Measurements Of Interaction Cross Sections Research Articles

First operation of an ALICE OROC operated in high pressure Ar-CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext {Ar-CO}}_2$$\\end{document} and Ar-CH4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {Ar-CH}_4$$\\end{document}

New neutrino–nucleus interaction cross-section measurements are required to improve nuclear models sufficiently for future long baseline neutrino experiments to meet their sensitivity goals. A time projection chamber (TPC) filled with a high-pressure gas is a promising detector to characterise the neutrino sources used for such experiments. A gas-filled TPC is ideal for measuring low-energy particles, which travel further in gas than in solid or liquid detectors and using high-pressure increases the target density, resulting in more neutrino interactions. We examine the suitability of multiwire proportional chambers (MWPCs) from the ALICE TPC for use as the readout chambers of a high-pressure gas TPC. These chambers were previously operated at atmospheric pressure. We report the successful operation of an ALICE TPC outer readout chamber (OROC) at pressures up to 4.2 bar absolute (barA) with Ar-CH4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {Ar-CH}_4$$\\end{document} mixtures with a CH4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {CH}_{4}$$\\end{document} content between 2.8 and 5.0%, and so far up to 4 bar absolute with Ar-CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext {Ar-CO}}_2$$\\end{document} (90-10). The charge gain of the OROC was measured with signals induced by an 55Fe\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{55}\ ext {Fe}$$\\end{document} source. The largest gain achieved at 4.2 bar was (29±1)·103\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(29\\pm 1)\\cdot 10^{3}$$\\end{document} in Ar-CH4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {Ar-CH}_4$$\\end{document} with 4.0% CH4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {CH}_{4}$$\\end{document} with an anode voltage of 2975V\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${2975}\\,\\hbox {V}$$\\end{document}. In Ar-CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext {Ar-CO}}_2$$\\end{document} with 10% CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {CO}_{2}$$\\end{document} at 4 barA, a gain of (4.2±0.1)·103\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(4.2\\pm 0.1)\\cdot 10^{3}$$\\end{document} was observed with anode voltage 2975V\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${2975}\\,\\hbox {V}$$\\end{document}. We extrapolate that at 10 barA, an interesting pressure for future neutrino experiments, a gain of 5000 in Ar-CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext {Ar-CO}}_2$$\\end{document} with 10% CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {CO}_{2}$$\\end{document} (10,000 in Ar-CH4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {Ar-CH}_4$$\\end{document} with ∼4%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim \\!{4}{\\%}$$\\end{document}CH4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {CH}_{4}$$\\end{document}) may be achieved with anode voltage of 4.6kV\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${4.6}\\,\\hbox {kV}$$\\end{document} (∼3.6kV\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim \\!{3.6}\\,\\hbox {kV}$$\\end{document}).

The Upgrade of the T2K ND280 Detector

The Tokai to Kamiokande (T2K) experiment is a long-baseline neutrino experiment taking data since 2010. The neutrino beam is detected on two sites, the near detector complex close to the neutrino production point, and Super-Kamiokande in a distance of 300 km. The ND280 detector is one of the near detectors and has the purpose to characterize the beam before oscillation as also the measurement of interaction cross sections. Both is crucial to reduce the systematic uncertainties. To improve the latter further, the T2K collaboration decided in 2016 an upgrade of ND280 which includes the installation of a novel scintillator tracker, two time projection chambers and a time of flight system. This upgrade, in combination of an increase of the neutrino beam power from currently 500 kW to 1.3 MW, will roughly increase the statistics by a factor 4 and reduce the systematic uncertainties from 6% to 4%. The new subdetectors are currently being assembled and will be installed in 2022. The upgraded ND280 will also serve as near detector of the next generation long-baseline neutrino oscillation experiment Hyper-Kamiokande.

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.

Electric dipole response of low-lying excitations in the two-neutron halo nucleus F29

The neutron-rich $^{28,29}$F isotopes have been recently studied via knockout and interaction cross-section measurements. The $2n$ halo in $^{29}$F has been linked to the occupancy of $pf$ intruder configurations. We investigate bound and continuum states in $^{29}$F, focusing on the $E1$ response of low-lying excitations and the effect of dipole couplings on nuclear reactions. $^{29}\text{F}$ ($^{27}\text{F}+n+n$) wave functions are built within the hyperspherical harmonics formalism, and reaction cross sections are calculated using the Glauber theory. Continuum states and $B(E1)$ transition probabilities are described in a pseudostate approach using the analytical THO basis. The corresponding structure form factors are used in CDCC calculations to describe low-energy scattering. Parity inversion in $^{28}$F leads to a $^{29}$F ground state characterized by 57.5% of $(p_{3/2})^2$ intruder components, a strong dineutron configuration, and an increase of the matter radius with respect to the core radius of $\Delta R=0.20$ fm. Glauber-model calculations for a carbon target at 240 MeV/nucleon provide a total reaction cross section of 1370 mb, in agreement with recent data. The model produces also a barely bound excited state corresponding to a quadrupole excitation. $B(E1)$ calculations into the continuum yield a total strength of 1.59 e$^2$fm$^2$ up to 6 MeV, and the $E1$ distribution exhibits a resonance at $\approx$ 0.85 MeV. Results using a standard shell-model order for $^{28}$F lead to a considerable reduction of the $B(E1)$ distribution. The four-body CDCC calculations for $^{29}\text{F}+^{120}\text{Sn}$ around the Coulomb barrier are dominated by dipole couplings, which totally cancel the Fresnel peak in the elastic cross section. These results are consistent with a two-neutron halo and may guide future experimental campaigns.

Measurements of production and inelastic cross sections for p+C , p+Be , and p+Al at 60 GeV/c and p+C and p+Be at 120 GeV/c

This paper presents measurements of production cross sections and inelastic cross sections for the following reactions: 60 GeV/c protons with C, Be, Al targets and 120 GeV/c protons with C and Be targets. The analysis is performed using the NA61/SHINE spectrometer at the CERN Super Proton Synchrotron. First measurements are obtained using protons at 120 GeV/c, while the results for protons at 60 GeV/c are compared with previously published measurements. These interaction cross section measurements are critical inputs for neutrino flux prediction in current and future accelerator-based long-baseline neutrino experiments.Received 9 September 2019DOI:https://doi.org/10.1103/PhysRevD.100.112001Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasParticle productionParticles & Fields

Matter radii of N16−23

I have used a simple model to compute matter radii for $^{16--23}\mathrm{N}$, paying special attention to the configurations of the valence neutron(s). I compare results with recent predictions and with earlier matter radii extracted from measurements of interaction cross sections. The present calculations are closer to the experimental radii than any of the results from the other procedures.

Examination of the C22 radius determination with interaction cross sections

A nuclear radius of $^{22}$C is investigated with the total reaction cross sections at medium- to high-incident energies in order to resolve the radius puzzle in which two recent interaction cross section measurements using $^1$H and $^{12}$C targets show the quite different radii. The cross sections of $^{22}$C are calculated consistently for these target nuclei within a reliable microscopic framework, the Glauber theory. To describe appropriately such a reaction involving a spatially extended nucleus, the multiple scattering processes within the Glauber theory are fully taken into account, that is, the multi-dimensional integration in the Glauber amplitude is evaluated using a Monte Carlo technique without recourse to the optical-limit approximation. We discuss the sensitivity of the spatially extended halo tail to the total reaction cross sections. The root-mean-square matter radius obtained in this study is consistent with that extracted from the recent cross section measurement on $^{12}$C target. We show that the simultaneous reproduction of the two recent measured cross sections is not feasible within this framework.

Recoil distance transmission method: Measurement of interaction cross sections of excited states with fast rare-isotope beams

The possible appearance of nuclear halos in ground and excited states close to the particle-decay threshold is of great importance in the investigation of nuclear structure and few-body correlations at the limit of stability. In order to obtain direct evidence of the halo structure manifested in nuclear excited states, we have considered a new method to measure the interaction cross sections of excited states. The combination of the transmission method and the recoil distance Doppler-shift method with a plunger device enables us to measure the number of interactions of the excited states in a target. Formulae to determine the interaction cross section are derived, and key issues to realize measurements are discussed. Dominant sources of errors are uncertainties in the excited-state lifetimes and γ-ray yields. We examine prototype experiments and perform simulations to study the impact of each uncertainty on the final result. This method provides a novel opportunity to perform cross section measurements on the excited states of rare isotopes.

Nuclear Physics with RIB’s: How it all started

Neutron halos were discovered through measurements of interaction cross sections and fragmentation cross sections of nuclei near the neutron drip line. Such measurements became possible with the use of radioactive ion beams (RIBs) produced though projectile fragmentations of high-energy heavy-ion collisions. RIBs were invented 30 years ago at the Bevalac facility in Berkeley. In this article, I describe how they were invented and how neutron halos were discovered. What happened at that time was a series of small serendipities guiding us to the present prosperous field of RIB science.

Charge-changing cross sections ofNe30,Na32,33with a proton target

The total charge-changing, charge pick-up, and partial charge-changing cross sections of very neutron-rich nuclei (Ne30, Na32,33) with a proton target have been measured at ∼240A MeV for the first time. We introduced the phenomenological correction factor in Glauber-model calculations for the total charge-changing cross sections with the proton target, and applied it to deduce the proton radii of these nuclei. For Ne30 and Na32, the neutron skin thicknesses of the nuclei were deduced by comparing the proton radii with the matter radii deduced from the interaction cross-section measurements. A significant thick neutron-skin has been observed for the nuclei. We also found that the charge pick-up cross sections are much larger than those in the systematics of stable nuclei.Received 30 January 2014Revised 7 March 2014DOI:https://doi.org/10.1103/PhysRevC.89.044602©2014 American Physical Society

Measurements of interaction cross sections for22–35Na isotopes

Interaction cross sections ( I) for 22 35 Na isotopes from the stability line to the vicinity of the neutron drip line have been measured at around 240 MeV/ nucleon. The I for 33 35 Na were measured for the first time. Enhancement in cross sections is clearly observed from the systematics for stable nuclei, for isotopes with large mass numbers. From the known values of the nuclear-deformation parameters 2 of 22 31 Na, these en- hancement can be mainly ascribed to the nuclear deformation. Large enhancement in heavier isotopes suggest that these nuclei are strongly deformed. The root-mean-square (RMS) nuclear matter radii were deduced from the I by using Glauber-type calculation. Furthermore, a monotonic growth of the neutron-skin thickness has been deduced with increasing neutron number for Na isotopes.

Highlights from T2K

T2K is a long baseline neutrino oscillation experiment. A high intensity proton beam at J-PARC produces a narrow-band muon-neutrino beam with a peak energy of 0.6 GeV at the far detector, Super-Kamiokande, 295km from the production point. The T2K experiment has observed electron neutrino appearance in a muon neutrino beam and measured sin22θ13 = 0.140−0.032+0.038 (0.170−0.037+0.045) assuming the normal (inverted) hierarchy. In addition the latest measurements of θ23 and ∆m322 are reported, along with the latest T2K neutrino interaction cross section measurements of the inclusive CC, CCQE and NCE channels.

Direct Mass Measurements ofB19,C22,F29,Ne31,Na34and Other Light Exotic Nuclei

We report on direct time-of-flight based mass measurements of 16 light neutron-rich nuclei. These include the first determination of the masses of the Borromean drip-line nuclei $^{19}$B, $^{22}$C and $^{29}$F as well as that of $^{34}$Na. In addition, the most precise determinations to date for $^{23}$N and $^{31}$Ne are reported. Coupled with recent interaction cross-section measurements, the present results support the occurrence of a two-neutron halo in $^{22}$C, with a dominant $\nu2s_{1/2}^2$ configuration, and a single-neutron halo in $^{31}$Ne with the valence neutron occupying predominantly the 2$p_{3/2}$ orbital. Despite a very low two-neutron separation energy the development of a halo in $^{19}$B is hindered by the 1$d_{5/2}^2$ character of the valence neutrons.

Measurement of interaction cross-sections for neutron-rich Na isotopes

The interaction cross-sections (σI) of neutron-rich Na isotopes, 23-35Na, on C target have been measured at 250A MeV using the RI beam factory (RIBF) at RIKEN. Mass dependence of σI for 27-35Na suggests monotonic growth of the skin thickness. The root-mean-square nuclear matter radii (rm) of 23-35Na were deduced from observed σI via a Glauber-type calculation. These rm are in a good agreement with the theoretical prediction by relativistic mean field model (RMF). rm of 33-35Na were determined for the first time.

Recent experiments for interaction and reaction cross-section

Recent experiments for interaction and reaction cross-sections are introduced: 1) Interaction cross-section measurements of Ar and Cl isotopes on carbon targets at energies of around 950A MeV at the FRS facility of GSI. 2) Reaction cross-section measurements at an energy of about 50A MeV by a new experimental setup at the RIBLL facility, IMP, China. 3) Reaction cross-section measurements at an energy of 83A MeV by a new experimental method at the RIPS facility, RIKEN.

Recent experiments for interaction and reaction cross-section

Recent experiments for interaction and reaction cross-sections are introduced: 1) Interaction cross-section measurements of Ar and Cl isotopes on carbon targets at energies of around 950 A MeV at the FRS facility of GSI. 2) Reaction cross-section measurements at an energy of about 50 A MeV by a new experimental setup at the RIBLL facility, IMP, China. 3) Reaction cross-section measurements at an energy of 83 A MeV by a new experimental method at the RIPS facility, RIKEN.

A new approach to estimate the geometrical factors, solid angle approximation, geometrical efficiency and their use in basic interaction cross section measurements

A new approach is developed to estimate the geometrical factors, solid angle approximation and geometrical efficiency for a system with experimental arrangements using X-ray tube and secondary target as an excitation source in order to produce the nearly monoenergetic K α radiation to excite the sample. The variation of the solid angle is studied by changing the radius and length of the collimators towards and away from the source and sample. From these values the variation of the total solid angle and geometrical efficiency is deduced and the optimum value is used for the experimental work.

Measuring Techniques for Compton, Rayleigh and Fluorescence Cross-Sections Excited by keV Photons : Potential Use for Various Applications

Compton, Rayleigh and fluorescence cross-sections for low, medium and high Z atoms are measured at low photon energies (<100 keV) using an X-ray tube with secondary target. A new approach is developed to estimate the solid angle approximation and geometrical efficiency for a system with experimental arrangement using X-ray tube and secondary target as excitation source. Using this arrangement basic interaction cross-section measurements are performed in vacuum and reasonable monochromacy is achieved. Our motivation is mainly based on fundamental radiation interactions and radiology in mind. The present X-ray system considering the geometrical effects of the measuring system is more advantageous as far as the reduction of incoherently scattered background and improvement of monochroamcy is concerned. The variation of the solid angle is studied by changing the radius and length of the collimators towards and away from the source and sample. From these values the variation of the solid angle and geometrical efficiency is deduced and the optimum value is used for the experimental work. The experimental system is very simple in design, compact and economical. Experimental results based on these systems are compared with theoretical estimates and good agreement is observed in between them.

Measurements of interaction cross sections for light neutron-rich nuclei at relativistic energies and determination of effective matter radii

We measured the interaction cross sections ( σ I ) of 10,11B, 12–20C, 14–23N, 16–24O and 18–26F on carbon targets at energies of around 950 A MeV. We then deduced the effective matter radii of the nuclei by a Glauber-model analysis. Based on the assumption of a core plus a valence neutron structure, we applied a Glauber-model analysis for a few-body system adapted for nuclei with an odd neutron number. We also deduced the effective nucleus-matter densities as well as some spectroscopic information for selected nuclei. Evidence for a one-neutron halo structure was found for 22N, 23O and 24F, as well as 19C.

Calculations of reaction cross sections for19Cat relativistic energies

Few-body Glauber theory calculations of reaction cross sections for the proposed single neutron halo nucleus ${}^{19}\mathrm{C}$ are presented for an incident energy of 960 MeV/nucleon on a ${}^{12}\mathrm{C}$ target. The calculated reaction cross sections are shown to be significantly smaller than those obtained using the optical limit approximation to the Glauber theory elastic profile function. The implications of these differences upon the deduced size and structure of the extended ${}^{19}\mathrm{C}$ ground state, from newly reported interaction cross-section measurements, are discussed, including the sensitivity of the cross sections to the assumed ${}^{19}\mathrm{C}$ single neutron separation energy.