Design Of Beamline Research Articles

Optical design of the time-resolved ARPES beamline of the new material spectroscopy experimental station for the update of CAEP THz-FEL facility

Abstract The Chinese Academy of Engineering Physics Terahertz Free Electron Laser Facility (CAEP THz FEL, CTFEL) is the only high-average power free electron laser terahertz source based on superconducting accelerators in China. The update of the CTFEL is now undergoing and will expand the frequency range from 0.1-4.2 THz to 0.1-125 THz. Two experimental stations for material spectroscopy and biomedicine will be built. A high harmonic generation (HHG) lightsource based beamline at the material spectroscopy experimental station for time-resolved angle-resolved photoemission spectroscopy (ARPES) research will be constructed and the optical design is presented. The HHG lightsource covers the extreme ultraviolet (XUV) photon energy range of 20-50 eV. A Czerny-Turner monochromator with two plane gratings worked in conical diffraction configuration is employed for maintaining the transmission efficiency and preserving the pulse time duration. The calculated beamline transmission efficiency is better than 5% in the whole photon energy range. To our knowledge, this is the first time in China to combine THz-infrared FEL with HHG light source, and this experimental station will be a powerful and effective instrument and give new research opportunities in the future for users doing research on dynamic evolution of excited electron band structure of material surface.

Design of an Optimized Terahertz Time-Domain Spectroscopy System Pumped by a 30 W Yb:KGW Source at a 100 kHz Repetition Rate with 245 fs Pulse Duration

Ytterbium laser sources are state-of-the-art systems that are increasingly replacing Ti:Sapphire lasers in most applications requiring high repetition rate pulse trains. However, extending these laser sources to THz Time-Domain Spectroscopy (THz-TDS) poses several challenges not encountered in conventional, lower-power systems. These challenges include pump rejection, thermal lensing in nonlinear media, and pulse durations exceeding 100 fs, which consequently limit the detection bandwidth in TDS applications. In this article, we describe our design of a THz-TDS beamline that seeks to address these issues. We report on the effectiveness of temperature controlling the Gallium Phosphide (GaP) used to generate the THz radiation and its impact on increasing the generation efficiency and aiding pump rejection while avoiding thermal distortions of the residual pump laser beam. We detail our approach to pump rejection, which can be implemented with off-the-shelf products and minimal customization. Finally, we describe our solution based on a commercial optical parametric amplifier to obtain a temporally compressed probe pulse of 55 fs duration. Our study will prove useful to the increasing number of laboratories seeking to move from the high-energy, low-power THz time-domain spectroscopy systems based on Ti:Sapphire lasers, to medium-energy, high-power systems driven by Yb-doped lasers.

Design of a large energy acceptance beamline using fixed field accelerator optics

Large energy acceptance arcs have been proposed for applications such as cancer therapy, muon accelerators, and recirculating linacs. The efficacy of hadron therapy can be improved by reducing the energy layer switching time, however this is currently limited by the small momentum acceptance of the beam delivery system (<±1%). A “closed-dispersion arc” with a large momentum acceptance has the potential to remove this bottleneck, however such a beamline has not yet been constructed. We have developed a design methodology for large momentum acceptance arcs with Fixed Field Accelerator optics, applying it to a demonstrator beam delivery system for protons at 0.5–3.0 MeV (±42% momentum acceptance) as part of the Technology for Ultra-Rapid Beam Operation project at the University of Melbourne. Using realistic magnetic fields, a beamline has been designed with zero dispersion at either end. An algorithm has been devised for the construction of permanent magnet Halbach arrays for this beamline with multipole error below one part in 104, using commercially available magnets. The sensitivity to errors has been investigated, finding that the delivered beam is robust in realistic conditions. This study demonstrates that a closed-dispersion arc with fixed fields can achieve a large momentum acceptance, and we outline future work required to develop these ideas into a complete proof-of-principle beam delivery system that can be scaled up for a medical facility. Published by the American Physical Society 2024

Design of a Facility for Simultaneous Irradiation with Two Ion Beams based on the HIPR Accelerator for Simulations Neutron Influence

Ion accelerator facility is a powerful tool to simulate neutron irradiation effects in reactor materials. Defects in the crystal lattice arise and the accumulation of transmutation products (helium and hydrogen) occurs in the structure of the material under the action of neutrons in the structural materials of nuclear installations. At Kurchatov Complex for Theoretical and Experimental Physics the heavy ion accelerator HIPr (heavy ion prototype) is used to simulate radiation damage in steels and alloys using a 5.6 MeV Fe2+ ion beam. The second beam line is designed at the HIPr facility to simultaneously implant helium (or hydrogen) into the region of defects. The second beam line provides a beam of helium ions with energy up to 300 keV. The report presents a description of second beam line design and a status of construction the second beam line.

Start-to-end modeling and transmission efficiency optimization for a cyclotron-based proton therapy beamline

Utilizing first-order beam dynamics models is adequate for studying the beam properties during the conceptual design of a cyclotron-based proton therapy beamline. After finishing lattice design, particle-matter interaction simulations for passive elements (e.g., degrader, collimators, energy slit) are required. The cascade simulation is used for lattice updates in each iteration, which is complicated. In addition, when the models involve particle tracking and particle-matter interaction, their optimization process is time-consuming. Therefore, this study proposes a start-to-end modeling method using Monte Carlo Beam Delivery Simulation (BDSIM) software that considers more realistic factors, such as particle-matter interaction and the realistic vacuum chamber, to precisely evaluate working parameters, along with an efficient optimization method that utilizes multi-objective Bayesian optimization (MOBO) to improve transmission efficiency. Taking the Huazhong University of Science and Technology proton therapy facility (HUST-PTF) as an example, beam loss along the beamline is located, quantified, and subsequently reduced by tuning the quadrupole strengths based on MOBO. The results show that: (i) By considering the particle-matter interaction and the realistic vacuum chamber, the precision in the prediction of the beam properties is improved; (ii) After optimization, the transmission efficiency of the entire beamline is relatively increased by an average of 6.52 % under different energy settings, especially 11.39 % at 70 MeV.

The concept for hard X-ray beamline optics atSLS2.0.

In the scope of the latest upgrade of the Swiss Light Source, five hard X-ray beamlines will be constructed or rebuilt. To use synergies between these beamline projects, a concept is developed here for hard X-ray beamlines that is tailored to the new storage ring. Herein, this concept is described from the source, via the front end, to the beamline optics. The latter will be outlined in detail, including a new and modular concept for hard X-ray monochromators, focusing optics and heat-load management. With a simple, easy-to-operate and robust beamline design, the new beamlines will greatly profit from the increased brilliance of the new storage ring. The performance increase is up to four orders of magnitude, while the beamline concept allows for the broad application of experimental techniques, from propagation-based methods, such as phase-contrast tomography, to imaging techniques with nanometre resolution. At the same time, spectroscopy experiments are possible as well as high-performance serial X-ray crystallography.

Incident beamline design for a modern cold triple axis spectrometer at the High Flux Isotope Reactor

A modern cold triple axis spectrometer is being planned for the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. Here, we describe the design of an incident beamline that will put a flux of ∼108ncm2s on a sample with an area of 2 cm × 2 cm. It takes current physical constraints at HFIR into account and it can accommodate both single and multiplexed analyzer-detector secondary spectrometers and large superconducting magnets. The proposed incident beamline includes a multi-channel guide with horizontal focusing, a neutron velocity selector, components to facilitate an incident beam polarization option, and a double-focusing pyrolytic graphite monochromator. This work describes the process of optimizing the guide system and monochromator and summarizes the expected performance of the incident beamline for non-polarized operation.

Design of RIXS beamline at Shenzhen innovation light facility

An optical design of the RIXS beamline for the Shenzhen Innovation Light Facility (SILF) was reported. The beamline will cover an energy range from 200 to 1500 eV, with three endstations: a Q-RIXS for momentum-dependent high-resolution resonant inelastic x-ray scattering, an e-RIXS for high-throughput resonant inelastic x-ray scattering and an APXPS. All endstations share the same undulator, front end optics and the main branch of beamline until the deflecting mirrors after the monochromator. The Q-RIXS and e-RIXS will be located in two separate branches, while the APXPS endstation is mounted on a free port located right between the exit slit and the refocusing optics for the e-RIXS endstation. This design allows for the mounting of different techniques and the preparation of sample environments without disrupting the operation of the other branch, thus maximizing the utilization of beamtime. The combined energy resolution is expected to be better than 50 meV for Q-RIXS and better than 100 meV for e-RIXS. Once available, it will provide in-demand, versatile and high-quality soft x-ray spectroscopy techniques to users in fields of quantum, energy and surface science.

Emittance growth analysis of laser-driven broad energy spectral proton beams

With the rapid development of high-gradient laser plasma acceleration, implementing it in practical applications has become a priority. However, to go from “acceleration” to “accelerator,” a beam line system is required to accurately control the beam parameters according to different irradiation requirements. The laser-accelerated proton beam is characterized by a micron-scale original source size and a small emittance as low as 0.004 mm mrad [T. E. Cowan , ]. However, due to the broad energy spread and large divergence, its initial ultralow emittance will increase rapidly in the subsequent transmission process. This indicates that designing a beamline for laser-driven protons is challenging and differs significantly from that of a conventional accelerator. As a fundamental parameter for beam line design, we have theoretically derived the emittance growth law for laser-driven protons in both drift space and in a focusing element. The results demonstrate that the beam emittance deteriorates sharply with the energy spread and the square of the divergence angle. These theoretical calculations have been verified both in experiments and simulations. This work is helpful for designing subsequent beam lines that pursue high transmission efficiency and achromatic ability. Published by the American Physical Society 2024

Technical design of an axial injection low-energy carbon beam line

Technical design of an axial injection low-energy carbon beam line

Beamline design for multipurpose muon beams at CSNS EMuS

A new muon beam facility, called the Experimental Muon Source (EMuS), was proposed for construction at the China Spallation Neutron Source (CSNS). The design of the complex muon beamlines for the EMuS baseline scheme, which is based on superconducting solenoids, superferric dipoles and room-temperature magnets, is presented herein. Various muon beams, including surface muons, decay muons and low energy muons, have been developed for multipurpose applications. The optics design and simulation results of the trunk beamline and branch beamlines are presented. With a proton beam power of 25 kW at a standalone target station that consists of a conical graphite target and high-field superconducting solenoids, the muon beam intensity in the trunk beamline varies from 107/s for surface muons to 1010/s for high-momentum decay muons. And at the endstations, these values vary from 105/s for surface muons to 108/s for decay muons.

X-ray Synchrotron Radiation to Look at Pigments in Antiquities: Overview and Examples

The recent upgrading of synchrotron radiation (SR) sources has favored, in the last few years, the construction and design of beamlines optimized for the study of cultural heritage materials, which may require ad hoc setups, specific spatial resolutions, and detection limits. In the field of cultural heritage, integrated approaches combining different techniques are often required, even at large facilities, where some beamlines offer the possibility of performing different types of measurements at the same point of analysis, complementing preliminary information usually obtained by conventional laboratory and/or portable in situ methods. An overview of the last ten years of synchrotron applications for the study of pigments is given, with discussion of upstream and downstream challenges to methods and techniques. The possibilities offered by the synchrotron techniques are illustrated by a case study of a particular class of painted ceramics, as an example of different research questions that are solved by a combination of SR-based methods.

VerSoX B07-B: a high-throughput XPS and ambient pressure NEXAFS beamline at Diamond Light Source.

The beamline optics and endstations at branch B of the Versatile Soft X-ray (VerSoX) beamline B07 at Diamond Light Source are described. B07-B provides medium-flux X-rays in the range 45-2200 eV from a bending magnet source, giving access to local electronic structure for atoms of all elements from Li to Y. It has an endstation for high-throughput X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine-structure (NEXAFS) measurements under ultrahigh-vacuum (UHV) conditions. B07-B has a second endstation dedicated to NEXAFS at pressures from UHV to ambient pressure (1 atm). The combination of these endstations permits studies of a wide range ofinterfaces and materials. The beamline and endstation designs are discussed in detail, as well as their performance and the commissioning process.

Design and characterization of an antiproton deceleration beamline for the PUMA experiment

We report on the design and characterization of an antiproton deceleration beamline, based on a pulsed drift tube, for the PUMA experiment at the Antimatter Factory at CERN. The design has been tailored to high-voltage (100kV) and ultra-high vacuum (below 10−10mbar) conditions. A first operation achieved decelerating antiprotons from an initial energy of 100keV down to (3898±3)eV, marking the initial stage in trapping antiprotons for the PUMA experiment. Employing a high-voltage ramping scheme, the pressure remains below 2×10−10mbar upstream of the pulsed drift tube for 75% of the cycle time. The beamline reached a transmission of (55±3)% for antiprotons decelerated to 4keV. The beam is focused on a position sensitive detector to a spot with horizontal and vertical standard deviations of σhoriz=(3.0±0.1)mm and σvert=(3.8±0.2)mm, respectively. This spot size is within the acceptance of the PUMA Penning trap.

Medical radionuclide research activities at JRC-Geel

A programme to study photon- and neutron-induced reactions of medical interest, as well as accelerator-based methods of medical radionuclide production, has been instituted at JRC-Geel, making use of both existing and new infrastructure. A new electron beamline that can deliver quasi-monoenergetic beams has been commissioned at the GELINA electron linac and will be primarily dedicated to the study of photonuclear reactions and for medical radioisotope production studies via photon irradiation. The recently renewed MONNET 3.5 MV Tandem accelerator provides light ion beams for reactionbased quasi-mono-energetic neutron production and has been used for the study of 99Mo production via neutron irradiation of molybdenum nanoparticles. In this work we present an overview of the medical radionuclide activities at JRCGeel, with particular attention to aspects of the design, development and operational challenges of the new GELINA electron beamline. Some future perspectives of the programme are also discussed.

Characterising the Pelletron beam at the University of Melbourne

The Pelletron at the University of Melbourne is a DC particle accelerator that has been used for materials analysis and ion implantation since its installation in the 1970s. Today, it is primarily used to produce proton and helium beams up to 3.5 MeV and 1.5 MeV respectively, for three beamlines with a range of different experiments. The beam stability and fundamental beam parameters such as the transverse phase space distribution and emittance have not been previously investigated in detail. We have performed systematic measurements to determine the beam current variation, finding persistent fluctuations: our study determined that internal wire scanners used for monitoring the beam profile contribute to a periodic current drop. We also found that large terminal voltage oscillations reduce the average current. In addition, the phase space has been measured using a custom-built slit-grid apparatus. We found that the Courant–Snyder (Twiss) parameters are a function of the operational characteristics of the Pelletron, with the emittance more than doubling between measurements. To parametrise the beam despite the fluctuations, we introduce a ‘minimum bounding ellipse’ described by a set of Courant–Snyder parameters that is representative of the beam characteristics for all the measurements: for our data, this has β= 8.2(5)m, α=-5.2(3), and an emittance of 0.34(3)mmmrad. These parameters will enable future beamline design in Melbourne, and give an indication for the requirements at other Pelletron facilities. Our characterisation techniques can provide a low-cost method to probe beam parameters for improvements in the operation and efficiency of similar DC accelerators, allowing for more accurate measurements and reduced data acquisition times.

Design of beam line for BNCT applications in HEC-1 channel of IRT-T research reactor

The feasibility of using the HEC-1 beam port of the IRT-T research reactor to generate an epithermal neutron beam for Boron Neutron Capture Therapy (BNCT) was investigated using MCNPX2.6 Monte Carlo simulation. The reactor was first simulated to design and optimize a Beam Shaping Assembly (BSA) that meets the neutron beam criteria recommended by the International Atomic Energy Agency (IAEA). The suggested BSA configuration consisted of a cylindrical geometry with 25 cm of MgF2 and 15 cm of Fluental® as a moderator, 15 cm of Pb as a reflector, two 5 cm Bi slabs as gamma-ray shields, and 4 mm of 6Li and 5 mm of borated polyethylene sheets as thermal neutron filters. The results showed that the epithermal neutron flux at the BSA exit was 2.3×109 n/cm2.s, and in-phantom dose analysis indicated that the designed beam could be used for the treatment of deep brain tumors within an allowable treatment time of 50 min.

New approach to space charge dominated beamline design

New approach to space charge dominated beamline design

Design of an out-of-tank neutron beam line for prompt gamma neutron activation analysis at low-power Miniature Neutron Source Reactor

Research reactors are strong and stable neutrons sources, and various researches and applications were carried out using their neutron and gamma beamlines. Some research reactors, such as Miniature Neutron Source (MNSR) Reactors, do not have beam tube in their original design, which can be considered as a disadvantage. The design and installation of beamlines can develop their applications. In this research, the design and optimization of a suitable neutron beamline for PGNAA is done at Isfahan MNSR. Designs are done to reach the appropriate neutron beam parameters and taking into account the geometrical limitations of the MNSR. Neutron beam parameters including thermal neutron flux, thermal to total neutron flux, and thermal neutron flux to gamma dose ratio are considered. For this, vertical beamlines with different diameters are simulated and the optimal diameter is determined. Also, for optimization of beam parameters, a thermal column and gamma filter are considered and optimal conditions are determined.

Beamline and vacuum system design of HEBT for the A-FNS accelerator

The Advanced Fusion Neutron Source (A-FNS) project is progressing at the QST Rokkasho institute, Japan. The A-FNS will conduct fusion neutron irradiation tests of materials for a fusion demonstration reactor (DEMO reactor). For these tests a high intensity deuteron beam accelerator is used to produce a high neutron flux with the neutron energies around 14 MeV. The accelerator system accelerates a deuteron beam to a beam energy of 40 MeV, guides the beam towards a liquid lithium target and shapes the uniform beam at the Li target using a magnet system.Two of the main considerations for the A-FNS high energy beam transport (HEBT) design are protection of the Superconducting Radio-Frequency linear accelerator (SRF) and vacuum system design for the interface of the HEBT and the target system. For the A-FNS, back streaming of Li vapor from the windowless free surface of the Li target is a concern. In addition, widely different vacuum pressure must be maintained between the accelerator system and the target system. This paper shows the detailed design of the A-FNS HEBT section regarding these considerations.