Kazuhisa Matsuda

Inelastic scattering of protons from Ti48, Cr52, Fe56, Ni58, Ni60 and Zn64 at an energy of 14.65 MeV

Abstract Energy spectra and absolute cross sections on inelastic protons from a number of even nuclei with masses between A = 48 and A = 64 have been obtained. The experiment was performed with a broad range magnetic analyzer. The energies of levels up to 6 MeV, excited appreciably, were determined from 60° spectra and compared with the results obtained by Buechner et al . Energy values of many new levels including “anomalous levels” have been assigned. The absolute differential cross sections and the rough angular distributions for some levels were measured over a range of angles from 15° to 145°. The angular distribution eexhibits a forward peak in general and is compared with the prediction of simple theories. The first 2 + state and the “anomalous” state are excited strongly and their angular distributions are fitted well at their forward peak with a simple Born approximation (SBA) prediction assuming Δl = 2 and Δl = 3, respectively. It is elucidated that the anomalous peak in the mass range concerned (even nuclei) is caused only from a single 3 − state. The yields for the first 2 + and the 3 − states are discussed quantitively. The excitation of other low lying states including the second 4 + or 2 + states have been investigated. The fact that the angular distributions for the first 2 + and the 3 − states can be fitted with the SBA curves permits an attempt to assign spin parity for some other excited states. The integrated cross sections for these levels are also presented and discussed.

A magnetic analyzer system for the INS Tokyo synchrocyclotron

Abstract A magnetic beam analyzer system and a product-particle spectrometer of a broad-range type for a 55-MeV proton beam from the INS Tokyo synchrocyclotron are described. The beam analyzer system consists of a beam analyzer magnet and a beam cleaning magnet. A well focused and cleaned beam is obtained at the target position. The beam intensity is about 45 nA when the energy spread of the analyzed beam is 0.1%. The product-particle spectrometer is composed of a uniform-field sectorial magnet and a preceding quadrupole-magnet doublet. The spectrometer can analyze and detect simultaneously particles over an energy range from Emax to 0.67Emax. A multicounter system of an array of 200 proportional counters followed by a large plastic scintillation counter system is arranged at the focal plane of the spectrometer. The 200 proportional counters serve as position detectors, and compose counter telescopes with the scintillation counters. A momentum spectrum of analyzed particles is stored and displayed by the use of the core memory of a 1024 channel pulse height analyzer. An over-all energy resolution 0.14% and a solid angle 2 × 10−3 sr are obtained. The design, construction, testing, and operation of the magnetic analyzer system are described. Results of various calibrations, i.e. plots of dispersion, resolution, solid angle, energy measurements, etc. are given.

ELASTIC AND INELASTIC SCATTERING OF PROTONS FROM N, Ne, Mg, Si, S AND A IN THE ENERGY RANGE FROM 7.6 Mev TO 14.2 Mev

The angular distributions of protons scattered elastically and inelastically by N, Ne, Mg, Si, S and A nuclei have been studied at several values of proton energy from 7.6 to 14.2 MeV. The distribution shapes for elastic scattering show generally diffraction patterns at E p >10 MeV. While the yields of inelastic scattering corresponding to the second excited state of N 14 are appreciable at higher energies, the yields for the first excited state with T =1 are markedly low. The inelastic scatterings for the first excited states of Ne 20 , Mg 24 and Si 28 are found to change their distribution shapes appreciably with proton energy. The excitation functions of the reaction for Si 28 were also studied. The results show prominent resonance features. These results seem to support that the formation of compound nucleus plays an appreciable role in the inelastic scattering from these light nuclei, especially at the lower energy. The distribution shapes of the inelastic scattering from S 32 are fairly insensitive ...

Elastic and Inelastic Scatterings of Protons from Ti, Cr, Ni, Zn, and O at 8 to 14 MeV

The elastic and inelastic (leading to the first excited states of target nuclei) scatterings of protons by medium weight nuclei (Ti, Cr, Ni, and Zn) were studied by observing the dependence of their angular distributions on bombarding energies from 8 MeV to 14 MeV. The angular distributions of protons elastically scattered from oxygen were also measured in the same energy range. There are appreciable regularities in the elastic scatterings by medium weight nuclei as regards the dependence of their angular distributions on the bombarding energy and on the atomic number except in the case of the bombarding energy of 8 MeV. The elastic scatterings from oxygen show an anomalous behaviour at energies about 9 MeV. The angular distributions of protons inelastically scattered from medium weight nuclei can be fitted by the predictions of the direct interaction theory with Born approximation at about 14 MeV, but at the lower bombarding energies they seem not to do so, although they have the prominent forward peaks....

Elastic and Inelastic Scattering of 14.1-MeV Protons Medium Weight Nuclei

The absolute differential cross sections for the elastic scattering and the inelastic scattering (proceeding to the 1st excited state) of 14.1Mev protons have been measured for Ni, Fe, Cr and Ti with a five-degree (or less) interval ranging from 20 to 165 degrees. The scattered protons were detected by NaI (Tl) scintillation counter whose energy resolution was about 2.3%. Even at small angles the protons inelastically scattered could be discriminated from those elastically scattered. The angular distributions of inelastic protons agree to that expressed by | j 2 ( q R )| 2 which one would expect from the theoretical prediction based upon the Born approximation.

A 160 cm Synchro- and Variable Energy Ordinary Cyclotron

A 160 cm cyclotron have been constructed as the first accelerator of the Institute for Nuclear Study, University of Tokyo. This cyclotron can be used as a variable energy ordinary cyclotron as well as a synchro-cyclotron by changing the dee-system and the oscillator system. As an ordinary cyclotron it can produce protons of any desired energy between 7.5 and 15 MeV, deuterons between 15 and 21 MeV, and α particles between 30 and 42 Mev. These beams are now being used for various experiments on nuclear reactions and for production of radioisotopes. As a synchro-cyclotron, it can produce protons of 57 MeV in energy and the beam is extracted with high efficiency at a radius near n =1 with an electrostatic deflector.

Elastic and Inelastic Scattering of Alpha-Particles from Even Mass Molybdenum Isotopes

Elastic and inelastic scattering of 30.87 MeV alpha-particles from 92,94,96,98,100 Mo nuclei were studied to determine relative values of β L for the first 2 + and 3 - states precisely. An optical model and DWBA analyses were made. Values of β L R for the 2 + and 3 - states are compared with those obtained by various reactions. The trend of variation of β L R value with regard to A agrees well for the 2 + state among various but some differences are found for the 3 - state. Values of β 3 /β 2 obtained by the present work are compared with those obtained by the inelastic proton scattering. It is found that the former are smaller than the latter as a whole.

Elastic scattering of 3He particles on Ca at five incident energies between 18.8 and 39.3 MeV

Abstract Differential cross sections for the elastic scattering of 3 He particles by natural Ca at incident energies of 18.8, 24.9, 31.0, 34.4 and 39.3 MeV were measured and analysed in terms of the optical model. Angular distributions have been measured in steps of 2.5° or 5° between 10° and 170°. The present analysis shows that the optical model gives a good description for the elastic scattering of 3 He particles on Ca in the measured energy range. However, there exist some ambiguities in optical-model parameters as in the case of other particles, that is, the parameter groups with the real potential depth of 90, 130, 180, 240 or 320 MeV and those with the imaginary potential of a volume or surface absorption type, reproduce experimental angular distributions of differential cross sections. The form factor of surface absorption does not need an anomalously large radius for the imaginary potential of the 3 He scatterings. Furthermore, comparisons of reproducibility of angular distributions with and without the real part of the spin-orbit potential are made for each parameter group. A spin-orbit potential of about 4 MeV explains the backward behaviour of angular distributions. The analysis was carried out with an automatic parameter search program.

Inelastic Proton Scattering from 90 Zr and 92 Zr

Differential cross sections of the inelastic proton scattering for low lying states of 90 Zr and 92 Zr were measured. The incident proton energy was about 14.5 MeV. Inelastic groups were analyzed with a precision magnetic analyzer. Attempts of DWBA fits were made. The general trend of experimental results is in agreement with that of the work of Corolado-ORNL group.

ELASTIC AND INELASTIC SCATTERING OF PROTONS FROM NICKEL ISOTOPES Ni

Angular and energy dependence of the elastic and the inelastic scattering of protons from nickel isotopes, Ni 58 and Ni 60 , were investigated in the energy range from 7.0 MeV to 15.3 MeV. Angular distributions in the high energy region ( E p ≥10 MeV) showed small difference between both isotopes. Energy dependence of the differential cross sections in the low energy region (7 MeV< E p <9 MeV) showed some fluctuations both for the elastic and the inelastic scattering. The inelastic yield for Ni 58 was larger than that for Ni 60 in the low energy region ( E p ≤9 MeV). These yields decreased gradually as the incident energy increased. The results of present work are compared with our previous one and with the investigations of Thirion et al., Greenlees et al., and Seward.