Micromegas Particle Detector

Nuclear physics research has a need for position sensitive charge particle and gamma ray tracking devices. The micromegas detector could achieve the best performance and lowest cost for the large structures required. These detectors will be exposed to intense radiation, operate in high magnetic fields, and must be affordable. Agiltron is developing a unique micro- fabrication process to produce micromegas with tailored device architectures, precisely controlled dimensions in large areas at low manufacturing cost. We are also optimizing critical design parameters such as mesh and pillar materials selection. The combination, optimizing component materials and device architectures, will increase in gain, count rate and spatial resolution, and significantly improve micromegas durability and reliability. In Phase I, Agiltron successfully established a unique micro fabrication process to produce micromegas with precision controlled dimensions, high reproducibility and reliable performances. The micromegas was produced in various configurations and dimensions which exhibited extremely low leakage current, in the pico-ampere range under bias conditions (without radiation), demonstrating well-constructed micromegas. We also clearly demonstrated the effectiveness of high Z material coatings on mesh for spark resistance. Furthermore, excellent gain was observed under 50KVp x-ray radiation. Agiltron will construct and test micromegas from 100 to 1,000 cm2 area by employing the established Phase I fabrication processes with pixelated ground planes to demonstrate energy and spatial resolution at increased gain. We will also investigate and optimize micromegas device structures tailored to various applications, including low energy x-ray detection and imaging. We will further demonstrate that Agiltrons micromegas can be commensurate with curved designs planned for large particle accelerators. Commercial Applications and Other Benefits: Improved experimental equipment reduces DOE costs directly through apparatus procurement and indirectly as improved performance achieves desired results faster. The low cost and large area micromegas will also be a suitable replacement for 3He neutron detectors for the advanced spectroscopic portal radiation monitor program. Furthermore, the detector to be developed in this program will have significant medical applications, digital x-ray images with high energy resolution.