Performance of 112 MHz SRF Gun at BNL (original) (raw)

SRF photoinjector for proof-of-principle experiment of coherent electron cooling at RHIC

Coherent Electron Cooling (CEC) based on Free Electron Laser (FEL) amplifier promises to be a very good way to cool protons and ions at high energies. A proof of principle experiment to demonstrate cooling at 40 GeV/u is under construction at BNL [1]. One of possible sources to provide sufficient quality electron beam for this experiment is a SRF photoinjector. In this paper we discuss design and simulated performance of the photoinjector based on existing 112 MHz SRF gun and newly designed single-cavity SRF linac operating at 704 MHz.

High-gradient High-charge CW Superconducting RF gun with CsK2Sb photocathode

Cornell University - arXiv, 2015

High-gradient CW photo-injectors operating at high accelerating gradients promise to revolutionize many sciences and applications. They can establish the basis for superbright monochromatic X-ray free-electron lasers, super-bright hadron beams, nuclearwaste transmutation or a new generation of microchip production. In this letter we report on our operation of a superconducting RF electron gun with a record-high accelerating gradient at the CsK 2 Sb photocathode (i.e. ~ 20 MV/m) generating a record-high bunch charge (i.e., 3 nC). We briefly describe the system and then detail our experimental results. This achievement opens new era in generating high-power electron beams with a very high brightness. Superconducting radio-frequency (SRF) electron guns are frequently considered to be the favorite pathway for generating the high-quality, high-current beams needed for future high-power energyrecovery linacs. SRF guns can find unique scientific and industrial applications, such as driving highpower X-ray and EUV CW FELs [1-10], intense γ-ray sources [11-14], coolers for hadron beams [15-18], and electron-hadron colliders [19-21]. The quality of the generated electron beam-both its intensity and brightness-is extremely important for many of these applications. The beam's quality frequently is described by its brightness, i.e., the number of generated electrons divided by the bunch's emittance (defined as the phase space-volume occupied by electrons). In this letter, we report the record performance of our SRF gun (Fig. 1) that was built for the Coherent electron Cooling (CeC) experiment at RHIC [16] that generated a 1.7-MeV CW electron-beam with a 3 nC bunch charge. This gun demonstrated CW operation with 18 MV/m accelerating field at the CsK 2 Sb cathode at the time of the electron's photo-emission. Table 1 summarizes the key results from CeC gun and compares them with previously commissioned SRF guns.

SRF Systems for the Coherent electron Cooling Demonstration Experiment

A short 22-MeV linac under development at BNL will provide high charge, low repetition rate beam for the Coherent electron Cooling (CeC) demonstration experiment in RHIC. The linac will include a 112 MHz SRF gun and a 704 MHz five-cell accelerating SRF cavity. The paper describes the two SRF systems, discusses the project status, first test results and schedule.

Record Performance of SRF Gun with CsK2Sb Photocathode

2016

High-gradient CW photo-injectors operating at high accelerating gradients promise to revolutionize many sciences and applications. They can establish the basis for super-bright monochromatic X-ray and gamma-ray sources, high luminosity hadron colliders, nuclearwaste transmutation or a new generation of microchip production. In this paper we report on our operation of a superconducting RF electron gun with a record-high accelerating gradient at the CsK2Sb photocathode (i.e. ~ 20 MV/m) generating a record-high bunch charge (i.e., 2 nC). We briefly describe the system and then detail our experimental results. INTRODUCTION The coherent electron cooling experiment (CeC PoP) [1, 2] is expected to demonstrate cooling of a single hadron bunch in RHIC. A superconducting RF gun operating at 112 MHz frequencies generates the electron beam. 500MHz normal conducting cavities provide energy chirp for ballistic compression of the beam. 704-MHz superconducting cavity will accelerate beam to the fin...

Status of Proof-of-Principle Experiment of Coherent Electron Cooling at BNL

2018

An FEL-based Coherent electron Cooling (CeC) has a potential to significantly boosting luminosity of high-energy, high-intensity hadron-hadron and electron-hadron colliders. In a CeC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we pursue a proof-of-principle experiment at Relativistic Heavy Ion Collider (RHIC) using an SRF accelerator and SRF photoinjector. In this paper, we present status of the CeC systems and our plans for next year.

Experimental characterization of the high-brightness electron photoinjector

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1996

Operational experience of the emittance compensated photoinjector at the Brookhaven Accelerator Test Facility (ATF) is presented in this paper. The photoinjector has demonstrated the stability and reliability required for UV and X-ray FEL applications. The RF gun has been routinely running at more than 100 MV/m peak acceleration field; the laser system of the photoinjector has achieved 2% peak to peak energy stability, 0.5 % point stability and better than 2 ps timing jitter. The highest measured quantum efficiency of the Cu cathode is 0.05%. The electron beam bunch length was measured to be 10 ps using a linac RF phase scan. The normalized rms emittance for a 0.5 nC charge was measured, to be from 1 to 2 mm-mad, which agrees with PARMELA simulations.

A New Thermionic RF Electron Gun for Synchrotron Light Sources

2017

A thermionic RF gun is a compact and efficient source of electrons used in many practical applications. RadiaBeam Systems and the Advanced Photon Source of Argonne National Laboratory collaborate in developing of a reliable and robust thermionic RF gun for synchrotron light sources which would offer substantial improvements over existing thermionic RF guns and allow stable operation with up to 1A of beam peak current at a 100 Hz pulse repetition rate and a 1.5 μs RF pulse length. In this paper, we discuss the electromagnetic and engineering design of the cavity, and report the progress towards high power tests of the cathode assembly of the new gun.

Thermocathode radio-frequency gun for the Budker Institute of Nuclear Physics free-electron laser

Physics of Particles and Nuclei Letters, 2016

A radio-frequency (RF) gun for a racetrack microtron-recuperator injector driving the free-electron laser (FEL) (Budker Institute of Nuclear Physics) is being tested at a special stand. Electron bunches of the RF gun have an energy of up to 300 keV and a repetition rate of up to 90 MHz. The average electro-beam current can reach 100 mA in the continuous operation regime. The advantages of the new injector are as follows: long lifetime of the cathode for high average beam current; simple scheme of longitudinal beam bunching, which does not require an additional bunching resonator in the injector; absence of dark-current contamination of the injector beam; and comfortable RF gun operation due to the absence of a high potential of 300 kV at the cathode control circuits. In this study we describe the RF gun design, present the main characteristics of the injector with the RF gun, and give the results of testing.

Performance of the Brookhaven photocathode rf gun

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1992

The Brookhaven Accelerator Test Facility (ATF) uses a photocathode rf gun to provide a high-brightness electron beam intended for FEL and laser acceleration experiments. The rf gun consists of 1-,' cells driven at 2856 MHz in 7r-mode with a maximum cathode field of 100 MV/m . To achieve long lifetimes, our photocathode development concentrates on robust metals such as copper, yttrium and samarium . We illuminate these cathodes with a 10 ps, frequency-quadrupled Nd : YAG laser . We describe the initial operation of the gun, including measurements of transverse and longitudinal emittance, quantum efficiencies, and peak current. These results are compared to models .