The MARS project goal is to develop high performance, yet cost effective, detector systems based on solid scintillator technology for the detection of neutrons and antineutrinos. This research, which has been recently patented, started in 2011 from early development work at Imperial College London and Oxford.
The MARS technology is inspired from state-of-the-art massive neutrino detector technology used in the STFC funded MINOS and T2K experiments. It responds to the need for next generation alternative to Helium-3 based neutron detectors. It can also be applied to the detection of anti-neutrinos thus providing a mean for the detection of multiple type of particles.
The neutron is detected using a stable mixture of Lithium-6 compounds (6LiF:ZnS(Ag)) which gives high scintillation yield (160 000 photons/neutron). Charged particles can also be detected when this compound is combined with plastic scintillators. The light produced is read out via a wavelength-shifting fibre into a solid-state photomultiplier.
The main advantages of the MARS technology is the ability to collect efficiently the scintillation light from either the neutron scintillation signal or from energy deposited by charged particles or gamma-rays (electromagnetic signal). The difference of signal pulse characteristics enables high discrimination capability (up to 10-8 neutron-gamma rejection). The flexibility of the design allow for a variety of compact detector geometries and sizes which is key to match the requirements of various neutron detector applications. Recent breakthroughs in inorganic and organic plastic scintillators has opened new prospects for MARS based systems and is part of the next stage of development.
Applications for neutron detection
The recent shortage of Helium-3 prompted a regain in interest in the development of neutron detectors and replacement of these instruments is planned over the next decades. A large effort around the world is ongoing to find viable alternatives and Lithium-6 based system are well positioned to fill that need. Since 2012, we are in contact with various companies to pursue the development of MARS-based products.
A first demonstration of the performance of the MARS technology, for the replacement of Radiation Portal (RPM), was conducted in 2012 with the construction and test of a full scale system (more here).
We are currently working towards increasing the sensitivity of the technology whilst keeping the overall cost down to build more affordable devices.
Applications for anti-neutrino detections
Measurements of anti-neutrinos at reactors have so far been used to understand the properties of neutrinos. The monitoring of the flux of antineutrinos emitted from commercial nuclear reactor can be done outside the containment area and over long period of time. Anti-neutrinos can’t be shielded and can provide information about the status of the reactor and the composition of the reactor core at any time. This unique signature can gives the IAEA, the nuclear watchdog, new ways of monitoring the peaceful use of nuclear materials at reactor with a better continuity of knowledge and ensuring the faithful declaration by operators. A compact anti-neutrino detector (1.5 m3) installed 30m away can provide real time information remotely and non-intrusively.
The MARS technology is well suited for anti-neutrino detection and provides a novel approach to measurement in harsh environment at the surface and close to reactors. A prototype anti-neutrino detector is currently in development and measurements at research and commercial reactors are being planned over the next few years. A successful development would represent the first application of neutrino physics.