40 K
19 21
Half life: 1.277E+9 y 8
Jp: 4-
Decay mode: b-, e+b+
Sn (keV): 7799.50 8
Sp (keV): 7582 5
Abundance: 0.0117 1 %
Prod. mode: Naturally occurring
Literature cut-off date: 1-Jun-1990
Author(s): P.M. Endt
ENSDF citation: NP A521,1 (1990)

Decay properties

Mode Branching (%) Q-value (keV)
b- 89.28 13 1311.09 12
e+b+ 10.72 13 1504.9 3

Gammas from 40K (1.277E+9 y 8)

Eg (keV) Ig (%) Decay mode
1460.830 11 e+b+

X-rays from 40K (1.277E+9 y 8)

E (keV) I (%) Assignment
0,251 0.0010 3 Ar Lb1
0,310 0.00028 10 Ar Lb4
0,310 0.00044 15 Ar Lb3
2,880 3.3E-08 4 Ar Ka3
2,955 0.31 3 Ar Ka2
2,957 0.62 6 Ar Ka1
3,190 0.025 3 Ar Kb3
3,190 0.049 5 Ar Kb1

Betas from 40K (1.277E+9 y 8)

>Eb endpoint (keV) Ib (%) Decay mode
44,04 10.67 18 e
482,9 0.00104 11 b+
1504,9 0.047 5 e