Overview on cooling and stacking methods at the GSI Experimental Storage Ring
Update on accelerator R&D with relevance for ST3 at HZB
The new synchrotron light source PETRA IV at DESY will use a fast orbit feedback system with hundreds of fast corrector magnets to meet stringent orbit stability requirements. These magnets are operated at high frequencies, creating strong eddy currents that result in Joule losses and a time delay between applied voltage and aperture field. User experiments impose challenging requirements on...
FLASH demonstrated recently for the first time seeded operation with the echo-enabled harmonic generation (EEHG) scheme. Additionally, the second FEL beamline was simultaneously operated in self-amplified spontaneous emission (SASE). This is a significant milestone towards the successful implementation of the FLASH2020+ project, aiming at the parallel operation of high repetition rate seeding...
In this talk, I will give an overview of the recent development of reinforcement learning-based controllers for particle accelerators, with a focus on the transverse beam tuning task at linear accelerators.
The ELBE timing system has been patched several times in order to meet changing requirements. In 2019 the development of a new timing system based on Micro Research Finland Hardware has been started which is designed to unify the heterogeneous structure and to replace obsolete components. The system generates complex beam patterns from single pulse, to macro pulse and 26 MHz cw operation...
In order to achieve unprecedented control over the phase space of electron beams in linear accelerators, the laser pulse of the photoinjector can be shaped by spatial light modulators (SLMs). Here, we use a convolutional neural network (CNN) from a proof-of-principle test with a visible diode laser on the TiSa-800-nm photoinjector laser system of the Ferinfrarot Linac- und Test-Experiment...
A fast orbit feedback system is currently being developed for the upcoming fourth generation of the PETRA IV light source at DESY Hamburg. The performance of the FOFB system depends mainly on the frequency response of the subsystems, i.e. the corrector magnets, power supplies, cables, and vacuum chamber. A test bench is being developed for measuring the field quality of FOFB corrector magnets...
While the time arrival stability of the electron bunches in an FEL can be as good as 5-10 fs rms, the arrival time of the optical laser pulses is on the order of 10 fs rms or worse. Here will be presented the update on a laser pulse arrival time monitor: the arrival time of the optical pulses will be measured against a reference from the laser-based optical synchronization system. With a...
Research and development of an accelerator-based THz source prototype for pump-probe experiments at the European XFEL are ongoing at the Photo Injector Test Facility at DESY in Zeuthen (PITZ). Proof-of-principle experiments have been performed to generate a high-gain THz Free-electron Laser (FEL) based on the Self-Amplified Spontaneous Emission scheme. The first lasing with a central...
The temporal quality on the 100 micro-second scale of the slowly extracted spill from GSI SIS18 is crucial for fixed-target experiments, which is influenced by the power supply ripples that act on the quadrupole magnets, causing temporal fluctuations, the so-called spill micro structure. Extensive simulations regarding the dependency of spill quality and transit time on the power supply...
Externally seeded high-gain FELs provide fully coherent radiation with high shot-to-shot stability at wavelengths tunable down to the soft X-ray range (applying harmonic conversion). However, the lack of suitable seed laser sources has been limiting the generation of such short-wavelength FEL radiation to low repetition rates. So, such setups have been unable to make use of the full repetition...
THz free electron laser (FEL) prototype has been developed at the Photo Injector Test Facility at DESY in Zeuthen (PITZ) for obtaining high intensity radiation for THz-pump and X-ray-probe experiments at the European XFEL. In this development, a magnetic bunch compressor (BC) was recently installed in the facility to manipulate the longitudinal properties of the electron bunch, resulting in...
R. Bazrafshan(1,4), G.H. Kassier(1), M. Fakhari(1), H. Delsim-Hashemi(2), T. Rohwer(1), K. Flöttmann(2), N.H. Matlis(1) and F. X. Kärtner(1,3,4)
(1) Center for Free-Electron Laser Science (CFEL), Deutsches Elektronen-Synchrotron, Hamburg, Germany
(2) Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
(3) The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Germany
(4)...
Plasma-based accelerators that impart energy gain as high as several GeV to electrons or positrons within a few centimeters have engendered a new class of diagnostic techniques very different from those used in connection with conventional radio-frequency (rf) accelerators [1]. The need for new diagnostics stems from the micrometer scale and transient structure of plasma accelerators, and from...
We present the preliminary experimental results of electron beam momentum modulation by a DLA at ARES. A fused silica micrometer scale grating was illuminated by a picosecond infrared laser. The timing was scanned to produce a crosscorrelation between the electron bunch and the laser pulse. The current limitations will be discussed and the planned improvement steps of the experiment. An...
Steady-State Microbunching (SSMB) has been proposed as a new mechanism to generate coherent synchrotron radiation at a storage ring facility with short wavelengths up to the EUV range. This promises a narrow band, high average power radiation source. A proof-of-principle experiment at the Metrology Light Source has shown the viability of the underlying mechanism. A summary of recent results...
Perhaps one of the most crucial diagnostic targets in the operation of accelerator facilities is the phase space density (PSD) of the accelerated particle bunches. The knowledge of the PSD not only governs the emission spectrum of the bunches, but it also determines other fundamental properties such as bunch length, energy spread, and more sophisticated, intra-bunch interactions. Importantly,...
Besides the classical Feschenko monitor also Fast Faraday Cups (FFC) and GHz Transition Radiation monitors (GTR) are able to measure the longitudinal bunch shape. While the Feschenko monitor observes an averaged bunch shape, both latter devices can measure the shape bunch by bunch within a bunch train. In this contribution we want to show the current research at GSI ion LINAC on FFCs and GTRs...
Regulating the arrival time of electron bunches is a crucial step to improve the temporal resolution of accelerator-based time-resolved experiments. Nowadays, a regulation method, called beam-based feedback, has been shown to work well for stabilizing the arrival time on pulsed accelerator machines. Essentially, this method resembles a typical design of a simple proportional regulator, where...
During the last decades, the precision of the measurement of length variations has increased drastically to reach the nanometer scale, or a sub-femtosecond timescale, based on transit time-stabilized optical fibers using femtosecond laser pulses. Thanks to the high precision of the stabilization system, the influence of different perturbations can be investigated, such as environmental changes...
At the KIT storage ring KARA (Karlsruhe Research Accelerator), two electro-optical (EO) diagnostical setups are implemented: An EO near-field monitor within the beam pipe in vacuum as a tool for longitudinal bunch profile measurements and an EO far-field setup to measure the temporal profile of the coherent synchrotron radiation (CSR).
The EO near-field monitor performs very well in...
The microstrip based pickup monitor (MPM) suited for arrival time detection is carefully investigated and the voltage signal at the feedthrough exit has been studied to obtain the optimized symmetrical signal amplitude and reduced wakefields prior to and subsequent to the bunch. Due to the superior potential behavior of the microstrip line with ultra-low charge signals (1pC) at 100 GHz...
Within the FLASH 2020+ project, the injector and linac had undergone substantial upgrades and changes, bringing along also adaptations of longitudinal diagnostics. The main advances have been made on the electronics and automation side, with regard to the special burst-mode bunch pattern with individual tuning capabilities for FLASH1 and FLASH2 beamlines. Here we present the most recent...
The Cryogenic Current Comparator (CCC) is able to provide a calibrated non-destructive measurement of beam currents with a resolution of 10 nA or better. The non-interceptive, absolute intensity measurement of weak ion beams (< 1 µA) is essential in heavy ion storage rings and in transfer lines, as the ones in FAIR. With standard diagnostics, this measurement is challenging for bunched beams...
At the Photo Injector Test facility at DESY in Zeuthen, Longitudinal Phase
Space (LPS) tomography is done to reconstruct the LPS before the booster. In
order to improve the existing technique, methodical studies were done where
some core concerns were addressed e.g. booster phase scan range, momentum
resolution and space-charge effects. An analytical model was developed to
quantify RMS...
At HZDR, the development of the Dresden Advanced Light Infrastructure (DALI) - a successor of the existing ELBE user facility, is ongoing. The new user facility will operate several SRF linac-based MIR-THz sources. The main motivation for the new facility is the user community request to increase the photon pulse energy from a few µJ, available now, to a few hundred µJ and even a mJ, in the...
The future proton injector Linac (pLinac) for the Facility of Antiproton and Ion Research (FAIR) at GSI, Darmstadt, will provide a 68 MeV, up to 70 mA proton beam at a duty cycle of max. 35µs / 2.7 Hz for the SIS18/SIS100 synchrotrons, using the existing UNILAC transfer beamline. The Linac will operate at 325 MHz and consists of a novel so called ‘Ladder’ RFQ, followed by a chain of...
Accelerator-Based Terahertz (THz) radiation sources[1] open new domains for both physical matter as well as application based research in the Terahertz domain. The generated THz Spectrum as well as its pulse shape is of importance for both, beam line scientists in order to study the beam dynamics[2] as well as for the experimental scientists in order to use THz signals for numerous studies....
Reliability and reproducibility of the measurement is what separates proof of principle or experimental diagnostics from systems used for day to day accelerator operation. The poster describes the steps that were taken to bring the Bunch Arrival Time Monitors of EuXFEL and FLASH to steady operation.
In most accelerator facilities the machine synchronization is crucial. It depends on bunch arrival-time measurements with high precision, which can be achieved either by RF synchronization or by an electro-optical detection scheme. For very low bunch charges down to a few pC, a single-digit fs resolution cannot not be reached with the state-of-the-art bunch arrival-time monitors (BAM). A new...
In preparation of future streaking experiments at the FLUTE linear accelerator using a split-ring resonator (SRR) structure we present measurements of the laser-based THz generation setup. We also show some efforts to improve the THz pulse strength using a different lens material and a dry air box to reduce the impact of water vapor.
2021-2027 PoF 4 (4th program-oriented funding period of the Helmholtz Association) => 2028-2035 PoF 5
Information material from the transition preparation from PoF 3 to PoF 4:
https://indico.desy.de/event/20689/contributions/40054/attachments/25682/32513/MT_ST3_POF4.pdf
The vision for MT ARD ST3 (PoF 4, 2021-2027):
https://indico.desy.de/event/36133/page/4250-vision
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