Search results for "ELECTRONICS"
showing 10 items of 4340 documents
Coupling MCNP-DSP and LAHET Monte Carlo Codes for Designing Subcriticality Monitors for Accelerator-Driven Systems
2001
The design of reactivity monitoring systems for accelerator-driven systems must be investigated to ensure that such systems remain subcritical during operation. The Monte Carlo codes LAHET and MCNP-DSP were combined together to facilitate the design of reactivity monitoring systems. The coupling of LAHET and MCNP-DSP provides a tool that can be used to simulate a variety of subcritical measurements such as the pulsed neutron, Rossi-α, or noise analysis measurements.
Microwave induced co-tunneling in single electron tunneling transistors
2002
Abstract The influence of microwaves on the co-tunneling in single electron tunneling transistors has been investigated as function of frequency and power in the temperature range from 150 to 500 mK. All 20 low frequency connections and the RF line were filtered, and the whole cryostat was suspended on rubber bellows. Cross-talk was minimized by using individual coaxial lines between the sample and the room temperature electronics. The co-tunneling experiments were performed at zero DC bias current by measuring the voltage response to a very small amplitude 2 Hz current modulation with the gate voltage fixed at maximum Coulomb blockade. With the microwave signal applied to one side of the t…
Cryogenic setup for trapped ion quantum computing
2016
We report on the design of a cryogenic setup for trapped ion quantum computing containing a segmented surface electrode trap. The heat shield of our cryostat is designed to attenuate alternating magnetic field noise, resulting in 120~dB reduction of 50~Hz noise along the magnetic field axis. We combine this efficient magnetic shielding with high optical access required for single ion addressing as well as for efficient state detection by placing two lenses each with numerical aperture 0.23 inside the inner heat shield. The cryostat design incorporates vibration isolation to avoid decoherence of optical qubits due to the motion of the cryostat. We measure vibrations of the cryostat of less t…
Optimal filtering algorithm implementation in FPGAs for the ATLAS TileCal Read-Out drivers
2011
TileCal is the hadronic calorimeter of the ATLAS experiment in the LHC (CERN). Its Read-Out Drivers (RODs) process, in real time, the digitized information coming from the front-end electronics and send it to the Read-Out System. Data processing in the ROD boards is performed in Processing Unit Mezzanine Cards that use commercial DSPs to run the Optimal Filtering (OF) algorithms.
Ultrafast beam shaping with high-numerical-aperture microscope objectives
2009
Ultrafast diffraction results in spatiotemporal un-coupling of the wave field, inducing spectral anomalies and pulse stretching. Localized compensation may be achieved via angular dispersion driven by diffractive optical elements (DOEs). We report on an DOEs-based beam shaper of ultrashort optical pulses with high spatiotemporal resolution. Inspection of the validity of our approach is performed in the single-cycle regime.
Differential operator formalism for axial optical vortex beam and the double-phase-ramp converter
2019
A systematic study of the properties of the output dark rays or singular skeleton for the Laguerre-Gaussian beam LG 01 passed through double-phase-ramp converter is presented. When the DOE is discontinuous at the origin, as is the case here, the transfer function is not analytical, so that a special theoretical approach is needed. The previously reported formalism of scattering modes, which permitted the analytical calculation of arbitrary multisingular Gaussian beams, requires analyticity everywhere. We present here an adaption of this formalism that overcomes this limitation. The procedure is based on the differential operator algebra used in the previous construction. We give an example …
Diffraction-managed superlensing using plasmonic lattices
2012
Abstract We show that subwavelength diffracted wave fields may be managed inside multilayered plasmonic devices to achieve ultra-resolving lensing. For that purpose we first transform both homogeneous waves and a broad band of evanescent waves into propagating Bloch modes by means of a metal/dielectric (MD) superlattice. Beam spreading is subsequently compensated by means of negative refraction in a plasmon-induced anisotropic medium that is cemented behind. A precise design of the superlens doublet may lead to nearly aberration-free images with subwavelength resolution in spite of using optical paths longer than a wavelength.
The ATLAS TileCal read-out drivers signal reconstruction
2009
TileCal is the hadronic calorimeter of the ATLAS experiment at the LHC collider at CERN. The Read-Out Drivers (ROD) are the core of the off-detector electronics. The main components of the RODs are the Digital Signal Processor (DSP) placed on the Processing Unit (PU) dautherboards. This paper describes the DSP code and its performance with calibration and real data. The code is divided into two different parts: the first part contains the core functionalities and the second one the reconstruction algorithms. The core acts as an operating system and it controls the configuration, the data reception, transmission, online monitoring and the synchronization between front-end data and the Trigge…
Short-wavelength soft-x-ray laser pumped in double-pulse single-beam non-normal incidence
2010
We demonstrated a $7.36$ nm Ni-like samarium soft-x-ray laser, pumped by $36$ J of a neodymium:glass chirped-pulse amplification laser. Double-pulse single-beam non-normal-incidence pumping was applied for efficient soft-x-ray laser generation. In this case, the applied technique included a single-optic focusing geometry for large beam diameters, a single-pass grating compressor, traveling-wave tuning capability, and an optimized high-energy laser double pulse. This scheme has the potential for even shorter-wavelength soft-x-ray laser pumping.
Integrated InGaAlAs/InP laser-modulator using an identical multiple quantum well active layer
2005
We present experimental results on 40 Gb/s large-signal modulation performance of 1.31 μm monolithic integrated laser-modulator in the InGaAlAs/InP material system, exploiting the gain and absorption properties of an identical multiple quantum well (MQW) active layer. In continuous wave operation, at 15◦ C, the devices achieved threshold currents < 28 mA, fiber coupled optical power levels up to +0.4 dBm. The measured small signal modulation bandwidth was about 32 GHz. An air-cavity based Fabry-Perot interferometer has been realized to characterize the spectral chirp of the integrated structures in the time domain up to 40 Gb/s.