The 33rd EGS Users’ Meeting in Japan Held at KEK
arlThe 33rd EGS Users’ Meeting in Japan was held on 15 and 16 September 2026, hosted by the Radiation Science Center at KEK. The meeting is intended for those who are new to radiation simulation or who wish to strengthen their grasp of the fundamentals, and it combines hands-on exercises in Monte Carlo radiation transport calculations with an introductory course on photon and electron transport simulation using the EGS5 code. It was held in a hybrid format, with an on-site venue and Zoom. There were 15 participants (4 in person and 11 online) and 5 lecturers. Total attendance over the two days was 25 (15 on 15 September and 10 on 16 September, lecturers not included).
The course consisted of three main parts. The first covered the fundamentals of Monte Carlo radiation simulation. After an explanation of how photons and electrons interact with matter, participants worked through a Monte Carlo simulation by hand using random numbers. The second part addressed the use of the EGS5 code. EGS5 is a Monte Carlo code in which users write and run their own user code, so this part was conducted as a hands-on session, with the aim of enabling participants to define the source, geometry, and scoring on their own. The third part was an exercise based on a realistic application. Taking a practical problem brought in by one of the participants as the subject, the lecturers and participants worked together to develop a calculation. For the participant who supplied the problem, this produced a template that can be applied directly to their work; for the others, it served as a concrete example to adapt to problems of their own.
