Nuclear Data Sheets for A = 168

Abstract

Nuclear structure data pertaining to all nuclei with mass A=168 (Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt) have been evaluated and incorporated into the ENSDF data file. This evaluation supersedes the previous publication (V.S. Shirley, Nuclear Data Sheets 71, 261 (1994) (literature cutoff date July 1993)) and subsequent ENSDF file revisions for Tb and Dy (C. Baglin, literature cutoff date of 15 June 1999) and Hf (B. Singh, literature cutoff date of 30 April 2001), and includes literature available by 15 June 2010. Since the above evaluations, the first excited states in 168Pt have been identified (1998Ki20, 2009Go16) and α decay from 172Hg has been observed (2009Sa27, 2004Ke06, 1999Se14). New levels in 168Dy have been excited using the 170Er( 82Se, 84Kr γ) reaction (2010So03). (HI,xn γ) studies have significantly expanded our knowledge of level structure in 168Lu (1999Ka17, 2002Ha33), 168Ta (2008QiZZ), 168Yb (1995Fi01), 168Tm (2007CaZW), 168Hf (2009Ya21), 168Os (2001Jo11, 2009Od02) and, for 168Tm, important information has come also from (d,2n γ) and ( α,n γ) reactions (1995Si20). Revised decay schemes are available following new studies of 168Hf ε decay (6.7 min) (1997Ba26), 168Lu ε decay (1999Ba65), 168Ta ε decay (2007Mc08) and 172Au α decay (2009Ha42). Significant new information for 168Er is available from (p,t) (2006Bu09), (d,p) and (t,d) (1996Ma50), ( γ, γ′) (1996Ma18), (136Xe, X γ) (2010Dr02), ( 238U, 238 U ′ γ ) (2003Wu07) and (n, n ′ γ) (1998Be20, 1998Be62) reactions, and the availability of γγ coin data (1994Ju02, 1996Gi09) for the (n, γ) E=thermal reaction has resulted in some significant level scheme revisions.