Detection Of Short-Lived Particles Using Holography

Abstract

Vertex detectors with good spatial resolution are ideal devices for the detection of short-lived particles (mean lifetime > 10-13 s; mean distance traveled before decay- um) produced in high energy interactions. The bubble chamber equipped with high resolution photography is one such vertex detector. However, improving the resolution in photography results in a very rapid decrease of the depth of field, thereby rendering most of the chamber optically inaccessible. Using holography instead of photography remedies this problem by decoupling resolution and depth of field. This paper reports on our recent work in the use of a two-beam holographic technique for a large Freon bubble chamber (80 cm in diameter and 100 cm deep). The results reported here are for a full-scale setup in air with test targets to simulate bubble chamber tracks and in some cases a full-scale 28 cm thick glass plate to simulate chamber windows. This bubble chamber is the vertex detector for a hybrid spectrometer system that will be used for two of our forthcoming experiments at the Fermi National Accelerator Laboratory: the first to search for the short-lived charmed particles and the second to establish the existence of the T neutrino by observing the decay of the T lepton. We demonstrate that a 30 resolution can be achieved throughout the entire volume of the chamber. Specific details pertinent to achieving this resolution are also discussed. We also report on the construction of a semiautomated high precision measuring apparatus that will be used to scan and measure bubble chamber holograms.