coil is installed into a common vacuum vessel with another co-axial cryogenic component, LAr-Cal, to save the wall material to trajectories for particles. Triangle-shape supporting elements on both ends of the coil are newly introduced to reduce a radial thickness of the cryostat.

A thin superconducting solenoid magnet for the WASA detector

A thin superconducting solenoid magnet has been developed for the WASA detector. The magnet consists of a pair of coils and it provides a central magnetic field of 1.3 T at 900 A in a cylindrical volume of 0.65 m in diameter and 0.555 m in length. The features of this solenoid magnet are the excellent transparency for particles, conducting cooling, thermo siphon method, applying aluminum strip for conduction cooling and corrugated outer wall. Recently, the performance test was successfully carried out. In this report, magnet design and fabrication of the WASA superconducting solenoid magnet will be presented and the test results will be described.

Mechanical characteristics of a coil support system for the ATLAS central superconducting solenoid magnet

Mechanical characteristics of the support system for the ATLAS (A Toroidal LHC Apparatus) central superconducting solenoid magnet have been investigated. The coil support system was designed with a unique triangular-shape configuration made of GFRP and with spherical bearings at the joints. A mechanical performance test has been carried out to simulate various operational conditions. This paper describes the mechanical design and test results.

Performance of a superconducting solenoid magnet for BELLE detector in KEKB B-factory

A large superconducting solenoid magnet with an inner warm bore of 3.4 m in diameter and 4.1 m in length has been developed for the BELLE particle detector, which is installed in the KEKB colliding beam ring. The solenoid was installed into the BELLE iron structure. The solenoid was cooled down by using a computer-controlled cooling system and was successfully energized up to a design field of 1.5 T with no training quenches.