SBIR-STTR Award

Cold neutron scattering is rapidly gaining importance as a tool for studying structure in materials. Neutron detection arrays are used with such neutron scattering experiments to reduce counting times and increase accuracy. With the advent of stronger sources of cold neutrons, there is a need for much higher response speeds in these arrays. Existing two dimensional wire arrays are limited to about 40,000 counts/s total with 10 percent dead time, and are further handicapped by ghost images resulting from pile-up problems. Approaching 105 counts/s per pixel, with little cross talk, would amount to a revolution in cold neutron physics. This project will combine sub-arrays of silicon pixel detectors with a neutron-to-charged-particle convertor to allow substantially spherical array systems with good efficiency, very high count rate capability, and low image distortion from pile-up. Each sub-array features parallel processing within four hybrid components: a 196 pixel monolithic detector array (7 cm x 7 cm), an ASIC parallel signal conditioning array, a data logic and storage array, and a data transmission integrated circuit. These sub-arrays will be combined to provide a large imaging array.

Commercial Applications and Other Benefits as described by the awardee:
These instruments should be able to handle very high count rates without the usual problems of pile-up induced ghost images. The technology should also prove useful for other applications such as particle physics arrays and x-ray imaging.

Cold neutron scattering is rapidly gaining importance as a tool for studying structure in materials. Neutron detection arrays are used with such neutron scattering experiments to reduce counting times and increase accuracy. With the advent of stronger sources of cold neutrons, there is a need for much higher response speeds in these arrays. Existing two dimensional wire arrays are limited to about 40,000 counts/s total with 10% dead time and are handicapped by ghost images resulting from pile-up problems. This project will develop a 100 pixel sub-array which provides high rate detection, event time, and efficient data collection for the angular distribution of low-energy neutrons scattered during structure studies. Furthermore, the project will demonstrate that these sub-arrays can be combined in a relatively seamless manner to minimize dead regions between them. The Phase I project demonstrated the ability of a small Si pixel detector array to accommodate count rates well in excess of 105 counts/s per pixel, as well as the capability to do the fast timing required for simultaneous neutron time-of-flight analysis. A conceptual design was developed for a 104 pixel array (composed of 100 pixel sub-arrays, each with parallel processing), a 100 pixel monolithic detector array, and an ASIC parallel signal conditioning array. The Phase II project will design and produce a few neutron imaging sub-arrays with good efficiency and fast timing capability; demonstrate timing and efficiency; and show that adjacent sub-arrays can be combined with minimal dead zone between sub-arrays.

Commercial Applications and Other Benefits as described by the awardee:
Instruments for studying long range structural order in materials (by detecting scattered cold neutrons) should benefit by the ability to handle very high rates without the usual problems of pile-up induced ghost images. The technology developed will also prove useful for other applications such as particle physics arrays and x-ray imaging.