Perturbed angular correlation measurements on the 40.9 keV level of 62Cu. A preliminary study of 2Zn-insulin

Time-differential PAC measurements have been made using 62Zn, both in aqueous solution at pHproportional6.0 and also incorporated into crystalline 2Zn-insulin. Three NaI(Tl) detectors were used - a 2.54 cm thick scintillator detecting the 'stop' 41 keV gamma ray and two 5.0 cm thick scintillators at 900 and 1350 detecting the 'start' 597 keV gamma rays. The need to separate the 597 keV line from the 511 keV background was found to require very careful setting-up conditions in the case of a fixed-detector spectrometer. The solution data produced a fast relaxation time of (75+-25) ns, while the three 2Zn-insulin batches gave data which were analyzed using a static interaction with an assumed axial symmetry to give an electric quadrupole frequency of (77+-8) MHz. (orig.)