R. Kwiatkowski, R. Nietubyc, J. Szewiński, D.R. Zaloga
NCBJ, Świerk/Otwock, Poland
A.I. Wawrzyniak
NSRC SOLARIS, Kraków, Poland
Funding:European Regional Development Fund in the framework of the Smart Growth Operational Programme and Regional Operational Programme for Mazowieckie Voivodeship. The Beam Loss Monitor (BLM) system is primarily used for machine protection and is especially important in the case of high energy density of accelerated beam, when such a beam could cause serious damages due to uncontrolled loss. PolFEL linear accelerator is designed with the beam parameters, which made BLM an essential system for machine protection. The design of BLM system for PolFEL is composed of several scintillation probes placed along and around the accelerator. The paper reports on design and first tests of prototype detector, which is planned to be used for PolFEL project. The prototype was tested in NCBJ and SOLARIS, using radioactive calibration samples and linear electron accelerator as a sources. We also present results of numerical investigation of radiation generated due to interaction of fast electrons with accelerator components.
B. Keil, R. Ditter, M. Gloor, G. Marinkovic, J. Purtschert
PSI, Villigen PSI, Switzerland
We have developed a new BPM electronics platform based on a MultiProcessing System-on-Chip (MPSoC). This contribution introduces the first application of the platform at the Paul Scherrer Institute (PSI), which is the cavity BPM system for the SwissFEL soft X-ray undulator beamline called ’Athos’ [1], where a larger number of systems are now operational. Measurement results and differences to the predecessor system will also be presented.
C.J. Richard, Z. Aboulbanine, G.D. Adhikari, N. Aftab, P. Boonpornprasert, G.Z. Georgiev, M. Groß, A. Hoffmann, M. Krasilnikov, X.-K. Li, A. Lueangaramwong, R. Niemczyk, H.J. Qian, F. Stephan, G. Vashchenko, T. Weilbach
DESY Zeuthen, Zeuthen, Germany
Funding:This work was supported by the European XFEL research and development program The Photo Injector Test Facility at DESY in Zeuthen (PITZ) characterizes and optimizes electron sources for use at FLASH and European XFEL. AT PITZ, the transverse phase space is measured using a single slit scan and scintillator screen method. With the trend in photoinjectors towards lower current and emittance, these measurements become increasingly influenced by systematic errors including camera resolution and scintillator response due to smaller spot sizes. This study investigates the effects and corrections of the systematic errors for phase space measurements at PITZ.
A.I. Novokshonov, G. Kube, S. Strokov
DESY, Hamburg, Germany
Z. Aboulbanine, G.D. Adhikari, N. Aftab, P. Boonpornprasert, G.Z. Georgiev, J. Good, M. Groß, C. Koschitzki, M. Krasilnikov, X. Li, O. Lishilin, A. Lueangaramwong, D. Melkumyan, F. Mueller, A. Oppelt, H.J. Qian, F. Stephan, G. Vashchenko, T. Weilbach
DESY Zeuthen, Zeuthen, Germany
A standard technique to measure beam profiles in linear accelerators are screen monitors using scintillating screens. This technique is used e.g. at the European XFEL in order to overcome coherence effects in case of OTR usage [*]. During the XFEL commissioning it was found out that screens based on LYSO:Ce as scintillating material revealed a nonproportional light output [**]. Reason for it is the high particle beam density. As consequence it was decided to exchange LYSO:Ce by GAGG:Ce scintillators because the excitation carriers can rapidly transfer their energy to excited states of gadolinium, and a rapid migration of this energy among the Gd sub-lattice is expected. Driven by the observations at XFEL a series of measurements was started to investigate the properties of various scintillator materials (LYSO:Ce, YAP:Ce, YAG:Ce, LuAG:Ce and GAGG:Ce). The last measurement campaign was carried out at PITZ which allows to operate at higher beam charge and lower electron energy compared to the XFEL. The present work summarizes the results of these measurements. * S.Wesch and B.Schmidt, in Proc. DIPAC’11, Hamburg, WEOA01, pp. 539-543. ** G.Kube, A.Novokshonov, S.Liu, M.Scholz, in Proc. FEL’19, Hamburg, WEB01, pp. 301-306.
K. Łasocha
Jagiellonian University, Kraków, Poland
For the needs of diagnostics of the longitudinal electron beam characteristics at the first Polish free electron laser (PolFEL) project, a Coherent Diffraction Radiation (CDR) system is being developed and tested. It will allow for nondestructive bunch length measurement based on the power balance of CDR radiation collected by Schottky diodes in different ranges of sub-THz radiation. The first tests and measurements will be performed at the end of the Solaris synchrotron injector linac, where the beam profile is already known from previous studies. In addition the camera system with automatic focus was developed and tested. In this contribution the theoretical background of the measurement, calculations and first experimental steps will be presented.
Currently developed nuclear accelerators more and more widely use superconducting elements especially in windings of superconducting electromagnets and current leads to them. These elements are however sensitive to the irradiation caused by primary beam as well as by secondary particles, as it is the case for PolFEL. In the paper it is discussed how this irradiation damages the subtle structure of superconducting materials, leading to columnar defects formation in 2D HTc superconductors. It is analysed, in which way created nano-sized structural defects influence the critical current properties of the superconducting materials, in the process of capturing of the magnetic pancake vortices. Various initial positions of the captured vortices are analysed; their movement leads to potential barrier variations. Influence of the irradiation effects on the current-voltage characteristics of superconductors are investigated then and maximal current density detected as the function of irradiation dose, nano-defects size and physical parameters as magnetic field and temperature.
C. Bloomer, L. Bobb
DLS, Oxfordshire, United Kingdom
W. Freund, J. Grünert, J. Liu
EuXFEL, Schenefeld, Germany
M.E. Newton
University of Warwick, Coventry, United Kingdom
The European XFEL can generate extremely intense, ultra-short X-ray pulses at MHz repetition rates. Single-crystal CVD diamond detectors have been used to transparently measure the photon beam position and pulse intensity. The diamond itself can withstand the power of the beam, but the surface electrodes can be damaged since a single pulse can already exceed the damage threshold of the electrode material. Presented in this work are pulse intensity and position measurements obtained at the European XFEL using a new type of all-carbon single-crystal diamond detector developed at Diamond Light Source. Instead of traditional surface metallisation, the detector uses laser-written graphitic electrodes buried within the bulk diamond. There is no metallisation in the XFEL X-ray beam path that could be damaged by the beam. The results obtained from a prototype detector are presented, capable of measuring the intensity and 1-dimensional X-ray beam position of individual XFEL pulses. These successful measurements demonstrate the feasibility of all-carbon diagnostic detectors for XFEL use.
C. Szwaj, S. Bielawski, C. Evain, E. Roussel
PhLAM/CERLA, Villeneuve d’Ascq, France
C. Gerth, B. Steffen
DESY, Hamburg, Germany
B. Jalali
UCLA, Los Angeles, California, USA
Funding:ULTRASYNC ANR-DFG project, CPER Photonics for Society, CEMPI LABEX Recording electric field evolutions in single-shot and with sub-picosecond resolution is required in electron bunch diagnostics, and THz applications. A popular strategy consists of transferring the unknown electric field shape onto a chirped laser pulse, which is eventually analyzed. The technique has been investigated and/or been used as routine diagnostics at FELIX, DESY, PSI, Eu-XFEL, KARA, SOLEIL, etc. However fundamental time-resolution limitations have been strongly limiting the potential of these methods. We review recent results on a strategy designed for overcoming this limit: DEOS [1] (Diversity Electro-Optic Sampling). A special experimental design enables to reconstruct numerically the input electric signal with unprecedented temporal resolution. As a result, 200 fs temporal resolution over more than 10 ps recording length could be obtained at European XFEL - a performance that could not be realized using classical spectrally-decoded electro-optic detection. Although DEOS uses a radically novel conceptual approach, its implementation requires few hardware modifications of currently operating chirped pulse electro-optic detection systems. [1] E. Roussel, C. Szwaj, C. Evain, B. Steffen, C. Gerth, B. Jalali and S. Bielawski, Light: Science & Applications 11, 14 (2022). https://www.nature.com/articles/s41377-021-00696-2
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