Ultrafast quantum key distribution using fully parallelized quantum channels

The field of quantum information processing offers secure communication protected by the laws of quantum mechanics and is on the verge of finding wider application for information transfer of sensitive data. To overcome the obstacle of inadequate cost-efficiency, extensive research is being done on the many components required for high data throughput using quantum key distribution (QKD). Aiming for an application-oriented solution, we report on the realization of a multichannel QKD system for plug-and-play high-bandwidth secure communication at telecom wavelength. For this purpose, a rack-sized multichannel superconducting nanowire single photon detector (SNSPD) system, as well as a highly parallelized time-correlated single photon counting (TCSPC) unit have been developed and linked to an FPGA-controlled QKD evaluation setup allowing for continuous operation and achieving high secret key rates using a coherent-one-way protocol.Comment: 13 pages, 6 figure

A CMOS Charge Sensitive Amplifier with sub-electron equivalent noise charge

We present a CMOS Charge Sensitive Amplifier (CSA) specifically designed for low capacitance pixel or silicon drift detectors for high resolution X-ray spectrometry. The intrinsic noise of the CSA has been measured at different operating temperatures with a triangular shaping with peaking time from 0.8 μs to 102 μs. At room temperature, the intrinsic Equivalent Noise Charge (ENC) shows a minimum of 1.18 e- r.m.s. and at -30°C a minimum ENC of 0.89 e- r.m.s. has been measured, corresponding to a line width of 7.8 eV FWHM for a Silicon detector

VEGA: A low-power front-end ASIC for large area multi-linear X-ray silicon drift detectors: Design and experimental characterization

We present the design and the first experimental characterization of VEGA, an Application Specific Integrated Circuit (ASIC) designed to read out large area monolithic linear Silicon Drift Detectors (SDD’s). VEGA consists of an analog and a digital/mixed-signal section to accomplish all the functionalities and specifications required for high resolution X-ray spectroscopy in the energy range between 500 eV and 50 keV. The analog section includes a charge sensitive preamplifier, a shaper with 3-bit digitally selectable shaping times from 1.6 µs to 6.6 µs and a peak stretcher/sample-and-hold stage. The digital/mixed-signal section includes an amplitude discriminator with coarse and fine threshold level setting, a peak discriminator and a logic circuit to fulfill pile-up rejection, signal sampling, trigger generation, channel reset and the preamplifier and discriminators disabling functionalities. A Serial Peripherical Interface (SPI) is integrated in VEGA for loading and storing all configuration parameters in an internal register within few microseconds. The VEGA ASIC has been designed and manufactured in 0.35 µm CMOS mixed-signal technology in single and 32 channel versions with dimensions of 200 µm×500 µm per channel. A minimum intrinsic Equivalent Noise Charge (ENC) of 12 electrons r.m.s. at 3.6 µs peaking time and room temperature is measured and the linearity error is between −0.9% and +0.6% in the whole input energy range. The total power consumption is 481 µW and 420 µW per channel for the single and 32 channels version, respectively. A comparison with other ASICs for X-ray SDD’s shows that VEGA has a suitable low noise and offers high functionality as ADC-ready signal processing but at a power consumption that is a factor of four lower than other similar existing ASICs

A programmable System-on-Chip based digital pulse processing for high resolution X-ray spectroscopy

none18noIt is described the global architecture of a digital pulse processing system for high resolution X-Ray spectroscopy based on single photon detection and photon energy measurement. The core of the system is implemented in a modern hybrid device (Xilinx Zynq) that integrates an FPGA fabric along with a dual core 32-bits processor (ARM Cortex). It is also described the adopted strategy to deal with high input photon rates while preserving a good energy resolution. The digital performance of the system is ultimate determined by few key functional blocks including two finite impulse response filters and an algorithmic state machine. It is presented a numerical procedure to optimize the digital filters according to different constrains and goals, and it is described the analysis of experimental data to obtain the necessary information for the optimization of the system.Cicuttin, Andres; Crespo, Maria Liz; Mannatunga, Kasun Sameera; Garcia, Victor Villaverde; Baldazzi, Giuseppe; Rignanese, Luigi Pio; Ahangarianabhari, Mahdi; Bertuccio, Giuseppe; Fabiani, Sergio; Rachevski, Alexander; Rashevskaya, Irina; Vacchi, Andrea; Zampa, Gianluigi; Zampa, Nicola; Bellutti, Pierluigi; Picciotto, Antonino; Piemonte, Claudio; Zorzi, NicolaCicuttin, Andres; Crespo, Maria Liz; Mannatunga, Kasun Sameera; Garcia, Victor Villaverde; Baldazzi, Giuseppe; Rignanese, Luigi Pio; Ahangarianabhari, Mahdi; Bertuccio, Giuseppe; Fabiani, Sergio; Rachevski, Alexander; Rashevskaya, Irina; Vacchi, Andrea; Zampa, Gianluigi; Zampa, Nicola; Bellutti, Pierluigi; Picciotto, Antonino; Piemonte, Claudio; Zorzi, Nicol

A novel multi-cell silicon drift detector for Low Energy X-Ray Fluorescence (LEXRF) spectroscopy

The TwinMic spectromicroscope at Elettra is a multipurpose experimental station for full-field and scanning imaging modes and simultaneous acquisition of X-ray fluorescence. The actual LEXRF detection setup consists of eight single-cell Silicon Drift Detectors (SDD) in an annular configuration. Although they provide good performances in terms of both energy resolution and low-energy photon detection efficiency, they cover just about 4% of the whole photoemission solid angle. This is the main limitation of the present detection system, since large part of the emitted photons is lost and consequently a high acquisition time is required. In order to increase the solid angle, a new LEXRF detection system is being developed within a large collaboration of several institutes. The system, composed of 4 trapezoidal multi-cell silicon drift detectors, covers up to 40% of the photoemission hemisphere, so that this geometry provides a 10 times improvement over the present configuration. First measurements in the laboratory and on the TwinMic beamline have been performed in order to characterize a single trapezoidal detector, configured and controlled by means of two multichannel ASICs, which provide preamplification, shaping and peak-stretching, connected to acquisition electronics based on fast ADCs and FPGA and working under vacuum

A new detector system for low energy X-ray fluorescence coupled with soft X-ray microscopy: First tests and characterization

The last decades have witnessed substantial efforts in the development of several detector technologies for X-ray fluorescence (XRF) applications. In spite of the increasing trend towards performing, cost-effective and reliable XRFsystems, detectors for soft X-ray spectroscopy still remain a challenge, requiring further study, engineering and customization in order to yield effective and efficient systems. In this paper we report on the development, first characterization and tests of a novel multielement detector system based on low leakage current silicon drift detectors (SDD) coupled to ultra low noise custom CMOS preamplifiers for synchrotron-based low energy XRF. This new system exhibits the potential for improving the count rate by at least an order of magnitude resulting in ten-fold shorter dwell time at an energy resolution similar to that of single element silicon drift detectors

Towards a multi-element silicon drift detector system for fluorescence spectroscopy in the soft X-ray regime

In spite of the constant technological improvements in the field of detector development, X-ray fluorescence (XRF) in the soft X-ray regime remains a challenge. The low intrinsic fluorescence yield for energies below 2 keV indeed renders the applicability of low-energy XRF still difficult. Here, we report on a new multi-element multi-tile detection system currently under development, designed to be integrated into a soft X-ray microscopy end station. The system will be installed at the TwinMic beamline of Elettra synchrotron (Trieste, Italy) in order to increase the detected count rate by up to an order of magnitude. The new architecture is very versatile and can be adapted to any XRF experimental setup. Even though the first results of the previous version of such a multi-element system were encouraging, several issues still needed to be addressed. The system described here represents a further step in the detector evolution. It is based on four trapezoidal-shaped monolithic silicon drift detector tiles (matrices) with six hexagonal elements each equipped with a custom ultra-low noise application-specific integrated circuit readout. The whole signal processing chain has been improved leading to an overall increase in performances, namely, in terms of energy resolution and acquisition rates. The design and development of this new detection system will be described, and recent results obtained at the TwinMic beamline at Elettra will be presented. Future perspectives and improvements will also be discussed