Editing Cadmium (section)

===Isotopes===
[[File:Cadmium cutoff.png|thumb|left|The cadmium-113 total cross section clearly showing the cadmium cut-off]]
{{Main|Isotopes of cadmium}}
Naturally occurring cadmium is composed of eight [[isotope]]s. Two of them are [[radionuclide|radioactive]], and three are expected to [[radioactive decay|decay]] but have not measurably done so under laboratory conditions. The two natural radioactive isotopes are <sup>113</sup>Cd ([[beta decay]], half-life is {{val|7.7|e=15|u=y}}) and <sup>116</sup>Cd (two-neutrino [[double beta decay]], half-life is {{val|2.9|e=19|u=y}}). The other three are <sup>106</sup>Cd, <sup>108</sup>Cd (both [[double electron capture]]), and <sup>114</sup>Cd (double beta decay); only lower limits on these half-lives have been determined. At least three isotopes&nbsp;– <sup>110</sup>Cd, <sup>111</sup>Cd, and <sup>112</sup>Cd&nbsp;– are stable. Among the isotopes that do not occur naturally, the most long-lived are <sup>109</sup>Cd with a half-life of 462.6&nbsp;days, and <sup>115</sup>Cd with a half-life of 53.46&nbsp;hours. All of the remaining radioactive isotopes have half-lives of less than 2.5&nbsp;hours, and the majority have half-lives of less than 5&nbsp;minutes. Cadmium has 8 known [[meta state]]s, with the most stable being <sup>113m</sup>Cd (''t''<sub>1⁄2</sub>&nbsp;= 14.1&nbsp;years), <sup>115m</sup>Cd (''t''<sub>1⁄2</sub>&nbsp;= 44.6&nbsp;days), and <sup>117m</sup>Cd (''t''<sub>1⁄2</sub>&nbsp;= 3.36&nbsp;hours).<ref name="NUBASE">{{NUBASE 2003}}</ref>

The known isotopes of cadmium range in [[atomic mass]] from 94.950&nbsp;[[atomic mass unit|u]] (<sup>95</sup>Cd) to 131.946&nbsp;u (<sup>132</sup>Cd). For isotopes lighter than 112&nbsp;u, the primary [[decay mode]] is [[electron capture]] and the dominant [[decay product]] is element&nbsp;47 ([[silver]]). Heavier isotopes decay mostly through [[beta emission]] producing element&nbsp;49 ([[indium]]).<ref name="NUBASE" />

One isotope of cadmium, <sup>113</sup>Cd, [[neutron capture|absorbs neutrons]] with high selectivity: With very high probability, neutrons with energy below the ''cadmium cut-off'' will be absorbed; those higher than the ''cut-off will be transmitted''. The cadmium cut-off is about 0.5&nbsp;eV, and neutrons below that level are deemed [[slow neutron]]s, distinct from intermediate and [[fast neutron]]s.<ref>
{{cite book
 |last=Knoll |first=G. F.
 |date=2000
 |title=Radiation Detection and Measurement
 |page=505
 |publisher=[[John Wiley & Sons|Wiley]]
 |isbn=978-0-471-07338-3
}}</ref>

Cadmium is created via the [[s-process]] in low- to medium-mass stars with masses of 0.6&nbsp;to 10&nbsp;[[Sun|solar masses]], over thousands of years. In that process, a [[silver]] atom captures a [[neutron]] and then undergoes [[beta decay]].<ref>
{{cite book
 |last1=Padmanabhan |first1=T.
 |date=2001
 |chapter=Stellar Nucleosynthesis
 |chapter-url=https://books.google.com/books?id=TOjwtYYb63cC&pg=PA230
 |title=Theoretical Astrophysics, Volume II: Stars and Stellar Systems
 |pages=230–236
 |publisher=[[Cambridge University Press]]
 |isbn=978-0-521-56631-5
}}</ref>