Collection Of Radiated Light

About

Abstract This unique cell configuration significantly improves light collection and registration efficiency through light generated in active media such as a scintillator. Instead of the traditional flat surface, this design involves removing part of the material in the cell volume just in front of the photo detector thereby producing a concave surface. The concave surface in the cell allows direct coupling between the cell and the photo detector without the use of optical glue or grease. The photo detector faces the cell through a volume of air restricted by the concave surface of the cell. The cell functions by reflecting light inside the cell striking at the concave surface, scattering the light and registering the scattered light with a photo detector. The curved cell shape provides a modified volume of active media in front of the photo detector in such a way that the probability of light scattering in all areas in front of the photo detector is significantly higher. Although the maximum achievable yield of light is less than with optical contact, the uniformity of light yield through the area is significantly higher. Potential commercial use and users: Applications utilizing radiation which are monitored through the light generated in media, such as solid state scintillation detectors, Cerenkov detectors, or scintillator based calorimeters; radiation monitoring, medical physics, educational products; mass spectroscopy and high performance liquid chromatography (HPLC). Advantages: The cell can be made of any suitable type of plastic through which light can exit. Multiple cells can be arranged together and, with appropriate concavities, can also be of any size and/or shape. The concave surface is a source of additional light scattering which increases the registration probability independent of the size of the cell used. The concave surface can be minimally concave or maximally concave according to the light collection requirements thereby allowing for a uniform response across the entire area of the cell. The flat cell methods currently in use entrap a majority of the generated light inside of the cell due to full internal reflection. The large concave surface of this technology, however scatters the entrapped light and changes the light’s direction, and in doing so releases additional light. The invention also simplifies coupling of an active media to a photo detector because expensive light guides or optical fibers are not needed to match the small active area of a photo detector to a larger crystal or scintillator thereby saving in the cost of optical fiber and polishing.