Yoshinari Kondo

Performance of the TOPAZ Thin Superconducting Solenoid Wound with Internal Winding Method

A large thin wall superconducting solenoid magnet was constructed as a major component of the high energy particle detector TOPAZ for the TRISTAN e+e- collider at KEK. A newly developed internal winding method was an essential technique to fabricate a large coil as thin as possible. The magnet has been successfully tested with iron return yoke. It has been cooled down to 4.5 K and excited up to the rated current of 3650 A with a magnetic field of 1.21 T. Results of the tests and preliminary analyses are reported.

Fabrication and mechanical performance of the ATLAS central solenoid

Fabrication of the central solenoid for ATLAS detector in the CERN-LHC project was completed, and the performance test has been successfully carried out in Japan. The solenoid has arrived at CERN to be assembled with the LAr calorimeter. This paper describes the fabrication and mechanical, performance of the ATLAS central solenoid.

Ultimate Performance of the ATLAS Superconducting Solenoid

A 2 tesla, 7730 ampere, 39 MJ, 45 mm thin superconducting solenoid with a 2.3 meters warm bore and 5.3 meters length, is installed in the center of the ATLAS detector and successfully commissioned. The solenoid shares its cryostat with one of the detectors calorimeters and provides the magnetic field required for the inner detectors to accurately track collision products from the LHC at CERN. After several years of a stepwise construction and test program, the solenoid integration 100 meters underground in the ATLAS cavern is completed. Following the on-surface acceptance test, the solenoid is now operated with its final cryogenic, powering and control system. A re-validation of all essential operating parameters is completed. The performance and test results of underground operation are reported and compared to those previously measured.

Quench protection and safety of the ATLAS central solenoid

Fabrication of the ATLAS central solenoid was completed and the performance test has been carried out. The solenoid was successfully charged up to 8.4 kA, which is 10% higher than the normal operational current of 7.6 kA. Two methods for quench protection, pure aluminum strips accelerating quench propagation and quench protection heaters distributing normal zones, are applied in order to safely dissipate the stored energy. In this paper, quench characteristics and protection methods of the ATLAS central solenoid are described.

ATLAS superconducting solenoid on-surface test

The ATLAS detector is presently under construction as one of the five LHC experiment set-ups. It relies on a sophisticated magnet system for the momentum measurement of charged particle tracks. The superconducting solenoid is at the center of the detector, the magnet system part nearest to the proton-proton collision point. It is designed for a 2 Tesla strong axial magnetic field at the collision point, while its thin-walled construction of 0.66 radiation lengths avoids degradation of energy measurements in the outer calorimeters. The solenoid and calorimeter have been integrated in their common cryostat, cooled down and tested on-surface. We review the on-surface set-up and report the performance test results.

On-surface integration and test of the ATLAS central solenoid and its proximity cryogenics

The ATLAS detector for the LHC at CERN requires a superconducting solenoid, which provides the magnetic field for the inner detector. The ATLAS central solenoid and its associated proximity cryogenics system has been designed by KEK in collaboration with CERN. Following construction and preliminary tests at Toshiba in Japan the equipment has been shipped to CERN. The system is being prepared for the integration in the common cryostat with the LAr calorimeter, whereafter a full on-surface test has to be completed before its final installation 100 m underground in the ATLAS cavern. For this purpose a provisional set-up for commissioning of the final proximity cryogenics, the connecting chimney and the solenoid has been established. A number of tests and simulations have been conducted in applying a new process control system to validate the cryogenics functionalities, the electrical powering scheme as well as the magnet control and safety systems. The present status of the solenoid project and the results of the various cryogenic and electrical tests are reported.

The chimney and superconducting bus lines for the ATLAS central solenoid

A thin superconducting solenoid magnet for the ATLAS detector in the CERN-LHC project is under construction as a cooperative work between KEK and CERN. A control dewar at the top of the detector is connected with a coil through a long chimney placed in the gap of the outer detectors and toroidal magnets. A set of superconducting bus lines and cooling tubes is arranged in the chimney. The fabrication of the chimney and the control dewar has been completed and the performance test was carried out. The current leads in the control dewar and the superconducting bus lines in the chimney were successfully tested with a current of 10 kA including 2 kA contingency. Quench characteristics of the bus was measured and also analyzed. A superconducting quench detector worked well to pick up quenches.

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.

Quench Characteristics and Operational Stability of the TOPAZ Thin Superconducting Solenoid

A large thin wall superconducting solenoid magnet adopting a newly developed internal winding method has been constructed for the high energy particle detector TOPAZ at the TRISTAN e+e- collider. Various measurements were carried out on stability of such a thin solenoid in forced quench, sudden switch-off and forced mass flow during excitations. The results of these measurements are presented and evaluated.

Design and Construction of the QC2 Superconducting Magnets in the SuperKEKB IR

The first stage commissioning of SuperKEKB is going on without the final focus system from Feb. 2016. The final focus system, which consists of 55 superconducting magnets, is still in the construction stage. The 8 main superconducting quadrupole magnets are designed to consist of quadrupole doublets as QC1 and QC2 for each beam line. All of the quadrupole magnets were constructed. In this paper, the design and the construction of the quadrupole magnets, QC2, are presented. INTRODUCTION SuperKEKB with a target luminosity of 8×10, which is 40 times higher than KEKB [1], is now being operated without the final focus system from February 2016 as the Phase-1 commissioning [2]. The accelerator design is based on the Nano Beam Scheme [3] with a large horizontal crossing angle of 83 mrad between the electron (e-) and positron (e+) beams and the beam sizes of about 50 nm at the interaction point (IP), where the beam energies of eand e+ are 7 GeV and 4 GeV, respectively. The final focus system [4] was designed with 55 superconducting magnets of 8 main quadrupoles, 4 compensation solenoids and 43 correctors [5]. Final beam focusing is obtained with quadrupole doublets of the main quadrupoles, QC1 and QC2, for each beam. For the e+ beam line, QC2LP and QC2RP were constructed for the left and right hand side to IP, respectively, and for the ebeam line, QC2LE and QC2RE were constructed. These superconducting magnets are assembled into two cryostats, and they are installed inside of the particle detector, Belle II [6]. Therefore, the final focusing system is operated under the magnetic field of 1.5 T by the Belle solenoid. For reducing the influence of this solenoid field on the beam collision, the compensation solenoids, which generate the solenoid fields of the opposite field direction, are installed into the cryostats. QC2LP and QC2RP are assembled inside of the compensation solenoid bores. QC2LE and QC2RE are assembled out of the solenoids. The QC1 magnets were already reported in the reference [7]. In this paper, the design and the construction of the QC2 magnets are reported.