Characterization of the electron source at the photo injector test facility at DESY Zeuthen (original) (raw)
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First beam measurements at the photo injector test facility at DESY Zeuthen
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2003
The Photo Injector Test facility at DESY Zeuthen (PITZ) was built to develop electron sources for the TESLA Test Facility Free Electron Laser (TTF-FEL) and future linear colliders. The main goal is to study the production of minimum transverse emittance beams with short bunch length at medium charge (~1nC). The facility includes a 1.5 cell L-band cavity with coaxial rf coupler, a solenoid for space charge compensation, a laser capable to generate long pulse trains, an UHV photo cathode exchange system, and different diagnostics tools. Besides an overview of the facility, its main components and their commissioning, this contribution will concentrate on the first measurements at PITZ with photo electrons. This will include measurements of the transverse and longitudinal laser profile, charge and quantum efficiency, momentum and momentum spread, transverse electron beam profiles at different locations and first results on transverse emittance. PACS codes: 29.25 Bx electron sources, 29.27 Fh beam characteristics, 41.60 Cr Free electron Laser, 41.75 Fr electron and positron beam, 41.85 Ew beam profile
Recent electron beam measurements at PITZ with a new photocathode laser system
The Photo Injector Test facility at DESY, Zeuthen site, (PITZ) aims to develop and optimize electron sources for frontiers linac based FELs such as FLASH and the European XFEL. A new laser system has been commissioned at PITZ in late autumn 2008. It is capable to deliver trains of laser pulses with challenging temporal shape: flat-top profile with ~20 ps FWHM and rise and fall times of ≤2 ps. This laser system, being a significant step towards the European XFEL photo injector specifications, has been used in a 1.6-cell L-band rf gun with up to ~60MV/m electric field at the cathode to produce high brightness electron beams. A major part of the PITZ measurement program is the optimizing of the transverse phase space. Recent electron beam measurements at PITZ will be presented.
Status of the Photo Injector Test Facility at DESY, Zeuthen Site (PITZ)
2010
The PITZ facility is established for the development and testing of electron sources for FELs like FLASH and the European XFEL. The facility has been upgraded during the shutdown starting in summer 2007 to extend the capability of the facility to produce and characterize low emittance electron beams. The upgraded setup mainly includes a photo cathode L-band RF gun with solenoid magnets for space charge compensation, a post acceleration booster cavity and several diagnostic systems. The diagnostic systems consist of charge and beam profile monitors, emittance measurement systems and spectrometers with related diagnostics in dispersive arms after the gun and the booster cavities. RF gun operation with an accelerating gradient of 60 MV/m at the cathode is realized with this setup. A new photo cathode laser system with broader spectral bandwidth was installed for optimizing the temporal distribution of the laser pulses regarding to electron beam properties. Experimental results with thi...
STATUS OF THE PHOTO INJECTOR TEST FACILITY AT DESY, ZEUTHEN SITE
The PITZ facility is established for the commissioning and testing of electron sources for FELs like FLASH and the European XFEL. The facility has been upgraded during the period from summer 2007 to summer 2008 to extend its capability to produce and characterize low emittance electron beams. The upgraded setup mainly includes a photo-cathode L-band RF gun with solenoid magnets for space charge compensation, a post acceleration booster cavity and several diagnostic systems. The diagnostic systems consist of charge and beam profile monitors, emittance measurement systems and spectrometers with related di-agnostics in dispersive arms after the gun and the booster cavities. The RF gun was dry-ice cleaned and operated with an accelerating gradient of 60 MV/m at the cathode. A new photocathode laser system with broader spectral bandwidth was installed for optimizing the temporal distribution of the laser pulses regarding to electron beam properties. In this contribution, the PITZ facility setup in the years 2008/2009 will be presented. Experimental results from this setup surpassed the electron beam quality requirements for the photoinjector source of the European XFEL [1].
Recent Electron Beam Optimization at Pitz
2014
High brightness electron sources for linac based free- electron lasers operating at short wavelength such as FLASH and the European XFEL are characterized and optimized at the Photo Injector Test Facility at DESY, Zeuthen site (PITZ). In the last few years PITZ mainly was used to con- dition RF guns for their later operation at FLASH and the European XFEL. Only limited time could be spent for beam characterization. However, recently we have performed emit- tance measurements and optimization for a reduced gun ac- celerating gradient which is similar to the usual operation conditions at FLASH. The results of these measurements are presented in this paper. tight time schedule. However, recently we got the possibility to partially perform electron beam characterization with an RF gun which was conditioned at PITZ and will be delivered for further usage at the European XFEL. Due to lack of time, the measurements were performed only for 1n Cand 100 pC electron beam charges. Only emittanc...
Recent results and perspectives of the low emittance photo injector at PITZ
The Photo Injector Test Facility at Zeuthen (PITZ) was built to study the production of minimum transverse emittance electron beams for Free Electron Lasers and future Linear Colliders. Until November 2003, the electron beam from the rf gun has been fully characterized at PITZ. For a bunch charge of 1 nC a minimum normalized projected beam emittance of 1.5 π mm mrad in the vertical plane and a minimum geometrical average of both transverse planes of 1.7 π mm mrad have been achieved. This fulfills the requirements of the VUV-FEL at DESY. In this contribution, an overview of the measured electron beam and high duty cycle rf parameters including transverse emittance, thermal emittance, bunch length, momentum, and momentum spread will be given. In addition, planned major upgrades and first results towards fulfilling the even more challenging requirements for the European XFEL will be discussed. This includes measurements with increased average and peak rf power and the improvement of th...
Physical Review Special Topics-accelerators and Beams, 2010
The photoinjector test facility at DESY, Zeuthen site (PITZ), was built to develop and optimize photoelectron sources for superconducting linacs for high-brilliance, short-wavelength free-electron laser (FEL) applications like the free-electron laser in Hamburg (FLASH) and the European x-ray free-electron laser (XFEL). In this paper, the detailed characterization of two laser-driven rf guns with different operating conditions is described. One experimental optimization of the beam parameters was performed at an accelerating gradient of about 43 MV=m at the photocathode and the other at about 60 MV=m. In both cases, electron beams with very high phase-space density have been demonstrated at a bunch charge of 1 nC and are compared with corresponding simulations. The rf gun optimized for the lower gradient has surpassed all the FLASH requirements on beam quality and rf parameters (gradient, rf pulse length, repetition rate) and serves as a spare gun for this facility. The rf gun studied with increased accelerating gradient at the cathode produced beams with even higher brightness, yielding the first demonstration of the beam quality required for driving the European XFEL: The geometric mean of the normalized x On leave from MEPHI, Russia. ‡ Now at Siemens AG. † On leave from YERPHI, Armenia. * On leave from INRNE Sofia, Bulgaria. PHYSICAL REVIEW SPECIAL TOPICS -ACCELERATORS AND BEAMS 13, 020704 1098-4402=10=13(2)=020704 020704-1 Ó 2010 The American Physical Society projected rms emittance in the two transverse directions was measured to be 1:26 AE 0:13 mm mrad for a 1-nC electron bunch. When a 10% charge cut is applied excluding electrons from those phase-space regions where the measured phase-space density is below a certain level and which are not expected to contribute to the lasing process, the normalized projected rms emittance is about 0.9 mm mrad.
2007
The Photo Injector Test facility at DESY in Zeuthen (PITZ) was built to test and optimize electron guns for short wavelength Free-Electron Lasers (FELs) like FLASH and XFEL at DESY in Hamburg. For a detailed analysis of the behaviour of the electron bunch, the longitudinal phase space and its projections can be measured behind the gun cavity. The electric field at the photo cathode was increased from 40 MV/m to 60 MV/m to optimize the transverse emittance. The momentum distributions for different gradients and gun phases will be presented. In order to study emittance conservation, a booster cavity and additional diagnostics were installed. The evolution of the longitudinal phase space in the booster cavity will be investigated. Measurements of the momentum distribution and longitudinal distribution behind the booster cavity will be discussed.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2012
High brightness electron sources for linac based short-wavelength free-electron lasers are developed and optimized for small transverse projected emittance at the photo-injector test facility at DESY, location Zeuthen (PITZ). A major part of the measurement program at PITZ is dedicated to transverse phase space optimization in order to fulfill the requirements of the European X-ray free-electron laser (European XFEL). A laser-driven RF-gun, treated with a dry-ice sublimation-impulse cleaning technique, a new photocathode laser system allowing short rise and fall times of the flat-top temporal distribution as well as several new diagnostic components have been installed at PITZ in 2008. The electrons generated via the photo-effect at a cesium telluride (Cs 2 Te) cathode are accelerated by a 1.6 cell L-band RF-gun cavity with a maximum accelerating gradient at the cathode of about 60 MV/m. The transverse projected emittance is measured using a single slit scan technique. In the 2008-2009 run period, a detailed characterization of the projected transverse emittance was performed at different operating conditions. Optimizations and measurement results as well as simulation predictions of the transverse projected emittance for bunch charges of 1, 0.5, 0.25 and 0.1 nC are presented and discussed in this paper. The geometric mean of the normalized projected rms emittance in both transverse directions for an electron bunch charge of 1 nC was measured to be 0.8970.01 mm mrad for a 100% rms phase-space distribution.
Transverse-emittance measurements on an S-band photocathode RF electron gun
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2002
Proposed fourth generation light sources using SASE FELs to generate short pulse, coherent, X-rays require demonstration of high brightness electron sources. The Gun Test Facility (GTF) at SLAC was built to test high brightness sources for the proposed Linac Coherent Light Source at SLAC. The transverse emittance measurements are made at nearly 30 MeV by measuring the spot size on a YAG screen using the quadrupole scan technique. The emittance was measured to vary from 1 to 3.5 mmmrad as the charge is increased from 50 to 350 pC using a laser pulse width of 2 ps FWHM. The measurements are in good agreement with simulation results using the LANL version of PARMELA.