Multicomponent approximation for evaluation of nonequilibrium charge fractions of ions passing through thin films

A method is proposed to calculate the nonequilibrium charge fractions and mean charges of light ions, depending on film thickness. The calculated results are presented for three charge fractions of 0.75 MeV/nucleon B ion beam, passing through the organic film, and for four charge fractions of 2 MeV/nucleon Ne beam, passing through the carbon film. The dependence of energy loss on the initial charge of projectile Ne ions and target thickness in the nonequilibrium conditions is examined.     

Effect of the capture and loss of two electrons on the charge distributions of ions

The effect of the processes of capture and loss of two electrons on the width of the equilibrium charge distribution of ions in different materials is studied. These processes increase the width of the equilibrium charge distribution in the energy region of E < 0.1 MeV/nucleon. The effect increases with decreasing ion nuclear charge and reaches 10–15% for boron ions.     

Semi-empirical calculations for the ranges of fast ions in silicon

A semi-empirical method is proposed to calculate the ion ranges in energy region E?=?0.025–10?MeV/nucleon. The dependence of ion ranges on the projectile nuclear charge, mass and velocity is analysed. The calculations presented for ranges of ions with nuclear charges Z?=?2–10 in silicon are compared with SRIM results and experimental data.     

40MeV/u 40Ar与Cu相互作用的靶余核

使用离线y能谱法和厚靶──厚收集箔技术测量了40MeV/u ⁴⁰Ar和Cu相互作用中靶余核的生成截面和前向平均反冲射程FW值.根据电荷分布假设得到了靶余核的质量产额分布.从FW值导出了重离子碰撞中的线性动量转移.与¹²C+Cu和²⁰Ne+Cu的类似结果比较指出,在相同的弹核速度下,相应于中心碰撞的相对线性动量转移随弹核质量增加而减小,但是在⁴⁰Ar离子和Cu的中心碰撞中产生的复合系统的激发能比¹²C和²⁰Ne离子碰撞情况下更高,达到每核子5.3MeV.     

Spectra of Fe ions in powerful SCR events

Large solar cosmic ray (SCR) events are registered by PLATAN equipment in September–October 1989 aboard the MIR orbital station and in October–November 2003 aboard the International Space Station (ISS). The energy spectra of Fe ions in the energy intervals of 5–200 MeV/nucleon (1989) and 25–90 MeV/nucleon (2003) are measured. Spectra for SCR events of 1989 and 2003 are approximated with high accuracy by the power law function of energy. The SCR events of 1989 greatly exceed those of 2003 in the fluence of Fe particles. High enrichment of the elemental composition of the SCR events 2003 with Fe ions is observed.     

Inflections (knees) in wide-range spectra of solar energetic protons and heavy ions: Their form,parameters, and regularities

An analysis of fluences of solar cosmic rays (SCRs), measured by the ACE (ULEIS, SIS) and GOES satellites for 1998–2006 over the wide energy range of 0.05 to 500 MeV/nucleon, is performed. It is shown that the energy spectra of the fluences have two sections described by power functions of the energy per nucleon: a hard spectrum at low energies (E < 1–10 MeV/nucleon) and a soft spectrum at high energies (E > 10–30 MeV/nucleon). The main regularities inherent to the parameters of the spectra of different particles are determined.     

Production of heavy nuclei in the interaction of <Superscript>7</Superscript>Li ions with copper nuclei at an energy of 35 MeV per nucleon

The absolute values of the cross sections for the production of target fragments in the interaction of copper with ⁷Li ions at an energy of 35 MeV per nucleon were measured. The measurements were performed by recording the yields of radioactive nuclear residues with the aid of a semiconductor detector from ultrapure germanium. The charge and isobaric distributions in the mass-number range 22–69 amu were used to deduce the mass yield of reaction products and to calculate the total interaction cross section. The results are presented that were derived from a comparison with data obtained for ¹²C + Cu reactions and with estimates based on theoretical models.     

Fluxes of GCR and SCR iron nuclei in the international space station orbit

The anticipated flux of iron nuclei and ions in the energy interval 26–168 MeV/nucleon in the orbit of the international space station (ISS) during the exposure of the PLATAN-M dielectric track detector from January 26, 2002, to August 3, 2004, has been estimated. The calculation is based on the data obtained using the SIS spectrometer onboard the ACE space station and the last version of the model describing the penetration of charged particles into the Earth’s magnetosphere. The time variations in the GCR iron nuclei intensity in the ISS orbit during solar cycle 23 have been obtained using the data of the PLATAN-4 and PLATAN-5 earlier experiments onboard the Mir space station.     

Suprathermal <Superscript>4</Superscript>He,O, and Fe ions at 1 AU in the quiet time of 2006–2012

The energy spectra of ⁴He, O, and Fe ions with energies of 0.04–2 MeV/nucleon, obtained by the ULEIS device on board the ACE satellite in the quiet time of 2006–2012, are analyzed. The obtained spectra of suprathermal ions from coronal holes were approximated by either a power function or a combination of a power and an exponential function. The approximation of 98 spectra yielded 2 < γ < 6, which could indicate different conditions in regions of particle acceleration in solar wind streams from coronal holes.     

Target Residues from the Interaction of Copper with 40MeV/u 40Ar Ions

Cross Sections and average forward recoil range FW were measured for target residues from the interaction of Cu with 40MeV/u ⁴⁰Ar ions using off-line y-ray spectroscopy.The mass yield distribution was obtained with assumption of charge distribution.The linear momentum transfer was calculated from FW values.A comparison with similar results of ¹²C+Cu and ²⁰Ne+Cu reactions indicates that the fractional linear momentum transfer,corresponding to central collisions,decreases with increasing projectile mass at the same energy per nucleon. However,the excitation energy of the composite system created from the collisions of Cu with ⁴⁰Ar ions reached the value of 5.3MeV /u and was higher than those from the collisions with ¹²C and ²⁰Ne ions.     

Quasi-elastic nucleon transfer and single charge exchange in 48Ti + 42Ca collisions

Single nucleon transfer and single charge exchange have been studied for quasi-elastic collisions of ⁴⁸Ti and ⁴²Ca at E_lab = 240, 300 and 385 MeV. Specific features below 12 MeV excitation energy are displayed in all of the measured particle energy spectra for each channel. These have been accounted for in the case of nucleon transfer by a one-step direct transfer mechanism in which all of the available hole and bound particle states in the donor and acceptor nucleus, respectively, have been included. This core excitation model was extended to single charge exchange (SCX) two-step transfers in which a proton and a neutron are exchanged. The absolute magnitude and distribution of strength in the SCX channel was obtained. The contributions from direct charge exchange via the isovector parts of the NN interaction has also been investigated in a microscopic model and is found to contribute of the order of 1–5% to the charge exchange cross section. The distribution of Fermi and Gamow-Teller strength is discussed.     

Energy losses of beryllium ions penetrating through thin films before the attainment of charge equilibrium

The dependences between the energy losses of beryllium ions penetrating through thin organic (celluloid) films and the initial ion charge i ₀ and target thickness t are calculated. The proposed modified method is used to determine the charge fractions and average charge of an ion beam and the half-width and skewness of the charge distributions before the attainment of charge equilibrium. Calculations are performed for Be ⁱ⁺ ions with a velocity of 8 × 10⁸ cm/s (E = 0.33 MeV/nucleon).     

Array of scintillation detectors for the MONICA spectrometer

An array of scintillation detectors of the MONICA Spectrometer, whis is aimed at investigating fluxes of cosmic-ray ions (from H to Ni) in the extraterrestrial space within the energy range from 10 to 300 MeV per nucleon, is considered. The basic goal of the MONICA experiment is the measurement of the ionic and isotopic composition of cosmic rays of the galactic and solar origin, as well as the measurement of their energy spectrum. This problem was intensely studied by numerous investigators [1–10]; nevertheless, a lot of questions remain unsolved up to now, in this field of science. The array of scintillation detectors plays the important role in achieving the goals of the MONICA experiment. The composition of the array, tuning procedure, and characteristics of scintillation detectors are discussed in detail.     

Cosmic-ray low-energy abundances from calcium to nickel

Summary We have measured the elemental composition and mean masses of the cosmic rays from calcium to nickel using a Lexan polycarbonate stack exposed in a balloon flight. We obtain a 3% charge resolution for iron at an energy interval of (255÷545) MeV/nucleon at the top of the atmosphere. We have propagated the spectrum measured through the detector, the residual atmosphere, the solar cavity and the interstellar medium, obtaining the composition at sources with a 7% resolution for iron. We observe that it is not possible to resolve adjacent isotopes with the Lexan polycarbonate.     

Charge states of heavy ions, as determined from the parameters of solar energetic particle spectra

The charge states of He, C, O, and Fe ions are determined for 51 gradual solar energetic particle (SEP) events of solar cycle 23 using the parameters of the particle energy spectra consisting of two power-law regions separated by the so-called knee. Experimental data from the GOES satellites (protons) and ULEIS (all particles) and SIS (H, C, O, Fe ions) instruments are employed. The charge states of the heavy ions are found to be independent of the SEP event magnitude and particle energy (in the interval of 0.3 to 30 MeV/nucleon).     

Mass yield distributions of target fragments from the reactions of iron with 135 MeV/nucleon 12C and 80 MeV/nucleon 16O ions

Cross sections for the production of target fragments in the reactions of iron with 135 MeV/nucleon ¹²C and 80 MeV/nucleon ¹⁶O ions have been measured by off-line γ-ray spectroscopy. Through these data, the mass yield distributions have been obtained. The result of the experiment for the reaction with 135 MeV/nucleon ¹²C ions is compared with theoretical calculations using the fusion-fragmentation model and the GEMINI code for sequential binary decay, following a calculation with the fireball model. Reveived: 24 March 1999 / Revised version: 16 July 1999     

Temperature and excitation energy of hot nuclei in the reaction of 40Ar+197Au at 25 MeV/nucleon

The coincidence measurements between heavy fission fragments and light charged particles with Z ⩽ 2 were carried out for the ⁴⁰Ar+¹⁹⁷Au reaction at 25 MeV/nucleon, to study the properties of hot nuclei in heavy ion induced reactions. The linear momentum transfers (LMTs) were deduced from the folding angle and the time-of-flight difference between two fission fragments of heavy residues. The relationship of the nuclear temperature (slope parameter of the energy spectrum) and the excitation energy was determined independently from the measurement of the kinetic energy spectra in the frames of the emitting sources and from the LMT analysis. Both the temperature and the excitation energy increase with decreasing impact parameter, which suggests that a plateau temperature of 5.5 MeV is reached at an excitation energy of 3.1 MeV/nucleon. The result was also compared with various statistical models that explain the plateau by the multifragmentation process, where the excitation energy is assumed to be stored in compression and expansion effects.     

Neutron–Deuteron Scattering Observables at E lab = 14.1 MeV

Inelastic neutron–deuteron scattering is studied on the basis of configuration-space Faddeev equations. Calculated are neutron–deuteron breakup amplitudes using AV14 nucleon–nucleon potential at incident neutron energy of 14.1 MeV. The results of calculations are presented for the differential cross sections under quasi free scattering and space–star configurations, and compared with those of the previous calculations and experimental data. The choice of the cutoff radius R _cutoff for asymptotic conditions is discussed.     

Solar modulation of cosmic deuteron fluxes in the PAMELA experiment

The preliminary results from measurements of deuteron fluxes in galactic cosmic rays (GCR) in the vicinity of the Earth in 2006–2009 are presented. The results are obtained by analyzing data from the PAMELA experiment aboard the Resurs DK-1 satellite. High-precision detection instruments provided an opportunity to identify GCR deuterons and measure their spectrum in the energy interval of 90–650MeV/nucleon. Spectra averaged over six-month intervals from the summer of 2006 to the summer of 2009 (the solar activity minimum) are presented. The influence of solar modulation on the observed spectrum is clearly seen in the results.     

Investigation of the reaction <Superscript>4</Superscript>Нe(γ, <Emphasis Type="Italic">pn</Emphasis>)<Emphasis Type="Italic">d</Emphasis> at energies below the meson-production threshold

Themomentum distributions of deuterons and nucleons from the reaction ⁴Не(γ, pn)d induced by bremsstrahlung photons whose spectrum extends up to the endpoint energy of 150 MeV weremeasured by means of a diffusion chamber placed in a magnetic field. These measurements were performed in four photon-energy intervals for deuterons and in the energy range between 100 and 150 MeV for nucleons. Angular and energy correlations of nucleons were measured at photon energies in the interval between 50 and 70 MeV. The results obtained in this way were analyzed on the basis of the quasideuteron model. The probability for final-state nucleon–deuteron interaction was estimated.