Unique process will lead to larger, more efficient elementary particle detectors. Arradiance is developing an ultra-fast, high resolution alternative to scintillators in direct detection of high energy (fast) neutrons.
– By Stephen Heiser –
Arradiance, Inc. has been awarded a grant under the Department of Energy Small Business Innovation Research (DOE SBIR) program to develop large-area microchannel plates for use as an alternative to traditional photomultipliers.
Novel Plastic Microchannel Plate Enables New Generation of Fast Neutron Detectors
Arradiance is developing an ultra-fast, high resolution alternative to scintillators in direct detection of high energy (fast) neutrons. Using our proprietary engineered nanofilm technology, the company has succeeded in making microchannel plates (MCP) from high-hydrogen content poly(methyl methacrylate) which, when bombarded with fast neutrons, produces free protons through neutron-proton collisions. These recoiled protons strike the wall of the nearest “pore” creating secondary electrons and which are then amplified in the MCP. The use of microchannel structures makes the resultant detector have very high spatial and temporal resolution. Some potential benefits to nuclear monitoring include:
1. Direct fast neutron counting: high timing resolution flux monitoring.
Event counting with low background at very low fluxes (standoff monitoring) as well as directionality at relatively high fluxes since the dynamic range of nanofilm MCP devices is very high.
2. Angular and Energy: elucidating the angle and energy of point sources. The detector would be compact compared to other technologies with scintillators and Photomultiplier Tubes (PMTs) and can be used in coincidence more for discovery of source location and energy spread.
3. High spatial resolution fast neutron imaging, providing spatial distribution of flux on a ~0.2mm scale in 2 dimensions.
4. Sensitivity to both high energy gamma and fast neutrons in the same device.
5. High timing resolution of fast neutron and gamma counting (<4 ns), enabling event synchronization to a given process (active irradiation, multiplicity).
6. Radiation hardness – electronics will not have to be at the detector head for event counting. MCP itself should not degrade at high radiation fields except for scrubbing which can be controlled by the gain level adjusted for a given counting mode.
7. No high pressure/harmful substances are present in the device. It is a solid state-type device and can be flown, vibrated, etc.
“We believe our technology has the potential to enable very compact, hand held or a backpack-sized devices for directional detection of fast neutron flux”, explains Ken Stenton, President and CEO of Arradiance, “and in case of point sources, it will provide very accurate angular resolution and spectral information for the neutron flux.”
Microchannel plates are used in numerous imaging and detection applications where high spatial and temporal resolution coupled with high signal to noise ratio are important. Example applications include: astrophysical and earth-observing satellite instrumentation, biotechnology, analytical instrumentation, homeland security and night vision. The ability to make these plates larger without using costly lead-glass multiple draw processes will expand market penetration by lowering cost and enhancing overall performance of any detector in which they are a component.
“For decades, microchannel plate performance has improved only marginally due to a manufacturing process which has been constrained by available materials and processes,” explains Neal Sullivan, CTO of Arradiance. “The requisite lead‐glass substrate material has limited the ability to optimize microchannel plate performance for applications where lifetime, gain, substrate size and composition are important. Arradiance’s proprietary nanofilm technology makes it possible to fabricate microchannel plates from many substrate materials, including lead or non‐lead containing glasses, ceramics, silicon and even plastic. The independence of the nanofilms from the substrate material enables both optimization of performance and a move to larger substrate sizes.”
The basis for the grant is the development of a lower cost plate up to 8” x 8”. This plate would be used in MCP-based Photomultipliers (MCP-PMTs) and tiled together in such a way as to achieve very large, very fast detectors for projects like the large neutrino detectors currently in development by the National Science Foundation.
“Prior to this, making MCP-PMTs larger than about two inches square has been difficult and costly,” explains David Beaulieu, Arradiance Chief Operating Officer. “Our nano-engineered activating thin films allow us to employ less expensive substrate manufacturing techniques, thereby driving down the overall cost of the detector while improving performance”.
Arradiance is enabling us to better perceive the hidden world all around us. Their functional film technologies greatly enhance the performance of imaging and detection systems, providing resolution, gain and lifetime improvements that were previously unattainable. Their enabling processes will open the door to a new world of flexible, robust, electro-optic systems that will change the way we see our world.