[25p-F308-1~10] CS.1 Code-sharing Session of 2.3 & 7.5

▼ [25p-F308-6] Time-of-Flight detection system at MALT and its performance

〇(DC)Li Zheng¹, Hiroyuki Matsuzaki¹, Takeyasu Yamagata¹ (1.Tokyo Univ.)

Keywords:Time-of-flight, Monte Carlo method, 236U AMS

Currently, accelerator mass spectrometry (AMS) is the most sensitive technique to measure ²³⁶U with its absolute elimination of molecular interference. Due to small energy difference among ²³⁵U, ²³⁶U and ²³⁸U, it is difficult to completely identify ²³⁶U from ²³⁵U and ²³⁸U with the characteristic of energy deposition difference in a gas detector or semiconductor detector. With the distinct velocity difference of ²³⁵U, ²³⁶U and ²³⁸U in a nearly identified energy, it is visible to use time-of-flight (TOF) technique to separate them. A TOF detection system for the measurement of ²³⁶U AMS has been set up at Micro Analysis Laboratory, Tandem accelerator (MALT), The University of Tokyo. As a first test of the system, 3 standards with 10^-5, 10^-8 and 10^-11 of ²³⁶U/²³⁸U have been measured by TOF detection system. The measured results have shown an unambiguous separation for ²³⁶U from the interference of ²³⁵U and ²³⁸U, which improve the sensitivity of ²³⁶U/²³⁸U from 3×10^-10 to 6×10^-12. The time resolution of 1 ns has been achieved by TOF detection system, which makes a high resolution to separate ²³⁶U from ²³⁵U and ²³⁸U. The experimental results are highly consistent with Geant4 Monte Carlo simulation results, which demonstrate that this simulation can provide a prediction for experiment. The results of Geant4 Monte Carlo simulation demonstrate that the thinner carbon foil, the better efficiency and time resolution.