Problems of short beta-gamma delayed coincidence method lifetime measurements - lifetime of the 3.105 Mev level in 37 Cl.

A method based on the possibility of experimentally discriminating between 0 and y radiations is devised to reduce the statistical error in corrections for pulse height dependence of 9-y delayed coincidence lifetime measurements. The timing properties of small cylindrical scintillation detectors are briefly studied and delayed coincidence measurements of the delays between the 3 and v radiations following the decay of ^Na were carried out. Both indicate that the mean propagation delay for the scintillation photons is only weakly dependent on the point of origin in the scintillator. Further measurements were made following the (3 decay of 3^3. Corrections for unknown 0-y delays were obtained from ^^a data and the known lifetimes of the 1.37 and 2.75 MeV levels in ^^g. These were applied to the S results to evaluate the lifetime of the 3.105 MeV level in 37Cl. A preliminary estimate of T(3.105) = 7 + 3 ps is reported for this lifetime.