Energy Particle Beams Research Articles

Extension of evaluated cross section database for charged particle monitor reactions

The evaluation and deduction of recommended cross section values allowing extension of the database to monitor energy and intensity parameters of charged particle beams is presented. Included are 53 charged particle (p, d, 3He, 4He) induced reactions on suited C, Al, Ti, Fe, Ni, Cu, Nb and Au targets. The new data allow more systematic simultaneous use of multiple reactions on the same target and promote the backings of electrodeposited and sedimented targets as monitoring aids. Where possible the energy range is extended to above 100 MeV. Integral yield curves over the studied energy range are derived and compared to experimentally measured yields at specific energy points. A comparison with the theoretical excitation curve prediction of the TALYS-code as available in the TENDL 2021–2023 libraries is shown.

High average power ultrafast laser technologies for driving future advanced accelerators

Large scale laser facilities are needed to advance the energy frontier in high energy physics and accelerator physics. Laser plasma accelerators are core to advanced accelerator concepts aimed at reaching TeV electron electron colliders. In these facilities, intense laser pulses drive plasmas and are used to accelerate electrons to high energies in remarkably short distances. A laser plasma accelerator could in principle reach high energies with an accelerating length that is 1000 times shorter than in conventional RF based accelerators. Notionally, laser driven particle beam energies could scale beyond state of the art conventional accelerators. LPAs have produced multi GeV electron beams in about 20 cm with relative energy spread of about 2 percent, supported by highly developed laser technology. This validates key elements of the US DOE strategy for such accelerators to enable future colliders but extending best results to date to a TeV collider will require lasers with higher average power. While the per pulse energies envisioned for laser driven colliders are achievable with current lasers, low laser repetition rates limit potential collider luminosity. Applications will require rates of kHz to tens of kHz at Joules of energy and high efficiency, and a collider would require about 100 such stages, a leap from current Hz class LPAs. This represents a challenging 1000 fold increase in laser repetition rates beyond current state of the art. This whitepaper describes current research and outlook for candidate laser systems as well as the accompanying broadband and high damage threshold optics needed for driving future advanced accelerators.

Uncertainty in the range of the protons and C-ions in particle therapy due to a hydration level of a human body model

Cancer treatment with protons and carbon ions relies on the property of the accelerated charged particles to deposit most of their energy in the vicinity of their range (around the Bragg peak). The level of hydration in a cancer patient's body may vary within hours. Some patients may be heavy to moderately dehydrated, and some may be well and even excessively hydrated. In this research, we aim to estimate the uncertainty of the protons and C-ion ranges because of the different hydration levels of the human body. For the study of the impact of body hydration level on the particle's ranges, we have designed a new phantom model – a homogeneous mixture of an Average HUuman BOdy constituting elements (AHUBO) in three states of hydration: normal (n), dehydrated (d), and excessively hydrated (e) by applying corresponding recalibration in the “atomic-stoichiometry model” due to the water sufficiency/deficiency. The purpose of the study is to estimate the shift in the ranges depending on the hydration level, possibly suggest particle beam energy adjustments to overcome the range uncertainties, to deliver the prescribed dose to the tumour while sparing the healthy tissue. Herein we present the results of the FLUKA-Flair simulations of the therapeutic range of energies of protons (50–105 MeV) and C-ions (30–210 MeV) respectively, into an AHUBO head phantom model at three levels of hydration (normal, dehydrated, and excessively hydrated). The range uncertainty was estimated via the shifts of the Bragg-peaks position for the three different hydration levels. The estimations showed that the range uncertainty (ΔR) due to body hydration for the maximum energy in the range for protons at 105 MeV is about 0.04 mm and for C-ions at 190 MeV/u is about 0.06 mm.

Collision-System and Beam-Energy Dependence of Anisotropic Flow Fluctuations.

Elliptic flow measurements from two-, four-, and six-particle correlations are used to investigate flow fluctuations in collisions of U+U at sqrt[s_{NN}]=193 GeV, Cu+Au at sqrt[s_{NN}]=200 GeV and Au+Au spanning the range sqrt[s_{NN}]=11.5-200 GeV. The measurements show a strong dependence of the flow fluctuations on collision centrality, a modest dependence on system size, and very little if any, dependence on particle species and beam energy. The results, when compared to similar LHC measurements, viscous hydrodynamic calculations, and trento model eccentricities, indicate that initial-state-driven fluctuations predominate the flow fluctuations generated in the collisions studied.

The All-sky Spectrometer of Hot Cosmic Plasma

The main instruments for analyzing the processes occurring in cosmic plasma are energy and mass analyzers of charged particle beams. The analyzers’ operation is based on the separation of charged particles according to the energies of their motion or their masses in electric or magnetic fields. Currently, the top-hat analyzer is considered the main instrument for obtaining information about the state of cosmic plasma. However, it has a number of disadvantages: a significant time cycle for registering angular dependences in a total solid angle of 4π sr and low accuracy of determining the polar angles, which are associated with the need to rotate the analyzer during measurements. Over the past 20 years, plasma analyzers with a large viewing angle have been developed as an alternative to the top-hat analyzer. The design of the analyzer proposed in this work is capable of measuring plasma characteristics in a solid angle of 2π sr in one act of data registration. The all-sky spectrometer of hot cosmic plasma consists of two stages: the first stage is a conical lens of an original design, which serves to transform an extremely wide entrance flow of particles into a narrow cone-shaped beam; the second hexapole-cylindrical stage plays the role of an energy analyzer of a narrow cone-shaped flow. The paper describes the calculations and modeling of the proposed analyzer on the basis of original numerical and approximate analytical methods for designing systems of electron and ion optics. The main parameters of the device are calculated.

Investigation of non-uniform magnetic field on the beam particle energy exchange

Investigation of non-uniform magnetic field on the beam particle energy exchange

Development of a high-gradient X-band RF gun with replaceable field emission cathodes for RF breakdown studies

The contradiction between people’s infinite pursuit of charged particle beam energy and finite laboratory space has led to the development of high gradient acceleration structure. As X-band high gradient structures are worldwide used in Collider, FELs and compact light sources, a more detailed observation and deeper understanding of the bottleneck of gradient improvement—RF breakdown are strongly demanded. To this end, an X-band electron gun with a replaceable field emission cathode has been developed at Tsinghua university to serve as the observation object. Said gun is composed of 2.37 cavities and a pluggable cathode, with a tapered tip that was machined on the cathode centre to increase the local emission current. To ensure the cathode replaceability while eliminating the leaking field, a novel design of the first cavity working at TM02 mode was adopted. After conditioning of around 107 pulses, the peak electric field of the cathode tip achieved more than 1 GV/m, and a stable current of 3 mA averaged over rf pulse was detected. These results lay a foundation for the observation of RF breakdown in our next stage.

LUE-200 Accelerator—A Photo-neutron Generator For The Pulsed Neutron Source “IREN”

This article reports about the construction and status of the accelerator facility at the Laboratory of Neutron Physics (FLNP) in the Joint Institute for Nuclear Research (JINR, Dubna), the driver of an intense pulsed resonance neutron source. The general scheme of the electron linear accelerator and features of its basic systems are presented. LUE-200 consists of two accelerating sections on a traveling wave with an operating frequency of 2856 MHz with RF power compression systems of the SLED type. The pulse current of the beam at the output of the accelerator reaches 2 A with a pulse duration of 80–100 ns. At the average energy of beam particles from 60–65 MeV and a cycle repetition rate of 50 Hz, the average beam power reaches ≈ 600 W. The integral neutron flux from the non-multiplying target reaches ∼ 1012 s−1.

Production of energetic protons, deuterons, and neutrons up to 60 MeV via disruption of a current-carrying plasma column at 3 MA

Acceleration of ions to multi-MeV energies is investigated in various plasma devices to better understand processes in astrophysical plasmas and to develop efficient accelerators for a variety of applications. This paper reports the production of proton, deuteron, and electron beams in a z-pinch—a cylindrically symmetric plasma column that is compressed by its own magnetic field. For this work, the GIT-12 pulsed-power generator was used to drive a novel configuration of z-pinch that dramatically enhanced ion acceleration associated with disruption of the current by instabilities in the compressed plasma. During the disruption of 3 MA current, hydrogen ions were accelerated up to at least 50 MeV, which is almost a hundred-times the ion energy provided by the generator driving voltage of 0.6 MV. Under optimal conditions, the total numbers of hydrogen ions with energies above 20 and 50 MeV were 4 × 1013 and 1011, respectively. Accelerated deuterons produced one 20 ns (full width at half maximum) pulse of fast neutrons via D(d, n)3He and other nuclear reactions. A maximum neutron output of (1.0 ± 0.2) × 1012 neutrons/sr was observed downstream, i.e., in the anode to cathode direction. In this direction, the maximum neutron energy reached 58 ± 7 MeV. Both ion and neutron beams in our experiment reached an end-point energy of about 60 MeV, which is the highest value observed in pulsed-power devices. A localized peak voltage of ≳60 MV was driven by the inductive energy that was stored around the plasma column and that was extracted during a sub-nanosecond current drop. Considering the natural occurrence of current-carrying columns in laboratory and space plasmas, the current interruption observed in z-pinches could represent a more general physical process that contributes to the efficient conversion of magnetic energy into the energy of particle beams in various plasmas.

CALIBRATION OF A SYSTEM FOR ON-LINE MONITORING OF ELECTRON ENERGY AND ABSORBED DOSE AT AN INDUSTRIAL ACCELERATOR LU-10

Particle beam energy and absorbed dose are critical parameters of product processing at industrial electron accelerators. For on-line monitoring of those parameters, a method based on measuring of distribution of the charge induced by irradiation in a wide-aperture stack-monitor, positioned behind an irradiated object, has been developed. A brief review of a control system for monitoring of the processing parameters created with the use of the EPICS package as well as the data of its operating experience at an LU-10 Linac of NSC KIPT are presented in the article. The procedure and results of calibration of the measuring channels within the electron energy range 8…10 MeV are described.

Multi-stage proton acceleration controlled by double beam image technique

A double beam image (DBI) technique is coupled in the two-stage accelerating mechanism to simultaneously improve the spectra and maximum energy of the proton beam. A proton beam with a narrow-spectrum center at 5.4 MeV and a long tail up to 14.4 MeV is generated in the experiment. Experimental and simulation results show that spatial collineation, time synchronization, and real-time monitoring are needed for optimum two-stage proton acceleration and are realized by the DBI technique to a certain extent in our experiment. This DBI technique can be used to achieve optimum two-stage acceleration in a feasible manner and will allow precise manipulation of multistage acceleration to improve the energy and spectra of particle beams.

A potent approach for the development of FPGA based DAQ system for HEP experiments

With ever increasing particle beam energies and interaction rates in modern High Energy Physics (HEP) experiments in the present and future accelerator facilities, there has always been the demand for robust Data Acquisition (DAQ) schemes which perform in the harsh radiation environment and handle high data volume. The scheme is required to be flexible enough to adapt to the demands of future detector and electronics upgrades, and at the same time keeping the cost factor in mind. To address these challenges, in the present work, we discuss an efficient DAQ scheme for error resilient, high speed data communication on commercially available state-of-the-art FPGA with optical links. The scheme utilises GigaBit Transceiver (GBT) protocol to establish radiation tolerant communication link between on-detector front-end electronics situated in harsh radiation environment to the back-end Data Processing Unit (DPU) placed in a low radiation zone. The acquired data are reconstructed in DPU which reduces the data volume significantly, and then transmitted to the computing farms through high speed optical links using 10 Gigabit Ethernet (10GbE). In this study, we focus on implementation and testing of GBT protocol and 10GbE links on an Intel FPGA. Results of the measurements of resource utilisation, critical path delays, signal integrity, eye diagram and Bit Error Rate (BER) are presented, which are the indicators for efficient system performance.

Upgrade to DIII-D National Fusion Facility PCS and Neutral Beam Systems: In-Shot Variation of Neutral Beam Particle Energy

On the DIII-D National Fusion Facility tokamak plasma diagnostics continue to improve and experiments increase in complexity. Hence the utility of dynamic control of the beam energy (and therefore also the injected torque, ion heating fraction, etc.) has become apparent. Here we report on upgrades that have been incorporated into the DIII-D Plasma Control System (PCS) and Neutral Beam Injection (NBI) systems in order to allow the beam acceleration voltage (Vaccel) to be varied continuously in a ≤20 kV range during a shot for the first time, generating new capabilities such as smooth plasma transitions and controllable interactions with Alfvén waves.

Hard X-ray Sources for the Mexican Synchrotron Project

One of the principal tasks for the design of the Mexican synchrotron was to define the storage ring energy. The main criteria for choosing the energy come from studying the electromagnetic spectrum that can be obtained from the synchrotron, because the energy range of the spectrum that can be obtained will determine the applications available to the users of the future light source. Since there is a public demand of hard X-rays for the experiments in the synchrotron community users from Mexico, in this work we studied the emission spectra from some hard X-ray sources which could be the best options for the parameters of the present Mexican synchrotron design. The calculations of the flux and the brightness for one Bending Magnet and four Insertion Devices are presented; specifically, for a Superconducting Bending Magnet (SBM), a Superconducting Wiggler (SCW), an In Vacuum Short Period Undulator (IV-SPU), a Superconducting Undulator (SCU) and for a Cryogenic Permanent Magnet Undulator (CPMU). Two commonly available synchrotron radiation programs were used for the computation (XOP and SRW). From the results, it can be concluded that the particle beam energy from the current design is enough to have one or more sources of hard X-rays. Furthermore, a wide range of hard X-ray region can be covered by the analyzed sources, and the choice of each type should be based on the specific characteristics of the X-ray beam to perform the experiments at the involved beamline. This work was done within the project Fomix Conacyt-Morelos ”Plan Estrategico para la construccion y operación de un Sincrotron en Morelos” (224392).

A scaled experiment to study energy dissipation process during longitudinal compression of charged particle beams

Beam behavior during longitudinal bunch compression of charged particles was investigated using a compact simulator device based on electron beams. Beam current waveforms and bunch compression ratios were measured as a function of the initial beam current. We found that the current waveform became blunt and the compression ratio degraded at higher beam currents. These results indicate that space-charge fields dissipate the kinetic energy of beam particles.

Electrostatic charged-particle spectrograph made up of discrete plane and box electrodes

A simple spectrograph is suggested for rapid analysis of the charged particle beam energy. The device is protected against the penetration of stray self-fields and extraneous fields into its operating region. A distinctive feature of such a spectrograph is that potentials applied to different parts of the split plane electrode vary in proportion to the square root of the distance from the frontal end electrode to the middle of the respective part. Optimal operating conditions for the spectrograph are found using computer simulation. Under these conditions, the range of energies recorded simultaneously covers two orders of magnitude, which is several times larger than the maximal range of the spectrographs currently available.

Characterizing the modulation transfer function (MTF) of proton/carbon radiography using Monte Carlo simulations

To characterize the modulation transfer function (MTF) of proton/carbon radiography using Monte Carlo simulations. To assess the spatial resolution of proton/carbon radiographic imaging. A phantom was specifically modeled with inserts composed of two materials with three different densities of bone and lung. The basic geometry of the phantom consists of cube-shaped inserts placed in water. The thickness of the water, the thickness of the cubes, the depth of the cubes in the water, and the particle beam energy have all been varied and studied. There were two phantom thicknesses considered 20 and 28 cm. This represents an average patient thickness and a thicker sized patient. Radiographs were produced for proton beams at 230 and 330 MeV and for a carbon ion beam at 400 MeV per nucleon. The contrast-to-noise ratio (CNR) was evaluated at the interface of two materials on the radiographs, i.e., lung-water and bone-water. The variation in CNR at interface between lung-water and bone-water were study, where a sigmoidal fit was performed between the lower and the higher CNR values. The full width half-maximum (FWHM) value was then obtained from the sigmoidal fit. Ultimately, spatial resolution was defined by the 10% point of the modulation-transfer-function (MTF10%), in units of line-pairs per mm (lp/mm). For the 20 cm thick phantom, the FWHM values varied between 0.5 and 0.7 mm at the lung-water and bone-water interfaces, for the proton beam energies of 230 and 330 MeV and the 400 MeV/n carbon beam. For the 28 cm thick phantom, the FWHM values varied between 0.5 and 1.2 mm at the lung-water and bone-water interface for the same inserts and beam energies. For the 20 cm phantom the MTF10% for lung-water interface is 2.3, 2.4, and 2.8 lp/mm, respectively, for 230, 330, and 400 MeV/n beams. For the same 20 cm thick phantom but for the bone-water interface the MTF10% yielded 1.9, 2.3, and 2.7 lp/mm, respectively, for 230, 330, and 400 MeV/n beams. In the case of the thicker 28 cm phantom, the authors observed that at the lung-water interface the MTF10% is 1.6, 1.9, and 2.6 lp/mm, respectively, for 230, 330, and 400 MeV/n beams. While for the bone-water interface the MTF10% was 1.4, 1.9, and 2.9 lp/mm, respectively, for 230, 330, and 400 MeV/n beams. Carbon radiography (400 MeV/n) yielded best spatial resolution, with MTF10% = 2.7 and 2.8 lp/mm, respectively, at the lung-water and bone-water interfaces. The spatial resolution of the 330 MeV proton beam was better than the 230 MeV proton, because higher incident proton energy suffer smaller deflections within the patient and thus yields better proton radiographic images. The authors also observed that submillimeter resolution can be obtained with both proton and carbon beams.

Unfolding of event-by-event net-charge distributions in heavy-ion collision

We discuss a method to obtain the true event-by-event net-charge multiplicity distributions from a corresponding measured distribution which is subjected to detector effects such as finite particle counting efficiency. The approach is based on the Bayes method for the unfolding of distributions. We are able to faithfully unfold back the measured distributions to match their corresponding true distributions obtained for a widely varying underlying particle production mechanism, beam energy and collision centrality. Particularly the mean, variance, skewness, kurtosis and their products and ratios of net-charge distributions from the event generators are shown to be successfully unfolded from the measured distributions constructed to mimic a real experimental distribution. We demonstrate the necessity to account for detector effects before associating the higher moments of net-charge distributions with physical quantities or phenomena. The advantage of this approach is that one need not construct new observables to cancel out detector effects which lose their ability to be connected to physical quantities calculable in standard theories.

Development of rapid-cycling superconducting magnets and the SIS300 cryogenic accelerator system

The SIS300 ion synchrotron is the last stage of the FAIR facility for antiproton and ion research. Its magnet structure is based on rapid-cycling superconducting magnets, making it possible to increase the energy and time-averaged intensity of particle beams. In 2008, the Institute of High Energy Physics (IFVE) developed and successfully tested the SIS300 model dipole, which reached a central magnetic field 6.8 T with ramping 1.15 T/sec, which is higher than that of existing analogues. At the present time, the IHEP is developing with the financial support from Rosatom prototypes of rapid-cycling quadrupole and corrector magnets for SIS300 and is developing in collaboration with the Bochvar All-Russia Research Institute for Inorganic Materials (VNIINM) a superconducting conductor for these magnets and developing the SIS300 cryostating system, which will be built by Kriogenmash and Geliimash. The status of this work is presented.

Photonic-crystal mediated charged particle beam velocity modulation and electromagnetic wave generation

We present the first experimental results of a photonic crystal (PC) structure-mediated charged particle beam velocity modulation and energy exchange. Our structure was based on two photonic lattices working at 9.532 GHz: a modulation lattice (ML) driven by a 2.5–6 W signal to velocity-modulate an electron beam of dc voltage from 15 to 30 kV and current from 50 to 150 μA, and an excitation lattice (EL) to exchange energy with the modulated beam, similar to a two-cavity klystron. Experimental results successfully demonstrated high spectral purity from signals excited by the velocity-modulated beam in the EL, with power level in excellent agreement with conventional theories.