We propose a novel scheme to implement tunable multi-tap complex coefficient filters based on optical single sideband modulation and narrow band optical filtering. A four tap filter is experimentally ...demonstrated to highlight the enhanced tuning performance provided by complex coefficients. Optical processing is performed by the use of a cascade of four phase-shifted fiber Bragg gratings specifically fabricated for this purpose.
The design and field test of a novel sensor system based in autonomous wireless sensors to measure the temperature of the heat transfer fluid along a borehole heat exchanger (BHE) is presented. The ...system, by means of two special valves, inserts and extracts miniaturized wireless sensors inside the pipes of the borehole, which are carried by the thermal fluid. Each sensor is embedded in a small sphere of just 25 mm diameter and 8 gr weight, containing a transceiver, a microcontroller, a temperature sensor and a power supply. A wireless data processing unit transmits to the sensors the acquisition configuration before the measurements, and also downloads the temperature data measured by the sensor along its way through the BHE U-tube. This sensor system is intended to improve the conventional thermal response test (TRT) and it allows the collection of information about the thermal characteristics of the geological structure of subsurface and its influence in borehole thermal behaviour, which in turn, facilitates the implementation of TRTs in a more cost-effective and reliable way.
The radio frequency (RF) laboratory hosted in the Corpuscular Physics Institute (IFIC) of the University of Valencia is designed to house a high-power and high-repetition-rate facility to test normal ...conduction RF accelerator cavities in the S-Band (2.9985 GHz) in order to perform R&D activities related to particle accelerator cavities. The system, which manages the entire process of RF signal generation, data acquisition and closed-loop control of the laboratory, is currently based on a modular and compact PXI platform system. This contribution details the development of a platform with similar features, but which is based on open architecture standards at both the hardware and software level. For this purpose, a complete system based on the μTCA platform has been developed. This new system must be able to work with accelerator cavities at other operating frequencies, such as 750 MHz, as well as to explore different options at firmware and software levels based on open-source codes.
This contribution shows how to perform Time of Flight (TOF) measurements in PET systems using low-cost Field Programmable Gate Array (FPGA) devices with a resolution better of 100ps. This is achieved ...with a proper management of the FPGA internal resources and with an extremely careful device calibration process including both temperature and voltage compensation. Preliminary results are reported.
Due to the lateral inscription process, photo-induced birefringence is present in fiber Bragg gratings (FBGs) written into photosensitive single mode fiber. The birefringence value is generally too ...small to be perceived in the grating spectral response but it can lead to significant polarization dependent loss (PDL) and differential group delay (DGD) evolutions. In this paper, we first theoretically analyze the evolution with wavelength of PDL and DGD as a function of the grating parameters and the birefringence value. We demonstrate that the PDL and DGD evolutions with wavelength can be strongly enhanced by a modification of the grating parameters. Simulations carried out using the coupled mode theory and the Jones formalism are then confirmed by experiments conducted on FBGs written into photosensitive single mode fiber. Our work brings a complete characterization of polarization related phenomena in FBGs and presents a great interest for the evaluation of system performances and the design of gratings for specific applications, either for telecommunications or sensing purposes. In addition, based on the comparison between experimental and simulated evolutions, we are able to verify that the birefringence value is strongly dependent on the fluence of the laser used for the grating inscription.
Time of flight measurements based on FPGA and SiPMs for PET–MR Aguilar, Albert; García-Olcina, Raimundo; Martínez, Pedro A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2014, Letnik:
734
Journal Article
Recenzirano
Coincidence time measurements with SiPMs have shown to be suitable for PET/MR systems. The present study is based on 3×3mm2 SiPMs, LSO crystals and a conditioning signal electronic circuit. A ...Constant Fraction Discriminator (CFD) is used to digitalize the signals and a TDC FPGA-implemented is employed for fine time measurements. TDC capability allows processing the arrival of multiple events simultaneously, measuring times under 100ps. The complete set-up for time measurements results on a resolution of 892±41ps for a pair of detectors. The details of such implementation are exposed and the trade-offs of each configuration are discussed.
Electromagnetic noise absorber sheets have become a solution for solving complex electromagnetic interference (EMI) problems due to their high magnetic losses. This contribution is focused on ...characterizing a novel structure that is based on an absorber film with a metal layer attached on its top side. Two different absorber compositions were combined with Al and Cu metal layers in order to study the improvement on the performance of these structures, depending on the complex permeability, absorber film thickness, and type of metal. The transmission attenuation power ratio of the absorber films is analyzed and compared to the performance of absorber and metal structures. The measurement procedure is carried out attaching the films into a microstrip line that has been designed based on IEC standard (IEC 62333-2). This test fixture is employed as a transmission line to simulate a general noise path. The performance of absorber composites to filter electromagnetic noise is evaluated through analyzing
and
parameters. This is carried out with the aim of finding out in which conditions the absorption loss is improved when a metal layer is attached. In addition, the possible re-radiation effect, due to the magnetic field that is generated by the eddy currents induced in the metal layer, is examined.
The gap of standardization for conducted and field coupled electromagnetic interferences (EMI) in the 2-150 kHz frequency range can lead to Electromagnetic Compatibility (EMC) problems. This is ...caused by power systems such as Pulse Width Modulation (PWM) controlled rectifiers, photovoltaic inverters or charging battery units in electric vehicles. This is a very important frequency spectral due to interferences generated in a wide range of devices and, specifically, communication problems in the new technologies and devices incorporated to the traditional grid to convert it into a Smart Grid. Consequently, it is necessary to provide new solutions to attenuate this kind of interference, which involves finding new materials that are able to filter the electromagnetic noise. This contribution is focused on characterizing the performance of a novel material based on nanocrystalline and comparing it to most common material compositions such as MnZn and NiZn. This research is carried out from the point of view of the manufacturing process, magnetic properties and EMI suppression ability. This last item is carried out through two analysis procedures: a theoretical method by determining the attenuation ratio by measuring impedance parameter and proposing a new empirical technique based on measuring directly the insertion loss parameter. Therefore, the main aim of this characterization process is to determine the performance of nanocrystalline compared to traditional cable ferrite compositions to reduce the interferences in this controversial frequency range. From the results obtained, it is possible to deduce that nanocrystalline cable ferrite provides the best performance to filter the electromagnetic noise in the 2-150 kHz frequency range.
The Large Hadron Collider (LHC) has envisaged a series of upgrades towards a High Luminosity LHC (HL-LHC) delivering five times the LHC nominal instantaneous luminosity. It will take place throughout ...2026–2028, corresponding to the Long Shutdown 3. During this upgrade, the ATLAS Tile Hadronic Calorimeter (TileCal) will replace completely on- and off-detector electronics adopting a new read-out architecture. Signals captured from TileCal are digitized by the on-detector electronics and transmitted to the TileCal PreProcessor (TilePPr) located off-detector, which provides the interface with the ATLAS trigger and data acquisition systems.
TilePPr receives, process and transmits the data from the on-detector system and transmits it to the Front-End Link eXchange (FELIX) system. FELIX is the ATLAS common hardware in all the subdetectors designed to act as a data router, receiving and forwarding data to the SoftWare Read-Out Driver (SWROD) computers. FELIX also distributes the Timing, Trigger and Control (TTC) signals to the TilePPr to be propagated to the on-detector electronics. The SWROD is an ATLAS common software solution to perform detector specific data processing, including configuration, calibration, control and monitoring of the partition
In this contribution we will introduce the new read-out elements for TileCal at the HL-LHC, the interconnection between the off-detector electronics and the FELIX system, the configuration and implementation for the test beam campaigns, as well as future developments of the preprocessing and monitoring status of the calorimeter modules through the SWROD infrastructure.
The Large Hadron Collider (LHC) is undergoing a series of upgrades towards a High Luminosity LHC (HL-LHC) that will deliver five times the LHC nominal instantaneous luminosity. The ATLAS experiment ...is one of the experiments at the LHC that investigates elementary particle interactions in collisions of high-energy proton beams. To prepare for data taking in high-luminosity conditions, the ATLAS Tile Hadronic Calorimeter (TileCal) will replace completely on- and off-detector electronics using a new read-out architecture. The TileCal detector signals will be digitized by on-detector electronics and transferred to the TileCal PreProcessors (TilePPr), which comprise the main component of the off-detector electronics. In the TilePPr, the digitized data will be stored in pipeline buffers and be packed and read out to the Front-End LInk eXchange (FELIX) system upon the reception of a trigger decision. FELIX is a new detector readout component being developed as part of the ATLAS upgrade effort. FELIX is designed to act as a data router between the data acquisition detector control and TTC (Timing, Trigger and Control) systems and the new or updated trigger and detector front-end electronics. Whereas previous detector readout implementations relied on diverse custom hardware platforms, the idea behind FELIX is to unify all readout across one well supported and flexible platform.
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