The KEK Education and Training Accelerator (KETA) at KEK is a small electron linear accelerator aimed at developing human resources who can contribute to accelerator projects. KETA comprises of an RF source, an electron gun and a 2 m accelerator guide which accelerates beam up to 25 MeV and has three operating modes: a main dump mode, a sub-dump mode and an irradiation mode. The beam commissioning began in spring of 2022 and has been used for the educational purpose. We have been planning to provide accelerator hands-on practicing with KETA for young researchers, such as graduate students of SOKENDAI and other universities, university engineers and industrial people involved in accelerators. This activity is also reported in this paper.

Machine learning methods have been applied to XFEL optimization, fault prediction, and anomaly detection with the common goal of rationalizing the accelerator operations at SACLA. A Gaussian process optimizer was developed to maximize the XFEL performance, and the spectral brightness was improved by a factor of 1.7 with a new high-resolution inline spectrometer. Further ongoing efforts are also described. As for fault prediction and anomaly detection, three applications were developed: 1) failure prognosis of thyratrons, 2) prediction of recovery time after an interruption of operation, and 3) numerical reading of instruments by image recognition. Although the accuracy of the prototype applications of 1) and 2) are not yet sufficient, they will be improved in future developments. The application 3) has enough accuracy and the readout error of a variable-area flowmeter is a few %.

ISBA22 (International School on Beam dynamics and Accelerator technology) marked the fifth iteration. The program, which took place from November 21 to November 29, 2022, had the distinction of being held in-person at the Hiroshima International Plaza in Higashihiroshima, Japan. Despite the unforeseen circumstances leading to a decrease of attendees from the anticipated 29 students, the gathering of 24 attendees from Japan, Korea, China (online), Taiwan, and India emphasized the importance of direct dialogue in the realm of education. In addition to the enlightening lectures delivered, the curriculum of ISBA22 included an excursion to the Shimanami Kaido (sea route) and nightly simulation hands-on training sessions. The training culminated in a presentation of the results, where awards were given to groups with the highest marks. The certificates of completion presented to each student at the close of the program were met with beaming smiles, which spoke volumes about the success of the school. This first local school among three years demonstrated the importance of fostering meaningful connections in academia and the potential for hands-on learning to impact and inspire.

The Particle Accelerator Society of Japan (PASJ) has launched the Special Committee for the PASJ Activation in 2022 to address various issues surrounding the current academic society. We would like to implement initiatives to activate the PASJ, such as fostering young human resources and exchanges among society members, and initiatives to create PASJ member–member connections. Furthermore we would like to think together with all the society members about a vision and duties of the PASJ in this era of change. Background of the establishment and current activities of the Special Committee for the PASJ activation will be presented.

For the mitigation of the electron cloud effect (ECE), which will be a serious problem in high-intensity positron/proton ring, we used a commercial method called “thermal spraying,” (by which copper powder is melted and sprayed onto an aluminum substrate) to create a rough surface with a low secondary electron yield (SEY) on the inner wall of the beam pipes, and investigated its suitability for accelerators.

First, to the copper thermal spray (T.S.)-coated small samples, we measured the following key properties of T.S. coating: SEY profile, roughness parameters, surface composition, outgassing rate, adhesive strength, impedance, and dust generation rate.

Next, an aluminum beam pipe with an optimized T.S. coating was produced and installed in the positron ring (LER) of SuperKEKB. We measured the electron density in the beam pipe, and tried to interpret the behavior of this electron density data via simulations.

The lowest δ_max (the maximum SEY within the scanning range) of the T.S. coating reached ～0.7 after conditioning. The measured electron densities of the T.S.-coated beam pipe were comparable with those of the TiN-coated beam pipe. Thus, the T.S. coating can be considered a candidate technology for reducing ECE, though room for improvement remains, such as relatively high levels of dust and impedance.