Sun-Tae Hwang

Impurity correction factor of MnSO4 compound for the determination of neutron emission rate on the manganese bath method

The manganese sulphate bath method is widely used for measurements of neutron source strength. In this study, the analytical chemistry method based on the Inductively Coupled Plasma (ICP) spectrometry was used for examining the impurity contents of MnSO4·H2O, to induce55Mn(n,γ)56Mn reactions. From the analytical results, mainly K, Co, and Zn as well as trace amounts of Cd, Li, etc., have turned out to be the relevant impurities absorbing the neutrons and the fraction of neutron absorbed by the total impurities was determined to be 1.37%.

Measurements of sealed radioactive sources by using isothermal microcalorimetry

We have studied to validate the calorimetric method by comparing the 123I radioactivity measurement results with the national standard. The reason for using 123I was to determine how much it absorbs radiation decay energy due to γ and electron capture transitions. In addition, due to the characteristic of the calorimeter, stabilization time is required, and we have determined that the half-life time of 123I is long enough to overcome this problem. We compared two measurement results (calorimeter and ion chamber) and confirmed that the rate of power reduction in the calorimeter was similar to the half-life time of 123I.

Collisional processes in muon catalyzed fusion as studied by the classical collision theory

Collisional processes involving a negative muon in the deuterium and tritium system were studied using the classical binary encounter theory. The time needed for slowing down of a 10 keV muon was found to be of the order of 10−8s to 10−12s, depending on the density of the system. The “Sticking Probabilities” for the d-t and d-d fusions were obtained to be 0.48% and 10.2%, respectively. The usefulness of the classical model for understanding fundamental processes in muon catalyzed fusion is suggested.

Ion beam induced emissions from solid europium compounds

Impact of energetic heavy particles on europium compound surfaces gives rise to radiative optical emission from reflected and sputtered particles and from the excited states of the solid compounds. In the present paper we discuss the optical spectrum and the sputtered secondary ion mass spectrum observed when solid europium oxide (Eu2O3) and europium chloride (EuCl3) are bombarded with 90 keV Ar+ ions from an ion accelerator. We observe the reduction reaction in solid europium chloride (EuCl3) by bombardment with a 20 μA/cm2 beam of 90 keV Ar+ ions.