Radiography Of High Z Material With Cosmic Ray Muon

Radiography of high Z material with cosmic ray muon is a novel technology for heavy nuclear material detection. Using cosmic ray muon as particle source and a novel resistive plate chamber with high position resolution as muon tracking detector, a system is successfully developed to realize high Z material radiography with cosmic ray. The system achieved good experimental result on radiography of 20cm×10cm×15cm lead cube with cosmic ray.The possibility of radiography of high Z material with cosmic ray has been firstly discussed. Basing on the Monte-Carlo calculations for muon interaction with matters, the Multiple Coulomb scattering (MCS) is studied. MCS represents an information source that is almost as sensitive to material Z as energy loss. Materials with different Z can be discriminated by MCS angle distribution with cosmic ray muon. The research on scattering angle distribution shows that less than a millimeter position resolution and high efficiency is required for muon detector due to low muon rate on sea level.In this article, it has been introduced the principle of imaging of heavy nuclear material distribution with cosmic-ray muon. The method has been described in details for the judgment of existence of heavy nuclear materials in scanned space and the imaging algorithm of its distribution. This imaging method has some advantages for heavy nuclear material monitor when comparing with traditional X-ray imaging method. Our own endeavor for application of this new imaging method has also been given.Point of Closet Approach algorithm ( PoCA ) is formalism of cosmic ray muon radiography using MCS as information source. It is an extending of traditional tomographic methods for different z materials discrimination. A process based on PoCA algorithm is developed and tested with simulation data derived from Monte-Carlo calculation. Some random signal simulated real data error is added to simulation data for the research on resolution of imaging reconstruction result.RPC has been used widely for high energy charged particle detection, especially for muon detection in large scale spectrometer in the domain of high energy physics due to its superior time resolution, high efficiency above 95%, moderate position resolution, simple manufacture and more important low cost. The charge dispersion of induced signal on resistive plane affects position resolution. The influence of surface resistivity of high voltage provider which is usually carbon film and the selection of integrated FADC time window on the dispersion of induced charge is studied by theoretical calculation and experimental results. A new kind of resistive plate chamber with less than 1mm statistical position resolution is developed and then extended to large area with 2D readout structure. The position resolution and efficiency factors have been level ahead of the world in the same field.Finally, the system of radiography with cosmic ray muon is established. It has a 40cm×40cm×80cm effective detecting field and the efficiency is up to 80% . A research on muon tacking reconstruction and calibration for groups of detector displacements is carried out. The result of radiography of 20cm×10cm×15cm lead cube has high qualities in reconstructed image.This dissertation is to set up a radiography system with cosmic ray and get good reconstruction results of high Z material. Meanwhile, the main technology on high position resolution detector and radiography algorithm is developed.