153 research outputs found
Effect of Beam Dynamics Processes in the Low Energy Ring ThomX
As part of the R\&D for the 50 MeV ThomX Compton source project, we have
studied the effect of several beam dynamics processes on the evolution of the
beam in the ring. The processes studied include among others Compton
scattering, intrabeam scattering, coherent synchrotron radiation. We have
performed extensive simulations of a full injection/extraction cycle (400000
turns). We show how each of these processes degrades the flux of photons
produced and how a feedback system contributes to recovering most of the flux.Comment: Submitted to IPAC'14, WEPRO00
A collimation system for ELI-NP Gamma Beam System - design and simulation of performance
The purpose of this study was to evaluate the performance and refine the design of the collimation system for the gamma radiation source (GBS) currently being realised at ELI-NP facility. The gamma beam, produced by inverse Compton scattering, will provide a tunable average energy in the range between 0.2 and 20Ă‚ MeV, an energy bandwidth 0.5% and a flux of about 108Ă‚ photons/s. As a result of the inverse Compton interaction, the energy of the emitted radiation is related to the emission angle, it is maximum in the backscattering direction and decreases as the angle increase [1,2]. Therefore, the required energy bandwidth can be obtained only by developing a specific collimation system of the gamma beam, i.e. filtering out the radiation emitted at larger angles. The angular acceptance of the collimation for ELI-NP-GBS must be continuously adjustable in a range from about 700 to 60Ă‚ ĂŽÂĽrad, to obtain the required parameters in the entire energy range. The solution identified is a stack of adjustable slits, arranged with a relative rotation around the beam axis to obtain an hole with an approximately circular shape. In this contribution, the final collimation design and its performance evaluated by carrying out a series of detailed Geant4 simulations both of the high-energy and the low-energy beamline are presented
Quadrupole scan emittance measurements for the ELI-NP compton gamma source
The high brightness electron LINAC of the Compton
Gamma Source at the ELI Nuclear Physics facility in Roma-
nia is accelerating a train of 32 bunches with a nominal total
charge of
250 pC
and nominal spacing of
16 ns
. To achieve
the design gamma flux, all the bunches along the train must
have the designed Twiss parameters. Beam sizes are mea-
sured with optical transition radiation monitors, allowing a
quadrupole scan for Twiss parameters measurements. Since
focusing the whole bunch train on the screen may lead to
permanent screen damage, we investigate non-conventional
scans such as scans around a maximum of the beam size
or scans with a controlled minimum spot size. This paper
discusses the implementation issues of such a technique in
the actual machine layou
Generation of primary photons through inverse Compton scattering using a Monte Carlo simulation code
Photon sources based on inverse Compton scattering, namely, the interaction between relativistic electrons and laser photons, are emerging as quasimonochromatic energy-tunable sources either as compact alternatives to synchrotron facilities for the production of low-energy (10–100 keV) x rays or to reach the 1–100 MeV photon energy range, which is inaccessible at synchrotrons. Different interaction layouts are possible for electron and laser beams, and several applications are being studied, ranging from fundamental research in nuclear physics to advanced x-ray imaging in the biomedical field, depending on the radiation energy range, intensity, and bandwidth. Regardless of the specific application, a reliable tool for the simulation of the radiation produced is essential for the design, the commissioning, and, subsequently, the study and optimization of this kind of source. Different computational tools have been developed for this task, based on both a purely analytical treatment and Monte Carlo simulation codes. Each of these tools has strengths and weaknesses. Here, we present a novel Monte Carlo code based on GEANT4 for the simulation of inverse Compton scattering in the linear regime. The code produces results in agreement with CAIN, one of the most used Monte Carlo tools, for a wide range of interaction conditions at a computational time reduced by 2 orders of magnitude. Furthermore, the developed tool can be easily embedded in a GEANT4 user application for the tracking of photons generated through inverse Compton scattering in a given experimental setup
Synchronised TeraHertz radiation and soft X-rays produced in a FEL oscillator
In this paper, we present the generalities of the Compton interaction process; we analyse the different paradigms of Inverse Compton Sources, implemented or in commissioning phase at various facilities, or proposed as future projects. We present an overview of the state of the art, with a discussion of the most demanding challenges
Intrinsic mono-chromatic emission of x and gamma-rays in symmetric electron-photon beam collisions
This paper explores the transition between Compton Scattering and Inverse
Compton Scattering (ICS), which is characterized by an equal exchange of energy
and momentum between the colliding particles (electrons and photons). This
regime has been called Symmetric Compton Scattering (SCS) and has the unique
property of cancelling the energy-angle correlation of scattered photons, and,
when the electron recoil is large, transferring mono-chromaticity from one
colliding beam to the other, resulting in back-scattered photon beams that are
intrinsically monochromatic. The paper suggests that large-recoil SCS or
quasi-SCS can be used to design compact intrinsic monochromatic gamma-ray
sources based on compact linacs, thus avoiding the use of GeV-class electron
beams together with powerful laser/optical systems as those typically required
for ICS sources
State of the art of high-flux Compton/Thomson X-rays sources
In this paper, we present the generalities of the Compton interaction process; we analyse the different paradigms of Inverse Compton Sources, implemented or in commissioning phase at various facilities, or proposed as future projects. We present an overview of the state of the art, with a discussion of the most demanding challenges
Compton sources for the observation of elastic photon-photon scattering events
We present the design of a photon-photon collider based on conventional Compton gamma sources for the observation of elastic \u3b3\u3b3 scattering. Two symmetric electron beams, generated by photocathodes and accelerated in linacs, produce two primary gamma rays through Compton backscattering with two high energy lasers. The elastic photon-photon scattering is analyzed by start-to-end simulations from the photocathodes to the detector. A new Monte Carlo code has been developed ad hoc for the counting of the QED events. Realistic numbers of the secondary gamma yield, obtained by using the parameters of existing or approved Compton devices, a discussion of the feasibility of the experiment and of the nature of the background are presented
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