E. Chevallay

European Organization for Nuclear Research

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V. N. Fedosseev

European Organization for Nuclear Research

S. Doebert

European Organization for Nuclear Research

R. Apsimon

Lancaster University

T. Lefèvre

European Organization for Nuclear Research

S. Mazzoni

European Organization for Nuclear Research

M. Martyanov

Institute of Applied Physics

E. Granados

European Organization for Nuclear Research

A. Pardons

European Organization for Nuclear Research

E. Gschwendtner

European Organization for Nuclear Research

F. Friebel

FHNW University of Applied Sciences and Arts

Cooperative Institutions

European Organization for Nuclear Research

645

Campbell Collaboration

137

Centre National de la Recherche Scientifique

106

Max Planck Society

University of Latvia

Cockcroft Institute

Institut National de Physique Nucléaire et de Physique des Particules

Google (United States)

Max Planck Institute for Physics

University of Adelaide

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Synthesis, surface chemical analysis, lifetime studies and degradation mechanisms of Cs-K-Sb photocathodes

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (2020)

H. Panuganti E. Chevallay V. N. Fedosseev Marcel Himmerlich

We report synthesis and characterization of a batch of three cesium potassium antimonide photocathodes that have been grown on pure copper substrates via a ternary co-deposition method whose procedure is described herein. A deposition system that was designed for synthesis of two-element photocathodes has been utilized for synthesis of the aforementioned three-element photocathodes with slope of the in situ photocurrent as the driver for the growth process. A variation of substrate temperature and deposition parameters among the three photocathodes during synthesis has yielded a maximum quantum efficiency of 6% for 140°C substrate temperature. Lifetime studies performed in a 65-kV DC electron gun on two of the photocathodes, but under oxidized states, at tens of μA average currents (ampere-level peak currents) extracted utilizing a 532-nm wavelength, 1-kHz repetition rate laser, have resulted in charge-lifetimes of 6.13 C and 13.78 C, respectively. X-ray photoelectron spectroscopy analysis of the photocathode with the highest quantum efficiency has revealed a nearly impurity-free surface with stoichiometry Cs1.3K1.8Sb1.0 when pristine. Furthermore, it has been found that oxidation of the alkali surface atoms as well as carbon adsorption from hydrocarbons and minor fluorine uptake are the causes of quantum efficiency reduction during laser illumination in the utilized experimental set-up.

Photocathode

Quantum Efficiency

Antimonide

Photocurrent

Photoelectric effect

10.1016/j.nima.2020.164724

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Citations (11)

Correction to ‘Proton-driven plasma wakefield acceleration in AWAKE’

Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences (2019)

E. Gschwendtner M. Turner E. Adli Amit Ahuja O. Apsimon

In this article, we briefly summarize the experiments performed during the first Run of the Advanced Wakefield Experiment, AWAKE, at CERN (European Organization for Nuclear Research).The final goal of AWAKE Run 1 (2013 -2018) was to demonstrate that 10-20 MeV electrons can be accelerated to GeVenergies in a plasma wakefield driven by a highlyrelativistic self-modulated proton bunch.We describe the experiment, outline the measurement concept and present first results.Last, we outline our plans for the future.

Plasma acceleration

10.1098/rsta.2019.0539

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Citations (1)

HIGH CHARGE PHIN PHOTO INJECTOR AT CERN WITH FAST PHASE SWITCHING WITHIN THE BUNCH TRAIN FOR BEAM COMBINATION

M. Divall Alexandra Andersson Benoît Bolzon E. Bravin E. Chevallay

The high charge PHIN photo-injector was developed within the framework of the European CARE program to provide an alternative to the drive beam thermionic gun in the CTF3 (CLIC Test Facility) at CERN. In PHIN 1908 electron bunches are delivered with bunch spacing of 1.5 GHz and 2.33 nC charge per bunch. Furthermore the drive beam generated by CTF3 requires several fast 180 deg phase-shifts with respect to the 1.5 GHz bunch repetition frequency in order to allow the beam combination scheme developed at CTF3. A total of 8 subtrains, each 140 ns long and shifted in phase with respect to each other, have to be produced with very high phase and amplitude stability. A novel fiber modulator based phase-switching technique developed on the laser system provides this phase-shift between two consecutive pulses much faster and cleaner than the base line scheme, where a thermionic electron gun and sub-harmonic bunching are used. The paper describes the fiber-based switching system and the measurements verifying the scheme. The paper also discusses the latest 8nC charge production and cathode life-time studies on Cs2Te.

Electron gun

Bunches

Harmonic

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Citations (2)

Photocathodes tested in the dc gun of the CERN photoemission laboratory

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (1994)

E. Chevallay J-D. Durand S. Hutchins G. Suberlucq M. Wurgel

Photocathode

Electron gun

10.1016/0168-9002(94)91293-9

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Citations (65)

The AWAKE Run 2 programme and beyond

arXiv (Cornell University) (2022)

E. Gschwendtner К. В. Лотов P. Muggli M. Wing R. Agnello

Plasma wakefield acceleration is a promising technology to reduce the size of particle accelerators. Use of high energy protons to drive wakefields in plasma has been demonstrated during Run 1 of the AWAKE programme at CERN. Protons of energy 400 GeV drove wakefields that accelerated electrons to 2 GeV in under 10 m of plasma. The AWAKE collaboration is now embarking on Run 2 with the main aims to demonstrate stable accelerating gradients of 0.5-1 GV/m, preserve emittance of the electron bunches during acceleration and develop plasma sources scalable to 100s of metres and beyond. By the end of Run 2, the AWAKE scheme should be able to provide electron beams for particle physics experiments and several possible experiments have already been evaluated. This article summarises the programme of AWAKE Run 2 and how it will be achieved as well as the possible application of the AWAKE scheme to novel particle physics experiments.

Plasma acceleration

Bunches

Particle (ecology)

10.48550/arxiv.2206.06040

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Citations (0)

Production of long bunch trains with4.5 μCtotal charge using a photoinjector

Physical Review Special Topics - Accelerators and Beams (2012)

Ö. Mete E. Chevallay M. Csatári Anne Dabrowski S. Doebert

A photoinjector, PHIN (PHotoINjector), has been realized at CERN by a joint effort of several institutes within the European Coordinated Accelerator Research in Europe program. The test facility has been installed and commissioned at CERN with the aim to demonstrate the beam parameters needed for the CLIC Test Facility 3 (CTF3). This beam is unique with respect to its long bunch train and high average charge per bunch requirements. The nominal beam for CTF3 consists of 1908 bunches each having a 2.33 nC charge and a bunch frequency of 1.5 GHz. Thus, a total charge of $\ensuremath{\sim}4.4\text{ }\text{ }\ensuremath{\mu}\mathrm{C}$ has to be extracted and accelerated. The stability of the intensity and the beam parameters along this exceptionally high average current train is crucial for the correct functioning of the CLIC drive beam scheme. Consequently, extensive time-resolved measurements of the transverse and longitudinal beam parameters have been developed, optimized, and performed. The shot-to-shot intensity stability has been studied in detail for the electron and the laser beams, simultaneously. The PHIN photoinjector has been commissioned between 2008 and 2010 during intermittent operations. This paper reports on the obtained results in order to demonstrate the feasibility and the stability of the required beam parameters.

Bunches

Intensity

10.1103/physrevstab.15.022803

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Citations (6)

Analysis of Proton Bunch Parameters in the AWAKE Experiment

arXiv (Cornell University) (2021)

Vasyl Hafych A. Caldwell R. Agnello C. Ahdida M. Aladi

A precise characterization of the incoming proton bunch parameters is required to accurately simulate the self-modulation process in the Advanced Wakefield Experiment (AWAKE). This paper presents an analysis of the parameters of the incoming proton bunches used in the later stages of the AWAKE Run 1 data-taking period. The transverse structure of the bunch is observed at multiple positions along the beamline using scintillating or optical transition radiation screens. The parameters of a model that describes the bunch transverse dimensions and divergence are fitted to represent the observed data using Bayesian inference. The analysis is tested on simulated data and then applied to the experimental data.

Bunches

Divergence (linguistics)

Experimental data

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Production of Mass-Separated Erbium-169 Towards the First Preclinical in vitro Investigations

Frontiers in Medicine (2021)

Zeynep Talip Francesca Borgna Cristina Müller J. Ulrich Charlotte Duchemin

The β--particle-emitting erbium-169 is a potential radionuclide toward therapy of metastasized cancer diseases. It can be produced in nuclear research reactors, irradiating isotopically-enriched 168Er2O3. This path, however, is not suitable for receptor-targeted radionuclide therapy, where high specific molar activities are required. In this study, an electromagnetic isotope separation technique was applied after neutron irradiation to boost the specific activity by separating 169Er from 168Er targets. The separation efficiency increased up to 0.5% using resonant laser ionization. A subsequent chemical purification process was developed as well as activity standardization of the radionuclidically pure 169Er. The quality of the 169Er product permitted radiolabeling and pre-clinical studies. A preliminary in vitro experiment was accomplished, using a 169Er-PSMA-617, to show the potential of 169Er to reduce tumor cell viability.

Erbium

10.3389/fmed.2021.643175

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Citations (11)

Recent Developments at the High-charge PHIN Photoinjector and the CERN Photoemission Laboratory

5th Int. Particle Accelerator Conf. (IPAC'14), Dresden, Germany, June 15-20, 2014 (2014)

Christoph Heßler E. Chevallay Steffen Döbert V. N. Fedosseev Irene Martini

The high-charge PHIN photoinjector has originally been developed to study the feasibility of a photoinjector option for the drive beam of the CLIC Test Facility 3 (CTF3) at CERN and is now being used to investigate the feasibility of a drive beam photoinjector for CLIC. In this paper recent R&D efforts to improve the parameters of the existing system towards CLIC requirements will be discussed. This includes studies of a feedback loop for intensity stabilization, the upgrade of the PHIN vacuum system and the planned upgrade of the driving laser system. For photocathode production and R&D a dedicated photoemission laboratory is available at CERN. To increase the production rate of photocathodes and the availability of the photoemission lab for other studies, an upgrade of the photocathode preparation system with a load-lock system is under study and will also be presented.

Upgrade

Photocathode

10.18429/jacow-ipac2014-mopri042

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Citations (2)

Cesium-Telluride Photocathode No. 166

A Barbiero R. Losito K. Elsener E. Chevallay

Photocathode

Caesium

Telluride

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