Low-Level Light Imaging(LLLI) devices are now been widely used in military, astronomy, scientific, and even in surveillance for our daily uses. The traditional devices like ICCD, EBCCD, EMCCD, which either complicated in structure or require extra cooling system. However, a novel device called Electron Bombarded Active Pixel Sensor(EBAPS) has been developed, it is a proximity focused device which lead photoelectrons produced by photocathode hitting directly towards back illuminated CMOS and cause the semiconductor bombard phenomenon to amplification and then being readout. EBAPS is relatively small in size, less weight, with high sensitivity, and can be used to detect single photon event, etc. Although it has been proven to have excellent sensitivity in the field of LLLI, the performance today is still considered far from its maximum potential. Here, we modeled the structure of EBAPS and studied the factors influencing the performance of the device. By selecting proper parameters like proximity distance, acceleration voltage, photocathode quantum efficiency, etc., we achieved the single photon image mode with a satisfactory sensitivity. Besides, we simulated the electron scattering trajectories among the semiconducting multiplication area by using Monte Carlo method, we compared the simulation results in different conditions and successfully in finding the optimum parameter, which achieved a relatively high sensitivity. The simulation results in this paper could have a profound theoretical foundation in developing higher gain EBAPS.
Delay line anode detector has high spatial resolution and high count rate. It has been an important technical means for
single photon imaging from near earth space to deep space. A two dimensional delay line anode is designed using
multilayer circuit board technology. A complete set of PCB delay line anode single photon detection system is established.
The spatial resolution of the detector is theoretically analyzed. Moreover, the signal transmission characteristic of PCB
delay line and the dark count rate of the detector are tested. Theoretical analysis and experimental results show that the
detector spatial resolution is about 100um and the overall dark count rate is 4counts/cm<sup>2</sup> at 2.3KV.
The structural models of micro-channel plate (MCP) and fluorescent screen of the framing camera were established. By
combining the finite element integration and Monte Carlo method, software Simion and Lorenz were respectively used to
simulate the effects of different voltages loaded on the fluorescent screen, different closed distance between fluorescent
screen and MCP, and electrode immersion depth at MCP output on the spatial resolution, in order to obtain an
axisymmetric distribution curve. Results showed that the closed distance between MCP and fluorescent screen had the
largest impact on the framing camera’s spatial resolution. In addition, higher fluorescent screen voltage did not
necessarily result in better spatial resolution, as it was influenced by the light-emitting mechanism of the fluorescent
screen. At the framing camera’s current closed distance of 0.8mm, a fluorescent screen voltage of 5000V could achieve
the best spatial resolution.
The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads of the cosmic light house program onboard China's Space Station, which is planned for operation starting around 2020 for about 10 years. Beam test with a HERD prototype, to verify the HERD specifications and the reading out method of wavelength shifting fiber and image intensified CCD, was taken at CERN SPS in November, 2015. The prototype is composed of an array of 5*5*10 LYSO crystals, which is 1/40th of the scale of HERD calorimeter. Experimental results on the performances of the calorimeter are discussed.
A new method to get a X-ray framing camera with picoseconds time resolution was proposed based on time amplification. Its principle comes from that we use high voltage electrical pulse to get speed dispersion of the photoelectrons pulse first, and then the photoelectrons pulse will be stretched in axial direction by drift area, at the end the photoelectrons pulse after stretched will be framing imaged by a traditional MCP（microchannel plate）gated framing camera. A model of the camera was built according to this method. Time amplification of the system is about 30, and image magnification of the system is about 0.4. Parameters for designing the camera system were presented after theoretical deriving and model simulation. At last, theoretical time resolution and spatial resolution of the camera were given.
Framing camera based on gated Micro-channel plate (MCP) was widely used in inertial confinement fusion (ICF) and Z-pinch because of its ultrafast time-resolve. Electrons with imaging information are multiplied when the HV pulse propagating through the MCP strip line. Obviously, the HV pulse was used as a shutter here, then the exposure time of the imagine will be determined by the width of the pulse. Theoretical analysis indicates that thegating pulse(200ps) has a bandwidth of 5GHz, thus, impedance match in the propagating path of the pulse will be very important. Impedance mismatch will cause reflecting of the pulse and decrease the transmission efficiency. This will cause un-uniformity of the dynamic gain of the MCP, and finally resulting in imagedistortion. A new designed impedance matching circuit is developed in this paper. Simulated results showedthatthe newdesignedimpedance matching circuit couldreduce the reflection of thegating pulse significantly, and dynamicgain uniformity of the MCP was increased simultaneously
Imaging systems with high temporal resolution are needed to study rapid physical phenomena ranging from shock waves, including extracorporeal shock waves used for surgery, to diagnostics of laser fusion and fuel injection in internal combustion engines. However, conventional streak cameras use a vacuum tube making thus fragile, cumbersome and expensive. Here we report an CMOS streak camera project consists in reproducing completely this streak camera functionality with a single CMOS chip. By changing the mode of charge transfer of CMOS image sensor, fast photoelectric diagnostics of single point with linear CMOS and high-speed line scanning with array CMOS sensor can be achieved respectively. A fast photoelectric diagnostics system has been designed and fabricated to investigate the feasibility of this method. Finally, the dynamic operation of the sensors is exposed. Measurements show a sample time of 500 ps and a time resolution better than 2 ns.
Based on the principle of capacitor pre-charging, an analog pulse stretch circuit is designed for detecting peak power of narrow laser impulse. Experimental test were carried out. And it could achieve regulation accuracy of 5ps, jitter<600ps. Due to the need of different delay ranges during the practical applications, the analog pulse stretch circuit is optimized. It doesn’t only meet the different adjustment ranges, but also maintains high regulation accuracy.
We present evidence that transmission loss in gated x-ray framing cameras can affect relative gains. Transmission loss is caused by a variety of factors including: incident voltage waveform, matched load, width of Au electrode gap, and so on. The transition electrode in MCP (Micro-channel Plate) is continuous gradual change line, and it has good capability of compensation. When continuous gradual change micro-strip line is designed, dielectric loss tangent is one of transmission loss factors too. The model structure is designed based on the analysis of modeling and simulation techniques and experiment data as well as forecast target. The transmission loss is reduced from 50% to 25%, the transmission efficiency is greatly improved.
Here we report an ultrafast x-ray imaging sensor based on optical measurement of the effects of x-ray absorption and
electron hole pair creation in a direct band-gap semiconductor. Our results indicate that this technology can be used to
provide a new approach for x-ray detectors and x-ray imaging systems with picosecond temporal resolution at x-ray
energies ~10 keV. The x-ray absorption in GaAs produces a transient, non-equilibrium, electron-hole pair distribution
which is then sensed by the phase modulation of the optical probe beam. The basic physics of the detector,
implementation considerations, and preliminary experimental data are presented and discussed. Through further
development, this x-ray imaging sensor could provide insight into previously unmeasurable phenomena in many fields.
A novel method to realize fast photoelectric diagnostics using ordinary CCD is presented. By changing the mode of charge
transfer of CCD, fast photoelectric diagnostics of single point with linear CCD and high-speed line scanning with array CCD can
be achieved respectively. A fast photoelectric diagnostics system of single point based on linear CCD has been designed and
fabricated to investigate the feasibility of this method. A pulsed blue light emitting diode (LED) has been used to measure the
system. As a proof of concept, the rate of photoelectric diagnostics of single point reachs up to 20 MHz. The results demonstrated
that the method of fast photoelectric diagnostics based on ordinary CCD is feasible.
Proc. SPIE. 7658, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology
KEYWORDS: CMOS sensors, Cameras, Data storage, Field programmable gate arrays, Control systems, Data acquisition, Image sensors, Signal processing, Charge-coupled devices, Camera shutters
The detection of high-speed dynamic spectrum is the main method to acquire transient information. In order to obtain the
large amount spectral data in real-time during the process of detonation, a CMOS-based system with high-speed
spectrum data acquisition is designed. The hardware platform of the system is based on FPGA, and the unique
characteristic of CMOS image sensors in the rolling shutter model is used simultaneously. Using FPGA as the master
control chip of the system, not only provides the time sequence for CIS, but also controls the storage and transmission of
the spectral data. In the experiment of spectral data acquisition, the acquired information is transmitted to the host
computer through the CameraLink bus. The dynamic spectral curve is obtained after the subsequent processing. The
experimental results demonstrate that this system is feasible in the acquisition and storage of high-speed dynamic
spectrum information during the process of detonation.