Yusuke Uozumi

Single-particle strengths measured with 48Ca(d, p)49Ca reaction at 56 MeV

Single-particle states in 49Ca have been investigated through the 48Ca(d, p)49Ca reaction initiated by vector-polarized deuterons of Ed = 56 MeV. Thirty-six levels were observed up to 8 MeV excitations. Transferred l, j values were deduced for these levels by measured angular distributions of cross section and analyzing power. We observed many additional states and corrected some previous jπ assignments. The total values of spectroscopic factors C2S obtained with zero-range distorted-wave-Born-approximation (DWBA) calculations are almost unity for the shells 2p32, 2p12 and 1f52, and no 1f72 states are observed. It is confirmed that 48Ca has a good closed-shell structure, the feature of which is consistent with occupation probabilities predicted from an extended second RPA theory.

Semi-microscopic formula for gas gain of proportional counters

Abstract A semi-microscopic formula of Townsends first ionization coefficient α is proposed for the gas gain of a proportional counter. The electron movement in a counter is expressed in terms of cross sections of inelastic and ionization collisions with gas molecules by introducing a simple model which has four fixed parameters for a gas. The model parameters have been determined for typical counter gases. The results of gas gain calculated by the obtained formula indicate good agreement with experimental results for several filling gas mixtures at a variety of mixing ratios and for various counter geometries.

A simple method of energy calibration for thin plastic scintillator

A thin plastic scintillator is used as a trigger counter of charged particle spectrometers. Since its Compton edge is not clear, it is difficult to check up the thin plastic scintillator counters with a standard gamma-ray source. In this paper a simple method is proposed to determine the Compton edge and the energy resolution of the thin plastic scintillator by fitting the simulated spectrum to the measured. The simulated spectrum was made with a Monte Carlo program considering geometries of the plastic scintillator. This technique was examined with the plastic scintillator having thickness of 2 mm to 10 mm.

Absolute Neutron Sensitivity of a GSO(Ce) Scintillation Detector

A detector system with a cerium-doped gadolinium orthosilicate Gd 2 SiO 5 (Ce) scintillator coupled to a photomultiplier tube was investigated in terms of an absolute sensitivity for thermal neutron detection

Intranuclear cascade model for 50-MeV-region (p, p′x) reactions over a wide target mass range

In our previous study, the applicable range of the intranuclear cascade model was successfully extended to lower incident energy (p, p′x) reactions by introducing trajectory deflections and low-energy-loss process due to collective excitations. However, the models validity was confirmed only for a 56Fe target. In the present work we widen the applicable range of masses of the target nucleus. First, we derive an expression for the response function, which gives the probability of collective excitation strengths, to fit the distorted-wave Born approximation results as a function of the target mass number and the beam energy. Second, the barrier transmission coefficient was investigated. An expression with a modified Gamow penetration factor was chosen from four phenomenological forms of one-dimensional barrier transmission coefficients. Calculations with the proposed model followed by a generalized evaporation model were carried out for double-differential cross sections of (p, p′x) reactions at 30–60 MeV. Although the response function and the transmission coefficient were only parameterized approximately, the proposed model showed good agreements with experimental observations for a variety of nuclear targets from 12C to 209Bi.

Drug Delivery System Using Nano-Magnetic Fluid

Nano-size magnetic magnetide is considered important for various medical applications. Dynamic motion of the magnetic particle is investigated in two essential models from a theoretical point of view. One is a drag model of the magnetic particle in an artery. The second is a pull model towards the surface of artery. Threshold conditions of external variables are obtained by dimensional analysis. On the basis of all these results, it is concluded that the movement of magnetic fluids can be controlled by external magnetic fields in blood vessels.

Light output response of GSO(Ce) and NaI(Tl) to protons up to 160 MeV

An experimental study on GSO(Ce) scintillation crystals was made in terms of the light output response to proton in an energy range up to 161 MeV. The experiment was carried out for cubic crystals of 43 mm edge length by using a 392 MeV proton beam. A good linearity was observed between 30 and 161 MeV, and a slight non-linearity below 30 MeV. A relation of dLdE versus E was determined with stopping protons. A calculation using the relation has agreed with measured pulse heights of protons penetrating the crystal, as well as those of stopping protons. Similar measurements were made for NaI(Tl) crystals of 2 in. cubic. Rather large non-linearity was observed in the proton energy range 0–122 MeV.

A two-dimensional transmission counter with a backgammon-drift read-out technique

A new type of two-dimensional position sensitive gas counter for transmission counter with a backgammon-shaped flat electrode has been developed. The two dimensional position read-out can be achieved with the combination of a backgammon-shaped flat electrode read-out as horizontal position and the drift time measurement read-out as vertical position. The gas counter is designed as a transmission trajectory counter that can be used to determine angle of incident charged particles in charged particle detecting system. To check the characteristics of this gas counter, test experiments are performed with coincidence plastic scintillation counter and /spl beta/-ray source of /sup 90/Sr.

Hole strengths and spreading widths observed in 92Mo(p, d)91Mo reaction at 65 Me V

Abstract Differential cross sections and analyzing powers have been measured for the 92 Mo ( p , d ) 91 Mo reaction with a polarized proton beam of 65 MeV incident energy for investigating the level structure of 91Mo up to 10 MeV. The data analysis with the standard DWBA theory provides transferred angular momenta lj values and spectroscopic factors for 42 transitions to the single-hole 1 g 9 2 , 2 p 1 2 , 2 p 3 2 , 1 f 5 2 and 1 f 7 2 st analog states. The spreading widths are deduced and compared with theoretical predictions for discussing the damping mechanism of the single-hole states.

Fragmentation of neutron-hole strengths in 59Ni observed in the 60Ni(p,d) 59Ni reaction at 65 MeV

Abstract The 60Ni(p, d) 59Ni reaction has been studied with 65 MeV polarized protons. Angular distributions of the differential cross section and analyzing power have been measured for neutron hole states in 59Ni up to the excitation energies of 7 MeV. The data analysis with a standard distorted-wave Born approximation theory provides transferred angular momenta l, j and spectroscopic factors for thirty-nine transitions. The nuclear damping mechanism of the single hole states is discussed.