Determination of the 129I transmutation rate and 129I(n, 2n)128I correction using gas mass spectrometry

Two groups of I-129 and I-127 targets were analyzed using a gas quadrupole mass spectrometer (QMS) to determine the transmutation rates via the melting method. Sodium iodide was chosen to make the target. The iodine composition in the I-129 targets is 82.7% I-129 and 17.3% I-127. The transmutation rate of the I-129(n, )I-130 reaction was determined by measuring the Xe-130 with QMS. An equivalent corrective method was brought out to correct the I-129(n, 2n)I-128 branch which is interfered with by the I-127(n, )I-128 reaction. And the correction formula was deduced in theory. For very little Xe-128 from the I-129(n, 2n)I-128 reaction, the equivalent corrective method could not be suitable here. However, it is suitable for the mass of Xe-128 from I-129(n,2n)I-128 reaction that reaches the accurately detective level of the mass spectrometry.