Number Of Detection Channels Research Articles

Accurate Detection of Arbitrary Photon Statistics.

We report a measurement workflow free of systematic errors consisting of a reconfigurable photon-number-resolving detector, custom electronic circuitry, and faithful data-processing algorithm. We achieve an unprecedented accurate measurement of various photon-number distributions going beyond the number of detection channels with an average fidelity of 0.998, where the error is primarily caused by the sources themselves. Mean numbers of photons cover values up to 20 and faithful autocorrelation measurements range from g^{(2)}=6×10^{-3} to 2. We successfully detect chaotic, classical, nonclassical, non-Gaussian, and negative-Wigner-function light. Our results open new paths for optical technologies by providing full access to the photon-number information without the necessity of detector tomography.

Transformer Coupling and Its Modelling for the Flux-Ramp Modulation of rf-SQUIDs

Microwave SQUID (Superconducting QUantum Interference Device) multiplexing is a suitable technique for reading a large number of detector channels, using only a few connecting lines. In the HOLMESexperiment, this is based on inductively coupled rf-SQUIDs fed by TES (Transition Edge Sensors). Operation of the whole rf-SQUID chain is achieved with a single transmission line, by means of the recently introduced flux-ramp modulation technique—a sawtooth signal which allows signal reconstruction while operating the rf-SQUIDs in an open loop condition. Due to the crucial role of the sawtooth signal, it is very important that it does not suffer from ground-loop disturbances and electromagnetic interference (EMI). Introducing a transformer between the sawtooth source and the SQUID is very effective in suppressing disturbances. The sawtooth signal has both slow and fast components, and the frequency can vary between a few kHz up to a MHz, depending on the TES signal and SQUID characteristics. A transformer able to handle such a broad range of conditions must have very stringent characteristics and needs to be custom designed. Our solution exploits standard commercial and inexpensive transformers for LAN networks, stacked in a user-selectable number, to better fit the bandwidth requirements. A model that allows handling of the low- and high-frequency operating range has been developed.

Об эффективности функционирования мультикритериального пожарного извещателя

Now detectors that sensing on two and more fire physical factors have appeared and get popular application. These detectors are different concerning usual combined fire detectors and they use more difficult algorithm of information processing. The considered classification of multicriterial fire detectors has allowed to dedicate two features accounting various ways of their technical implementation. The first feature is probably number of used types of monitored physical environment parameters. Now four main channels of detection are actively used in such detectors: heat, smoke, flame and gas. However, this list doesn’t limit possible detected factors of ignition. Now there are known, for example, devices which use acoustic effects, conducting fire, change video image within scene of specter and others. The second feature is way of technical implementation of detection channel. They can be joined by one constructively completed unit or be multiblock structure, with wire communication lines between cooperated components and with fire control panel. Construction complication and the introduction additional connections negatively influence on detector’s reliability. Thus, during evaluating of efficiency it is necessary additionally to consider important indicator - reliability, which can be characterized by degree of readiness of multicriterial fire detector to perform its main function of fire detection at any moment of time. In this article the opportunity of introduction of complex indicator “technical readiness” of multicriterial fire detector is considered. This indicator is probability of performance by multicriterial fire detector the main preset task (objective function), that consists in insured fire detection. The mathematical expression for technical efficiency of multicriterial fire detector is received. Its numeric analysis for determination of dependences character of “technical efficiency” from number of detection channels at different values of detection channels characteristics and parameters their reliability is carried out. The opportunity of construction detector’s optimization by usage of introduced parameter is shown in this article. The offered parameter of technical efficiency may be used in well-founded cases for designing and application of multicriterial fire detector and also for modular complexes and fire alarm systems.

Progress and Advances in Serial Powering of Silicon Modules for the ATLAS Tracker Upgrade

It is expected that at SLHC the number of detector channels in the ATLAS Semiconductor Tracker will increase by a factor 10, to cope with the increased luminosity. Currently every detector module has its own power cable, known as independent powering (IP). In the upgrade, this arrangement will no longer be tenable, due to cable volume and power losses. The serial powering alternative scheme, in which supermodules, with many readout hybrids, are connected in a serially powered chain, has been proposed and actively pursued over the last few years by the ATLAS Tracker Upgrade Community. This scheme presents some benefits, including simplicity, lower mass and reduced power losses. On the other hand, grounding, shielding and data transmission schemes are modified with respect to the conventional arrangement. Custom components specifically for serial powering have been produced, including the ABCN-25 readout ASICs and the SPI serial powering regulation ASIC, both in 250 nm CMOS, a dedicated programmable current source and power protection elements. In this paper the latest measurements from testing of the new custom electronics are presented and future plans are outlined.

Scalable time-correlated photon counting system with multiple independent input channels

Time-correlated single photon counting continues to gain importance in a wide range of applications. Most prominently, it is used for time-resolved fluorescence measurements with sensitivity down to the single molecule level. While the primary goal of the method used to be the determination of fluorescence lifetimes upon optical excitation by short light pulses, recent modifications and refinements of instrumentation and methodology allow for the recovery of much more information from the detected photons, and enable entirely new applications. This is achieved most successfully by continuously recording individually detected photons with their arrival time and detection channel information (time tagging), thus avoiding premature data reduction and concomitant loss of information. An important property of the instrumentation used is the number of detection channels and the way they interrelate. Here we present a new instrument architecture that allows scalability in terms of the number of input channels while all channels are synchronized to picoseconds of relative timing and yet operate independent of each other. This is achieved by means of a modular design with independent crystal-locked time digitizers and a central processing unit for sorting and processing of the timing data. The modules communicate through high speed serial links supporting the full throughput rate of the time digitizers. Event processing is implemented in programmable logic, permitting classical histogramming, as well as time tagging of individual photons and their temporally ordered streaming to the host computer. Based on the time-ordered event data, any algorithms and methods for the analysis of fluorescence dynamics can be implemented not only in postprocessing but also in real time. Results from recently emerging single molecule applications are presented to demonstrate the capabilities of the instrument.

New differential absorption lidar for stratospheric ozone monitoring in Patagonia, South Argentina

As part of environmental studies concerned with measurements of the stratospheric ozone layer, CEILAP has developed a new differential absorption lidar (DIAL) instrument. Since the initial construction of the first DIAL instrument, the Lidar Division of CEILAP has made important financial and scientific investments to upgrade this initial prototype. The new version has a bigger reception system formed by four Newtonian telescopes, each of 50 cm diameter, and a larger number of detection channels: four different wavelengths are detected simultaneously and six digital channels record the Rayleigh and Raman backscattered photons emitted by a ClXe excimer laser at 308 nm and the third harmonic of a Nd–YAG laser at 355 nm. A number of different changes have been made to increase the dynamic range of this lidar: a mechanical chopper was installed together with a gated photomultiplier in the high-energy detection channels to avoid the detector being overloaded by strong signals from lower atmospheric layers. This new version was installed inside a shelter, giving the possibility to make field campaigns outside CEILAP laboratories, for example the SOLAR campaign made in the Argentine Patagonian region during 2005 and 2006 spring periods. In this paper a full description of the instrument update is given. Intercomparisons with the ozone sonde and satellite platform instrument are presented. The results show agreement better than 10% in 16–38 km altitude range when the same airmasses are sampled. The comparison with five quasi-coincident sondes launched in Punta Arenas during spring 2005 shows good agreement between both types of measurement, with relative differences inside 1σ deviation of the lidar measurement. The comparison of the integral of height integrated lidar profiles with total ozone column measured with a Brewer photometer shows good agreement, with relative differences less than 10%.

Silicon array detector system for high-rate, low-noise X-ray spectroscopy

A silicon array detector system is being developed for X-ray fluorescence applications at synchrotron light sources. The detector is wire-bonded to integrated circuits which features 32 channels of charge-sensitive preamplifiers followed by variable-gain pulse shaping amplifiers. The ICs directly drive CAMAC-based A/D boards designed for this application. The data are transferred from the custom designed 16-channel ADC modules via FERABUS readout to commercially available histogramming modules and memory lookup units. The system features fully parallel signal processing to maintain high count rate capability and to preserve the position information. Special LabVIEW-based software has been developed for data acquisition and analysis. The system, currently being assembled for 64-channels, can easily be expanded by increasing the number of detection channels and hardware modules.