CERENKOV COUNTER APPLICATIONS

CERENKOV COUNTERS ARE USED FOR DISCRIMINATING BETWEEN CARGED PARTICLES HAVING DIFFERENT VELOCITIES CLOSE TO THE SPEED OF LIGHT. AT LOW RELATIVISTIC VELOCITIES, CORRESPONDING TO PARTICLE ENERGY-TO-MASS RATIOS OF 0.8 OR LESS, A VARIETY OF SOLID AND LIQUID MATERIALS CAN BE USED HAVING INDICES OF REFRACTION ABOVE 1.24. AT VERY HIGH VELOCITIES, CORRESPONDING TO PARTICLE ENERGY-TO-MASS RAIOS OVER 10, COMPRESSED GASES MUST BE USED TO ACHIEVE THE VERY LOW INDICES OF REFRACTION REQUIRED FOR DISCRIMINATING BETWEEN PARTICLES. HOWEVER, IN THE INTERMEDIATE ENERGY RANGE OF MEDIUM ENERGY NUCLEAR PHYSICS, CERENKOV DETECTION IS HAMPERED BY THE LACK OF NATURALLY OCCURRING SUBSTANCES WITH INDICES OF REFRACTION BETWEEN ABOUT 1.01 AND 1.20. SILICA AEROGELS HAVE BEEN PROPOSED TO FILL THIS GAP, AND TETECTORS HAVE BEEN MADE USING THEM WITH VARYING DEGREES OF SUCCESS. PART OF THE PROBLEM WITH THE PREVIOUSLY AVAILABLE AEROGELS HAS BEEN THEIR POOR OPACITY, ESPECIALLY AT THE BLUE END OF THE VISIBLE SPECTRUM, BECAUSE OF SCATTERING AND SOME ABSORPTION. RECENT IMPROVEMENTS IN FORMULATING AND PROCESSING THESE MATERIALS HAVE SHOWN THAT SMALL LABORATORY SAMPLES OF HIGH CLARITY CAN BE PRODUCED. THIS PROJECT AIMS TO STUDY MANUFACTURE OF THESE AEROGELS OF IMPROVED CLARITY, WITH CONTROLLABLE INDICES OF REFRACTION IN THE RANGE 1.01 TO 1.20, HAVING LINEAR DIMENSIONS OF 20 TO 30 CM FOR CERENKOV COUNTER APPLICATIONS IN NUCLEAR AND HIGH ENERGY PHYSICS.