福堀　順敏・小山　由起子（実験実習支援センター）
協力：蕪木　宏行（パーキンエルマージャパン）　　

１. 英語講義

Basic knowledge for Scintillation counting method

　In the radio-isotope centers as shared facility of University, many types of radio-isotope detection instruments are installed. Many compounds labeled with tritium or ¹⁴C as β-ray emitted isotope, ¹²⁵I and ⁵¹Cr as γ-ray emitted isotope are used as tracers. Scintillation counters are used for measuring the radio-activity.

　Photons are produced when emitted nuclear energy hit fluorophore. Scintillation counting is the method to detect the photons as electrons via scintillator by Photomultiplier Tube (PMT). Direct and precise detection of β-ray and γ-ray activity is impossible by the scintillation counting method.
　Because the sample condition and sample preparation affect the counting efficiency. For β-ray counting with scintillation counting method, the direct output from the detectors is shown as CPM (count per minute) value、and it is relative activity. To get absolute activity, value of CPM should be corrected to DPM (disintegration per minute) and it is important to understand scintillation counting method.
　One of the most important factors which should not be forgotten is quenching phenomenon. The purpose of this seminar is to learning the origin of quenching and others effectors on scintillation counting and their correction. The scintillator for beta-ray detection is now scintillation cocktail. To get precise counting result, sample preparation is important. And importance of sample preparation on counting efficiency would be experienced through hands-on training using scintillation cocktails.

２. 液体シンチレーションカウンターの操作説明（ＲＩ研究施設２階 測定室）