Jacek Sekutowicz

Jacek Sekutowicz
Deutsches Elektronen-Synchrotron · MPY - Machine Physics

PhD

About

170
Publications
14,919
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2,204
Citations
Citations since 2017
12 Research Items
587 Citations
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120
2017201820192020202120222023020406080100120

Publications

Publications (170)
Article
A photocathode composed of a Pb layer deposited on Nb substrate is an attractive solution proposed for fully superconducting, radio frequency electron gun to be used in the linear accelerator of the European X-ray free electron laser (Eu-XFEL) operating at Deutsches Elektronen Synchrotron (DESY) and in other, similar devices. Much effort has been p...
Article
Close to 780 superconducting 1.3 GHz accelerating cavities made of bulk niobium have been installed in the European X-ray Free Electron Laser (E-XFEL) linear accelerator. The linac can operate at a mean gradient (Eacc) of ca. 23 MV/m in the nominal short pulse (SP) operation mode with 1.4 ms pulses and a repetition rate of 10 Hz. An R&D program at...
Conference Paper
Full-text available
At DESY, the development of a 1.6-cell, 1.3 GHz all su-perconducting gun cavity with a lead cathode attached to its back wall is ongoing. The special features of the structure like the back wall of the half-cell and cathode hole require adaptations of the procedures used for the treatment of nine-cell TESLA cavities. Unsatisfactory test results of...
Poster
Full-text available
Layout of European XFEL accelerator Cryo Module Test Bench (CMTB) To achieve the required stability of the accelerating RF field (max 0.01% error on amplitude and 0.01° on phase) a LLRF control system is required. To regulate fast RF disturbances an RF control loop in Vector Sum configuration is used. To compensate detuning effects the fast piezoel...
Conference Paper
Full-text available
The ever growing request for machines with a higher average beam pulse rate and also with a relaxed (< 1 MHz) pulse separation calls for superconducting linacs that operate in Long Pulse (LP) or Continuous Wave (CW) mode. For this purpose the European X-ray Free Electron Laser (European XFEL) could be upgraded to add the ability to run in CW/LP mod...
Article
The paper presents the recent studies carried out at National Centre for Nuclear Research (NCBJ) focused on improving adhesion between Pb films and Nb substrate. The impact of additional intermediate layers of Ti and Sn on the adhesion properties was also discussed. Structural and microstructural properties of the layers were investigated by using...
Conference Paper
Full-text available
In the years 2010-2017 some of the Polish research institutes - members of the European-XFEL consortium, took responsibility for production and delivery of components, test infrastructure and procedures for the superconducting (sc) linear electron accelerator (LINAC) and PLC units of slow control system for the first experimental instruments of the...
Conference Paper
Full-text available
The paper deals with dark current emission from a lead layer photocathode depending on its surface morphology. The simulation is aimed at theoretical prediction of operating conditions of a superconducting TESLA/XFEL-type RF electron gun photoinjector in
Article
Modern digital Low Level Radio Frequency (LLRF) control systems used to stabilize the accelerating field in facilities such as Free Electron Laser in Hamburg (FLASH) or European X-Ray Free Electron Laser (E-XFEL) are based on the Field Programmable Gate Array (FPGA) technology. Presently these accelerator facilities are operated with pulsed RF. In...
Conference Paper
Modern digital low level radio frequency (LLRF) control systems used to stabilize the accelerating field in facilities such as Free Electron Laser in Hamburg (FLASH) or European X-Ray Free Electron Laser (E-XFEL) are based on the Field Programmable Gate Array (FPGA) technology. Presently these accelerator facilities are operated with pulsed RF. In...
Conference Paper
An R&D program at DESY exploring the potential of the production of 1.3 GHz TESLA shape cavities from large grain or ingot niobium material has been carried out as a feasibility study for using ingot niobium material for the European X-ray Free-Electron Laser project. The most important issues like feasibility of the fabrication of niobium discs fr...
Conference Paper
Full-text available
SRF Gun Cavity is an ongoing accelerator R&D project at DESY, being developed since several years. Currently several SRF gun cavity prototypes were simulated, built and tested in our Lab and elsewhere [1] - [11]. Lately the 1.6 cells niobium cavity with Pb thin film cathode was tested in a vertical cryostat with different cathode plug configuration...
Conference Paper
Full-text available
Results are reported on using evaporation and UHV arc lead deposition to create thin-layer superconducting Pb photocathodes on niobium wall of electron gun. Evaporated photocathodes were prepared and tested for the first time in 2014. A complete XFEL-type photoinjector with an evaporated photocathode underwent successful quality check at DESY-an ac...
Article
Full-text available
We discuss the progress in the R program for a future upgrade of the European XFEL facility, namely for an operation in the continuous wave (cw) and long pulse (lp) modes, which will allow for significantly more flexibility in the electron and photon beam time structure. Results of cw/lp runs with preseries XFEL cryomodules and status of components...
Article
Full-text available
A combination of a ultra high vacuum arc deposition system and a recrystallization method was used to optimize the smoothness and thickness of thin-layer lead cathodes for superconducting niobium electron injectors. A non-filtered arc system was chosen to deposit Pb films on niobium. The films then underwent melting and recrystallization by treatin...
Article
This paper describes the scientific aims and potentials as well as the preliminary technical design of IRIDE, an innovative tool for multi-disciplinary investigations in a wide field of scientific, technological and industrial applications. IRIDE will be a high intensity “particles factory”, based on a combination of high duty cycle radio-frequency...
Article
The European XFEL will operate nominally at 17.5 GeV in SP (short pulse) mode with 0.65 ms long bunch train and 10 Hz repetition rate. A possible upgrade of the linac to CW (continuous wave) or LP (long pulse) modes with a corresponding reduction of electron beam energy is under discussion since many years. Recent successes in the dedicated R&D pro...
Chapter
Full-text available
European XFEL is planned to be a fourth-generation source of coherent, hard X-rays. The paper summarizes the results obtained till the middle of 2014 of the effords of Polish institutions involved in construction of the device. Wroclaw University of Technology was in charge of design and Wroclaw Technology Park with its subcontructors were responsi...
Chapter
Full-text available
Works on deposition and optimization of lead layer photocathodes for niobium superconducting electron injectors of TESLA/XFEL type are performed at National Centre for Nuclear Research (Otwock-Swierk, Poland) in collaboration with Deutsches Elektronen Synchrotron (DESY, Hamburg) and Helmholtz Zentrum Berlin (HZB). Three procedures of lead depositio...
Article
Full-text available
Photocathodes are a limiting factor for the next generation of ultrahigh brightness photoinjectors. We studied the behavior of a superconducting Pb cathode in the cryogenic environment of a superconducting rf gun cavity to measure the quantum efficiency, its spatial distribution, and the work function. We will also discuss how the cathode surface c...
Article
Full-text available
We report the efforts undertaken at NCBJ and some of its collaborating laboratories dedicated to prepare pure and flat lead films coated onto niobium to operate as superconducting photocathodes. Three approaches to lead cathodic arc deposition have been implemented and tested: active plasma flux filtering, passive filtering and unfiltered flux. Non...
Article
Full-text available
In the years 2010-2011 Polish research institutes - members of the European-XFEL consortium, took responsibility for production and delivery of important components and test procedures for the superconducting linear electron accelerator (linac) of the X-ray free electron laser at DESY (Hamburg).. The paper briefly summarizes the progress of the...
Conference Paper
Full-text available
The cryomodule test bench (CMTB) at the Deutsches Elektronen Synchrotron (DESY) in Hamburg is equipped with a 100 kW inductive output tube (IOT) allowing the test of superconducting cryomodules in continuous wave (CW) operation mode. Although significantly different from the nominal pulsed operation mode of the European x-ray free electron laser (X...
Conference Paper
Full-text available
Photocathodes are a limiting factor for the next generation of ultra-high brightness photoinjector driven accelerators. We studied the behavior of a superconducting Pb cathode in the cryogenic environment of a superconducting RF gun cavity related to the quantum efficiency (QE), its spatial distribution and the work function. The cathode surface co...
Conference Paper
Full-text available
Superconducting rf photo-electron injectors (SRF photoinjectors) hold the promise to deliver high brightness, high average current electron beams for future light sources or other applications demanding continuous wave operation of an electron injector. This paper discusses results from beam commissioning of a hybrid SRF photoinjector based on a Pb...
Article
In this paper we present studies on the shape optimization of 1.6-cell cavity with solenoid for a 1-mA class photo injector, meant as an electron source for FEL facilities. The main criterion for the optimization was the lowest slice emittance. The inclination angle of the cavity back wall, solenoid magnetic field and amplitude of the accelerating...
Article
The development of a simple and robust SRF photoinjector capable of delivering 1 mA average current in c.w. operation continues to advance with the horizontal RF testing of the 1.6 cell Pb/Nb hybrid photoinjector. This injector utilizes a sputtered lead coating on a removable Nb cathode plug as the photoelectron source and has recently been tested...
Article
The European XFEL superconducting linac is based on cavities and cryomodules (CM) developed for TESLA linear collider. The XFEL linac will operate nominally in short pulse (sp) mode with 1.3 ms RF pulses (650 μs rise time and 650 μs long bunch train). For 240 ns bunch spacing and 10 Hz RF-pulse repetition rate, up to 27000 bunches per second can be...
Article
R&D programs based on various approaches, at BNL, FZ-Rossendorf, Beijing University and AES generate optimism that low emittance continuous wave operating SRF-guns and injectors will be available in the near future. This contribution covers present status of these programs and it presents recently proposed alternative approach for the SRF-gun desig...
Article
We present the results of our investigation of lead and niobium as suitable photocathode materials for superconducting RF injectors. Quantum efficiencies (QE) have been measured for a range of incident photon energies and a variety of cathode preparation methods, including various lead plating techniques on a niobium substrate. The effects of opera...
Article
Full-text available
We give a brief overview of the history, state of the art, and future for elliptical superconducting cavities. Principles of the cell shape optimization, criteria for multi-cell structures design, HOM damping schemes and other features are discussed along with examples of superconducting structures for various applications.
Conference Paper
Full-text available
In collaboration with Jefferson Laboratory, DESY and the A. Soltan Institute HZB developed a fully superconducting RF photo-injector as a first step towards a high average current electron source for the BERLinPro ERL. This setup consists of a 1.6 cell superconducting gun cavity with a lead cathode plasma-arc deposited on the half cell backwall and...
Article
Full-text available
As part of the BERLinPro study, HZB is developing an SRF photoelectron injector. The R&D will be carried out in three stages, the first of which is currently being installed at HZB's HoBiCaT facility. It consists of an SRF cavity with SC solenoid, electron beam diagnosics and drivelaser systems.
Article
Full-text available
ERLs have the powerful potential to provide very high current beams with exceptional and tailored parameters for many applications, from next-generation light sources to electron coolers. However, the demands placed on the elec-tron source are severe. It must operate CW, generating a current of 100 mA or more with a normalized emittance of order 1...
Article
Full-text available
As part of a CRADA (Cooperative Research and Development Agreement) between Forschungszentrum Dresden (FZD) and JLab we have fabricated and tested after appropriate surface treatment a 1.5 cell, 1300 MHz RRR niobium photo-injector cavity to be used in a demonstration test at BESSY*. Following a baseline test at JLab, the cavity received a lead spot...
Article
In preparation for a high brightness, high average current electron source for the energy recovery linac BERLinPro an all superconducting radio-frequency (SRF) photoinjector is now in operation at Helmholtz-Zentrum Berlin. The aim of this experiment is beam demonstration with a high brightness electron source able to generate short, few ps long pul...
Article
The European XFEL will use superconducting (sc) TESLA cavities operating with 650 μs long bunch trains. With 220 ns bunch spacing and 10 Hz RF-pulse repetition rate, up to 27000 high quality bunches/s will be delivered to insertion devices generating unprecedented high average brilliance photon beams at very short wavelength. While many experiments...
Article
Full-text available
Since 1993, DESY ordered 166 1.3GHz 9-cell superconducting cavities. The cavities have been developed for the TeV-Energy Superconducting Linear Accelerator (TESLA) [1-4] and are used in the LINAC of the Free Electron LASer in Hamburg (FLASH). The fabrication of all cavities was done in 10 production groups at industry. From the beginning the indust...
Article
Full-text available
This paper reports on our efforts to develop a flangeable coaxial coupler for both higher order mode and fundamental coupling for nine-cell ILC-type cavities, which were designed in the early 1990's for pulsed operation with a duty factor less than 1%. The design of the coupler has been done in such a way that the rf magnetic flux B at the flange c...
Article
Full-text available
This paper reports about our efforts to develop a flangeable coaxial coupler for both HOM and fundamental coupling for 9-cell TESLA/ILC-type cavities. The cavities were designed in early 90s for pulsed operation with a low duty factor, less than 1 %. The proposed design of the coupler has been done in a way, that the magnetic flux B at the flange c...
Article
Full-text available
In this contribution, we report Quantum Efficiency (QE) test results with a hybrid lead/niobium superconducting RF (SRF) photoinjector at 2K and new Pb arc deposited cathodes at 300K. The ultimate goal of our effort is to build a Nb injector with the superconducting cathode made of lead, which, as reported in the past, demonstrated superior QE comp...
Article
Full-text available
High frequency Higher Order Modes (HOM) propagating in the beam line of a superconducting linac can carry a substantial fraction of the energy deposited by the beam in accelerating structures. In this contribution, we report tests results of the beam line absorber (BLA), which was designed and fabricated at DESY, and installed in the FLASH accelera...
Article
The availability of a superconducting connection between adjacent niobium radio-frequency (RF) cavities with the capability to carry up to 30 mT of the magnetic flux would be particularly of great benefit to layouts of long accelerators like the International Linear Collider (ILC). It would shorten the distances between structures and therefore the...
Article
Full-text available
The collaborative development of an optimised cavity/cryomodule solution for application on ERL facilities has now progressed to final assembly and testing of the cavity string components and their subsequent cryomodule integration. This paper outlines the verification of the various cryomodule sub-components and details the processes utilised for...
Article
Full-text available
In this paper we describe the R&D roadmap at HZB for the development of a high-brightness, high average current SRF electron gun for an energy-recovery linac based synchrotron radiation source.
Article
Full-text available
We present the results of our investigation of lead as a suitable photocathode material for superconducting rf injectors. Quantum efficiencies (QE) have been measured for a range of incident photon energies and compared to predictions from the three-step model of photoemission. A variety of cathode preparation methods have been used, including vari...
Book
Full-text available
This volume, which is the first in the EuCARD Editorial Series on “Accelerator Science and Technology”, is closely combined with the most advanced particle accelerators – based on Superconducting Radio Frequency (SRF) technology. In general, SRF research includes following areas: high gradient cavities, cavity prototyping, thin film technologies, l...
Article
Full-text available
The Continuous Electron Beam Accelerator Facility (CEBAF) recirculating accelerator at Jefferson Lab consists of two linacs carrying beam for up to five passes of acceleration. The design of this accelerator anticipated the onset of multipass beam break-up (BBU) at a beam current of approximately 20 mA, far above the operational peak current of 200...
Article
Higher Order Modes generated by a particle beam passing through a superconducting accelerating cavity have to be damped to avoid beam instabilities. A coaxial coupler located in the beam pipes of the cavities provides for better propagation of HOMs and strong damping in appropriate HOM dampers. The whole damping device can be designed as a detachab...
Article
A superstructure for accelerating charged particles at relativistic speeds. The superstructure consists of two weakly coupled multi-cell subunits equipped with HOM couplers. A beam pipe connects the subunits and an HOM damper is included at the entrance and the exit of each of the subunits. A coupling device feeds rf power into the subunits. The su...
Article
R&D programs based on various approaches, at BNL, FZ-Rossendorf, Beijing University and AES generate optimism that low emittance continuous wave operating SRF-guns and injectors will be available in the near future. This contribution covers present status of these programs and it presents recently proposed alternative approach for the SRF-gun desig...
Article
Full-text available
This paper reports on recent progress in the application of ultrahigh vacuum arc technology, which was proposed as an alternative solution for the deposition of thin superconducting films of pure niobium upon the inner surfaces of RF cavities designed for particle accelerators. New experiments were conducted to deposit superconducting films of pure...
Article
Approximately two years ago we started to develop high performance niobium accelerating cavities based on large grain or single crystal high purity niobium. We have fabricated and tested 15 single cell cavities of various shapes and frequencies between 1300 MHz and 2300 MHz using material from a total of 9 different very large grain niobium ingots...
Conference Paper
Full-text available
We report on the progress and status of an electron RF* gun made of two superconductors: niobium and lead [1]. The presented design combines the advantages of the RF performance of bulk niobium superconducting cavities and the reasonably high quantum efficiency of lead. The design of RF-gun and performance of 3 test cavities without and with the em...
Conference Paper
Full-text available
We report recent progress in the development of a hybrid lead/niobium superconducting RF (SRF) photoinjector. The goal of this effort is to produce an injector with the SRF properties of a niobium cavity along with the superior quantum efficiency (QE) of a lead photocathode. Quantum efficiency measurements have been performed on an RF cavity with a...
Conference Paper
Full-text available
The low-loss shape cavity design has been proposed as a possible alternative to the baseline TESLA cavity design for the ILC main linacs. The advantages of this design over the TESLA cavity are its lower cryogenic loss, and higher achievable gradient due to lower surface fields. High gradient prototypes for such designs have been tested at KEK (ICH...
Conference Paper
Full-text available
Several, partially successful attempts have been made in the past to develop a superconducting connection between adjacent niobium cavities with the capability to carry up to 30 mT of the magnetic flux. Such a connection would be particularly of great benefit to layouts of long accelerators like ILC because it would shorten the distances between st...
Book
Full-text available
This report contains a full technical description of the European X-ray Free-Electron Laser Facility, a new international scientific infrastructure to be built in the north west of Hamburg. The purpose of the facility is to generate extremely brilliant (peak brilliance ~ 1033 photons/s/mm2/mrad2/0.1%BW), ultra-short (~ 100 fs) pulses of spatially c...
Article
Superconducting standing wave structures have been used for charged particle acceleration for almost 40 years. A brief introduction to this application with examples, test procedures and recently achieved results are discussed in this paper.