Sea Level Muon Spectrum Derived from the All Particle Primary Spectrum of GRIGOROV et al.

The all particle primary spectrum of GRIGOROV et al. surveyed by HILLAS has been fitted by a power law fit of the form I_{all particle}(>E) = 1.3 E^?1.65 (cm² s sr)^?1 where E is the energy in GeV/nucleus. Using our recently determined conversion factor for protonnuclei flux ratio of equal energies the primary proton spectrum has been calculated and the result agrees with the Goddard Space Flight Centre primary proton spectrum data satisfactorily. The primary nucleon spectrum has also been calculated and follows the form N_nucleons(E) dE = 2.664 E^?2.75 dE (cm² s sr GeV/nucleon)^?1. Using this primary nucleon spectrum as the source of hadrons and accelerator data for various inclusive reactions viz. used for the estimation of hadronic energy moments in the frame work of FEYNMAN- Scaling, the differential meson spectra have been estimated. The meson atmospheric diffusion equation after Bugaev et al. has been considered for the derivation of sea level muon spectrum. The magnetic spectrograph data of Allkofer et al., Ayre et al., Green et al., and MUTRON group are in accord with the calculated muon spectrum.     

Sea Level Muon Spectrum Derived from Bugaev Model

The pion and kaon spectra in the atmosphere are derived from primary nucleon spectrum determined by GRIGOROV et al.; they satisfy the relations N(E_π) dE_π = 0.187 EdE_π and N(E_k) dE_k = 0.017 E dE_k, respectively. By using the pion-kaon atmospheric diffusion equation the sea level muon spectrum is calculated and the result compared with the magnetic spectrograph data of ALLKOFER et al. and AYRE et al.     

Estimation of Sea Level Muon Energy Spectrum at High Latitude from the Latest Primary Nucleon Spectra Near the Top of the Atmosphere

The vertical muon energy spectra at sea level have been estimated from directly measured primary cosmic-ray nucleon spectrum. The hadronic energy moments have been calculated from the CERN LEBC EHS data on the Lorentz invariant cross-section results on pp ^±X and pp K^±X inclusive reactions and are duly corrected for A–A collisions. Finally, the sea level muon energy spectra have been calculated from the decay of conventional mesons, using standard formulation. The estimated muon spectra are found to be in good agreement with the directly measured muon spectra obtained from the different experiments.     

Sea Level Muon Spectrum Derived from Bugaev Model Using the Primary Cosmic Ray Energy Spectrum of Grigorov et al

In a recent paper BHATTACHARYYA has derived the pion and kaon production spectra in the atmosphere using a form of the primary nucleon energy spectrum of the measurements of GRIGOROV et al. and the interaction model of BUGAEV et al. The sea level muon spectrum derived from these meson spectra agrees with the magnetic spectrograph data of ALLKOFER et al. and AYRE et al. In this report a critical analysis of the paper has been made and some obvious mistakes in the formulation have been pointed out. The formulation of BUGAEV et al. and the data of GRIGOROV at al. have been misinterpreted by BHATTACHARYYA . The corrected results have been properly interpreted in this report.     

Dao Scaling Model and Sea Level Cosmic Ray Muon Spectrum from Goddard Space Flight Group Measured Primary Proton Spectrum

A new type of scaling model for p + p → π^? + X inclusive reactions, proposed by DAO et al., is applied to derive the sea level muon spectrum. The nucleon spectrum data of Goddard Space Flight Group were taken as input. It is found that the sea level muon spectrum depends explicitly on the average value of the FEYNMAN variable x whose most probable value is estimated to be 0.18.     

中能区类弹碎片中质比的靶核相关性

基于实验测量并结合模型分析,讨论了中能区重离子周边碰撞过程中出射的类弹碎片(PLF)的中质比(N/Z)与靶核N/Z相关现象的产生原因.     

Impact Parameter Dependence of the Double Neutron/Proton Ratio of Nucleon Emissions in Isotopic Reaction Systems

Within the transport model IBUU04, we investigate the double neutron/proton ratio of free nucleons taken from two reaction systems using two Sn isotopes at a beam energy of 50 MeV/nucleon and with impact parameters 2fm, 4fm and 8fm, respectively. It is found that the double neutron/proton ratio from peripheral collisions is more sensitive to the density dependence of the symmetry energy than those from mid-central and central collisions.     

基于空间谱的玉米叶片铜铅污染区分及程度监测

利用高光谱遥感技术监测并识别农作物受重金属污染信息是当今热点,研究设置了不同浓度铜离子(Cu2+)、铅离子(Pb2+)胁迫梯度的玉米盆栽实验,并测取了玉米叶片的光谱及叶片中重金属离子与叶绿素含量。基于获取的光谱数据,将光谱划分为紫谷、蓝边、绿峰、红谷、红边和红肩六个光谱特征区间,通过光谱的一阶微分和二维多重信号分类(2D-MUSIC)算法构造空间谱,对各光谱特征区间进行变换分析。实验结果表明：蓝边、绿峰和红边阵列信号的空间谱在Cu2+胁迫下为双高峰,在Pb2+胁迫下为单高峰,以此能够快速、直观地区分玉米叶片所受重金属污染的Cu2+和Pb2+元素类别。红谷和红肩阵列信号空间谱的方位角谱峰值与玉米叶片中Cu2+含量的相关系数分别达到-0.954 5和-0.964 8,说明用于监测Cu2+污染程度时效果理想;紫谷阵列信号空间谱的方位角谱峰值与玉米叶片中Pb2+含量的相关系数达到-0.999 8,说明用于监测Pb2+污染程度时效果理想。同时通过与常规重金属污染监测方法绿峰高度(GH)、红边位置(REP)、红边最大值(MR)、红边一阶微分包围面积(FAR)的应用结果进行比较分析,空间谱法的应用结果与玉米叶片中重金属离子含量的相关性较高,从而验证了空间谱应用于玉米重金属污染信息监测具有更好的有效性和优越性。     

Muon Spectra at Different Altitudes Derived from Bose-Type Model

The spectra of cosmic pions and kaons produced at the top of the atmosphere have been derived from the primary cosmic ray spectrum of GRIGOROV et al. by using the Bose-type model. With the help of pion and kaon atmospheric diffusion equations the muon spectra at different atmospheric depths viz., 690, 535 and 1033 g cm^?2 have been estimated. The results are in accord with the magnetic spectrograph data of KOCHARIAN et al. and ALLKOFER et al.     

Cosmic Antiproton Spectrum at the Top of the Atmosphere Derived from the New Scaling Model

The new scaling variable model explains the scaling behavior of p + p → p + X inclusive reactions at ISR energies. The cosmic antiproton spectrum has been derived from this model using the primary proton spectrum of RYAN et al. The derived antiproton-proton flux ratio lies within the upper limit value of BOGOMOLOV et al. and CHEN. The estimated antiproton spectrum follows the relation where the antiproton energy E_p is expressed in GeV and the intensity in units (cm² sec sr GeV)^?1.     

Enhanced K+/π+ Ratio from Central Collisions Between Heavy Nuclei at 1 GeV/Nucleon

We generalized the previous relativistic Vlasov-Uehling-Uhlenbeck model to be able to identify the isospin degree of freedom of particles and used it to simulate the particle production in Au + Au collisions at 1 GeV/nucleon. The momentum spectra of proton, π⁺ and K⁺ particles, the multiplicities of π⁺ and K⁺, and the K⁺/π⁺ ratio as functions of the number of participating nucleons are studied. The theoretical results agree very well with experimental data. We also analyzed the physical origin of the significant rising of K⁺/π⁺ ratio when peripheral collision goes to central collision.     

Estimation of the Sea Level Muon Spectra at Different Zenith Angles below 10 TeV Energy

The moderate energy primary cosmic ray nucleon spectrum has been calculated from the direct measurements of Webber et al., Seo et al., and Menn et al. along with the other results surveyed by Swordy. Using these directly measured primary mass composition results all particle primary nucleon energy spectrum has been constructed using superposition model to estimate the energy spectra of muons from the decay of the cosmic ray non-prompt and prompt mesons in the atmosphere. The Z-factors have been estimated from the CERN LEBC-EHS on the Lorentz invariant cross section results on pp ^±X and pp K^±X inclusive reactions and FNAL data on ^±p ^±X reactions, and duly corrected for A--A collisions. Using these Z-factors the meson energy spectra in the atmosphere have been calculated. The sea level muon energy spectra at zenith angles 0°, 45°, 72°, and 75° have been derived from the decay of non-prompt mesons by adopting standard diffusion equation of hadronic cascades. The contribution of charmed mesons to muon spectrum has also been accounted by adapting the conventional procedure. The derived differential sea level muon energy spectra for energies 10 TeV have been found to follow the power law fits of the form N (E) const. E ^-. Our estimated muon energy spectra at zenith angles 75° have been found comparable with the global spectrograph muon flux results of MARS, DEIS, and MSU groups.     

New Methods for Fully Automated Isotope Ratio Determination from Hydrogen at the Natural Abundance Level

Abstract

A variety of methods for measurement of ²H/¹H from H₂ are evaluated for their ability to be fully automated and for applicability to automated isotopic analysis of water and organic compounds. Equilibration of water with H₂ gas with the aid of a platinum catalyst has been commercialized into a fully automated sample preparation device. A second and newer technique, involving injecting water, methane, or other volatile organic compounds onto hot chromium in a reactor attached to the dual inlet system of a gas isotope ratio mass spectrometer, can be integrated with a conventional GC-autosampler to allow automated analysis of a variety of substrates. Both techniques result in precisions around 1‰ (δ notation) on the VSMOW scale, and are fast and accurate, and with appropriate mass spectrometers require only negligible scaling for the SLAP/VSMOW difference. Several experimental methods which show considerable promise employ “isotope ratio monitoring” (irm) inlet systems, in which a carrier gas is used for transport of H₂ to the mass spectrometer. Any such method has to address the problem of He ions corrupting the measurement of the H₂ ions. One such approach uses a heated palladium membrane for selective introduction of H₂ into the mass spectrometer, and a second involves modifications to the ion optics to control the stray helium ions. Both approaches have significant limitations that must be overcome before irm techniques can be used in routine applications, in particular for measuring hydrogen isotopes from GC effluents (irm-GCMS).     

Model of a Doppler Spectrum of Microwaves Backscattered from a Sea Surface at Small Grazing Angles

On the basis of known experimental data, we propose a model for a Doppler spectrum of a horizontally polarized 3-cm microwave signal backscattered from a sea surface at small grazing angles about 10^° for wind velocities 3-11 m/s. The model is represented as the superposition of Lorentz and Voight spectral lines with coefficients describing relative energy contributions of different scattering mechanisms as functions of the surface-wind velocity.     

Disentangling the Effects of Thickness of the Neutron Skin and Symmetry Potential in Nucleon Induced Reactions on Sn Isotopes

The effects of density dependence of symmetry energy and the thickness of the neutron skin in proton （neutron） induced reactions on Sn isotopes are investigated by means of the improved molecular dynamics model. The investigation shows that the target size dependence of the reaction cross sections for proton induced reactions on Sn isotopes is sensitive to the density dependence of the symmetry energy and less sensitive to the thickness of the neutron skin of the target nuclei, but that, for neutron induced reactions on Sn isotopes, it is less sensitive to the density dependence of the symmetry energy and sensitive to the thickness of the neutron skin of the target nucleus.     

Derivation of Absolute Depth-Intensity Spectrum under Standard Rock from the Recently Estimated Primary Cosmic Ray Spectrum

Using the recently derived primary cosmic ray nucleon spectrum from JACEE and GSFC balloon flight data and Fermilab results for pp → π^± + X anything inclusive reaction data in the light of Feynman scaling the depth-intensity spectrum under standard rock has been estimated. A precisely constructed range-energy relation has been applied in this analysis. The derived spectrum when corrected for range fluctuation agrees approximately with the experimental data under standard rocks measured by MIYAZAKI , BARTON , CASTAGNOLI et al., MEYER et al., BERGAMASCO et al., SHELDON et al. and BASCHIERA et al.     

Fragmentation Cross Sections of 12C on Different Targets at Beam Energies from 50 to 100MeV/Nucleon

The fragmentation cross sections of reactions ^12C＋^2H, ^12C, ^14N, ^16O at beam energies from 50 to 100 MeV/nucleon are investigated using the isospin-dependent Boltzmann-Langevin equation model. It is found that fragment species increase approximately with the increasing target mass. The fragment species and some fragments production cross sections in reactions of ^12C＋^12C, ^14N, ^16O show an obvious variation at the beam energies from 50 to 80 MeV/nucleon. However the calculated fragment production cross sections do not change much when the incident energy increases from 80 to 100 MeV/nucleon.