One meter square high rate neutron imaging panel based on boron straws

In order to fully realize the enhanced potential of the powerful neutron scattering technique provided by high intensity facilities like SNS, large area high rate detectors must be developed that do not depend upon the dwindling stock of 3He. We have developed a neutron detector that offers a large sensitive area (1 m²), 3D spatial resolution, high sensitivity and high count rate capability, and it is economical and practical to produce. The detector technology is based on ¹⁰B thin film conversion of neutrons in long straw-like gas detectors, as a novel and superior replacement of ³He detectors. Twenty-two detector modules, each consisting of 50 straws (1 m long, 4 mm in diameter, natural boron carbide coated), have been constructed and mounted into a robust housing to form a square meter panel detector. Readout electronics including preamplifiers, signal conditioning modules and digitization modules have been designed and tested to meet the required count rate in a 1 m² detector. We have successfully tested the panel detector, by imaging objects of different materials and different shapes. Additionally, one enriched detector module has been fabricated. The enriched module was integrated into the panel and produced a factor of four enhanced sensitivity in agreement with modeling predictions based on five fold higher ¹⁰B content. The neutron imaging detector has achieved the required performance for SNS applications and substantially increases performance compared with ³He while utilizing a cheap and inexhaustible conversion medium.