High-accuracy filtered neutron beam and high-energy transmission measurements at the Gaerttner Laboratory

Abstract. Recently a method for high accuracy total cross section measurement in the energy range of 24 keV to 940 keV using an iron filtered beam was developed at RPI. Measurements the total cross section of carbon and beryllium are discussed. A new neutron detection system was developed at RPI and the first measurement with this system is reported here. 1 Filtered beam measurements The idea of a filtered beam measurement was previously explored at RPI for transmission measurements of deuterium [1]. Recently a 238U filtered beam was also used [2] and further explored in ref. [3]. The iron filtered beam utilized a 30 cm thick iron piece placed in a collimated neutron beam between the neutron source and the sample being measured. The experiment was done using the conventional time-of-flight (TOF) method with the detector placed at a flight path distance of 25.55 m. Most of the neutrons that interact with the thick iron filter