SBIR-STTR Award

Visible light photon counters, fabricated several years ago for high energy physics research, showed significant promise as compact, high gain, high-efficiency detectors in the wavelength range from 400 to 850 nm. However, the counters suffered from significant variations in gain. This project will develop next generation visible light photon counters with improved properties, including much narrower gain dispersion. In addition, the capability to use wafers of six-inch diameter will be developed, and the expected higher yields should allow for a significant cost reduction in the fabrication of these visible light photon counters. Phase I will design an improved visible light photon counter in sufficient detail to define epitaxial layer requirements, develop the process to grow the epitaxial structure, characterize the layers grown, and grow product wafers that will be used to fabricate the first round of devices in Phase II.

Commercial Applications and Other Benefits as described by the awardee:
In addition to providing high performance, the visible light photon counters should be significantly more cost effective than alternative photomultiplier tubes. In combination with plastic scintillators, applications include electromagnetic and hadronic calorimetry, shower max detectors, preshower detectors, photon vetos, large scale neutrino detectors, muon hodoscopes, and high resolution tracking systems.

The successful development of high quality plastic wavelength-shifting optical fibers coupled to a plastic scintillator for nuclear and high energy particle detection applications has created a need for compact, high-gain, high efficiency detectors in the visible and near-infrared. Visible light photon counters (VLPCs), fabricated several years ago, showed significant promise but suffered from significant variations in gain. This project will utilize epitaxial process expertise to develop a new generation of VPLCs with improved properties, including much narrower gain dispersion and lower cost. In Phase I, eighty 5-inch wafers were produced, 10 each of 8 different combinations of donor and acceptor doping. Low defect density and excellent uniformity were demonstrated. In Phase II, visible light photon counters will be fabricated from the Phase I wafers and tested. Based on the results, the design will be modified and a second round of epitaxial wafers will be grown. Devices fabricated from the second round will be provided to end-users.

Commercial Applications and Other Benefits as described by the awardee:
Applications for visible light photon counters in combination with plastic scintillator include electromagnetic and hadronic calorimetry, shower max detectors, preshower detectors, photon vetos, large-scale neutrino detectors, muon hodoscopes, and high resolution tracking systems.