 Because a 129Xe nucleus has a spin of 1 / 2 , and therefore a zero electric quadrupole moment , the 129Xe nucleus does not experience any quadrupolar interactions during collisions with other atoms , and thus its hyperpolarization can be maintained for long periods of time even after the laser beam has been turned off and the alkali vapor removed by condensation on a room @-@ temperature surface . Spin polarization of 129Xe can persist from several seconds for xenon atoms dissolved in blood to several hours in the gas phase and several days in deeply frozen solid xenon . In contrast , 131Xe has a nuclear spin value of 3 ⁄ 2 and a nonzero quadrupole moment , and has t1 relaxation times in the millisecond and second ranges . 
 Because a 129Xe nucleus <a href='got' title='1'><mark>has</mark></a> a spin of 1 / 2 , and therefore a zero electric quadrupole moment , the 129Xe nucleus <a href='uninflect' title='2'><mark>does</mark></a> not experience <a href='None' title='3'><mark>any</mark></a>quadrupolar <a href='negative_concord' title='4'><mark>interactions</mark></a> during <a href='negative_concord' title='5'><mark>collisions</mark></a> with other atoms , and thus its hyperpolarization can be maintained for long periods of time even after the laser beam <a href='been_done' title='6'><mark>has</mark></a> been turned off and the alkali vapor removed by condensation on a room @-@ temperature surface . Spin polarization of 129Xe can persist from several seconds for xenon atoms dissolved in blood to several hours in the gas phase and several days in deeply frozen solid xenon . In contrast , 131Xe <a href='got' title='7'><mark>has</mark></a> a nuclear spin value of 3 ⁄ 2 and a nonzero quadrupole moment , and <a href='got' title='8'><mark>has</mark></a> t1 relaxation times in the millisecond and second ranges . 
Because a 129Xe nucleus got a spin of 1 / 2 , and therefore a zero electric quadrupole moment , da 129Xe nucleus do not experience quadrupolar no interactions during no collisions with other atoms , and thus its hyperpolarization can b maintained for long periods of time even after the laser beam done been turned offf and the alkali vapor removed by condensation on a room @-@ temperature surface . Spin polarization of 129Xe can persist from several secs for xenon atoms dissolved in blood to several hours in the gas phase and several days in deeply frozen solid xenon . In contrast , 131Xe got a nuclear spin value of 3 ⁄ 2 and a nonzero quadrupole moment , and got t1 relaxation times in the millisecond and second ranges .