Neutron imaging detector based on multiple layers of boron-coated straws

In previous projects funded by the DOE, Proportional Technologies, Inc. developed the basic design of a neutron imaging detector, based on the boron-coated straw technology, aimed to replace
³
He tubes in large-scale neutron science instruments. Recent efforts have focused on automated production methods, including a critical
¹⁰
B
₄
C high volume sputter coating system, and automated in-line straw tube production system, in order to dramatically increase production capacity and reduce cost. A limited-scale prototype developed during Phase I of the project was operated successfully in the Cold Neutron Chopper Spectrometer (CNCS) at the SNS (ORNL) over a period of 6 months, for more than 2500 hours logging more than 200 million events. The prototype demonstrated longitudinal spatial resolution of 5.5 mm (FWHM), and good image uniformity (2%). A 5-layer deep, fully operational, imaging panel has been completed recently. The panel was installed in the CNCS instrument, and tested in real neutron scattering experiments. Results of detection efficiency over a range of neutron wavelengths, image uniformity, and time-of-flight distribution are reported.