The decay of93g Ru,93m Ru,91g Mo,91m Mo,91g Tc and91m Tc

Abstract

Decay studies on a number of short-lived odd nuclei in the N = 50 region are described.The 59.6-s 93Ru ground state decay was studied in detail for the first time; in these experiments the 10.8-s activity 93mRu was discovered. The 91Tc activities were also observed for the first time. The ground state and an isomeric state of this nucleus decay with nearby equal half-lives (3.14 and 3.3-min). The activities 91gMo (16.6-min) and 9S"Mo (65.1-s) have been reinvestigated. A number of v-rays, previously erroneously assigned to the 91Mo activities, could be eliminated. A strong similarity is noted for the decay schemes of the N=49 isotones 91mMo and 93mRU. The energy of the 1/2-isomeric state in 93Ru and the B(M4)-value of the isomeric transition fit well into the systematics of the previously known N = 49 isotones. E Radioactivity: 93gRu, 93mRu [from 92Mo(3He, 2n)l, 91gTc, 91rnTc [from 92Mo(p, 2n)], 91gMo [from 92Mo(p, d)], 91mMo [from 9~2n)1; measured T 89 E~, I~, 7-7 coin. 93Tc, 91Mo, 91Nb deduced levels, log ft, J, re. Enriched and natural targets. Ge(Li) detectors.

The decay of 26-s 94Rh and 71-s 94Rh isomers

“…About 100 y-rays induced by such reactions were observed and their nuclei of origin determined by their half-lives, production threshold energy, and the constancy of their relative intensities as a function of bombarding energy. Almost all the unwanted ~-rays were identified as coming from 96Rh [10], 95Rh Ill], 9SRu, 94Ru, 94Tc, 9ZTc [12], and 9aMo [13]. Gamma-rays from the decay of both 94Rh isomers were clearly identified and several of them coincide with those observed in the in-beam spectroscopy work by Lederer et al [3].…”

Half-lives andQ ? measurements for new nuclei of89Tc and89mTc

“…Neither the observed ratio of intensities of 268.5 to 118.8 keV 7-rays nor the systematical trend of spinparities in this mass region is likely to support a single parent state in 89Tc. A very similar feature is also discussed in detail on the/?-decay of 9~Tc by Lange et al [5]. In 91Tc, there are a (9/2 +) state with a half-life of 3.14 min and (1/2-) state with a half-life of 3.3 min.…”

“…The value of 7"1/2 is consistent with E 3 assignment for 268. 5 In this article, we describe our recent measurements on the decay of 89mMo by v-ray spectroscopy, and of its population from the previously unknown isotopes 89Tc and 89mTc by /~-V coincidence techniques. The QEc for the decay of 89Tc has been deduced from the end point measurements and compared to results from several neighbouring nuclei and recent theoretical mass predictions [8].…”

The level scheme of91Tc and theβ decay of91Ru(9/2+)

“…The only information known about 91Tc concerned the fi++EC decay of its (9/2 + ) and (1/2 + ) states [1,2]. The only information known about 91Tc concerned the fi++EC decay of its (9/2 + ) and (1/2 + ) states [1,2].…”