Interaction Cross Sections Research Articles

The linear and nonlinear inverse Compton scattering between microwaves and electrons in a resonant cavity

The new scheme of the energy measurement of the extremely high energy electron beam with the inverse Compton scattering between electrons and microwave photons requires the precise calculation of the interaction cross section of electrons and microwave photons in a resonant cavity. In the local space of the cavity, the electromagnetic field is expressed by Bessel functions. Although Bessel functions can form a complete set of orthogonal basis, it is difficult to quantify them directly as fundamental wave functions. Fortunately, with the Fourier expansion of Bessel functions, the local electromagnetic field can be considered as the superposition of a series of plane waves. Therefore, with corresponding corrections of the cross section formula of the classical Compton scattering, the cross section of the linear or nonlinear microwave Compton scattering in the local space can be described accurately. As an important application of our results in astrophysics, corresponding ground verification devices can be designed to perform experimental verifications on the prediction of the Sunyaev–Zeldovich (SZ) effect of the cosmic microwave background radiation. Our results could also provide a new way to generate wave sources with strong practical value, such as the terahertz waves, the ultra-violet (EUV) waves, or the mid-infrared beams.

Integral nucleus-nucleus cross-sections

Abstract Expressions approximating the experimental integral cross-sections for elastic and inelastic interactions of light and heavy nuclei at energies up to several GeV/nucleon are presented. The calculated cross-sections are inside the corridor of experimental errors or very close to it.

Transforming Nuclear Medicine with Nanoradiopharmaceuticals.

Nuclear medicine is expected to make major advances in cancer diagnosis and therapy; tumor-targeted radiopharmaceuticals preferentially eradicate tumors while causing minimal damage to healthy tissues. The current scope of nuclear medicine can be significantly expanded by integration with nanomedicine, which utilizes nanoparticles for cancer diagnosis and therapy by capitalizing on the increased surface area-to-volume ratio, the passive/active targeting ability and high loading capacity, the greater interaction cross section with biological tissues, the rich surface properties of nanomaterials, the facile decoration of nanomaterials with a plethora of functionalities, and the potential for multiplexing several functionalities within one construct. This review provides a comprehensive discussion of nuclear nanomedicine using tumor-targeted nanoparticles for cancer radiation therapy with either pre-embedded radionuclides or nonradioactive materials which can be extrinsically triggered using various external nuclear particle sources to produce in situ radioactivity. In addition, it describes the prospect of combining nuclear nanomedicine with other modalities to enable synergistically enhanced combination therapies. The review also discusses advances in the fabrication of radionuclides as well as describes laser ablation technologies for producing nanoradiopharmaceuticals, which combine the ease of production with exceptional purity and rapid biodegradability, along with additional imaging or therapeutic functionalities. From a practical standpoint, these attributes of nanoradiopharmaceuticals may provide distinct advantages in diagnostic/therapeutic sensitivity and specificity, imaging resolution, and scalability of turnkey platforms. Coupling image-guided targeted radiation therapy with the possibility of in situ activation of nanomaterials as well as combining with other therapeutic modalities using a multifunctional nanoplatform could herald an era of exciting technological and therapeutic advances to radically transform the landscape of nuclear medicine. The review concludes with a discussion of current challenges and presents the authors' views on future opportunities to stimulate further research in this rewarding field of high societal impact.

Search for magnetic monopoles with ten years of the ANTARES neutrino telescope

This work presents a new search for magnetic monopoles using data taken with the ANTARES neutrino telescope over a period of 10 years (January 2008 to December 2017). Compared to previous ANTARES searches, this analysis uses a run-by-run simulation strategy, with a larger exposure as well as a new simulation of magnetic monopoles taking into account the Kasama, Yang and Goldhaber model for their interaction cross-section with matter. No signal compatible with the passage of relativistic magnetic monopoles is observed, and upper limits on the flux of magnetic monopoles with β=v/c≥0.55, are presented. For ultra-relativistic magnetic monopoles the flux limit is ∼7×10−18 cm−2s−1sr−1.

Demonstration of non-destructive and isotope-sensitive material analysis using a short-pulsed laser-driven epi-thermal neutron source

Neutrons are a valuable tool for non-destructive material investigation as their interaction cross sections with matter are isotope sensitive and can be used complementary to x-rays. So far, most neutron applications have been limited to large-scale facilities such as nuclear research reactors, spallation sources, and accelerator-driven neutron sources. Here we show the design and optimization of a laser-driven neutron source in the epi-thermal and thermal energy range, which is used for non-invasive material analysis. Neutron resonance spectroscopy, neutron radiography, and neutron resonance imaging with moderated neutrons are demonstrated for investigating samples in terms of isotope composition and thickness. The experimental results encourage applications in non-destructive and isotope-sensitive material analysis and pave the way for compact laser-driven neutron sources with high application potential.

Neutron transmission imaging with a portable D-T neutron generator

A portable fast-neutron imaging system is being developed to provide complementary information to field X-ray imaging. Applications include inspection of vehicles and infrastructure for corrosion, measurement of material levels in containers, and inspection of munitions and suspicious packages. While fast-neuron imaging generally provides lower imaging resolution compared to X-rays, fast-neutron interaction cross-sections have a weak dependence on material Z. This enables imaging of low-Z materials inside high-Z materials. Here, we discuss the limitations and current improvements in fast-neuron imaging. Limitations in portable fast-neutron imaging systems include low D-T neutron generator output, low light production in ZnS(Cu) imaging scintillators, low resolution due to scintillator thickness and D-T spot size, and digital-panel darknoise that varies in time and position and that can be 100× larger than the neutron signal. We have made improvements in these areas through development of a segmented high light yield scintillator, panel noise mitigation techniques, and testing of new high-output, small spot size D-T neutron generators. The segmented high light yield fast-neutron scintillator demonstrated 5× increase in light compared to ZnS(Cu). An additional 2× improvement in signal-to-noise was demonstrated with panel-noise mitigation techniques. Our MCNP calculations also show good agreement with neutron imaging results We have demonstrated improvements in fast-neutron imaging through development of a segmented high light yield neutron scintillator, mitigation of digital panel noise, and preliminary testing with new high-output, small spot size D-T neutron generators. We have also demonstrated good results modeling fast-neutron images and scatter effects using MCNP.

Gamma-Ray Cosmology and Tests of Fundamental Physics

The propagation of gamma-rays over cosmological distances is the subject of extensive theoretical and observational research at GeV and TeV energies. The mean free path of gamma-rays in the cosmic web is limited above 100 GeV due to the production of electrons and positrons on the cosmic optical and infrared backgrounds. Electrons and positrons cool in the intergalactic medium while gyrating in its magnetic fields, which could cause either its global heating or the production of lower-energy secondary gamma-rays. The energy distribution of gamma-rays surviving the cosmological journey carries observed absorption features that gauge the emissivity of baryonic matter over cosmic time, constrain the distance scale of ΛCDM cosmology, and limit the alterations of the interaction cross section. Competitive constraints are, in particular, placed on the cosmic star-formation history as well as on phenomena expected from quantum gravity and string theory, such as the coupling to hypothetical axion-like particles or the violation of Lorentz invariance. Recent theoretical and observational advances offer a glimpse of the multi-wavelength and multi-messenger path that the new generation of gamma-ray observatories is about to open.

Matter radii and skins of [formula omitted]He from reaction cross section of proton+[formula omitted]He scattering based on the Love–Franey [formula omitted]-matrix model

Background:For 4,6,8He, Tanihata et al. determined matter radii rm(σI)=1.57(4),2.48(3),2.52(3) fm from interaction cross sections σI for 4,6,8He scattering on Be, C Al targets at 790 MeV/nucleon. Lu et al. measured the atomic isotope shifts (AIS) for 4,6,8He and determined proton radii rp(AIS) for 4,6,8He. As for p+4,6,8He scattering, reaction cross sections σR(exp) are available at 700 MeV with high accuracy. Aim:Our aim is to determine matter radii rm and skins rskin for 6,8He from the σR(exp) and the rp(AIS). Method:Our model is the Love–Franey t-matrix folding model, since the model is better than the optical limit of Glauber model. Results:Our results for 6,8He are rm(exp)=2.48(3),2.53(2) fm and rskin=0.78(3), 0.82(2) fm. Conclusion:For 6,8He, our results rm(σR) agree with those of Tanihata et al.. For 8He, the distance between 4He and the center of mass of valence four neutrons is 2.367 fm.

Enhancement of Fast Neutron Detection in Liquid Scintillator Detectors

Organic liquid scintillators, such as EJ-309, are capable of detecting fast neutrons and discriminating gamma rays through pulse shape. Higher detection efficiency is a common objective for detector designs and research. This paper describes two methods to enhance fast neutron detection by increasing neutron collection and reducing gamma-ray interference. Neutron collection can be increased by using strong scattering material to reflect neutrons toward scintillators. Gamma-ray interference can be reduced by using heavy material to shield gamma rays; such a material could have a minimal impact on neutron detection because neutrons and gamma rays have different interaction cross sections. In this work, both effects were investigated, experimentally and by simulation. Using a graphite reflector with simple geometry, the fast neutron detection was measured to have an increase of 9%, and simulations predicted an approximately 50% increase for optimized geometry. Using a lead shielding of 8-mm thickness, the neutron detection with a Pu source was measured to have a factor of 2 increase. These methods could be useful when cost-effective and highly efficient fast neutron detection is desired.

Defect formation and bending properties in graphite under He atom implantation investigated by molecular dynamics method

The formation and evolution of radiation defects and their effects on bending property of a single graphite under low energy helium atom implantation have been studied at atomic scale through molecular dynamics simulations. Various simple interstitial and vacancy defects are observed during the implantation process, which is a function of incident energy and cross section of helium-carbon interaction. Large defects are observed after continuous helium atom implantations. The effects of incident energy on the density, size and distribution of defects are analyzed in detail. Furthermore, the kinetic evolution process of radiation defects at different annealing temperatures have also been simulated, including the migration, aggregation, transformation, coalescence, and self-healing. The large defect clusters, crossing several carbon layers, have been confirmed to be the primary reasons that affect the bending property of graphite. All these results provide a new understanding for further applications of graphite in nuclear reactors.

Laser incidence angle influence on energy density variations, surface roughness, and porosity of additively manufactured parts

The use of additive manufacturing (AM) technologies for fabricating structural and functional parts is rapidly rising due to their transformative design flexibility and customizability. However, maintaining the uniformity and consistency of the fabricated part across the build plate is a critical challenge. One of the main sources of variability across the build plate is laser spot elongation in laser beam powder bed fusion (LB-PBF) AM which typically occurs when the beam moves from the center of the plate to the edge at different incidence angles. This laser spot elongation may then result in the loss of laser power density which can potentially cause elongated melt pools, poor dimensional accuracy, and formation of lack of fusion and more gas entrapped pores in the final part. Here, we report both geometrical calculations and experimental evidence to show the behavior of the laser in the different areas of the build plate. A pulsed laser is first used to show and calculate the geometrical footprint of the beam elongations at different incidence angles. Then, the surface roughness, melt pool size, and porosity variations are investigated for varying laser interaction cross-section across the build plate by manufacturing AlSi10Mg (an aluminum alloy) parts and correlating them to theoretical calculations. It is found that for given optimized process parameters at the center of the build plate, as the beam goes farther away from the center, it becomes elongated. As the power density falls, melt pool width becomes wider, melt pool depth becomes shallower (depending on the elongation orientation with respect to the scan direction), and the number of lack of fusion defects increases. This work provides fundamental insight into possible sources of variations across the build plate in an LB-PBF process that may help design new strategies to compensate for such variations to enhance uniformity and reliability of AM parts.

Neutron skin in 48Ca determined from p+48Ca and 48Ca+12C scattering

Background:In our previous paper, we determined rskin208(exp)=0.278±0.035 fm from measured reaction cross sections σR for p+208Pb scattering, using the Kyushu (chiral) g-matrix folding model with the densities calculated with the Gogny-D1S Hartree–Fock–Bogoliubov (D1S-GHFB) with the angular momentum projection (AMP). The value agrees with that of PREX2. Reaction cross sections σR are available for p+48Ca scattering, whereas interaction cross sections σI(≈σR) are available for 48Ca + 12C scattering. As for 48Ca, the high-resolution E1 polarizability experiment (E1pE) yields rskin48(E1pE)=0.14∼0.20fm. Purpose:We determine rskin48(exp) from the data on σR for p+48Ca scattering and from the data on σI for 48Ca+12C scattering. Methods:We use the Kyushu g-matrix folding model with the densities calculated with the D1M-GHFB+AMP densities. The D1M-GHFB+AMP proton and neutron densities are scaled so as to reproduce the data under the condition that the radius rp of the scaled proton density equals the data rp(exp) determined from the electron scattering. We deduce skin values rskin=rn(exp)−rp(exp) from the resulting rn(exp) and the rp(exp) determined from electron scattering. The same procedure is taken for D1S-GHFB+AMP. Results:We regard rskin48(E1pE) as a reference skin value. Using the reference skin value and taking D1M-GHFB+AMP, we determine rskin48(exp)=0.158±0.025 fm for p+48Ca scattering and 0.160±0.058 fm for 48Ca +12C scattering. Conclusion:We take the weighted mean and its error for the two skin values. The result is rskin48(exp)=0.158±(0.023)exp±(0.012)thfm.

Folding-model approach to reaction cross section of [formula omitted]He+12C scattering at 790 MeV

Tanihata et al. (1988) determined matter radii rm(σI) for 4,6,8He from interaction cross sections σI of 4,6,8He+12C scattering at 790 MeV per nucleon, using the optical limit of the Glauber model. Lu et al. (2013) determined proton radii rp(AIS) for 4,6,8He with the atomic isotope shifts (AIS). We investigate whether the Love-Franey t-matrix folding model is good for 4,6,8He+12C scattering at 790 MeV per nucleon.

Elliptic flow for φ mesons measured by PHENIX

The systematic study of hadronic elliptic flow in various relativistic heavy ion collisions is important for the investigation of the initial geometry influence on the quark gluon plasma characteristics. The φ meson consists of strange and antistrange quarks and has a small interaction cross section with non-strange hadrons. Therefore, φ mesons are barely affected by late hadronic stage and reflect detailed information about hot and dense matter properties. Additionally, the comparison of elliptic flow for φ mesons to those of charged hadrons will provide additional information on the flavor dependence of flow. PHENIX has measured second order azimuthal anisotropy coefficients for φ mesons in Cu+Au collisions at √SNN = 200 GeV and in U+U collisions at √SNN = 193 GeV at midrapidity (| η | < 0.35). The obtained data suggest scaling of elliptic flow for φ mesons with eccentricity of participant nucleons in Cu+Au, U+U, and Au+Au collisions. Viscous hydrodynamic model iEBE-VISHNU provides a simultaneous description of the obtained data.

Simulation of neutron irradiation damage in lead lanthanum zirconate titanate by Monte Carlo method

Lead lanthanum zirconate titanate (PLZT) has a broad application prospect for energy storage devices with high energy density, since it possesses excellent dielectric and energy storage properties. To investigate the irradiation damage to the PLZT induced by neutrons with different energy, the primary energetic recoil spectra of each kind of element are first extracted from the transportation simulations of neutrons with energy ranging from 1 to 14 MeV, respectively. Then, the displacement damages (including vacancies and interstitial atoms) induced by each type of recoil with different energy are simulated based on the binary collision approximation method. Finally the number of defects in PLZT produced by neutrons with an energy range from 1 to 14 MeV is calculated based on the recoil energy spectra and the defect number produced by the recoils. The results show that the number of defects produced in the PLZT material with a thickness of 3 cm is approximately independent of the neutron energy for the fast neutrons with energy in a range from 1 to 14 MeV, even though the primary recoil energy spectra from neutrons with different energy are completely different. The average number of defects produced in 3-cm-thick PLZT is about 460 ± 120 vacancies/neutrons. For neutrons with energy ranging from 1 to 14 MeV, the produced defect concentration in PLZT decreases slightly with the depth increasing within a thickness of 3 cm. The difference in defect concentration in this 3 cm is in a range of 50%. This decrease is caused mainly by the fact that some of neutrons are back-scattered during transport. The average defect concentration produced by neutron irradiation in the PLZT with a thickness of 3 cm is slightly(～20%) higher than that in the PLZT with a thickness of 1 mm. The reason for the higher defect concentration in a thicker (3 cm) PLZT can be attributed to the following facts: (i) the (n, 2n) reactions between neutron and material can make the number of neutrons increase during transport; (ii) the scattering can make the path of neutron longer; (iii) the inelastic scattering can lead to a smallnumber of moderated neutrons, which have a slightly larger interaction cross section with materials. This indicates the damage produced in thick PLZT is quite complicated and closely related to the process of neutron transport. This work presents a method of calculating the displacement damage of neutrons in materials, and the simulation results can provide guidance for studying the neutron irradiation effects of PLZT-based electronic devices.

Determination of the nuclear radius parameter using the γ-ray spectrometer

The nuclear radius parameter of carbon, aluminium, iron, copper, and zinc nuclei has been determined by using (n,γ)-reaction. The neutrons from the americium-beryllium source are made to interact with the water moderator to produce the γ-rays of 2.2 MeV through (n,γ)-reaction. The γ-radiation emitted from the water medium is measured with a scintillation detector coupled to 8k multi-channel analyzer. The neutrons from the americium-beryllium source are allowed to transmit through carbon, aluminium, iron, copper, and zinc elemental targets of various thicknesses, and transmitted neutrons are again allowed to interact with water moderators to produce 2.2 MeV γ-radiation. By measuring the yield of γ-radiation produced in water moderators by neutrons transmitted through elemental targets of different mass number values, the total neutron interaction cross-sections are determined. By knowing the total neutron interaction cross-sections and mass number of the target nuclei, the radius parameter has been determined.

Evaluation of event reconstruction with small-scale water Cherenkov detectors

The Hyper-Kamiokande experiment is planned to start in 2027 aiming for precise measurement of neutrino oscillation using J-PARC neutrino beam including the search for CP violation in the lepton sector. The Hyper-Kamiokande detector is a 260 kiloton water Cherenkov detector. In order to achieve the precision measurement, systematic uncertainties should be suppressed. For this purpose, a new 1 kiloton scale Intermediate Water Cherenkov Detector (IWCD) is proposed to measure the neutrino flux and interaction cross section near the generation point of the neutrino beam before oscillation. Water Cherenkov Test Experiment (WCTE) is a 50 ton scale water Cherenkov detector and currently under preparation to validate the performance of IWCD. WCTE will use new photosensor called multi-PMT and study the response of small water Cherenkov detectors to electron, muon, and hadron beams at CERN. The performance of event reconstruction with the IWCD and WCTE detectors is evaluated using simulation.

Measuring high-energy neutrinos with FASERυ in the LHC Run-3

FASERυ at the Large Hadron Collider, LHC, is designed to directly detect collider neutrinos for the first time and study their cross sections at high energies, where no such measurements currently exist. The detector will be located in the far-forward region of ATLAS. Deployment on the beam collision axis maximizes the flux of all three neutrino flavors, and allows FASER to measure their interaction cross-sections in the currently unexplored TeV energy range. For electron and tau neutrinos, these measurements will extend existing cross section measurements to significantly higher energies. In 2018 we performed a pilot run with the aims of measuring particle fluxes at the proposed detector location and of possibly detecting neutrino interactions for the first time at the LHC. We installed a 30-kg lead/tungsten emulsion detector and collected data of 12.2 fb1. The analysis of this data has yielded several neutrino interaction candidates, excluding the no-signal hypothesis at the 2/sigma level. During Run-3 of the LHC starting from 2022, we will deploy an emulsion detector with a target mass of 1.1 tons, coupled with the FASER magnetic spectrometer. This would yield roughly 2000 υ e, 8000 υ μ, and 50 υ τ interacting in the detector. We present the status and prospects of FASERυ, as well as the neutrino detection in the pilot run data.

Running axial mass of the nucleon as a phenomenological tool for calculating quasielastic neutrino\u2013nucleus cross sections

We suggest an empirical rule-of-thumb for calculating the cross sections of charged-current quasielastic (CCQE) and CCQE-like interactions of neutrinos and antineutrinos with nuclei. The approach is based on the standard relativistic Fermi-gas model and on the notion of neutrino energy dependent axial-vector mass of the nucleon, governed by a couple of adjustable parameters, one of which is the conventional charged-current axial-vector mass. The inelastic background contributions and final-state interactions are therewith simulated using GENIE 3 neutrino event generator. An extensive comparison of our calculations with earlier and current accelerator CCQE and CCQE-like data for different nuclear targets shows good or at least qualitative overall agreement over a wide energy range. We also discuss some problematical issues common to several competing contemporary models of the CCQE (anti)neutrino–nucleus scattering and to the current neutrino interaction generators.

T2K latest results on neutrino-nucleus cross sections

Neutrino interaction cross section measurements are of high importance, in improving understanding for both oscillation measurements and nuclear modelling. The T2K experiment features a near detector complex with multiple detectors, providing multiple different nuclear targets at differing mean neutrino energies due to the off-axis configurations used. Along with constraining the flux for oscillation measurements, these near detectors provide the opportunity for a large programme of neutrino cross section measurements. Some recent such measurements are described in this proceeding.