A Monte Carlo Simulation Method For Studying Ion-atom Collisions Using The Reaction Microscope

In order to revise the”C⁶⁺puzzle”problem in collisions between 100 Me V/u C⁶⁺and He,reported by M.Schulz in 2003(Nature,2003,422(6927):48.),a simulation program has been developed based on the reaction microscope for studying ion-atom collision.The simulation introduces the uncertainty of the experimental instrument into quantum calculations via Monte Carlo method,and the origin of discrepancies between the experimental data and the quantum calculations based on the first Born approxima-tion in that work is discussed.One of two major tasks in the work is,to the largest extend,simulating the per-formance of the reaction microscope according to the physics laws and all possible un-certainties that should be considered in real experiments.It turns out that the position resolution of detectors,the size of the reaction zone,the uncertainty of the extraction voltage applied on the time-of-flight spectrometer and the target temperature play cru-cial roles in the reconstruction of the electron/recoil ion momenta.The other one is to form a large number of data base which should manifest itself the major characteristics of the simulated interaction channels.The latter has been achieved via sophisticated quantum calculations based on the first order Born approximation.Finally,a complete was done on the”C⁶⁺puzzle”problem and,after a careful scan on all possible experimental uncertainties,it is found that the position resolution of the reaction microscope,the target temperature and the jittering of the extraction voltage have significant influences on final simulated fully differential cross sections.Especially when the target temperature is set to 16 K,or the extraction voltage is set to0.05 V,the simulated fully differential cross sections reproduce the experimental data by M.Schulz et al.Our work thus provides an alternative explanation on the long-standing”C⁶⁺puzzle”.Moreover,such a program can be further generated to simulate real experimental data where experimental-parameter dependent collision dynamics can be analyzed.