We report on the performance of beveled-edge large-area avalanche photodiodes (LAAPDs) operating at liquid nitrogen (LN 2 ) temperatures. The twofold purpose was to evaluate performance characteristics of LAAPD devices and feasibility of their application for scintillation light read out at LN 2 temperatures. The measurements were carried out with unpackaged 5-and 16-mm-diameter bare LAAPD devices cooled in a modified cryostat used for Si(Li) X-ray detectors. Light pulses from a green light-emitting diode and X-rays from a 55 Fe source were used to characterize the performance of LAAPDs. Dark current below 1 pA was measured for a 16-mm LAAPD at a gain of 5000. The ratios of the LAAPD gain for X-rays and light pulses, the excess noise factor, and the dark noise contribution of the LAAPD preamplifier system were measured in device gain range up to 4000. Pulse-height spectra of about three photons were recorded with a 5-mm LAAPD operating at 100-K temperature and gain of 4000. A pure NaI crystal coupled to a 16-mm LAAPD was investigated, showing energy resolution of 5.9 0.2% for 662-keV -rays from a 137 Cs source.Index Terms-Avalanche photodiodes at liquid nitrogen temperatures, pure NaI, scintillation detectors.
The fault-tolerant robust non-fragile H∞ filtering problem for networked control systems with sensor failures is studied in this paper. The Takagi-Sugeno fuzzy model which can appropriate any nonlinear systems is employed. Based on the model, a filter which can maintain stability and H∞ performance level under the influence of gain perturbation of the filter and sensor failures is designed. Moreover, the gain matrix of sensor failures is converted into a dynamic interval to expand the range of allowed failures. And the sufficient condition for the existence of the desired filter is derived in terms of linear matrix inequalities (LMIs) solutions. Finally a simulation example is given to illustrate the effectiveness of the proposed method.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.