Abstract: The natural uranium targets are bombarded by 18 O(60 MeV/u) ions, and the heavy neutron rich isotope 237 Th is produced through the multi nucleon transfer reaction. A relatively fast radiochemical procedure is used to separate thorium from the uranium and complex reaction pruducts mixture. The thorium fractions chemically separated are studied by off line γ ray spectroscopy using a HPGe detector coupled to a 4 096 channel pulse height analyzer. The growth decay curve of 853.7 keV γ ray from 237 Pa ( 237 Th daughter) are analyzed and the half life of 237 Th is determined to be 4.69±0.60 min.