In the framework of the SARAF (Soreq Applied Research Accelerator Facility) project, CEA is in charge of the design, fabrication and commissioning of a superconducting linac accelerating up to 5 mA beams of either protons from 1.3 to 35 MeV or deuterons from 2.6 to 40 MeV. The superconducting Linac is composed of four 5 meter long and 2.1 meter high cryomodules. The first two cryomodules are composed of six or seven accelerating cavities and six superconducting solenoid packages while the two last cryomodules are composed of seven cavities and four solenoid packages. Each solenoid package is composed of a focusing solenoid with its two shielding coils and two pairs of steering coils to control the beam trajectory. The focusing solenoids have been designed to produce 6.31 T at the center while the steering coils generate horizontal and vertical fields of 0.1 T at the same point. The prototype was manufactured in industry and qualified in 2019 at CEA. Then 20 solenoid packages and 2 spares have been manufactured and all tested at 4.45 K before being assembled in the cryomodules. We report here the status of the series production and test of the solenoid packages. The manufacturing difficulties, the magnetic performances of the magnets and the cryomodules assembly and test will also be presented.
For the HL-LHC project, a 90 mm NbTi cos(2θ) double aperture quadrupole magnet with an operating gradient of 120 T/m at 1.9 K has been designed as an option to replace the 70 mm aperture LHC quadrupole MQY. CEA in collaboration with CERN designed and manufactured a single aperture short model magnet with a magnetic length of 1.215 m at 1.9 K called MQYYM. The MQYYM cold test occurred at CEA at 4.2 K in a vertical cryogenic station. During the power test, the operating gradient at 1.9 K has been reached after two training quenches. All along the test, magnetic and mechanical measurements were done using respectively a rotating probe and strain gauges. This paper describes the performance of the MQYYM at 4.2 K and gives an analysis of the data acquired during the test, including training behavior, quench detection, protection and field quality measurements.
The Iseult project started in 2001 and is a collaborative effort involving CEA and the University of Freiburg in academics, Guerbet, Siemens Healthineers and Bruker Biospin as industrial partners. One central aspect of the project has been the design by CEA of a whole-body magnet of 11.7T field strength with a 90-cm wide bore. After nearly 20 years of research and development, prototyping, integration and tests, first images have been acquired with this unique MRI scanner. Some key validation results are presented here.
The Iseult project is a French-German initiative focused on very high magnetic-field molecular imaging. The project includes a Whole Body 11.7 T MRI magnet installed at Neurospin, a neuroscience research center operating at CEA Saclay since November 2006. After 7 years of fabrication at Belfort by GE Power (Ex Alstom), the Iseult magnet was delivered to CEA in June 2017, its connection with the cryoplant and all the ancillary equipment was completed in October 2018. After 4 months of cooldown and another 4 months of tests, the Iseult magnet reached its nominal field of 11.72 T without any quench for the first time, on July 18th. This paper deals with the magnet connection at Neurospin with the cryoplant and with the electrical and control systems. Finally, the paper will present the magnet commissioning data, from the cooling phase to the step-by-step energization up to the nominal current.
In the framework of the French-German project Iseult, we chose to design the 4.5 K vapor cooled current leads of the 11.75 T MRI magnet using a burn-proof approach, i.e., they are able to withstand a 3-h current slow dump without any active cooling. This constraint led us to select brass instead of pure copper, resulting in higher mass and thus in higher thermal stability. The drawback is a slightly higher cryogenic consumption. We present here the design studies of those current leads and compare their theoretical characteristics with the experimental results obtained during the test campaigns at CEA-Saclay.
We report on a new liquid hydrogen and deuterium target dedicated to in-beam γ spectroscopy experiments in inverse kinematics at relativistic incident energies at GSI/FAIR. Target thicknesses from 10 to 80mm can be achieved for an effective diameter of 60mm. The target-cell and entrance window are maded of 200μm thick Mylar. The design has the advantage of being free of absorbing material at forward angles and 90°, allowing the detection of photons in a wide angular range. A commissioning experiment with a 54Cr beam at 130MeV/nucleon has been performed at GSI, using the Rare Isotopes INvestigation at GSI (RISING) detectors. The target has been shown to behave as expected and is ready for experiments at fragmentation Radioactive-Ion Beam Facilities.
The system of superconducting toroids in the ATLAS experiment at CERN consists of three magnets. The Barrel Toroid was assembled and successfully tested in 2006. Next, two End-Cap Toroids have been tested on surface at 77 K and installed in the cavern, 100-m underground. The End Cap Toroids are based on Al stabilized Nb-Ti/Cu Rutherford cables, arranged in double pancake coils and conduction cooled at 4.6 K. The nominal current is 20.5 kA at 4.1 T peak field in the windings and the stored energy is 250 MJ per toroid. Prior to final testing of the entire ATLAS Toroidal system, each End Cap Toroid passed a commissioning test up to 21 kA to guarantee a reliable performance in the final assembly. In this paper the test results are described. It includes the stages of test preparation, isolation vacuum pumping and leak testing, cooling down, step-by-step charging to full current, training quenches and quench recovery. By fast discharges the quench detection and protection system was checked to demonstrate a safe energy distribution within the magnet after a quench or a triggered fast dump.
The ATLAS Experiment at LHC, CERN will utilize a large, superconducting, air-cored toroidal magnet system with a long Barrel Toroid and two End Cap Toroids. Each End Cap Toroid contains eight racetrack coils mounted as a single cold mass in a cryostat vessel of approximately 10 m diameter and 5 m length. The operating current is 20.5 kA at 0.25 GJ stored energy and a peak field of 4.1 T in the windings. This paper presents the status of the End Cap Toroid Project. Final integration of the two cold masses, 120 tons each, into their respective vacuum cryostats is described. The specialized techniques, procedures and tooling infrastructure required for these operations are explained. Pre-installation cooldown to 85 K is reported. Installation of the toroids in the ATLAS cavern 100 m underground will be described. The final interfacing to the Barrel Toroid and services in the cavern will be reviewed along with preparations for final test and commissioning.
The ATLAS Barrel Toroid, the largest toroid ever built with 1.1 GJ stored energy, has been successfully tested after installation in the underground cavern in fall 2006. The eight coils of the Barrel Toroid were tested individually before and showed fully acceptable performances. We observed only one training quench during an individual coil test (at 30 A below the maximum test current) and no training during the test of the fully assembled toroid. At currents up to the nominal value of 20.5 kA, the toroid has been quenched inducing normal zones by means of heaters or by stopping the helium flow in the current leads. The quench safety system worked perfectly. Given the safe peak temperatures measured in the cold mass following various quenches, it is concluded that the Barrel Toroid can be operated safely. In this paper, the hot spot of the toroid is presented in detail: the measurement data are compared to various theoretical models.
Each superconducting coil of the ATLAS Barrel Toroid has to pass the commissioning tests on surface before the installation in the underground cavern for the ATLAS Experiment at CERN. Particular acceptance criteria have been developed to characterize the individual coils during the on-surface testing. Based on these criteria and the limited time of the test, a compressed test program was proposed and realized. In only a few cases some additional tests were required to justify the coil performance and acceptance. In this paper the analysis of the test results is presented and discussed with respect to the acceptance criteria. Some differences in the parameters found between the identical coils are analyzed in relation to coil production features
The Barrel Toroid (BT) provides the magnetic field for the muon detectors in the ATLAS experiment at CERN. The Toroid is built up from eight superconducting coils. Each coil consists of two 25 m times 5 m racetrack shape double pancakes impregnated and pre-stressed inside an aluminum coil casing. The 42-tons cold mass is cooled by forced-flow liquid helium circulating in aluminum pipes glued to its surface. The coils are tested on surface prior to their underground installation. The test program has started in September 2004 and finished in June 2005. This paper describes the test set up and various commissioning tests performed at the ATLAS Magnet Test Facility. It includes the aspects of test preparation, vacuum pumping, leak testing, cooling down, powering and warming up. The 8 coils have passed the tests successfully and have been assembled into the Toroid in the ATLAS cavern. The testing completes the production of the so far largest racetrack coils in the world
The Superconducting Barrel Toroid is providing (together with the two End-Cap Toroids not presented here) the magnetic field for the muon detectors in the ATLAS Experiment at the LHC at CERN. The toroid with outer dimensions of 25 m length and 20 m diameter, is built up from 8 identical racetrack coils. The coils with 120 turns each are wound with an aluminum stabilized NbTi conductor and operate at 20.5 kA at 3.9 T local field in the windings and is conduction cooled at 4.8 K by circulating forced flow helium in cooling tubes attached to the cold mass. The 8 coils of 25 m /spl times/ 5 m are presently under construction and the first coils have already been fully integrated and tested. Meanwhile the assembly of the toroid 100 m underground in the ATLAS cavern at CERN has started. The 8 coils are individually tested on surface before installation. In this paper the test of the first coil, unique in size and manufacturing technology, is described in detail and the results are compared to the previous experience with the 9 m long B0 model coil.
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.