Energy Spread Research Articles

Entropy, Said the Devil

Appearing to channel the Devil himself, writer Dorion Sagan reports on a deep Earth conference where the former, with technical and philosophical rigor, expands upon Bernard Stiegler’s notion of the Entropocene, the “generalised anthropogenic acceleration in the rate of terrestrial entropization” from which “[m]any of the world’s current politico-ecological crises derive” (White and Moore, 2022). The apparently possessed writer, whose stenography of the deep Earth demon appears to be for self-aggrandizement as part of a suspected Mephistophelean pact, argues that Stiegler’s Entropocene is in fact a specific form of thermodynamic planetary dysfunction. Unlike some other global concerns analyzed by philosophers—e.g., Immanuel Kant’s inquiries into the possibilities of world peace, and speculations, following Fontenelle, on the existence of life on other planets—the analysis of Earth’s planetary condition, is not unique: it is an example of thermodynamic dysfunction in general, which has important and investigable precursors: forest ecosystems exposed to heat and radiation from nuclear runoff, nonliving complex systems (e.g., Bénard cells, Taylor vortices, “multiplying” typhoons, and long-lived autocatalytic Belousov-Zhabotinski chemical reactions) that exhibit physiological malaise, and ultimately “death,” when the temperature, pressure, or electron potential gradients upon which their organization depends become too steep or insufficient. Among the many interwoven themes discussed in one of the Devil’s “outer dens” are senescence, the checkered history and thermodynamic reality of entropy as a measure of the spread of energy, Nietzschean eternal recurrence, life on other planets, and the mythical heat death of the universe.

A systematic approach for calibrating a Monte Carlo code to a treatment planning system for obtaining dose, LET, variable proton RBE and out-of-field dose

Objective. While integration of variable relative biological effectiveness (RBE) has not reached full clinical implementation, the importance of having the ability to recalculate proton treatment plans in a flexible, dedicated Monte Carlo (MC) code cannot be understated . Here we provide a step-wise method for calibrating dose from a MC code to a treatment planning system (TPS), to obtain required parameters for calculating linear energy transfer (LET), variable RBE and in general enabling clinical realistic research studies beyond the capabilities of a TPS. Approach. Initially, Pristine Bragg peaks (PBP) were calculated in both the Eclipse TPS and the FLUKA MC code. A rearranged Bortfeld energy-range relation was applied to the initial energy of the beam to fine-tune the range of the MC code at 80% dose level distal to the PBP. The energy spread was adapted by dividing the TPS range by the MC range for dose level 80%–20% distal to the PBP. Density and relative proton stopping power were adjusted by comparing the TPS and MC for different Hounsfield units. To find the relationship of dose per primary particle from the MC to dose per monitor unit in the TPS, integration was applied to the area of the Bragg curve. The calibration was validated for spread-out Bragg peaks (SOBP) in water and patient treatment plans. Following the validation, variable RBE were calculated using established models. Main results. The PBPs ranges were within ± mm threshold, and a maximum of 5.5% difference for the SOBPs was observed. The patient validation showed excellent dose agreement between the TPS and MC, with the greatest differences for the lung tumor patient. Significance. A procedure for calibrating a MC code to a TPS was developed and validated. The procedure enables MC-based calculation of dose, LET, variable RBE, advanced (secondary) particle tracking and more from treatment plans.

Towards a compact all-optical terahertz-driven electron source

In this study, we propose a physical design of a compact all-optical terahertz (THz)-driven electron source. The 300-mm accelerator beamline, powered by a Joule-level laser system, can be easily integrated into the tabletop scale. A THz-driven electron gun, a tapered dielectric-loaded cylindrical waveguide, THz-driven bunch compressors, and permanent magnetic solenoids (PMSs) have been designed and optimized. Dynamic simulations show that the electron source can deliver 19 fC electron beams at 3 MeV, with a normalized transverse emittance of 0.079 π.mm.mrad. A minimum relative energy spread of 0.04% or a minimum root-mean-square (RMS) bunch length of 6.1 fs can be achieved. Sensitivity analysis shows that the THz-driven electron source can effectively work with a laser power jitter within 1.5%. Simulation studies also reveal the potential of the designed THz-driven electron source for achieving high-quality ultrafast electron diffraction (UED). Prototype THz-driven electron guns have been fabricated and are currently under testing, and more comprehensive results will be reported in future works.

Measurements of proton beam flux and energy of APEP using foil activation technique

The activation method of metallic foils is an important technique to measure the flux and energy of proton beams. In this paper, the method was used to measure the CSNS APEP proton flux at seven nominal proton energies ranging from 10 MeV to 70 MeV for beam spot sizes of the 20 mm × 20 mm and 50 mm × 50 mm. The reactions of natTi(p, x)48V, natNi(p, x)57Ni, natCu(p, x)58Co, and 27Al(p, x)24Na were employed to measure the proton beam flux with a range of 107-109 p/cm2/s. Furthermore, we also proposed a method using the activity ratio with a stacked-foil target to determine the energy spread of a Gaussian-like distribution for different nominal proton energies. The optimal combinations of Al, Cu, Ti, Ni, Mo, Fe, Nb, and In foils were adopted for the proton energies. The measured energy spreads for degraded beams of 30 MeV–70 MeV were found to be smaller than 10.00%.

Quasi-real-time range monitoring by in-beam PET: a case for 15O

A fast and reliable range monitoring method is required to take full advantage of the high linear energy transfer provided by therapeutic ion beams like carbon and oxygen while minimizing damage to healthy tissue due to range uncertainties. Quasi-real-time range monitoring using in-beam positron emission tomography (PET) with therapeutic beams of positron-emitters of carbon and oxygen is a promising approach. The number of implanted ions and the time required for an unambiguous range verification are decisive factors for choosing a candidate isotope. An experimental study was performed at the FRS fragment-separator of GSI Helmholtzzentrum für Schwerionenforschung GmbH, Germany, to investigate the evolution of positron annihilation activity profiles during the implantation of ^{14}O and ^{15}O ion beams in a PMMA phantom. The positron activity profile was imaged by a dual-panel version of a Siemens Biograph mCT PET scanner. Results from a similar experiment using ion beams of carbon positron-emitters ^{11}C and ^{10}C performed at the same experimental setup were used for comparison. Owing to their shorter half-lives, the number of implanted ions required for a precise positron annihilation activity peak determination is lower for ^{10}C compared to ^{11}C and likewise for ^{14}O compared to ^{15}O, but their lower production cross-sections make it difficult to produce them at therapeutically relevant intensities. With a similar production cross-section and a 10 times shorter half-life than ^{11}C, ^{15}O provides a faster conclusive positron annihilation activity peak position determination for a lower number of implanted ions compared to ^{11}C. A figure of merit formulation was developed for the quantitative comparison of therapy-relevant positron-emitting beams in the context of quasi-real-time beam monitoring. In conclusion, this study demonstrates that among the positron emitters of carbon and oxygen, ^{15}O is the most feasible candidate for quasi-real-time range monitoring by in-beam PET that can be produced at therapeutically relevant intensities. Additionally, this study demonstrated that the in-flight production and separation method can produce beams of therapeutic quality, in terms of purity, energy, and energy spread.

Numerical and experimental study of ion energy distribution function in a dual-frequency capacitively coupled oxygen discharge

The plasma dynamics of a low pressure oxygen capacitively coupled plasma driven by dual frequencies (27.12 MHz and 271.2 kHz) is studied experimentally and numerically in this work. A retarding field energy analyzer system is employed in the experiment to measure the ion energy distribution function (IEDF) at the grounded electrode for different combinations of low-frequency voltages and pressures. One-dimensional particle-in-cell simulations of the oxygen plasma are conducted at the experimental conditions. A typical bimodal IEDF is observed and good agreement is obtained between experiments and simulations. A semi-analytical model based on the Child law sheath and fitted sheath voltage is constructed to study the structure of the IEDF. It is found that for the investigated conditions the low-energy peak of the IEDF is independent of the low frequency (LF) voltage but determined by the minimum sheath voltage during the sheath collapse; the energy spread of IEDF scales linearly with the LF voltage; both an increase of LF voltage and pressure create more low-energy ions.

Proton acceleration with multi-peak energy spectra tailored by vortex laser

A novel flying cascaded acceleration mechanism is proposed to generate energetic proton beams with multi-peak energy spectra using a circularly polarized (CP) Laguerre–Gaussian (LG) laser pulse in three-dimensional particle-in-cell simulations. Simulations show that the protons are initially accelerated and compressed into the beam center via the radiation pressure of the CP LG (σz = −1) laser pulse. Then, they are tailored by flying dipolar electric fields in this LG laser, resulting in a multi-peak energy spectrum. Each shaped proton peak exhibits a narrow energy spread of ∼5% and high flux of ∼2 × 108 protons/MeV at giga-electron volts energy. Such a flying cascaded acceleration mechanism extends the energy spectra of proton beams from monoenergetic to multi-peak structure, thereby potentially enhancing the generation efficiency of monoenergetic proton beams for various applications, such as proton-induced spallation reactions, proton radiography, and proton therapy.

A Radio-Frequency Ion Trap System for the Multi-Reflection Time-of-Flight Mass Spectrometer at SHANS and Its Offline Commissioning

To precisely measure atomic masses and select neutron-deficient isotopes produced by fusion evaporation reactions, an MRTOF-MS (multi-reflection time-of-flight mass spectrometer) at the SHANS (Spectrometer for Heavy Atom and Nuclear Structure) is being developed. One of the key parts, an RF ion trap system with the aim to provide brilliant ion pulses with a low energy spread and narrow pulse width for ion preparation prior to injection into the MRTOF mass analyzer, has been constructed and commissioned offline successfully. The principle, construction details and test results are reported. Pulsed beams of 39K1+, 85,87Rb1+ and 133Cs1+ ions have been tested and the amplitudes and frequencies of the RF signals, DC voltages, helium gas pressure and time parameters have been scanned. The corresponding time spreads have reached 0.252 µs, 0.394 µs and 0.450 µs, respectively.

Laser wakefield acceleration of electrons in a magnetically controlled plasma

In the present study, the laser wakefield acceleration of electrons in a magnetically-controlled plasma is investigated. The results indicate that by employing a linearly-chirped laser pulse propagating through magnetized plasma with a reversed external magnetic field, higher energy electrons are obtained than with unmagnetized plasma and/or a nonchirped laser pulse. By considering an appropriate constant chirping magnitude and an axial external magnetic field, one can obtain remarkable GeV electron energies. It is also found that the effect of the external magnetic field direction on the electron energy is not sensed much in the mildly relativistic regime, while the reversed magnetic field increases the peak of electron energy gains compared with the forward magnetic field in the highly relativistic regime. For the mildly relativistic case, a peak energy of 412 MeV and a relative energy spread of 7% is obtained. In addition, for the highly relativistic case, a peak energy of 1.55 GeV is obtained.

Mistuning Sensitivity of a Fan Bladed-Disk With Geometrical Nonlinearities

Abstract In order to decrease their environmental impact, turbo-engine manufacturers tend to increase the span of fan blades while maintaining a slender profile. This design leads to more pronounced geometrical nonlinear effects. Computing the frequency response function of such structures is complicated due to the size of their associated finite element model. Classical substructuring approaches are no longer efficient to reduce the size of the problem as all the nodes of the system must be kept since they experience nonlinear behaviors. Different reduction methodologies have been defined in the past decades to tackle such nonlinear systems. Among these strategies, the direct normal form (DNF) extends the theory of normal form to finite element models. This methodology is here applied to a single blade model. Based on the assumption of a fairly rigid disk and the cyclic symmetric properties, a full cyclic symmetric reduced-order model is computed. In this work, this methodology is extended to account for random mistuning. Such a strategy allows to perform, for instance, fast parametric studies. This paper studies the sensitivity of the random mistuning on a nonlinear open rotor system in order to help turbo-engineers in their design phase. Three ranges of the excitation level are studied. At a low level of excitation, the system is close to the linear case. For higher forcing amplitude, a high amplification factor (AF) due to the merge of an isolated branch is observed, which is detrimental for the structure. For the last range (containing the highest forcing amplitudes), the nonlinearities are highly activated, and low values of the amplification factor are obtained due to the spread of the vibrational energy over the frequency range.

Effects of a 4.3T superconducting wiggler on the electron beam optics and dynamics at NSLS-II

A superconducting wiggler (SCW) with a peak field of 4.3 T has recently been installed at NSLS-II. The wiggler generates a high-flux X-ray beam with a photon energy range from 20 keV to 200 keV for the High Energy Engineering X-ray Scattering beamline. This device induces significant distortions in the electron beam orbit and optics. We have corrected these adverse effects using feed-forward tables. The effects of the SCW on the electron beam emittance, energy spread, and bunch length were calculated and measured. The beam-induced heating of the cryogenic vacuum chamber was also studied. Finally, the superconducting wiggler has been commissioned for user operations.

Coherent ultrafast photoemission from a single quantized state of a one-dimensional emitter.

Femtosecond laser-driven photoemission source provides an unprecedented femtosecond-resolved electron probe not only for atomic-scale ultrafast characterization but also for free-electron radiation sources. However, for conventional metallic electron source, intense lasers may induce a considerable broadening of emitting energy level, which results in large energy spread (>600 milli-electron volts) and thus limits the spatiotemporal resolution of electron probe. Here, we demonstrate the coherent ultrafast photoemission from a single quantized energy level of a carbon nanotube. Its one-dimensional body can provide a sharp quantized electronic excited state, while its zero-dimensional tip can provide a quantized energy level act as a narrow photoemission channel. Coherent resonant tunneling electron emission is evidenced by a negative differential resistance effect and a field-driven Stark splitting effect. The estimated energy spread is ~57 milli-electron volts, which suggests that the proposed carbon nanotube electron source may promote electron probe simultaneously with subangstrom spatial resolution and femtosecond temporal resolution.

Manifestation of Triploid Heterosis in the Root System after Crossing Diploid and Autotetraploid Energy Willow Plants.

Successful use of woody species in reducing climatic and environmental risks of energy shortage and spreading pollution requires deeper understanding of the physiological functions controlling biomass productivity and phytoremediation efficiency. Targets in the breeding of energy willow include the size and the functionality of the root system. For the combination of polyploidy and heterosis, we have generated triploid hybrids (THs) of energy willow by crossing autotetraploid willow plants with leading cultivars (Tordis and Inger). These novel Salix genotypes (TH3/12, TH17/17, TH21/2) have provided a unique experimental material for characterization of Mid-Parent Heterosis (MPH) in various root traits. Using a root phenotyping platform, we detected heterosis (TH3/12: MPH 43.99%; TH21/2: MPH 26.93%) in the size of the root system in soil. Triploid heterosis was also recorded in the fresh root weights, but it was less pronounced (MPH%: 9.63-19.31). In agreement with root growth characteristics in soil, the TH3/12 hybrids showed considerable heterosis (MPH: 70.08%) under in vitro conditions. Confocal microscopy-based imaging and quantitative analysis of root parenchyma cells at the division-elongation transition zone showed increased average cell diameter as a sign of cellular heterosis in plants from TH17/17 and TH21/2 triploid lines. Analysis of the hormonal background revealed that the auxin level was seven times higher than the total cytokinin contents in root tips of parental Tordis plants. In triploid hybrids, the auxin-cytokinin ratios were considerably reduced in TH3/12 and TH17/17 roots. In particular, the contents of cytokinin precursor, such as isopentenyl adenosine monophosphate, were elevated in all three triploid hybrids. Heterosis was also recorded in the amounts of active gibberellin precursor, GA19, in roots of TH3/12 plants. The presented experimental findings highlight the physiological basics of triploid heterosis in energy willow roots.

Microdosimetric analysis of the radiation quality of two different proton beams in the distal edge of the depth-dose profile.

Proton-therapy exploits the advantageous depth-dose profile of protons to induce the highest damage to tumoral cells in the last millimetres of their range in sharp Bragg Peak. To cover the whole tumoral volume, beams of different energies are combined to create the Spread Out Bragg Peak (SOBP). In passive modulated beams, the energy spread is created with modulators in which the highest energy beam is degraded through different thicknesses of calibrated plastic materials. The highest energy is chosen depending on the deepest point that needs to be treated. This study aims to investigate differences in the radiation quality in the distal edge of SOBP beams with different initial energy and modulation techniques based on microdosimetric measurements with mini Tissue-Equivalent Proportional Counters. The beams investigated are the 62MeV proton SOBP of the clinical facility of CATANA and the 148MeV proton SOBP of the research beam line of the proton-therapy centre of Trento.

Realization and simulations of the new SPES Beam Cooler

One of the aim of the new project Selective Production of Exotic Species (SPES) is to produce and select new, neutron reach, isotopes [1,2,3,4]. The technique adopted to produce these species is the Isotope Selection On Line (ISOL) that postpones the separation of the isotopes after the beam production, using a High-Resolution Mass Spectrometer (HRMS).In order to allow a good separation of isotopes , the transverse emittance and the energy spread of the beam should have very low values, for this reason the Beam Cooler (BC) is located between the ISOL target, i.e. the beam source, and the HRMS.In the SPES project, where heavy isotopes are expected (mass number >100), the spectrometer resolution must be preferably higher than dm/m = 5 × 10-5 and thus the features of the beam at the entrance of the HRMS should be at least εn 95% < 8.3 × 10-3 π mm mrad and σE < 1.5 eV.BC devices are devoted to improve the beam features in terms of emittance and energy spread. A new BC has been designed and realized by the Laboratoire de Physique Corpuscolaire (LPC) at Caen, France, for the SPES facility at Laboratori Nazionali di Legnaro (LNL), near Padova, Italy.BCs cool down the beam thanks to a dissipative process in which the thermal energy passes from the beam ions to another medium whose constituent is typically much lighter, Helium gas in our case. This process takes place inside a confinement system that on the one hand to limit the spread of the cooling medium, and on the other to allow the beam to continue along the required trajectory, in the presented device it is a row of radio frequency quadrupoles in an almost closed chamber.Some specifications of the BC described in this document: the RFQ is 723 mm long, its internal radius is 5 mm; the RFQ is included in the gas chamber which is 730 mm×280 mm×220 mm. Before it there is the injection part composed by, following the beam trajectory, a grounded pipe (388 mm long) and three focusing electrodes. On the opposite side there is the extraction part with two focusing electrodes.This document presents the main features of the new BC together with the results of a preliminary study where the beam dynamic has been simulated. The analysis embeds also the investigation of the gas distribution inside and outside the BC.The beam dynamic simulations are based on the Simion code [5] while the estimation of the gas distribution is computed with MolFlow+ [6].Simulations show that accurately setting the BC leads to a large improvement of the emittance while the energy spread still needs to be improved. Limiting the gas pressure in the acceleration zone seems to allow the required final boost.

Technical Infrastructure for Clinical Translation of Electron FLASH

For safe clinical translation of electron FLASH, hardware tools for real-time beam control and software tools for treatment planning are necessary. The purpose of this study is to prototype high-throughput hardware for real-time beam control, along with accurate beam modeling of a modern clinical Linac configured to deliver FLASH dose-rates. For real-time beam current monitoring, a beam current transformer (BCT) was initially coupled to a fast digitizer and its linearity was established by varying dose per pulse. The radiation pulse width was modified, and this change was measured using the BCT. The BCT was then used to measure the variability of dose per pulse and pulse width due to a mistuned linear accelerator system. Next, the BCT was interfaced with a field programmable gate array (FPGA) which provides the ability for high-throughput and deterministic control of the Linac based on dose accumulation. For beam modeling, the program, TOol for PArticle Simulation (TOPAS), was used to obtain beam parameters by using Bayesian optimization of the beam energy, source size, angular, and energy spread via comparison of simulated and representative dose profiles. The beam model would then be employed to calculate 3D dose distribution in a CT scan of a 3D-printed anatomically realistic mouse phantom. The area under the current-time curve from the BCT exhibited excellent linearity (response = 12.80 nC/Gy) up to 2.5 Gy/Pulse (R2 = 0.99). The peak beam current for the electron FLASH beam was measured to be ∼10 mA for an instantaneous dose-rate of ∼5×105 Gy/s. The measured radiation pulse width agreed with the expected value (3.7 μs). The pulse width was then shortened and the measurement by the BCT indicated pulse widths of 1.8 μs and 0.5 μs corresponding to 0.7 Gy/pulse and 0.3 Gy/pulse, respectively. The beamline exhibited a ramp-up in dose per pulse and pulse width when using the automatic frequency controller (AFC). For the first pulse, the dose delivered was ∼0.1-0.3 Gy and the pulse width was 0.6 μs. The output stabilized to nominal values of dose and pulse width after 3-4 pulses. This ramp-up was mitigated by manually tuning the RF resonance with the AFC disabled, after which the BCT exhibited constant output and pulse width. The beam modeling work is in progress. We demonstrated that a BCT can provide real-time measurement of per-pulse output suitable as input for FLASH beam control based on dose accumulation. The next steps are to quantify the accuracy of the dose control mechanism with the FPGA-based hardware. Potential failure modes will be identified and mitigated in parallel with the development of the hardware. A 3D-printed mouse phantom has been constructed to facilitate beam modeling work for treatment planning (in progress). On completion of this work, it is expected that we will have key infrastructure elements needed to move towards an eventual FDA investigational device exemption for clinical trials.

Design and simulation of a radius-varying active plasma lens for focusing laser-accelerated protons

With plasma as the medium, laser driven accelerator can generate high energy pulsed particles with initially micron scale source size and broad energy spread. Efficient transport of the beam with above characteristics is a challenging task. Active plasma lenses (APLs) provide strong, tunable, axisymmetric focusing with weak chromatic dependencies, making them highly beneficial for compact laser accelerators. However, due to the large divergence angle of the laser-accelerated proton beams, a majority of the protons cannot be transmitted through the APLs, resulting in losses. In this study, we propose a radius-variable APL (RV-APL) that optimizes the capillary’s geometry based on the beam envelope. The collection angle of RV-APL under the design parameters in the article can be increased by about 80% compared to a cylindrical APL (C-APL) with a constant radius, achieving the transmission capacity of traditional magnets. The magnetic field distribution of the RV-APL was predicted using a two-dimensional axisymmetric plasma discharge model, and the focused beam’s chromaticity and emittance properties were theoretically analyzed through particle tracking simulation.

A boosted muon collider

A muon collider could produce the heavier Standard Model particles with a boost, for example in resonant processes such as μ−μ+→ h or μ−μ → Z. We propose machine configurations that produce the boost (asymmetric beam energies, tilted beams) and estimate how much the luminosity is reduced or perhaps enhanced. The feasibility of the proposed configurations, as well as an estimation of the beam-induced backgrounds and beam energy spread, needs to be evaluated in order to derive more solid conclusions on the physics potential of such boosted collider configurations. If achievable, the boost can provide new interesting observational opportunities. For example it can significantly enhance the sensitivity to long-lived new particles decaying in a far-away detector, such as dark higgses or sterile neutrinos produced in h or Z decays.

Stimulated Raman scattering by circularly polarized quadruple Gaussian laser beam and co-propagating electron beam in plasma

This study investigates the interplay between a co-propagating relativistic electron beam and a quadruple Gaussian laser beam in plasma, focusing on the suppression of stimulated Raman scattering (SRS) growth. The presence of the laser beam induces the excitation of a pair of plasma waves and side-scattered electromagnetic waves. As the side-scattered wave and pump wave couple together, they exert a ponderomotive force on the electron beam and plasma electrons, resulting in an enhancement of the plasma wave amplitude. Nonlinear coupling between the density perturbation in the plasma, induced by the plasma wave, and the pump wave leads to the excitation of a nonlinear current responsible for the growth of the side-scattered electromagnetic wave associated with SRS. Furthermore, the growth rate of SRS is shown to be highly sensitive to the phase matching between the relativistic electron beam and the plasma wave. In cases of phase mismatch, the growth rate experiences a significant reduction. Additionally, the effectiveness of the electron beam in driving the stimulated Raman process is greatly affected by the energy spread of the electron beam. A substantial reduction in effectiveness is observed due to this energy spread.

Dynamic heterogeneity of atomic transport in a body-centered cubic WTaVCr non-equiatomic high-entropy alloy

Compared to face-centered cubic (fcc) high-entropy alloys (HEAs), body-centered cubic (bcc) HEAs generally possess larger lattice distortion, resulting in distinct point defect properties. In this work, molecular dynamics (MD) simulations and molecular statics (MS) calculations were performed to study the dynamic heterogeneity in a bcc W40Ta35V10Cr15 non-equiatomic HEA with large lattice distortion. Defect energies in W40Ta35V10Cr15 HEA show a strong preference for a specific element and possess large energy spreads, resulting in dynamic heterogeneity of atomic transport in the process of defect diffusion and evolution. V and Cr interstitials exhibit higher occurrence probability and faster diffusion compared to W and Ta interstitials. Such diffusion heterogeneity brings about high recombination probabilities of W and Ta interstitials and large fractions of V and Cr in surviving interstitials during displacement cascades. The binding ability of interstitials correlates with the magnitude of interstitial formation energies. The smaller the interstitial formation energies, the weaker the binding abilities. A large number of surviving V and Cr interstitials with smaller interstitial formation energies exhibit weak binding abilities and discrete distribution. Our findings suggest that the dynamic heterogeneity in W40Ta35V10Cr15 HEA with large lattice distortion may be the underlying mechanism of outstanding irradiation resistance.