Li-Foil Multiwire Proportional Counter (MWPC) Neutron Detector

Li-Foil MWPC Neutron Detector Technology

A Low-Cost Large-Area Neutron Detector

Size matters and so does weight. The innovative Li-Foil Multi-wire Proportional Counter (MWPC) Neutron Detectors are just 0.7 kg (1.6 lbs) and are an affordable large-area alternative to the 3He-based detectors and much safer than BF3. They maintain a high thermal-neutron detection efficiency, at a comparable volume, mass, voltage, and power required. The technology has the flexibility to easily adjust available detection area to customer specifications with a 20% to 70% (40% standard) thermal-neutron detection efficiency. The Li-Foil MWPC are being integrated into existing electronics technology as replacements for 3He and BF3-based detectors. Li-Foil offers a lightweight solution while maintaining the high neutron detection sensitivity and ruggedness that are known of 3He-based detectors.

Eliminate the high voltage circuitry and interfacing hassle with 3He and BF3-based detectors.  The Li-Foil provides several connector types, USB, M8 or SMA while needing just nominal 3V power to operate.  No more setting high voltage or pulse shaping with the Li-Foil as HV is generated on-board and the output is TTL or digital USB. 

The following plot includes a normalized thermal-neutron reaction-product pulse height spectrum from Cf-252 at 1.5 meters from a Li-Foil MWPC backpack device. Background was collected in the same configuration, shown in blue. Gamma-ray rejection is inherent to the device design where the response to 50mR / Hr of Cs-137 662 keV gamma rays is shown in the gray curve. Monte Carlo N-Particle Transport (MCNP) response to Cf-252 modeled in an equivalent Li-Foil MWPC testing configuration is shown in the dotted line.



Electronics & Interfacing

    • Optional onboard readout electronics include pulse processing components (e.g. preamp, amp, etc.) with TTL output or output driven signal to interface with customer’s GUI.
    • Customizable connection interface - i.e. USB, M8, SMA, etc.
    • Optional microphonics rejection integrated into the electronics firmware


Interface Connector Options

Readout electronics can be outfitted with an M8 style waterproof connector (3.3V square pulse signal), USB-B (USB Communications Device Class), or other custom interface upon request.


Technical Specifications

y-reject* <1:10-8
40% (±1)
CTS / sec / nv 79.5
2.7 - 4.5 V
TTL or output driven
Temperature Range

-40oC to 85oC


Standard Size

49.5 * 5.6 * 3.6 cm
(19.5" * 2.2" * 1.4")
0.7 kg (1.6 lbs)


*Gamma-Ray Rejection Ratio

**Thermal-Neutron Detection Efficiency 

Technology Comparison

Li Foil MWPC BF3 3He
Pressure (atm) 1.7 0.52 1.5
Total Length (inch) 19.5 21.24 21.24
Active Length (inch) 18 18 18
Width / Diameter (inch)  2.2 x 1.4 2-inch cyl 2-inch cyl
cps / nv 79.5 ~55 ~85

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