MeV Linac Research Articles

Optimization concrete shielding composition composed of different minerals for neutron and gamma radiation emitted from 18 MeV Linac using Monte-Carlo simulation

This study was conducted to find the best combined ratio of galena, hematite and limonite in concrete shielding structure against neutron and gamma rays emitted from 18 MeV Linac source in radiation therapy centers. The MCNPX code was used to calculate the linear attenuation coefficient of different concretes for the 18 MeV Linac source. The concrete samples were then produced in a laboratory, and their compressive strength was measured. Then, by comparing the quality factor diagrams that simultaneously express the power of neutron and gamma attenuation and compressive strength, the optimal point for the percentage of different minerals in concrete was identified. The results showed that the used minerals have a high gamma absorption capacity due to their high atomic number and density. It also showed that the neutron attenuation power increases with the increase in the concentration of galena, limonite, hematite in concrete and reaches to its maximum value. And if the concentration of minerals rises above a certain value, the neutron attenuation power of concrete decreases, due to the decrease in the concentration of lighter elements such as hydrogen in the concrete structure, as well as the increase in the probability of secondary neutrons production.The highest value of QF was obtained for samples containing 40% galena, 50% hematite and 40% limonite, and the highest value of QF/ρ was obtained for samples G30, G40, H50, L30 and L40. This type of concretes can be used to create an effective concrete shield for radiotherapy centers.

Mutation profiling through whole genome sequencing of electron beam-induced black gram (Vigna mungo L. Hepper) mutant

Purpose Black gram (Vigna mungo [L.] Hepper) is an important annual legume with great economic, nutritional and ecological significance. Novel variations through induced mutagenesis can accelerate narrow genetic base-impeded black gram improvement. This is a first study on characterization of genome-wide mutation spectrum induced by electron beam (EB). Materials and methods Black gram genotype ‘Pant U-31’ was irradiated with 400 Gy EB generated in a 10 MeV LINAC. A stable mutant PM-32 (M6) was re-sequenced by combining Illumina (BIOO Scientific, Inc., Austin, TX) and Nanopore Technologies (Oxford, UK). Variants were predicted in reference to the available whole genome scaffold level draft assembly of parent ‘Pant U-31’. Results Genome analysis predicted a total of 76,893 genes of which 58,517 were annotated. The identified variants totaling 728,161, largely comprised (91.56%) of single base substitutions (SBSs) with a transition (Ti) to transversion (Tv) ratio of 1.95. Of the indels constituting 8.44% of total induced variants, insertions accounted for 4.29%, with preponderance of multiple bases (53.63%) and 2–5 bp insertions as the major class (33.71%). Multiple-base deletions (2–5 bases) formed the bulk (31.14%) of the total deletions. The genic variants (2438) with estimated high and moderate effects were located within 1271 predicted genes. A higher number of mutations were observed on chromosomes Vm1 (588) and Vm3 (428) with the highest frequency on chromosome Vm3 (every 0.07 Mb). Conclusions Our study reiterated the mutagenic utility of EB for inducing SBSs and small indels genome-wide. The knowledge gained from SNP-level profiling of EB-induced mutations can expedite comparative mutation breeding studies in legumes.

Simulation and commissioning of a Faraday cup for absolute charge measurements of very high-energy electrons in-air at PEER

The Pulsed Energetic Electrons for Research (PEER) beamline at the ANSTO Australian Synchrotron comprises a 100 MeV linac injector that is currently being developed for ultra-high dose-rate, very high-energy electron radiotherapy research. Previously, dosimetry studies discovered a lack of reliable charge measurement to the in-air end station, though no change in response was recorded in fast current transformer measurements, the only available diagnostic device for measuring charge. This work describes the process of simulating and then commissioning a purpose-built Faraday cup to ascertain absolute in-air charge measurements at PEER. By combining simulation data with experimental results, the PEER Faraday cup is shown to possess a primary electron capture efficiency of (99.22 ± 0.10)%, with a net capture efficiency due to secondary electron emission of (97.87 ± 0.24)%. These results show the PEER Faraday cup performs as intended and, when scaled against simulations, will be suitable for measuring absolute charge at PEER.

Design of a 250 MeV linac injector system for the Southern Advanced Photon Source

The Southern Advanced Photon Source (SAPS) is a 4th generation storage ring based light source under design started several years ago, which is planned to be constructed at Guangdong province at China. The equilibrium emittance of the storage ring(SR) will be below 100 pm.rad and the beam energy is determined to be 3.5 GeV. Over the past two years, the nominal current of the SR was increased from 200 to 500 mA, requiring the injector system to provide more bunch charge. Additionally, the injection beam energy for the booster has been increased from 150 to 250 MeV, which means two more accelerating cavities have to been added. This paper presents an update of the linac injector. And also a beam transfer line from linac to booster is presented.

Commissioning of the ThomX Storage Ring

We will report on the ongoing ThomX ring commissioning, its status, its main challenges, our results and our planning. ThomX is a compact Compton-based X-ray source under commissioning at IJCLab in Orsay (France). This facility is composed of a 50-70 MeV linac, a transfer line and a storage ring whose circumference is 18 m. Compton scattering between the 50 MeV electron bunch of 1 nC and the 30 mJ laser pulses stacked in a Fabry-Perot cavity will result in the production of X-rays with energy ranging between 45 keV and 90 keV. We aim at a total flux of about 1013 X-rays per second. The injector commissioning started in the spring of 2021. The ongoing storage ring commissioning faces many challenges due to the rings low energy, its compactness, its non-linear beam dynamics, the time-limited beam storage and the need to achieve a very accurate and stable geometry of the collision region between the laser pulses and the electron bunch. The commissioning and operational experience is of great importance for the future Compton sources.

Study of light element activation in human blood during 20 MeV linac operating

A series of experiments have been performed to study the activation of chemical macronutrients in human venous blood throughout radiation treatment with the 20 MeV linac. Some elements in the human blood can be activated as positron-emitting radionuclides by (𝛾, n)-reaction. We calculated the 11C, 13N, 15O, 30P, 34𝑚Cl, and 38K activities in irradiated human venous blood samples for the first time. As a result, we concluded that the main contribution to the dose from positron-emitting nuclides activated in human blood provides three nuclides: 15O, 34𝑚Cl, and 38K.

120 mA operation of J-PARC cesiated RF-driven H- ion source

The Japan Proton Accelerator Research Complex (J-PARC) cesiated RF-driven H- ion source (IS) has been stably operated for about eight years by using an internal-RF-antenna developed at the Spallation Neutron Source (SNS). From Sep. 2018, the J-PARC 400 MeV LINAC has been steadily operated with the design H- ion beam intensity (IH- ) of 50 mA, when an about 60 mA beam is injected from the IS. At each end of about 3 months J-PARC operation, the IS supplies a 52.5 keV 72 mA beam for the LINAC 60 mA acceleration. The IS superior emittances predicted in a test-stand were proven by the high RFQ acceleration efficiency of 94.3% (IH-RFQ = 67.9 mA). The high intensity beam with transverse emittances suitable for the RFQ is produced with several unique measures, such as, slight water molecules addition into hydrogen plasma, the low temperature (about 70°C) operation of 45°-tapered 16-mm thick plasma electrode with the precise cesium (Cs) density control, the impurity elimination in the hydrogen plasma along with the filter-field optimization, the continuous-wave igniter plasma driven with a 42-W 30-MHz RF, and so on. The 120 mA operation results of the IS in the test-stand are presented in this paper. A 69.9 keV 120 mA H- ion beam, about 107.8 mA of which was inside the transverse emittances used for a common RFQ design, was stably operated with a duty factor of 4% (1 ms × 40 Hz). The IS is the benchmark one for the next generation high energy H- LINACs aiming for 100 mA class intensity.

Shielding design aspects of SR in 3 GeV ILSF

Iranian Light Source Facility (ILSF) is an under-construction synchrotron radiation accelerator consisting of a 150 MeV linac, a booster synchrotron operating from 150 MeV to 3 GeV, and a 3 GeV storage ring that stores a maximum of 400 mA current of electrons. As the stored beam circulates, a fraction of the beam is lost due to interactions with gas molecules, interactions among beam particles, and orbital bending, which produce radiation. The bulk shielding calculation for the ILSF and the input parameters used for this analysis are discussed in this paper. The potential of skyshine neutrons to cause radiation hazards is investigated as well. Moreover, the design and shielding simulation using the FLUKA Monte Carlo code is presented for the linac beam stop and primary and scattered gas bremsstrahlung for the first optics enclosure of the ILSF spectro microscopy beamline. Our designed radiation shielding system guarantees that the annual dose in all areas around the ILSF machine does not exceed the dose limit of 1 mSv.

Physics design of the Shenzhen innovation light source storage ring

The Shenzhen innovation light source facility (SILF) is a fourth generation of medium energy synchrotron radiation light source, which focuses on supporting the development of the domestic core industries, basic science frontier research and major strategic requirement, such as integrated circuits, biomedicine, advanced materials and advanced manufacturing. With the Shenzhen Municipal Government's approval of the SILF project proposal on Sep10 2020, the feasibility study of the SILF was completed in 2022, and the preliminary design of the SILF are in progress. The accelerator complex is composed of the 200 MeV linac, the 0.2–3.0 GeV booster and the 3.0 GeV storage ring. The circumference of the storage ring is 696.0 m, which includes 28 hybrid seven-bend achromat lattice periodic units to achieve the emittance below 100 pm·rad. The detailed physics design of the SILF storage ring will be presented in this paper.

Development of a 6 MeV electron beam energy Linac for fruit sterilization

Treatment of fresh fruits, meat, and food with ionizing radiation has been frequently chosen to destroy harmful pathogenic microorganisms and oriental fruit flies. Electron beam linear accelerator (Linac) is commonly used as the source of irradiation to produce photons and electrons in megavolt energy. A 6 MeV Linac designed for medical therapy has been developed for fresh fruit sterilization at Synchrotron Light Research Institute (SLRI). Some physical design and beam dynamic results of the electron gun and 6 MeV Linac will be presented in this paper. Testing of each subsystem and installation of the 6 MeV Linac with major auxiliary systems will be described in this paper. It is the first system designed, fabricates, and tested in-house for the fruit sterilization application at SLRI. Measurement results of the Linac properties are presented as a resonant frequency and coupling coefficient at low power called a cold test. The Linac system with all sub-systems and the auxiliary systems will be installed and tested before x-rays production. During commissioning some electron beam parameters out of the electron gun and the Linac exit will be measured.

A novel approach for Venezia ovoid commissioning with a comprehensive analysis of source positions in high-dose-rate brachytherapy

PurposeThe lunar design of a Venezia ovoid makes commissioning of the applicator very challenging with traditional autoradiography. In this study, we propose a novel solution to ovoid commissioning and a quality assurance (QA) workflow to effectively assess the entire source path. Methods and materialsA two-step commissioning process, using electron radiation and radiochromic films, was developed to verify the most distal source position. The ovoid was first attached to a film and was irradiated with a 12 MeV linac beam. This process was repeated on a separate, unexposed film, followed by irradiating it with a HDR source at the most distal position. Two lengths, including the ovoid thickness and the distance between the irradiated spot and the ovoid's outer surface, were obtained from the films’ intensity maps. The offset value was calculated from the subtraction of the two measured lengths. Besides acquiring the offset, a source positional simulator (SPS) and a series of planar x-rays from two orthogonal orientations were used to characterize source movement within the ovoid. ResultsCompared to x-ray-based autoradiography, the electron exposure significantly improved the ovoid's visibility on film. Our approach did not use surrogate, which further improved measurement outcomes by decreasing inherent uncertainties. The SPS results suggested the source movement was complex within the cervicovaginal area, but it was predictable with the proposed QA workflow. ConclusionWe introduced a novel, surrogate-free method to commission the Venezia ovoid, which facilitated a manual applicator reconstruction. Additionally, we recommended QA multiple source positions to safely use the ovoid in clinical settings.

UNIVERSAL EXPERIMENTAL FACILITY OF IHEPNP NSC KIPT FOR RESEARCH OF HIGH-ENERGY ELECTRON BEAM INTERACTION WITH THIN AMORPHOUS AND SINGLE-CRYSTAL STRUCTURES

The description and bench test results of the developed universal experimental facility [1] are presented. It mounted at the direct beam line of IHEPNP NSC KIPT 30 MeV Linac for the fundamental and applied research of high energy electron interaction with amorphous and single-crystal structures. The universal facility consists of the following structural elements and systems: electron beam transportation system; electron beam parameters formation and measurement, secondary electron emission monitor (SEM); electron beam full absorption Faraday cups (FC), collimators, goniometrical device system and magnetic energy analyzer.

Application of 6 MeV LINAC in Food Industries: Enhancement of shelf life of onion, Potato and Mango

Electron LINACs are extensively used for medical and industrial applications worldwide. Pakistan has been using LINACs in the medical field for many years and is now working on indigenous development of electron LINAC considering its great demand and multiple applications. A major portion of Pakistan's economy is dependent on export of agricultural products, which get wasted due to improper management and deficiency of resources to extend the shelf life of products resulting in lack of compliance with international market requirements. Food irradiation is an effective method to enhance the shelf life of agricultural products to boost country's export. For this purpose, indigenously developed low dose 6 MeV LINAC has been used to test its suitability and applicability in the food irradiation field. Experiments have been performed on onions and potatoes to inhibit sprouting and on mangoes to increase their shelf life by delaying rotting on exposing them with low dose X-rays LINAC. Results of first experiment indicated inhibition of sprouting to more than 24 weeks post irradiation. The validity and acceptability of irradiation technology requires no effect of irradiation on nutritional contents of samples. For this purpose treated and controlled potato and onion samples are tested for nutritional contents, which showed successful results and no marked effects were observed on contents like moisture, ash or protein. Prolongation of life of fully ripened mangoes with low dose of X-rays is found successful enough to increase shelf life to more than double as compare to non-irradiated (controlled) mangoes.

Development of 200 MeV linac for the SKIF light source injector

The new fourth-generation synchrotron light source SKIF is under development in Novosibirsk, Russia. It consists of a 3 GeV electron storage ring with extremely low emittance, a booster synchrotron, and a linear accelerator. The paper discusses essential aspects of the design of the 200 MeV linear accelerator for SKIF, its main characteristics, and parameters in different operation modes. Description of the linac systems is presented.

Construction and beam commissioning of a compact proton synchrotron for space radiation environment simulation

The Xi’an Proton Application Facility (XiPAF) is dedicated to simulations of environments containing space radiation. The facility consists of a 7 MeV linac injector followed by a compact 200 MeV synchrotron. The project was officially launched in 2014. After six years of construction, the commissioning of the synchrotron began in early 2020. Several rounds of beam commissioning have yielded an extracted beam energy from 10 to 200 MeV, with the number of protons exceeding 5 × 1010 in each cycle at different energies. This study presents the latest results from beam commissioning at XiPAF.

Design, fabrication and relative bunch length measurement of S-band pre-buncher

A 10 MeV, 3 kW RF electron linear accelerator (linac) is in operation at EBC, Kharghar. A new horizontal linac rated for 10 MeV, 5 kW has been planned to be developed at EBC, Kharghar. The components of 10 MeV linac beam line consists of electron gun, a standing wave (SW) single cell pre-buncher cavity and a SW main linac cavity of length 0.9 m. In order to enhance the beam capture efficiency and to reduce the energy spread a pre-buncher cavity along with focusing elements will be introduced between the electron gun and the main linac cavity section. In this work the design simulation, fabrication, RF measurements and beam experimental trials of the 2856 MHz low Q, wide band pre-buncher cavity is presented. The measured RF parameters of pre-buncher cavity are f0=2854.4 MHz in air, QL=600, tuning range ±2.5 MHz. Electron beam transmission efficiency of 99% is achieved with minimum relative bunch length obtained at 400W of input RF power.

Detection and quantification of copper in scrap metal by linac-based neutron activation analysis

This paper presents the investigation carried out by CEA List and ArcelorMittal R&D in order to assess the potential of linac-based neutron activation analysis to detect and quantify copper in scrap metal. Performances are evaluated using MCNP6 and then validated experimentally using a 6 MeV linac coupled with heavy water. It is shown that (γ, n) reaction cross-sections for deuterium are likely to be undervalued in ENDF/B-VII and suggested that photoneutron production algorithms in Monte Carlo codes should be reexamined.

Effectiveness of Non-Local Means Algorithm with an Industrial 3 MeV LINAC High-Energy X-Ray System for Non-Destructive Testing.

Industrial high-energy X-ray imaging systems are widely used for non-destructive testing (NDT) to detect defects in the internal structure of objects. Research on X-ray image noise reduction techniques using image processing has been widely conducted with the aim of improving the detection of defects in objects. In this paper, we propose a non-local means (NLM) denoising algorithm to improve the quality of images obtained using an industrial 3 MeV high-energy X-ray imaging system. We acquired X-ray images using various castings and assessed the performance visually and by obtaining the intensity profile, contrast-to-noise ratio, coefficient of variation, and normalized noise power spectrum. Overall, the quality of images processed by the proposed NLM algorithm is superior to those processed by existing algorithms for the acquired casting images. In conclusion, the NLM denoising algorithm offers an efficient and competitive approach to overcome the noise problem in high-energy X-ray imaging systems, and we expect the accompanying image processing software to facilitate and improve image restoration.

Activation study of a 15MeV LINAC via Monte Carlo simulations

Medical linear accelerators are increasingly used in radiotherapy. During the operational life of the accelerator, the different components of the LINAC head become radioactive due to photonuclear reactions. Activation induced has to be evaluated to assess not only the dose due to residual activation but also the amount of radioactive waste that has to be managed in the dismantling phase of the facility. The aim of this work is to define a Monte Carlo approach for the preliminary assessment of activation levels of a LINAC head. In this work the MC code FLUKA was used to simulate the Elekta Precise Treatment System 15 MeV LINAC installed in 2004 at the Bellaria Hospital (Bologna, IT) and routinely used in radiotherapy treatments. The activation of the LINAC head was assessed in each component after 15 years of operation. The main long-lived radionuclides found in head components are W-181, Re-184, Ni-63, Co-57, Fe-55, Mn-54, while short-lived radionuclides are W-187, W-185, W-179, Re-188, Re-186, Re-184, Cu-64, Cu-62, Ni-65, Ni-57, Cr-55 and Mn-56. As expected the most active component is the target while no considerable activation were found in the ionization chamber and in the wedge.

The eRHIC spin rotator and the beam optics of the 400 MeV transfer line to RCS

The 400 MeV LINAC1 of the proposed eRHIC collider1 is the first acceleration stage of the 18 GeV electron accelerator. The second acceleration stage of the electron accelerator is the Rapid Cycling Synchrotron (RCS), which can increase the energy of the electron bunches to 18 GeV and subsequently extract transfer and inject the 18 GeV electron bunches into the 18 GeV electron Storage Ring (SR) to collide with the hadron bunches of the existing (Relativistic Heavy Ion Collider (RHIC)) accelerator. This paper describes the beam optics of the transfer line between the 400 MeV LINAC and the RCS accelerator (LtRCS). The function of the LtRCS line is twofold, first to transfer the electron beam from the exit of the 400 MeV LINAC to the injection point of the RCS1 and second to rotate the stable spin direction of the polarized electrons from the longitudinal direction to the vertical. A detailed description of the constraints to be satisfied by the LtRCS transfer line will be given. A section will also be devoted to discuss the spin rotator2.