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[1] [2] 129 Xe is a stable, naturally occurring isotope of xenon with 26.44% isotope abundance. It is one of two Xe isotopes, along with 131 Xe, that has non-zero spin, which allows for magnetic resonance. 129 Xe is used for MRI because its large electron cloud permits hyperpolarization and a wide range of chemical shifts
The first explicit recognition of non-atmospheric Xe in terrestrial samples came from the analysis of CO 2-well gas in New Mexico, displaying an excess of 129 I-derived or primitive source 129 Xe and high content in 131-136 Xe due to the decay of 238 U. [38] At present, the excess of 129 Xe and 131-136 Xe has been widely observed in mid-ocean ...
In terms of detecting ventilation defects, 129 Xe has a lower signal-to-noise ratio but is more sensitive to defects due to its higher density and lower diffusivity. [30] Currently, using a larger volume of 129 Xe (up to 1 liter per scan) can compensate for its decreased signal-to-noise ratio compared to 3He (usually 0.1-0.3 liters per scan).
Naturally occurring xenon (54 Xe) consists of seven stable isotopes and two very long-lived isotopes. Double electron capture has been observed in 124 Xe (half-life 1.8 ± 0.5(stat) ± 0.1(sys) × 10 22 years) [2] and double beta decay in 136 Xe (half-life 2.165 ± 0.016(stat) ± 0.059(sys) × 10 21 years), [7] which are among the longest measured half-lives of all nuclides.
Xenon-135 (135 Xe) is an unstable isotope of xenon with a half-life of about 9.2 hours. 135 Xe is a fission product of uranium and it is the most powerful known neutron -absorbing nuclear poison (2 million barns ; [ 1 ] up to 3 million barns [ 1 ] under reactor conditions [ 2 ] ), with a significant effect on nuclear reactor operation.
3,000 acquired by Armed Forces of the Philippines in 2017, for issue to all service branches. Majority went to the Philippine Army. [ 101 ] [ 102 ] AFP ordered 60,000 units under AFP 0.45 caliber Hammer Fired Pistol acquisition project, majority expected to go to the Philippine Army.
129 I is one of the seven long-lived fission products that are produced in significant amounts. Its yield is 0.706% per fission of 235 U. [7] Larger proportions of other iodine isotopes such as 131 I are produced, but because these all have short half-lives, iodine in cooled spent nuclear fuel consists of about 5/6 129 I and 1/6 the only stable iodine isotope, 127 I.
The noble gases up to xenon have multiple stable isotopes; krypton and xenon also have naturally occurring radioisotopes, namely 78 Kr, 124 Xe, and 136 Xe, all have very long lives (> 10 21 years) and can undergo double electron capture or double beta decay.