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The Linear IFMIF Prototype Accelerator (LIPAc) is a high intensity D⁺ linear accelerator; demonstrator of the International Fusion Material Irradiation Facility (IFMIF). In summer 2019 the IFMIF/EVEDA Radio Frequency Quadrupole (RFQ) accelerated its nominal 125 mA deuteron (D⁺) beam current up to 5 MeV, with >90% transmission for pulses of 1 ms at 1 Hz, reaching its nominal beam dynamics goal. The paper presents the benchmark simulations and measurements performed to characterize the as-built RFQ performances, in the low and high perveance regime. In this framework, the commissioning strategy with a particular focus on the reciprocal effects of the low-medium energy transfers lines and the RFQ is also discussed. In the last part of the paper, the future commissioning outlooks are briefly introduced., Proceedings of the 64\textsuperscript{th} ICFA ABDW on High-Intensity and High-Brightness Hadron Beams, HB2021, Batavia, IL, USA

Construction and validation of the Linear IFMIF Prototype Accelerator (LIPAc) have been conducted under the framework of the IFMIF/EVEDA project. The LIPAc consists, in its final configuration, of a 100 keV injector and the world longest 5 MeV RFQ accelerator, followed by a MEBT with high space charged and beam loaded re-buncher cavities, an HWR-SRF linac, HEBT with a Diagnostic Plate, ending in a Beam Dump (BD) designed to stop the world highest deuteron current of 125 mA CW at 9 MeV. The beam commissioning at a low duty cycle of ~0.1 % led to a successful RFQ acceleration of 125 mA and 5 MeV beam in 2019. The following beam commissioning phase was initiated in July 2021 with a temporary transport line replacing the SRF linac. The major goals of this phase are to validate the RFQ, MEBT and BD performances up to CW and to characterize the beam properties in preparation to the final configuration with the SRF linac. This paper will present progresses made in this phase so far, such as a low-current and low-duty beam commissioning completed in Dec. 2021, CW operation campaign of the injector towards the nominal beam current, and RF conditioning of the RFQ towards CW., Proceedings of the 31st International Linear Accelerator Conference, LINAC2022, Liverpool, UK

IFMIF原型加速器の研究開発が、日本とEUとの共同事業として進行中である。2014年11月の最初の水素ビーム加速後、RFQが設置され、2018年7月に初のビーム加速器に成功した。ビーム電流を公称値（最大60 mA）まで増やしたのち、最初の重水素ビーム加速が行われた。現在、短パルスビームによる125 mA 加速を目指した重水素ビーム試験が進行中である。並行して、RFQの下流に設置されるSRFリニアックの組み立てが進行中である。ビームダンプはすでに設置され、長パルス試験を2020年に開始する予定である。

The 1st proton beam acceleration of the Linear IFMIF Prototype Accelerator (LIPAc) through its novel RFQ was succeeded on 13th June 2018. Addition to plenty of beam diagnostics equipped in the beam line, we prepared some radiation detectors placed around the accelerator in order to acquire supplemental information of the beam, as an indirect measurement. In the first day of the beam injection to the RFQ, the gamma-rays corresponding to certain excited states of Al of the low power beam dump were successfully detected by a LaBr3(Ce) scintillation detector. Some neutrons, which would originate from the interaction of protons with Cu somewhere, were also observed. These results proved that the beam was certain-ly accelerated up to about 2.5 MeV, and provided us a definitive confidence that the RFQ was working appro-priately from the very beginning of the commissioning. Also, the comparison of the radiation yields with the RFQ transmission provided additional information on the beam energy distribution.

The Linear IFMIF Prototype Accelerator (LIPAc) is under construction as a collaboration between Europe and Japan for challenging the technical validation of the low energy part up to 9MeV of IFMIF deuteron accelerator unit with 40MeV-125mA CW. The staged installation and commissioning activities are ongoing at the BA site in Rokkasho Fusion Institute of QST, and the commissioning of RFQ is underway. A deuteron beam acceleration at 5 MeV, 125mA was achieved at short pulse (~1 ms pulse duration) at ~1 Hz repetition. Here, ~90 % beam transport was obtained. Here, 8-chains of 175 MHz CW RF sources are connected to the RFQ in parallel. After that, MEBT, D-plate, HEBT and high power beam dump were connected to the RFQ in series, and high duty cycle beam commissioning will be implemented., 30th International Linear Accelerator Conference 2020

国際核融合材料照射施設(IFMIF)の工学設計・主要機器の設計・製作・試験を行い、建設判断に必要な技術実 証を行うために、現在、原型加速器(Linear IFMIF Prototype Accelerator, LIPAc)の建設とコミッショニングを段階 的に進めている。コミッショニングのフェーズBは、125 mAの重陽子パルスピームをRFQで5 MeVまで加速する ことを目的とし、2019年8月に終了した。将来のコミッショニングフェーズC及びDにおいては、125 mAの重陽子の パルス及びCWピームをSRFで9 MeVまで加速する予定である。これらコミッショニングフェーズBとCの中間に位置 するコミッショニングフェーズB+に向けて現在準備が進められている。フェーズB+においては、SRFの前段加速器 であるRFQで、 125 mAの重陽子ビームについてCWを目指した⻑パルス試験を行う予定となっている。 コミッショニングフェーズB+のための初期設計は2019年4月に終了し、将来のSRFのインストール予定位置に、 四極電磁石4台、ステアリング電磁石2台、BPM2台で構成された代替のビームライン(MEL: MEBT Extension Line) が設置された(2020年3月)。 このコミッショニングフェーズB+初期設計終了時(2019年4月)からMEL設置(2020年3月)までの間に、 ・「RFQ出口での縦方向パラメータ取得」のための実験の追加(=初期設計時に比べMELでの四極磁場の自由度 が不足することとなった) ・MEL真空ダクト内径の減少(初期設計時に比べ、MELでビームロスしやすくなった) ・HEBTのファラデーカップでビーム停止するという運転シナリオの追加(初期設計からビーム径を絞る必要) の変更が日欧の協議により追加された。既にMELには電磁石が設置されているので、これら追加の要請を満たす べく、磁石の位置は変えず磁場係数のみ変更するという形でオプティクスの再設計を行った。, 第17回日本加速器学会年会

In summer 2019 the IFMIF/EVEDA Radio Frequency Quadrupole (RFQ) accelerated its nominal 125 mA deuteron beam current up to 5 MeV, with 90% transmission for pulses of 1 ms at 1Hz. The Linear IFMIF Prototype Accelerator (LIPAc) is a high intensity deuteron linear accelerator; it is the demonstrator of the International Fusion Material Irradiation Facility (IFMIF). In particular the RFQ is the longest and most powerful ever operated. An intense campaign of measurements have been performed in Rokkasho to characterize several performances of this complex machine: transmission, emittances, energy spectrum and beam loading. The history and the results of the commissioning until this important project milestone are here described. An overview of the activities planned to reach CW operation is also presented., Proceedings of the 11th International Particle Accelerator Conference, IPAC2020, Caen, France

The eight-chain RF system and radio frequency quadrupole (RFQ) linac were successfully integrated at the facility of the Linear IFMIF Prototype Accelerator (LIPAc). We achieved an unprecedented high current deuteron beam up to 55 mA in pulse operation (300 μs, 1 Hz). The keys of the success were (1) understanding reflected power from RFQ to RF system, (2) tuning each RF chain individually, (3) intensive RF conditioning for holding the stable RF power in the RFQ, and (4) optimizing the beam loading compensation control. Interestingly, the reflection at the breakdown in RF conditioning was higher than an estimation and reached up to 600 kW so far. In order to avoid damage on tetrodes by the high reflection, the impedance of each circulator was accurately adjusted.

超伝導加速器空洞のR&Dについて新技術や意見の共有を行うTTC(TESLA Technology Collaboration)会議にて、IFMIF/EVEDA原型加速器のコンポーネントの一つである超伝導加速器の組立に関する報告をする。超伝導加速器の組立や排気操作中の微粒子の混入による劣化を防ぐため、真空パーティクルモニタを導入し、微粒子の発生を最小限にするために排気系のパラメータ調整を行ったので、その内容について口頭発表する。, Optimization of the parameter of the slow pumping system with vacuum particle monitor on Liner IFMIF Prototype Accelerator (LIPAc)