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Introduction and aim Methods Results Conclusion Radiotherapy in cancer patients with a pacemaker or an implantable cardioverter defibrillator might damage the device and possibly result in malfunction of the device. We aimed to examine device malfunction and change in lead parameters in this group.The medical records of pacemaker/implantable cardioverter defibrillator patients who underwent radiotherapy at Aalborg University Hospital between July 1, 2016, and June 30, 2021, were reviewed. Treatment was planned according to risk of device malfunction, assessed using local guidelines. Bootstrap linear regression was used to identify possible differences in lead parameters depending on beam energy and anatomical location.One hundred nine patients with a pacemaker/implantable cardioverter defibrillator who received a total of 122 radiotherapy courses in the study period were identified. No device malfunctions or significant changes in lead parameters during radiotherapy were observed. Only the left ventricle lead threshold and impedance were found to be significantly different when compared by beam energy; however, these changes were relatively small and unlikely to be of clinical relevance.No device malfunction or clinically relevant changes in lead parameters were identified in this study, suggesting that radiotherapy of pacemaker/implantable cardioverter defibrillator patients can be regarded as safe when following relevant safety precautions. [ABSTRACT FROM AUTHOR]

Two linked gear wheels in a micromachine can be simultaneously rotated in opposite directions by using a laser beam that has in its section areas the spin angular momentum (SAM) of the opposite sign. However, for instance, a cylindrical vector beam has zero SAM in the focus. We alter a cylindrical vector beam so as to generate areas in its focus where the SAM is of opposite signs. The first alteration is adding to the cylindrical vector beam a linearly polarized beam. Thus, we study superposition of two rotationally symmetric beams: those with cylindrical and linear polarization. We obtain an expression for the SAM and prove two of its properties. The first property is that changing superposition coefficients does not change the shape of the SAM density distribution, whereas the intensity changes. The second property is that maximal SAM density is achieved when both beams in the superposition have the same energy. The second perturbation is adding a spatial carrier frequency. We study the SAM density of a cylindrical vector beam with a spatial carrier frequency. Due to periodic modulation, upon propagation in space, such a beam is split into two beams, having left and right elliptic polarization. Thus, in the beam transverse section, areas with the spin of different signs are separated in space, which is a manifestation of the spin Hall effect. We demonstrate that such light beams can be generated by metasurfaces, with the transmittance depending periodically on one coordinate. [ABSTRACT FROM AUTHOR]

To investigate the exposure parameters for thoracic spine/(TS) radiography that allows the image acquisition at the lowest dose possible, while maintaining an adequate image quality/(IQ) to identify all relevant anatomical criteria. An experimental phantom study was conducted, and 48 different radiographs of TS (24 AP/24 lateral) were acquired. The Automatic Exposure Control/(AEC) with the central sensor was used to select the beam intensity, while Source-to-Detector-Distance/(SDD) (AP:115/125 cm; Lateral:115/150 cm), tube potential (AP:70/81/90 kVp; Lateral: 81/90/102 kVp), use of grid/no grid and focal spot (fine/broad) were manipulated. IQ was assessed by observers with ViewDEX. Effective Dose (ED) was estimated using PCXMC2.0 software. Descriptive statistics paired with intraclass correlation coefficient (ICC) were applied to analyse data. The ED increased with a greater SDD for lateral-view, presenting a significant difference (p = 0.038), however IQ was not affected. For both AP and lateral, the use of grid had a significant effect on ED (p < 0.001). Despite the images acquired without grid had lower IQ scores, the observers considered the IQ adequate for clinical use. A 20% reduction in ED (0.042mSv–0.033 mSv) was observed when increasing the beam energy from 70 to 90 kVp for AP grid in. The observers ICC ranged from moderate to good (0.5–0.75) in lateral and good to excellent (0.75–0.9) for AP views. The optimised parameters in this context were 115 cm SDD, 90 kVp with grid for the best IQ and lowest ED. Further studies in clinical setting are necessary to enlarge the context and cover different body habitus and equipment. The SDD impacts on dose for TS; Higher kVp and grid are necessary to better image quality. [ABSTRACT FROM AUTHOR]

In an effort to measure electron-impact ionization (EII) cross-sections of He-like F e 24 + at the electron beam ion trap (EBIT) facility of the National Institute of Standards and Technology (NIST), we have experimentally determined the corrections to the nominal beam energy determined by the voltages applied to the EBIT. High-resolution X-ray spectra were recorded at nominal electron beam energies between 6660 eV and 6750 eV using X-ray microcalorimetry based upon an array of 192 transition-edge sensors (TES). A large-scale collisional-radiative simulation of the non-Maxwellian EBIT plasma using relevant atomic data calculated with Flexible Atomic Code allowed us to determine the space-charge correction due to the electron beam including the neutralization factor by the ion cloud of the EBIT. [ABSTRACT FROM AUTHOR]

Two linked gear wheels in a micromachine can be simultaneously rotated in opposite directions by using a laser beam that has in its section areas the spin angular momentum (SAM) of the opposite sign. However, for instance, a cylindrical vector beam has zero SAM in the focus. We alter a cylindrical vector beam so as to generate areas in its focus where the SAM is of opposite signs. The first alteration is adding to the cylindrical vector beam a linearly polarized beam. Thus, we study superposition of two rotationally symmetric beams: those with cylindrical and linear polarization. We obtain an expression for the SAM and prove two of its properties. The first property is that changing superposition coefficients does not change the shape of the SAM density distribution, whereas the intensity changes. The second property is that maximal SAM density is achieved when both beams in the superposition have the same energy. The second perturbation is adding a spatial carrier frequency. We study the SAM density of a cylindrical vector beam with a spatial carrier frequency. Due to periodic modulation, upon propagation in space, such a beam is split into two beams, having left and right elliptic polarization. Thus, in the beam transverse section, areas with the spin of different signs are separated in space, which is a manifestation of the spin Hall effect. We demonstrate that such light beams can be generated by metasurfaces, with the transmittance depending periodically on one coordinate.

Hydrophilicity is one of the essential properties of biocompatible materials to be placed in the body environment. In this research, improvement in hydrophilicity of the surfaces of polyethylene and polystyrene samples with implantation of helium ion was studied. A 10 µA helium ion beam with an energy of 10 keV delivered by the department of physics university of Tehran’s electrostatic accelerator was used. The samples were bombarded with a beam at two angles of 45° and 90° relative to the surface of the sample. No remarkable difference was observed in the hydrophilicity of the samples bombarded with the two mentioned above angles. Implantation was performed with various fluences in the range of . A variation of the fluence revealed that the contact angle may be reduced 14 and 16 degrees for polyethylene and polystyrene samples, respectively. The surface roughness of the samples was measured before and after ion implantation with an atomic force microscope (AFM). The reported roughness for each sample is the average of 30 measurements. It was observed that ion implantation has the opposite impact on the surface roughness of polyethylene and polystyrene. On average, the surface roughness of polyethylene samples decreased 32 nm, in contrast to the polystyrene roughness, which increased 33 nm.

We investigated benefits from raising the ion beam energy during measurements of 10Be with Accelerator Mass Spectrometry (AMS) at the 6 MV DREAMS (DREsden AMS) facility. Increasing the terminal voltage to ≥ 5 MV hardly reduces the yield of the Be 2 + charge state after the accelerator if one applies only a thin Ar gas stripper and makes use of an overpopulation of the 2+ charge state with respect to the expected equilibrium charge state yield. As a further stripping to the 4+ charge state is conducted in a degrader foil after the analysing magnet, it is desirable to hit the foil with the highest available velocity in order to have optimal stripping of Be 2 + to the fully stripped ion. At DREAMS the 10Be yield can be improved by a factor of 1.36. Applying a terminal voltage of 5.8 MV the transport efficiency of 10Be from the ion source to the detector is ca. 32.5%. [ABSTRACT FROM AUTHOR]

• Proton Beam Energy of a cyclotron at an energy between 10.8–18 MeV. • FLUKA simulation. FLUKA is a fully integrated particle physics MonteCarlo simulation package which has many applications in high energy experimental physics and engineering. When using a cyclotron for medical radionuclide production, it is important to know that the beam energy is suitable to cause the intended nuclear reaction and minimize unwanted impurities. This work focuses on the comparison of FLUKA as a tool to measure the beam energy of a cyclotron with experimental results using the method of stacked copper foils interspaced by an aluminum degrader. We compared two methods to determine the activity ratio: determining the activity in each foil using the experimentally measured cross-sections from the National Nuclear Data Center (NNDC) cross-section data and calculating the activity in the two Cu foils using the FLUKA program. These results were compared to those reported by Gagnon et al., 2011. The FLUKA results gave energy measurements that were different than the true energy by a percentage in the range of 2.4% to 13%, suggesting that FLUKA is not recommended for pre-calculating the cyclotron beam energy using these low Z materials without experimental confirmation. It also confirms that the experimental cross-section data from the NNDC database is superior for this application giving energy values that ranged from 0.1% to 1.6% from the true energy. [ABSTRACT FROM AUTHOR]

We analyze the propagation of hypergeometric beams with a parabolic initial wavefront in a homogeneous medium. While hypergeomentric beams have a central amplitude singularity in the initial plane and are of infinite energy, superposition of two such beams has no singularity and is of finite energy. A particular case of such a superposition we study in detail is a sinusoidal Gaussian beam with a unit topological charge. This beam belongs to the class of elegant laser beams since it is described by the same complex-argument function both in the initial plane and in the Fresnel diffraction zone. The diameter of the first light ring of the sinusoidal Gaussian beam is almost independent of the Gaussian beam waist radius.

The diffraction of elegant vortex hypergeometric (HyG) laser beams with a parabolic initial wavefront in a homogeneous medium is considered. While HyG beams have a central amplitude singularity in the initial plane and are of infinite energy, the superposition of two such beams has no singularity and is of finite energy. A particular case of this superposition, i.e., a sinusoidal Gaussian beam with a unit topological charge, is studied in detail. This beam belongs to the class of elegant laser beams since it is described by the same complex-argument function both in the initial plane and in the Fresnel diffraction zone. [ABSTRACT FROM AUTHOR]

In the present paper, we have developed a theoretical model of cylindrical magnetized plasma column consisting of electrons, K+ ions & heavy positive Ba+ ion species. A gyrating ion beam of potassium having radius ~1.5 cm and energy 10eV is launched through one end of the cylinder parallel to the static magnetic field and the electrostatic ion cyclotron wave is assumed to propagate nearly perpendicular to the magnetic field. The presence of heavy positive Ba+ ions in the collisionless magnetized plasma decreases the critical drift for the excitation of EIC waves and hence the injected beam drives the electrostatic ion cyclotron (EIC) waves to instability through Cerenkov interaction. Therefore, the plasma is observed to contains two excited EIC wave modes; a (light positive) K+ ion mode and a (heavy positive) Ba+ ion mode. The frequencies and growth rates for both the positive unstable modes are worked out using fluid theory for the typical existing experimental parameters which are found to increase with the increase in ion beam energy and beam density. It is also observed that the unstable wave frequency and growth rate for both the modes increases with the increase in relative ion concentration of K+ and heavy Ba+ positive ions respectively. Magnetic field is also one of the important factors which influence the plasma instabilities appreciably. As the magnetic field increases, the frequency of both the ion modes increases linearly [ABSTRACT FROM AUTHOR]

Purpose: The research intended to figure out the impact on treatment plan quality & dosimetric certainty of FF & FFF-VMAT plan using Photon beam energy (PBE) of 6MV & 10MV for prostate cancer (PC) along with lymph nodes (LN). Materials & Method: In this retrospective investigation, VMAT plans were created with FFF & FF mode of treatment using the eclipse TPS version 13.5. Each plan subsists two target volume structures: PTVPC comprised the entire prostate cancer& PTVPC + PTVLymph For statistical plan assessment, dosimetric factors were analyzed to measure Nodes. delivery performance. Result:No significant (p>0.05) differences observed for PTVPC & PTVPC+LN coverage in low & high PBE for both FF-VMAT & FFF-VMAT.Low PBE significantly (p<0.05) observed higher numbers of MUs as compared with high PBE, therefore, Lower MUs alleviate the head scattering & leakage radiation & the potential risk of secondary malignancy. A lightly higher low dose volumes were observed for 6MV VMAT plans compared to 10MV VMAT plans. Conclusion: The integral dose was higher in low energy photons (FF-FFF 6MV) when correlated with high energy photons (FF-FFF 10MV) while No significant difference was observed in respect of PTVPC & PTVPC+LN coverage and HI. Significant difference observed in MU value increases in FFF-VMAT. [ABSTRACT FROM AUTHOR]

Material hardening is a topic of much interest. In this paper, material hardening on AISI 1020 low carbon steel was done using INTI plasma focus (INTI PF) machine. It was found that the best distance for optimum hardening was to place the sample material 4 cm from the anode at a pressure of 1 Torr when the plasma machine is operating at 12 kV as it improves the hardening by 97.8%. Computation with the Lee codes produce plots of ion beam energy versus pressure and number of ions versus pressure. Thus we are able to correlate the optimum hardness of the treated sample surface to the interaction of optimum beam energy and number of ions. [ABSTRACT FROM AUTHOR]

Highlights • Degradation of proton beam energy within a target stack was monitored via product nuclide ratios. • Nuclear reactions employed included natNi(p,x)57Co and natNi(p,x)57Ni. • Natural nickel foils were used to determine proton beam energies ranging from 15 to 30 MeV. • Proton energies determined serve as a basis to optimize radionuclide production. Abstract The degradation of proton beam energy within a target stack was monitored via product nuclide ratios at the Los Alamos Isotope Production Facility (LANL-IPF). Nuclear reaction channels employed as energy monitors included NatNi(p,x)57Co and NatNi(p,x)57Ni. Natural nickel foils (thicknesses 0.025 mm) were used to determine proton beam energies ranging from 15 to 30 MeV. Energy values were estimated from a fitted 57Ni/57Co production activity ratio curve, which, in turn, was calculated from formation cross section data. Isotope production yields in the low energy "C" slot at LANL-IPF are very sensitive to beam energy, and differences of several MeV can translate into a drastic effect on overall production yields and radiochemical purity. Proton energies determined in this target stack position using nickel foils will serve as a basis to optimize radionuclide production in terms of product yield maximization and by-product minimization. [ABSTRACT FROM AUTHOR]

The helium focused ion beam (He-FIB) is widely used in the field of nanostructure fabrication due to its high resolution. Complicated forms of processing damage induced by He-FIB can be observed in substrates, and these damages have a severe impact on nanostructure processing. This study experimentally investigated the influence of the beam energy and ion dose of He-FIB on processing damage. Based on the experimental results, a prediction function for the amorphous damage profile of the single-crystalline silicon substrate caused by incident He-FIB was proposed, and a method for calculating the amorphous damage profile by inputting ion dose and beam energy was established. Based on one set of the amorphous damage profiles, the function coefficients were determined using a genetic algorithm. Experiments on single-crystalline silicon scanned by He-FIB under different process parameters were carried out to validate the model. The proposed experiment-based model can accurately predict the amorphous damage profile induced by He-FIB under a wide range of different ion doses and beam energies.

Background: Magnetic resonance imaging (MRI)-guided radiotherapy is a promising image-guided cancer radiotherapy method. For MRI-guided radiotherapy, the proper energy of a therapeutic beam is important for beam-designing processes, and the magnetic-induced dose perturbation would be mainly influenced, especially the perturbation surrounding the tissue-air or air-tissue interfaces. Thus, it was necessary to investigate the impact of beam energy from photon, proton, and carbon ion beams on the magnetic-induced dose perturbations.Materials and Methods: Using a phantom of a water-air-water structure, the dose distributions were calculated with or without the presence of a 1.5 T uniform magnetic field through GEANT4. Based on the calculated doses, magnetic-induced dose perturbations were then obtained. For investigating the effects of beam energies on magnetic-induced dose perturbations, low-, middle-, and high-beam energies were adopted for each beam type.Results and Discussion: For photon beams, the dose perturbations were increased as the beam energies increased. At the up water-air interface, the maximum perturbations exceeded 50%. Near the edge of the radiation field, perturbations of 5%-20% were achieved. For proton and carbon ion beams, their Bragg peaks were shifted from original positions, and the shifting distances were increased with the increased beam energies. However, no evident magnetic-induced dose perturbations were noted at the up water-air interface and bottom air-water interface for all the beam energies. To some extent, this study provided references for assessing the effects of beam energies on magnetic-induced dose perturbations, especially the perturbations around the air cavities inside cancer patients.Conclusion: In MRI-guided cancer radiotherapy, the dose perturbation effects for therapeutic beams are relatively obvious, and the beam energies of therapeutic beams have large impacts on the magnetic-induced dose perturbations with the presence of a 1.5 T transverse magnetic field. [ABSTRACT FROM AUTHOR]

Computed tomography (CT) imaging of fossils has revolutionised the field of palaeontology, allowing researchers to gain a better understanding of fossil anatomy, preservation and conservation. Micro focus X-ray computed tomography (µXCT) has been far more extensively used for these purposes than medical CT (XCT) -- mostly because of the exquisite detail that the µXCT scanning modality, using slices of micron thicknesses, can produce. High energy X-rays can potentially penetrate breccia more effectively than lower energy beams. This study demonstrates that lower energy beams produce superior images for prioritising breccia for preparation. Additionally, XCT scanners are numerous, accessible, fast and relatively cost-effective when compared to µXCT scanners -- the latter are not freely available, scanning times are much longer and there are significant limitations on the size and weight of scannable objects. Breccia blocks from Malapa were scanned at high and lower energy and images were analysed for image quality, artifact and certainty of diagnosis. Results show that lower energy images are deemed superior to higher energy images for this particular application. This finding, taken together with the limitations associated with the use of µXCT for the imaging of the large breccia from Malapa, shows that XCT is the better modality for this specific application. The ability to choose fossil-bearing breccia, ahead of manual mechanical preparation by laboratory technicians, would allow for the optimal use of limited resources, manual preparatory skills as well as the curtailment of costs. Significance: • 'Blind' manual preparation of fossil-bearing breccia is a costly and time-consuming exercise -- and often results in a low yield. • The ability to triage fossil-bearing breccia ahead of manual preparation would allow for the optimal use of limited resources. • Medical CT is better than micro-CT to triage breccia to allow for prioritisation of rocks for manual preparation. [ABSTRACT FROM AUTHOR]

Beam energy is one of the primary parameters of an electron irradiation accelerator, which affects the internal dose distribution of irradiated items. This study designs an energy monitoring device that can track the energy variation of an industrial electron accelerator in the range of 1.2–2.0 MeV. By using Monte Carlo simulation, the construction and parameters of the energy monitoring device were designed and optimized. An experimental measurement platform was designed and built according to the needs of the measurement environment. The experiments were performed under an industrially irradiation Dynamitron accelerator. The test results demonstrate that the designed energy monitoring device is capable of continuously monitoring beam energy and meeting the measurement requirement. This study identified a new correlation between the energy ratio and beam energy, which provides a reference to guide the design and application of future energy monitoring devices. • The energy monitoring device was investigated and designed by using the Monte Carlo simulation. • A new relationship between energy ratio and beam energy was discovered. • The relationship between the electron beam energy and the most probable energy was established. • A beam energy monitoring system was designed and tested under the industrial irradiation electron accelerator. [ABSTRACT FROM AUTHOR]