Medicinal Plants Classification Biosynthesis and ... - Index of

Metal Concentrations in Taiwanese Health Food, Angelica Keiskei...
which the γ-peaks of interest are situated. This Compton scattering plateau is mainly
generated by the 1778.8 keV γ-peak of 28 Al (Shirley and Lederer, 1978). In contrast, the
ENAA technique alters the γ-ray spectrum noticeably within the same activated sample. That
is, via the ENAA technique, either 128 I or 80 Br is identified clearly from the γ-ray spectrum
(Chen et al., 2003).
Table 1. Experimental parameters and irradiation positions for ENAA and INAA in this
work (the 65 Ni flux monitors are used for neutron fluence measurement)
Neutron
shield
ENAA
Irradiation
position
Element
Cd PT b Al
BPE VT c As
Cd PT b Br
Cd PT b Cl
Cd PT b I
Cd PT b K
Cd PT b Mg
Cd PT b Mn
Cd PT b Na
BPE VT c Sb
BPE VT c Sm
INAA
None VT d Cr
None VT d Fe
None VT d La
None VT d Rb
None VT d Sc
None VT d Se
None PT d V
None VT d Zn
None Ni
a m, minutes; h, hours; d, days
Nuclear
reaction
Half-lives a
γ-Ray energy
(keV)
27 28
Al (n, γ) Al 2 .24 m 1778 .8
75 76
As (n, γ) As 26 .32 h 559 .2
79 80
Br (n, γ) Br 16 .7 m 616 .7
37 38
Cl (n, γ) Cl 37 .2 m 1642 .7
127 128
I (n, γ) I 24 .99 m 442 .9
41 42
K (n, γ) K 12 .36 h 1524 .7
26
Mg (n, γ)
27
Mg
9 .46 m 843 .8
55 Mn (n, γ)
56 Mn 2 .58 h 846 .6
23 Na (n, γ) 24 Na 15 .0 h 1368 .6
121 Sb (n, γ)
122 Sb 2 .70 d 564 .1
152 Sm (n, γ)
153 Sm
46 .7 d 103 .2
50 Cr (n, γ) 51 Cr 27 .8 d 320 .0
58 Fe (n, γ) 59 Fe 44 .6 d 1099 .2
139 La (n, γ)
140 La 40 .22 h 1596 .5
85 Rb (n, γ) 86 Rb 18 .7 d 1076 .6
45 Sc (n, γ) 46 Sc 83 .8 d 889 .2
74 Se (n, γ) 75 Se
51 V (n, γ) 52 V
64 Zn (n, γ) 65 Zn
12
0
.4 d 280 .0
3 .75 m 1434 .1
24
4
.4 d 1115 .5
64 Ni (n, γ) 65 Ni 2 .52 h 1481 .8
b Epithermal neutron flux 1.4×10 11 n cm -2 s -1 ; Irradiation time: 10 m;decay time: 10 m;Counting time: 5 m.
c Epithermal neutron flux 1.1×10 11 n cm -2 s -1 ; Irradiation time: 24 h;decay time: 1-2 d;Counting time: 20 m.
d Neutron flux 2×10 12 n cm -2 s -1 ; Irradiation time: 24 h;decay time: 30-45 d;Counting time: 2 h
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