X-ray photon correlation spectroscopy (XPCS) provides an opportunity to study the dynamics of systems by measuring the temporal fluctuations in a far-field diffraction pattern. A two-dimensional detector system has been developed to investigate fluctuations in the frequency range of several Hz to kHz. The X-ray detector system consists of a thin 100 microm scintillation crystal coupled to a Gei...

The detection sensitivity (DS) of the commercial single-photon-receiver based on InGaAs gate-mode avalanche photodiode is estimated. Instalment of a digitalblanking-system (DBS) to reduce dark current makes the difference betweenDS, which is an efficiency of the detector during its open-gate/active state, and the total/overall detection efficiency (DE). By numerical simulations, it is found tha...

An efficient and low-noise 1.244-GHz gating InGaAs single-photon avalanche photodiode (SAPD) was developed for a high-speed quantum key distribution (QKD) system. An afterpulsing probability of 0.61% and a dark count probability per gate of 0.71 ×10-6 were obtained at a detection efficiency of 10.9% for 1.55-µm photons. Furthermore, our SAPD successfully coped with high detection efficiency (≤ ...

In the present work we intend to assess the readout feasibility of Avalanche Photodiode (APD) detectors via long signal lines for the development of a combined small-animal PET-MR prototype based on the ClearPEM technology. The detection performance of a LYSO-APD module was evaluated reading out the APD charge signals to the front-end ASIC via an 80 mm length flexible flat-cable (FFC). Experime...

We report on a high-speed temporal and spatial multiplexed single-photon counter with photon-number-resolving capability up to four photons. The infrared detector combines a fiber loop to split, delay and recombine optical pulses and a 200 MHz dual-channel single-photon detector based on InGaAs/InP avalanche photodiode. To fully characterize the photon-number-resolving capability, we perform qu...

We present a gated silicon single-photon detector based on a commercially available avalanche photodiode. Our detector achieves a photon-detection efficiency of 45±5% at 808 nm with 2·10(-6) dark count per nanosecond at 30 V of excess bias and -30°C. We compare gated and free-running detectors and show that this mode of operation has significant advantages in two representative experimental sce...

We report on a feasibility study of a free-space Quantum Key Distribution setup operating at a mid-infrared wavelength. Alice sends polarization-coded pseudo-single photons from a Quantum Cascade Laser at 4.6 μm to Bob, who uses a nonlinear crystal and a Silicon Avalanche Photodiode to perform the detection via Sum Frequency Generation. Theoretical predictions, based on a proof-of-principle exp...

We propose a design for a photon-counting detector that is capable of resolving multiphoton events. The basic element of the setup is a fiber loop, which traps the input field with the help of a fast electro-optic switch. A single weakly coupled avalanche photodiode is used to detect small portions of the signal field extracted from the loop. We analyze the response of the loop detector to an a...

A linear minimum mean-square error (LMMSE) equalizer for avalanche-photodiode (APD) based integrate-anddump receivers is designed to compensate for intersymbolinterference (ISI) introduced by the APD’s random impulse response. Recent work on the characterization of the joint probability distribution of the APD’s gain and buildup-time are adopted and utilized to determine the mean and correlatio...

A novel technique for the real-time measurement of the magnetic field pitch angle in JET discharges using the motional Stark effect diagnostic is presented. Kalman filtering techniques are adopted to estimate the amplitude of the avalanche photodiode signals' harmonics that are relevant for the pitch angle calculation. The proposed technique {for extended technical details of the generic algori...