Using some simplifying assumptions in a separate absorption and multiplication AVALANCHE photodiode (SAM-APD), in this paper we develop a circuit model. Then, using this circuit model, we calculate the gain and the quantum efficiency of the device. To examine the accuracy of the device, we compare the results obtained from the model with the experimental results. A fairly good correspondence between the model an the experimental results, shows that this model is capable of predicting the device behavior, while varying different parameters such as applied bias, device size, and hence the light wavelength.

Today snow and AVALANCHE studies have progressed dramatically throughout the world, and countries are experiencing AVALANCHE phenomena have established advanced research and development centers in this regard. For many years, they have used their research and results. In Iran, despite the presence of snow in some parts of the country, no official observing centers have made in the country. One of the important issues in the AVALANCHE studies are: the AVALANCHE risk map that identifies AVALANCHEs in snowy and mountainous regions, but this map is very different from the AVALANCHE risk map. Many domestic researchers find the two maps mistakenly the same. In this research, we have tried to determine the difference between AVALANCHE hazard map and AVALANCHE risk map.

Introduction: This paper analyses the ability of single-photon AVALANCHE diodes (SPADs) for neural imaging. The current trend in the production of SPADs moves toward the minimum dark count rate (DCR) and maximum photon detection probability (PDP). Moreover, the jitter response which is the main measurement characteristic for the timing uncertainty is progressing.Methods: The neural imaging process using SPADs can be performed by means of florescence lifetime imaging (FLIM), time correlated single-photon counting (TCSPC), positron emission tomography (PET), and single-photon emission computed tomography (SPECT).Results: This trend will result in more precise neural imaging cameras. While achieving low DCR SPADs is difficult in deep submicron technologies because of using higher doping profiles, higher PDPs are reported in green and blue part of light. Furthermore, the number of pixels integrated in the same chip is increasing with the technology progress which can result in the higher resolution of imaging.Conclusion: This study proposes implemented SPADs in Deep-submicron technologies to be used in neural imaging cameras, due to the small size pixels and higher timing accuracies.

model of a low noise high quantum efficiency n+np Germanium Photodiode utilizing ion implantation technique and subsequent drive-in diffusion in the n layer is presented. Numerical analysis is used to study the influence of junction depth and bulk concentration on the electric field profile and quantum efficiency. The performance of the device is theoretically treated especially at the wave-length region 1. 55μ m where the Silica optical fiber has minimum attenuation loss. It has been found that at this wave-length and for the optimum device design the quantum efficiency approaches about 90%.

Risk is an inevitable part of life, every day people are somehow at risk. Different risks in various forms and perspectives have different functions. Kurdistan province, with various heights and relatively good rainfall, It results the country's cold spots. Since most of seasonal rainfall occurs in winter, Snow cover is often the domain and passes it hillsides…..

AVALANCHE occurrence is one of the natural disasters that caused loss of life and damages in most mountainous areas of the world every year. Phenomenon of AVALANCHE downfall in Iran is caused to irreversible damages, specially on residents and passing travelers through mountainous roads (Dizin-Gagereh, Haji Abad - Dizin, beginning Karaj-Chalus, Karaj-Chalus middle, Haraz and Imam Zadeh Davoud) in Tehran province.Unknowing the time of AVALANCHE occurrence, exceeds the damages. Then, forecasting the AVALANCHE occurrence probability in the AVALANCHE paths help to reduce human and financial damages of passengers and residents. For investigation the probability of AVALANCHE occurrence in this region, the nearest neighbor method was used. This method carried out based on the AVALANCHE information and daily data of snow in the 22 snow stations during 10 years (from 1377-78 to 1387-88). In this method, the number of similar snowy days that were created former AVALANCHEs was determined using ArcGIS software. Then, by snow zoning in different months of investigative year by using kriging method, the rate of snow depth variations (that generates AVALANCHE) were obtained. Thereafter, warning level, positive neighbor's ratio (NN ratio) and probability of AVALANCHE occurrence were characterized in the every path. The results showed that in most communication paths, AVALANCHE phenomenon has occurred in snowy months and probability in month of March is more than other months. The important reason of this phenomenon is high snow depth and increasing the temperature. Finally, probability of AVALANCHE occurrence in Dizin–Gajereh path and Karaj–Chalous path was predicted very high. The reason of this point could be topographic conditions (high slope, slope subject to the sun), rock and mostly climate conditions (high snow depth, snow wind and temperature). The results of this research project can help to managers of AVALANCHE control, effectively as they warn people to avoid from non-essential travels in that time or choose the other paths.