A high-spin isomer in 145 Sm was discovered by using Inverse kinematic reactions, 20 Ne e Xe,a7n) 145 Sm and 16 0 e 36 Xe,7n) 145 Sm. The half life was determined to be 0.96 J.LSec. Sixty-five 1-rays were identified by the /')'-coincidence measurements to belong to the isomer decay. The low-lying level scheme of 145 Sm was established in detail by the in-beam 1-ray measurements using the 139 La e 0 B,4n) 145 Sm reaction. A complex decay scheme of this isomer was constructed by using the data obtained from the 136 Xe induced reactions, combining the informations of low-lying states mentioned above. The excitation energy of this isomer was determined to be 8.8 MeV. The /')'-coincidence measurement using the 138 Ba (13 C,6n) 145 Sm reaction was also performed. Based on this information, the level scheme above the high-spin isomer was extended up to the state at 14.6 MeV. A 1-ray angular distribution measurement using the same reaction with pulsed beam was carried out and was used to assign a spin value of each level. Low-lying states in 145 Sm were interpreted to originate from a single neutron coupled to the 144 Sm core excitation. Experimental yrast states were compared with a calculation of a deformed independent particle model (DIPM). A configuration of the high-spin isomer was deduced by the DIPM calculation to be { 7r h ll /2 2 v (f 7 /2 h 9/2 i 13/2) } 49/2+ .

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The accelerator mass spectrometry facility at the Seoul National University (SNU-AMS) was completed in December 1998 and a report was presented at the Vienna AMS conference in September 1999. At the conference, we described the basic components of our accelerator system and reported the results of the performance test. Since then, extensive testing of the accuracy and reproducibility of the system has been carried out, and about 200 unknown samples have been measured so far. We obtained a precision of 4‰ for modern samples, and an accuracy of approximately 40 yr was demonstrated by analyzing samples that were previously dated with a conventional technique and by other AMS laboratories. We present these results here, together with detailed descriptions of our data-taking and analysis procedures.

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