Status of the RFQ linac installation and conditioning of the Linear IFMIF Prototype Accelerator

Abstract The Radio Frequency Quadrupole (RFQ) linac and 1.6 MW RF power system of the Linear IFMIF Prototype Accelerator (LIPAc) facility in the International Fusion Energy Research Center (IFERC) in Rokkasho (Japan) has been installed and conditioned. During the assembly and tuning process, the RFQ cavity was protected with a temporary tent from the potential deterioration of performance caused by dust. The vacuum in the cavity was improved through the 100 °C baking process of the cavity. The high power test of the 175 MHz RF systems up to 200 kW in CW for each of the eight RF chains was performed for checking its stable output reproducibility in Japan, before connecting 9–3/16 inch coaxial transmission lines from the RF chains to the RF input couplers of the cavity. It was confirmed that the eight RF chains provided the balanced RF power to the single RFQ cavity in-phase using a feedback loop and a synchronization system. The peak power in the cavity achieved 150 kW in the pulsed mode, which corresponds approximately to the required electric field to accelerate proton beam. Such RF conditioning process is ongoing to achieve 600 kW approximately required for deuteron beam commissioning planned in 2018

Spontaneous Formation of Spherical Tokamak by ECH on LATE

Spontaneous formation of spherical tokamak is observed during a microwave discharge at the electron cyclotron resonance (ECR) under a steady vertical magnetic field. In the course of slow plasma current increase, a fast rise of current (usually within several ms) occurs and the magnetic field topology changes drastically from open field type to closed one. After this current jump, a steady plasma current is maintained. The plasma current in the steady stage is proportional to the strength of the vertical field which balances the outward hoop force of the plasma current and maintains the MHD equilibrium. When a 5GHz, 130kW, 60ms microwave power is injected at 85G vertical field, plasma current of 6.8kA is obtained

LIPAc RF POWER SYSTEM

The design of the LIPAc RF Power System main components will be presented in this contribution, including the RF modules, the SSPA (Solid State Power Amplifier) for the re-buncher cavities, the HVPS (High Voltage Power Supply) for the final amplifiers anodes and the RF water cooling system. Additionally, the main difficulties encountered during the first months of the RFPS commissioning and operation will be described, together with the applied improvements.31st Symposium on Fusion Technology (SOFT2020

Status of RFQ Linac installation and commissioning in Rokkasho for the Linear IFMIF Prototype Accelerator

IFMIFの実現へ向けて、工学実証及び工学設計活動（EVEDA）が日欧間のBA協定の下で実施されている。この活動の一環として、原型加速器(LIPAc)の建設が六ヶ所で進行中である。LIPAｃを構成する高周波四重極線形加速器(RFQ)は、175 MHzの高周波(最大1.3 MW)を用いて、125 mAの重水素ビームを0.1 MeVから5 MeVまで定常的に加速する革新的な設計となっている。本発表では、RFQのビーム軸を高精度にアライメントするためのレーザートラッカーを用いた測定、ビーズ引き出し試験によるRFQ空洞の調整等、RFQの据付けが完了するまでの工程について詳細に述べる。The 18th International Conference on Fusion Reactor Material

Preparation of the cryomodule assembly for the Linear IFMIF Prototype Accelerator (LIPAc) in Rokkasho

The commissioning of LIPAc (Linear IFMIF Prototype Accelerator) is ongoing at Rokkasho Fusion Institute of QST, Japan for the engineering validation of the low energy section of the accelerator up to 9 MeV. Several SRF cCryomodules are planned to be adopted in will be required for IFMIF at the downstream to accelerate deuterons from 5 MeV to 40 MeV, and . The first of these a cCryomodules will is currently being manufactured and will be installed and tested in on the LIPAc. This majority of the cryomodule Cryomodule, including the consists of 8 HWRs and RF couplers required for accelerating the beam, working at 4.45 K with 175 MHz RF and 8 RF couplers has been supplied by CEA. The and 8 superconducting solenoid magnet packages required for steering the beam will bes supplied by CIEMAT. The assembly of the cryomodule is will be completed under the responsible responsibility for of Fusion for Energy, with assembly work and has been carried out recently starting in at the QST Rokkasho site since in March 2019.In the initial plan of the project, the cryomodule was to be assembled in EU and transported to Japan. However, due to the design modification of the mechanical tuner, it was decided to perform the assembly in Japan in order to avoid a risk of damage by transportation after the assembly. Since there was no any working environment for such an assembly work in Rokkasho, Due to the cleanliness requirements for the assembly, QST took the responsibility to prepare the infrastructure of the an ISO 14644-1 class 5 cleanroom environment required for the cryomodule assembly from the scratch. A class 5 (ISO14644-1) clean room as well as some In addition, dedicated apparatus, e.g. a dedicated slow pumping system and other ancillary equipment, was prepared for the assembly. All equipment is now in operation having been installed and commissioned during 2018 and the early part of 2019. in Rokkasho so as to satisfy the requirement to provide the minimum cleaning equipment and working space just for the assembly of a cryomodule. In the present paper, the details of the preparation work for the cryomodule assembly made by QST will be presented

Preparation of the cryomodule assembly for the Linear IFMIF Prototype Accelerator (LIPAc) in Rokkasho

The commissioning of LIPAc (Linear IFMIF Prototype Accelerator) is ongoing at Rokkasho Fusion Institute of QST, Japan for the engineering validation of the low energy section of the accelerator up to 9 MeV. Several SRF cCryomodules are planned to be adopted in will be required for IFMIF at the downstream to accelerate deuterons from 5 MeV to 40 MeV, and . The first of these a cCryomodules will is currently being manufactured and will be installed and tested in on the LIPAc. This majority of the cryomodule Cryomodule, including the consists of 8 HWRs and RF couplers required for accelerating the beam, working at 4.45 K with 175 MHz RF and 8 RF couplers has been supplied by CEA. The and 8 superconducting solenoid magnet packages required for steering the beam will bes supplied by CIEMAT. The assembly of the cryomodule is will be completed under the responsible responsibility for of Fusion for Energy, with assembly work and has been carried out recently starting in at the QST Rokkasho site since in March 2019.In the initial plan of the project, the cryomodule was to be assembled in EU and transported to Japan. However, due to the design modification of the mechanical tuner, it was decided to perform the assembly in Japan in order to avoid a risk of damage by transportation after the assembly. Since there was no any working environment for such an assembly work in Rokkasho, Due to the cleanliness requirements for the assembly, QST took the responsibility to prepare the infrastructure of the an ISO 14644-1 class 5 cleanroom environment required for the cryomodule assembly from the scratch. A class 5 (ISO14644-1) clean room as well as some In addition, dedicated apparatus, e.g. a dedicated slow pumping system and other ancillary equipment, was prepared for the assembly. All equipment is now in operation having been installed and commissioned during 2018 and the early part of 2019. in Rokkasho so as to satisfy the requirement to provide the minimum cleaning equipment and working space just for the assembly of a cryomodule. In the present paper, the details of the preparation work for the cryomodule assembly made by QST will be presented.19th International Conference on RF superconductivit

Progress of 175 MHz RF system onthe Linear IFMIF Prototype Accelerator

IFMIFの実現へ向けて、工学実証及び工学設計活動（EVEDA）が日欧間のBA協定の下で実施されている。この活動の一環として、原型加速器(LIPAc)の建設が六ヶ所で進行中である。LIPAcの175MHzの高周波(RF)システムは、プラズマ加熱装置であるICRFシステムと同程度の周波数及び出力レベルを持ち、その増幅方法は同じく四極管を用いる。そのため、本ワークショップでLIPAcのRFシステムを紹介し、互いに意見を交わすのは有意義であると思われる。今回の発表では、重陽子ビーム加速レベルまで安定して出力されるように調整された、高周波四重極線形加速器(RFQ)用のRFシステムについて紹介し、その調整内容について主に発表する。また、LIPAcとしての進捗についても発表する。Workshop on RF Heating Technology of Fusion Plasmas 201