Measurement of scintillation decay curves in the nanosecond region (in Japanese)
An apparatus for the measurement of scinitiliations using the sampling oscilloscope SAS 500 was set up. Cherenkov radiation was observed and the ability of the apparatus was studied with this instrumental impulse response. Crystal scintillations of trans-stilbene, anthracene, and NaI(Tl) were observed. The linear energy transfer (L.E.T) effect of crystal scintillation of trans- stilbene was found when irradiated by alpha and BETA rays. When irradiated by BETA -rays, the ratio of intensity of fast component to that of slow component was larger than that by alpha -rays and the lifetimes of fast and slow components were smaller than those by alpha -rays. The initial spike originating from the two exiton annihilation was observed when the anthracene crystal was irradiated by alpha -rays. The liquid scintillation decay curves from the scintillator {toluene + 2,5-diphenyloxazole (PPO) 4 g/l} were observed and the lifetimes of two components were obtained. The lifetimes of the photofluorescences by ultraviolet excitation were measured with an FL l0 type phase fluorometer based on the phase shift method. The following results were studied. (1) Photo-fluorescent lifetimes of PPO solutions are shorter than the lifetimes of the liquid scintillator. Considerable processes besides the fluorescence process of PPO molecules exist in the case of liquid scintillation. (2) When the concentration of PPO is 4 g/l, reemissions of the fluorescence results from the absorption of the fluorescence or scintillation. The lifetimes become a little longer. (3) L.E.T. effect in the liquid scintillator exists as well as that of the trans-stilbene crystal. Different decay curves of liquid scintillators are delivered whether alpha or BETA -rays radiate scintillator. There is a good possibility of pulse shape discrimination using the liquid scintillator, the resolving time of which is smaller than that of trans-stilbene. (4) The influence of dissolved oxygen on the intensity and decay curves as studied, and the decrease of intensity of the slow component is pointed out. (5) The influence of the wavelergth shifter 1,4-bis 12-(5-phenyloxazolyl)l benzene (POPOP) on the intensity and decay curves is tested. From the fact that the decay curve does not change much, the importance of the non-radiative energy transfer from PPO molecules to POPOP molecules is pointed out. (auth)
- Research Organization:
- Nagasaki Univ.
- NSA Number:
- NSA-29-005175
- OSTI ID:
- 4405768
- Journal Information:
- Jap. Anal., v. 22, no. 9, pp. 1126-1135, Other Information: Orig. Receipt Date: 30-JUN-74; Bib. Info. Source: JA (JA)
- Country of Publication:
- Japan
- Language:
- Japanese
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