THE MEASUREMENT OF SHORT LIFETIMES BY A REFINEMENT OF THE RECOIL TECHNIQUE. THE LIFETIME OF THE FIRST EXCITED STATE OF Ra$sup 22$$sup 4$

Journal Article · Thu Oct 01 04:00:00 EDT 1959 · Nuclear Phys.

DOI:https://doi.org/10.1016/0029-5582(59)90319-0· OSTI ID:4216237

Severiens, J C; Richter, F W

It is shown that, by using a simple electron microscope lens to magnify the distance a nuclear recoil travels in the excited state, it is feasible to measure the time down to 2.0 x 10/sup -11/ sec in strongly converted transitions from states populated in alpha disintegration. The de-exciting conversion electrons are counted only if they are coming from recoils having a velocity selected by using a delayed coincidence technique. Further developments are discussed which may bring the limits down into the 10/sup -12/ sec range. The method was tested on the first excited state of Ra/sup 224/ populated in the Th/ sup 228/ alpha decay. The lifetime found was (6.0 plus or minus 1.6) x 10/sup - 10/ sec, in agreement with other reported measurements. (auth)

• Research Organization: Univ. of Copenhagen
• NSA Number: NSA-14-002990
• OSTI ID: 4216237
• Journal Information: Nuclear Phys., Journal Name: Nuclear Phys. Vol. Vol: 13
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALPHA DECAY-- COINCIDENCE METHODS-- CONVERSION-- ELECTRONS-- ENERGY LEVELS-- EXCITATION-- LIFETIME-- MEASURED VALUES-- RECOILS-- VELOCITY
ALPHA DECAY-- ENERGY LEVELS-- EXCITATION-- LIFETIME-- MEASURED VALUES-- RADIUM 224-- RECOILS-- THORIUM 228
ELECTRON MICROSCOPY-- ENERGY LEVELS-- EXCITATION-- LENSES-- LIFETIME-- MEASURED VALUES-- NUCLEI-- RECOILS
PHYSICS