FastTap and FastTrain: How to Create Neutron Multiplicity Pulse Train Data When You Are Not an Experimentalist

Both traditional as well as novel neutron multiplicity analysis methods using standard, newly designed or conceptually proposed instruments can be reliably tested with high fidelity simulated data. While the neutron transport inside the instrument can be simulated with a well- established MCNP code, the creation and analysis of synthetic pulse trains resembling genuine experimental results is performed by a pair of in-house developed software programs that are introduced in this paper. In the first step, the FastTrain program extracts the information about neutron detection times and positions from MCNP PTRAC files, and transforms this information into pulse trains corresponding to a user-defined source strength. These can then be preprocessed by FastTapX, which has the ability to inject various effects of physical detector imperfections into the individual pulse trains such as double pulsing with user-specified characteristics and dead time on different levels of the detector electronic architecture. Subsequently, FastTapX analyses the modified pulse trains and calculates multiplicity rates up to pentuples using a virtual shift register with user-defined predelay, long delay and gate-width, and constructs Rossi-alpha distribution and time interval distributions. These high-fidelity simulation and analysis tools, their capabilities and their current role in evaluation and development of traditional and novel neutron multiplicity analysis algorithms and instruments are summarized in this paper as is the discussion of their potential future applications.