Overturning Force Simulation on Chain of Quenches of Toroidal HTS-SMES

Hadron and proton therapy are cutting edge techniques for cancer treatment and a great development of specialized medical centers and research facilities is foreseen in the next decades. One of the main obstacles to the penetration of the use of charged particles for therapy is the construction of complex and expensive accelerating structures and rotating transfer lines, i.e. gantries, able to bend and focus the beam down to the patient. GaToroid is a novel concept of a fixed toroidal gantry, able to deliver the dose at discrete angles in the whole range of treatment energies in steady-state configuration. The steady-state current and magnetic field are appealing features, implying simplified demands on stability, powering, mechanics and cooling, as well as for the clinical perspective, allowing rapid variations of beam energy and treatment angle. In this work, we present the magnetic design of the toroidal coils composing the first instance of GaToroid, focusing the analysis on an option for a proton machine with an energy range of 70 MeV to 250 MeV. To create a proper magnetic field distribution, the coils have been designed with peculiar asymmetric shape and the windings have been graded. An initial winding geometry was obtained with an optimization aiming at maximum energy acceptance of the gantry. We are now progressing to the detailed engineering design. We describe here the overall magnet design, coil and conductor layout (LTS and HTS options), and mechanical studies involving the general torus structure. Quench protection is evaluated for LTS (Nb-Ti) configuration, as well as more innovative HTS (ReBCO) options. Finally, we present the design and the construction of a scaled-down demonstrator, intended as the proof of principle of winding procedure and mechanical coil structure.

Section: Mechanical Designmentioning

confidence: 99%

Section: Hts Demonstratormentioning

confidence: 99%

Magnetic Design of a Superconducting Toroidal Gantry for Hadron Therapy

Felcini

Bottura

Nugteren

et al. 2020

“…Fig. 6 shows the overturning forces of the 16-toroidal HTS-SMES without thermal analysis [11]. Comparing the simulation results of Figs.…”

Section: A Simulation Resultsmentioning

confidence: 93%

Overturning Force Simulation on Normal-State Transition of Toroidal HTS-SMES Taking Into Account an Electromagnetic and Thermal Condition

Noguchi

Itoh

Oga

et al. 2014

Abstract-Recently, many investigations about toroidal hightemperature superconducting magnetic energy storage systems have been reported. Some papers reported that there was a possibility that the chain of normal-state transitions occurred on the toroidal HTS-SMES magnet by normal-state-transition simulation. Hence, it should also be investigated that the behavior of unbalanced electromagnetic force during the sequential normal-state transition of the superconducting coil elements. In this paper, we have developed a simulation code to investigate the behavior of the overturning electromagnetic force on the toroidal HTS-SMES system during the normal-state transition. The magnetic field and the circuit analysis were coupled and solved in the previously developed simulation code. Additionally, in order to investigate the normal-state transition more accurately, we also take the thermal analysis into account. Carrying out the newly developed numerical simulation, we investigate the time transition of the transport current, the overturning force, and the magnetic field applied to the superconducting coil elements for a few toroidal HTS-SMESs.  Index Terms-Electromagnetic force, HTS-SMES, thermal analysis, superconducting magnet.

“…Thus, when the transport current of the HTS coil hardly decreases, the temperature on the hotspot would rise up more, and then the normal zone would spread rapidly. It may cause a serious accident due to the high stored energy or an overturning force [5]. Therefore, to clarify such a normal-transition phenomenon, we have been developing a simulation code coupling with a thermal, circuit, and magnetic field analysis.…”

Section: Introductionmentioning

confidence: 99%

Normal Transition Simulation on Toroidal HTS-SMES Considering Electromagnetic and Thermal Characteristics

Oga

Noguchi

Igarashi

2013

Self Cite

We previously investigated the stability of toroidal HTS-SMES magnets by simulation. The simulation took an electric circuit and a magnetic field phenomenon into account. However, a thermal condition is an important factor in investigating the behavior of an HTS-SMES magnet. Therefore, we have improved the previously developed simulation code to consider the thermal phenomenon. With the newly developed numerical simulation, we have investigated a time transition of a coil current, a critical current, and a temperature in the toroidal HTS-SMES magnets. As a result, it was confirmed that the temperature of all the HTS coils rose up quickly one after another, after the temperature at a certain local area of one HTS coil was increased.