Construction and commissioning of the compact energy-recovery linac at KEK

Self Cite

Operational experience of a 500 kV photoemission gun at the compact energy recovery linac (cERL) of the High Energy Accelerator Research Organization is presented. The gun, developed at the Japan Atomic Energy Agency, was found to have failures in two out of the ten-segment ceramic insulator just after installation at cERL. The gun had been operated at 390 kV with eight segments until April 2015 and provided a 0.9 mA beam. An additional two-segment insulator was installed on the top of the existing insulators to recover the high-voltage performance. The gun was then conditioned up to 539 kV and has been operated stably at 500 kV. No discharge caused by the gun itself was observed at 500 kVonce the high threshold voltage for stable operation exceeded 500 kV. A dark current of a few picoamperes was generated at 500 kV from a photocathode puck with a semiconducting wafer, while no dark current was observed without a semiconducting wafer. Stable generation of a 500 keV beam with current greater than 0.8 mA was demonstrated for more than two hours.

Section: Introductionmentioning

confidence: 99%

“…The gun was installed at the compact ERL (cERL) of the High Energy Accelerator Research Organization (KEK) in Oct. 2012 and a stable beam has been delivered since April 2013. The details of the cERL accelerator system are described elsewhere [10,14]. However, the operational voltage of the gun was limited to 390 kV until recently.…”

Section: Introductionmentioning

confidence: 99%

Operational experience of a 500 kV photoemission gun

Nishimori

Nagai

Hajima

et al. 2019

Self Cite

“…A photoemission electron gun injector, followed by a superconducting rf cavity for acceleration [23][24][25][26][27][28], was adapted as an electron source for LEReC. This choice took advantage of the high-voltage electron gun experience and the excellent beam quality achieved at Cornell University [29][30][31][32][33][34][35][36][37], in Japan [38][39][40][41][42][43][44] and at Jefferson National Lab [45][46][47][48]. It has been demonstrated that a high-voltage dc photoemission gun can have good beam quality, such as low emittance [30,31] and high average current [29].…”

Section: B the Lerec Acceleratormentioning

confidence: 99%

Stable operation of a high-voltage high-current dc photoemission gun for the bunched beam electron cooler in RHIC

Gu¹,

Altinbas²,

Badea³

et al. 2020

The Low Energy RHIC electron Cooling (LEReC) project at Brookhaven National Laboratory recently demonstrated for the first time cooling of hadron bunches with radio-frequency (rf) accelerated electron bunches. LEReC uses a high-voltage photoemission electron gun with stringent requirements for beam current, beam quality, and stability. The electron gun has a photocathode with a high-power fiber laser, and a novel cathode production, transport, and exchange system. It has been demonstrated that the high-voltage photoemission gun can continually produce a high-current electron beam with a beam quality suitable for electron cooling. We describe the operational experience with the LEReC dc photoemission gun in RHIC and discuss the important aspects needed to achieve the required beam current, beam quality, and stability.

“…ERLs have successfully been operated in normalconducting [2,3] or superconducting [4,5] versions at various laboratories before. Other ERLs are currently under operation/commissioning [6,7] or construction [8,9]. An overview of past, present and future ERL projects can be found in [10,11].…”

Section: Introductionmentioning

confidence: 99%

First operation of the superconducting Darmstadt linear electron accelerator as an energy recovery linac

Arnold

Birkhan

Pforr

et al. 2020

The superconducting Darmstadt linear electron accelerator (S-DALINAC) has been operated as an energy recovery linac (ERL) for the first time. The S-DALINAC is a recirculating superconducting radiofrequency (SRF) accelerator and had been upgraded with an additional recirculation beamline. It features a path length adjustment system that provides a freedom of choice of 360°for the rf phase difference between the electron bunches recirculated through the new beamline and the phase of the accelerating TM 010 mode of the oscillating electromagnetic field in the SRF cavities of the accelerator. A choice of around 180°f or this phase difference results in a deceleration of the recirculated beam and a corresponding transfer of the particles' kinetic energy back to the energy of the electromagnetic field in the cavities. The main components relevant for ERL operation are described and data of the first operation as an SRF-ERL are presented.