Corrections for positon annihilation in flight in nuclear spectrometry

Atomic masses of147m, 148m, 149m Tb,148Dy,150m, 152m Ho derived from decay properties

“…d) Annihilation of positrons in flight and three quantum annihilation were corrected for by (1 +F) [24,25], where F was about 3 % for the positron energies and the stopping material used here. e) Almost all positrons were stopped in the aluminium annihilator around the source, but a small fraction of G=0.5 % escaped by the tape-guiding slit.…”

New limits on double electron capture of40Ca and180W

“…For the 2ν2EC transition to the ground state the atom deexcites via the emission of X-rays and/or Auger electrons, and the observable energy equals the sum of the binding energies of the captured electrons. Because K electrons are closest to the nucleus, the most probable process is double K-capture (2ν2K) ‡, ‡ Using the code CAPTURAT [17], the probability of 2K (2L) capture can be estimated as 0.85 (0.01) for 40 Ca and 0.40 (0.14) for 180 W. a The limit in [20] is given for 2ν2EC assuming a probability of 0.81 for double K-capture. b The predicted half-life in [6] is calculated for m ββ = 50 meV.…”

Beta-delayed gammas and QEC-values in the decays of150m,152mHo and149Dy

“…For this derivation the conversion coefficients of the E2 v-transitions and the fraction of positron-annihilation in flight in the used Fe-annihilator were taken from the respective tabulations in [22] and [23]. The conversion (1), in all other cases is c~ < 0.01 [22].…”

“…The conversion (1), in all other cases is c~ < 0.01 [22]. The fractions of positron-annihilation in flight are 0.055(5) and 0.050(5) for the investigated /7-transitions of 15~ and 152mHo, respectively [23]. The 7-ray intensities of energies between 394 keV and 803 keV were compared with that of annihilation radiation in the respective coincidence spectrum.…”