99TC 99TC IT DECAY (6.0072 H) 201707 201709
99TC H TYP=FUL$AUT=E. BROWNE, J. K. TULI$CIT=NDS 145, 25 (2017)$
99TC2 H CUT=1-Jul-2017$
99TC D Modified by E. Browne (May 3, 2010; BRICC)
99TC c The {+99}Tc isomeric state decays mainly via the 2.17-keV E3
99TC2c transition which is highly converted. The decay constant
99TC3c depends slightly on the electronic environment of the
99TC4c nucleus. Experimentally studied dependence on
99TC5c chemical state: 1980Ma03, 1972Ni07, 1953Ba41;
99TC6c temperature: 1972Ni07, 1958Be92; pressure (1972Ma27);
99TC7c external electric field: 1970Le25;
99TC8c a theoretical study of these effects together with a review
99TC9c of the experimental results is reported by 1977Do07.
99TCAc See 2004BeZR for evaluated decay data.
99TC c For calculation of atomic electron densities and changes in
99TC2c |a caused by the chemical and ionization state see 1981Hi03.
99TC c The influence of the chemical environment on the conversion
99TC2c electron spectrum has been investigated in 1983Dr15 and 1982Ge01,
99TC3c the influence on I(K|a| x ray), I(K|b| x ray) in 1981Yo08.
99TC2c T{-1/2} affected by strong radiation (1993Bi15)
99TC3c T{-1/2} for source implanted in Sn and Pb (2000Ko54),
99TC4c chemical influence on E(ce) (1996FiZW)
99TC c Others: T{-1/2} 1939Se04, 1950Gl04; T{-1/2} (environment effect):
99TC2c 1960Po04, 1998Ko72.
99TC3c ce 1951Me18, 1951Mi21, 1952Mi38,
99TC4c 1952Sc27, 1956La40, 1958Ch08, 1995Dr08.
99TC DG CC$FROM BrIcc v2.3b (16-Dec-2014) 2008Ki07, "Frozen Orbitals" appr.
99TC CG MR$IF NO VALUE GIVEN IT WAS ASSUMED MR=1.00 FOR E2/M1,
99TC2CG MR=1.00 FOR E3/M2 AND MR=0.10 FOR THE OTHER MULTIPOLARITIES
99TC P 142.6836111/2- 6.0072 H 9
99TC N 0.89 3 0.89 3 0.999963 6
99TC cN NR$From |S(I(|g+ce) to g.s.)=99.9963% {I6}, deduced by evaluators
99TC2cN assuming an estimated uncertainty of 3% in the relative
99TC3cN intensity of I|g(140.5). See |b{+-} decay (6.0072 h) for
99TC4cN |b{+-} branching.
99TC PN 3
99TC DG CC$ FROM BrIcc v2.2 (31-Mar-2008) 2008KiAA, "Frozen Orbitals" appr.
99TC cG All experiments measuring E|g or ce are referenced with
99TC2cG {+99}Mo |b{+-} decay even if a separated {+99}Tc (6.0072 h) source has
99TCxcG been used.
99TC cG Measured Tc K| x ray intensity ratios: K|a{-2}| x
99TC2cG ray/K|a{-1}| x ray=0.528 {I2}, K|b{-1} x ray/K|a{-1}| x ray=0.1534
99TCxcG {I35}; K|b| x ray/K|a| x ray=0.1776 {I8} (2007Ya02).
99TC cG E,M,MR See {+99}Mo |b{+-} decay.
99TC CL E From Adopted Levels.
99TC L 0 9/2+
99TC L 140.5110107/2+
99TC G 140.511 1 100 3 M1+E2 +0.129 35 0.113 3
99TCS G KC=0.0988 25$LC=0.0120 5$MC=0.00218 8
99TCS G NC=0.000345 12$OC=2.22E-5 5
99TC CG E$From {+99}Mo |b{+-} Decay (1981He15), value adopted in 2000He14.
99TC cG RI Uncertainty in I|g has been estimated by evaluators.
99TC cG RI I|g(140.5)=100 {I3} x 0.89 {I3}=89.0% {I3}, per
99TC2cG 100 decays of {+99}Tc(6.0 h). The very low
99TC3cG uncertainty of 0.3% is due to the covariant relation between the
99TC4cG relative |g-ray intensity (100) and the normalization factor (0.89),
99TC5cG the latter deduced by evaluators from the decay scheme.
99TC L 142.6836111/2- 6.0072 H 9 M
99TC cL T From Adopted Levels.
99TC dL T$The half-life depends on the electronic environment of the
99TC2dL nucleus. Variations up to |?0.3% have been reported
99TC3dL (see 1980Ma03). The adopted value of 6.0072 h {I9}
99TC4dL is that evaluated and recommended in 2014Un01.
99TC5dL Other values: 6.0076 h {I12} (2004Sc04), 6.0071 h {I21} (2004Da05),
99TC6dL 6.0072 h {I9} (saline solution) and 6.012 h {I3} (acid solution)
99TC7dL both from (2002Un02), 6.0067 h {I5} (2004Wo02), and
99TC8dL 6.0016 h {I53} (saline solution) in (2011KI45).
99TC9dL 6.0072 h {I9} (saline solution) and 6.017 h {I2} (acid solution),
99TCAdL both from 1982HoZJ, 6.0062 h {I7} (1983Wa26),
99TCBdL 6.006 h {I2} (1980Ho17), 6.02 h {I1}, 6.049 h {I35} (both 1972Em01),
99TCCdL 6.031 h {I12} (1970Le07), 6.014 h {I4} (1969Vu03), 6.006 h {I7}
99TCEdL (1966Go22), 5.996 h {I11} (1958Be92).
99TC G 2.1726 4 E3 1.4E+10 111.3
99TCS G M/T=0.884 6
99TCS G N/T=0.1165 22$O/T=2.54E-6 5
99TCS G MC=1.211E10 17
99TCS G NC=1.596E9 23$OC=3.49E4 5
99TC CG E$From {+99}Mo |b{+-} Decay (1981Ge05).
99TC2CG Others: 2.17 {I1} (1971La12), 2.15 {I3} (1957Fr35).
99TC cG TI deduced from I(|g+ce)(2.17)=I(|g+ce)(140.5).
99TC G 142.63 3 0.025 2 M4 40.3
99TCS G KC=29.2 4$LC=9.08 13$MC=1.778 25
99TCS G NC=0.269 4$OC=0.01071 15
99TC cG RI from ce(K)(142.6)/ce(K)(140.5)=0.075 {I8} (1969Ag04).
99TC2cG Others: 0.021 {I3} (1980Di16), 0.032 {I6} (1968Va14), both from
99TC3cG {+99}Mo |b{+-} decay |g-spectra in equilibrium. The prompt
99TC4cG components have been subtracted by the evaluators.
99TC DG E. Browne recalculated RI (old value was 0.021).
99TC2DG From K(142)/K(140)=0.075 (8), KC(140)=0.0988, KC(142)=29.5, and
99TC3DG IG(140)=100; as shown below:
99TC4DG K(142)= IG(142) x 29.5; K(142)=0.075 x 100 x 0.0988.
99TC5DG IG(142) = 0.025 (2).