Izuo Hayashi

Elastic Scattering of 14 MeV Protons by Deuterons and by Protons

The differential cross sections for the elastic scattering of 13.93 MeV protons by deuterons were measured with accuracy varying from 1 to 3% at angles from 12° to 164° in the center-of-mass system. A shallow Coulomb-nuclear interference minimum near 17° was observed. The angular distribution is in good agreement with that of neutrons scattered by deuterons at 14 MeV, although the p – d cross sections seem systematically a little smaller than the n – d cross sections at backward angles. For forward angles, the experimental results contradict with the prediction of the existing theory. The small-angle p – d elastic scattering at 10.14 MeV was also investigated and a similar shallow Coulomb-nuclear interference was observed, in contrast with the theoretical curve of Christian and Gammel. The p – p scattering experiment at 14.16 MeV is also described. Measurements were made with accuracy of 1 to 2% for angles from 30° to 114° in the center-of-mass system.

Paramagnetic Resonance Absorption in K2CuCl4·2H2O

Single crystals of K 2 CuCl 4 ·2H 2 O and (NH 4 ) 2 CuCl 4 ·2H 2 O were examined at 7 different frequencies of microwaves (from 5.4 mm to 6.2 cm wave-lengths). If there were no exchange coupling, two absorption peaks would be expected corresponding to different g -values of two dissimilar Cu ++ ions in unit cell. Experimentally, however, only one peak can be observed at, longer wave-lengths, though the line width remarkably increases with decreasing wavelengths. At the wave-length of 5.4 mm two isolated peaks can be observed. These facts can be interpreted in terms of exchange interaction between dissimilar ions. The exchange energy estimated from these data is greater than 0.1 cm -1 . On the other hand, the width for the c -axis, where the situations of two Cu ++ groups are identical, decreases with decreasing wave-lengths to aboutthe value 1/4 of that at long enough wave-length. According to the treatment by Anderson and Weiss, this result may be explained by their “10/3” effect.

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.

On Line Widths of Paramagnetic Resonance Absorption

Paramagnetic resonance absorption of microwave (9970 MC) by thirteen salts containing manganese or copper ions was observed with special attention to obtain correct line shapes. The widths obtained were plotted against 1/ a 3 , a being the lattice constant when the arrangement of ions are considered as simple cubic lattice. For smaller values of 1/ a 3 , line shapes are near to gaussian type and the widths coincide with those by dipolar coupling calculated by Van Vleck. When 1/ a 3 is larger, that is, when ions come nearer, line shapes are near to resonance types and widths are in general smaller than those expected by dipolar coupling. This narrowing is caused by the existence of exchange coupling between magnetic ions. It is shown that the narrowing in salts of Mn ++ , Fe +++ (S-state) and C ++ can be related to the value of θ in the Curie-Weiss law of static susceptibility \(\chi_{s}{\backsim}C/(T+\theta)\).

MEASUREMENTS OF THE POLARIZATION IN PROTON-HELIUM ELASTIC SCATTERING

The polarization of protons elastically scattered by helium was measured by the double scattering method. Incident proton or alpha-particle beam was obtained from the INSJ 160-cm variable energy cyclotron. Three interdependent measurements, in which the polarization product was equul to P/sub 1/P/sub 2/, P/ sub 2/P/sub 3/, or P/sub 3/P/sub 1/, were made. The following results were obtained: P/sub 1/(6.2 Mev, 130.0 deg ) = 0.92 plus or minus 0.11: P/sub 2/(11.5 Mev, 61.1 deg ) =--0.45 plus or minus 0.06; and P/sub 3/(9.1 Mev, 61.1 deg ) = - -0.45 plus or minus 0.06, where angles and energies are those in the center-of- mass system. Experimental values of the polarization agreed well to the values calculated by using phase shifts, which were obtained from the analysis of the angular distribution of the scattering cross sections. (auth)

Efficient beam extraction from a synchro-cyclotron at n = 1

Abstract With an electrostatic deflector placed at n = 1 (the point of maximum Br ), about 50 percent of the internal beam (inside n = 0.2) of the 260 cm synchro-cyclotron could be extracted, and most of the extracted beam was confined within a 2.5 cm diameter area at the tank exit by inserting a magnetic channel acting as a focusing lens. The homogeneity of the magnetic field is essential for this method of beam extraction. The configuration and position of the ion source, and the dee bias voltage were found to affect the transmission of the beam through n = 0.2 to n = 1. Under the optimum conditions, 70 to 80 percent of the beam inside n = 0.2 reached n = 1.

Protons from the p + d Breakup Reaction at Proton Energies of 14 MeV and 10 MeV

The energy spectra of the protons from the p + d breakup reaction as a function of angle were measured for the incident proton energies of 13.9 MeV and 10.1 MeV, using a particle selecting counter telescope consisting of a three- or five-layer proportional counter for the energy loss measurement and of an NaI scintillation counter for the energy measurement. Each of the observed energy spectra shows a rather steep rise at the maximum energy followed by a slight shoulder at large angles at the incident proton energy of 14 MeV, while the energy spectra at small angles do not show such shoulder. For both energies, each of the spectra has a maximum in its low energy side.

Comparison between variable-energy synchrocyclotron and sector-focused cyclotron

A variable-energy synchrocyclotron is proposed. Then the comparison between this machine and the sector-focused cyclotron is made.