Achievement of 200,000 hours of operation at KEK 7-GeV electron 4-GeV positron injector linac

TL;DR

This paper celebrates the achievement of 200,000 hours of operation for KEK's electron-positron injector LINAC over 39 years, highlighting its continuous service and technological developments for multiple physics projects.

Contribution

It documents the long-term operational success and technological advancements of KEK's injector LINAC from 1982 to 2020, including recovery from earthquake damage.

Findings

Accumulated 200,000 hours of operation by May 2020.

Supported multiple major physics projects over 39 years.

Implemented advanced injection techniques like two-bunch acceleration.

Abstract

KEK electron positron injector LINAC initiated the injection operation into Photon Factory (PF) light source in 1982. Since then for 39 years, it has served for multiple projects, namely, TRISTAN, PF-AR, KEKB, and SuperKEKB. Its total operation time has accumulated 200 thousand hours on May 7, 2020. We are extremely proud of the achievement following continuous efforts by our seniors. The construction of the injector LINAC started in 1978, and it was commissioned for PF with 2.5 GeV electron in 1982. In parallel, the positron generator linac was constructed for the TRISTAN collider project. The slow positron facility was also commissioned in 1992. After the KEKB asymmetric-energy collider project was commissioned in 1998 with direct energy injections, the techniques such as two-bunch acceleration and simultaneous injection were developed. As the soft structure design of the LINAC was too weak against the great east Japan earthquake, it took three years to recover. Then the construction and commissioning for the SuperKEKB project went on, and the simultaneous top-up injection into four storage rings contributes to the both elementary particle physics and photon science.