The radio emission pattern of air showers as measured with LOFAR - a tool for the reconstruction of the energy and the shower maximum

The pattern of the radio emission of air showers is finely sampled with the Low-Frequency ARray (LOFAR). A set of 382 measured air showers is used to test a fast, analytic parameterization of the distribution of pulse powers. Using this parameterization we are able to reconstruct the shower axis and give estimators for the energy of the air shower as well as the distance to the shower maximum.Comment: 15 pages, 10 figures, accepted for publication in JCA

A low power and low signal 5-bit 25MS/s pipelined ADC for monolithic active pixel sensors

For CMOS monolithic active pixels sensor readout, we developed a 5 bit low power analog to digital converter using a pipelined architecture. A non-resetting sample and hold stage is included to amplify the signal by a factor of 4. Due to the very low level of the incoming signal, this first stage compensates both the amplifier offset effect and the input common mode voltage dispersion. The converter consists of three 1.5 bit sub-ADC and a 2 bit flash. We present the results of a prototype, made of eight ADC channels. The maximum sampling rate is 25MS/s. The total DC power consumption is 1.7mW/channel on a 3.3V supply voltage recommended for the process. But at a reduced 2.5V supply, it consumes only 1.3mW. The size of each ADC channel layout is only 43μm*1.43mm. This corresponds to the pitch of two pixel columns each one would be 20μm wide. The full analog part of the converter can be quickly switched to a standby idle mode in less than 1μs; thus reducing the power dissipation to a ratio better than 1/1000. This fast shutdown is very important for the ILC vertex detector as the total DC power dissipation becomes directly proportional to the low beam duty cycle

Realtime processing of LOFAR data for the detection of nano-second pulses from the Moon

The low flux of the ultra-high energy cosmic rays (UHECR) at the highest energies provides a challenge to answer the long standing question about their origin and nature. Even lower fluxes of neutrinos with energies above $10^{22}$ eV are predicted in certain Grand-Unifying-Theories (GUTs) and e.g.\ models for super-heavy dark matter (SHDM). The significant increase in detector volume required to detect these particles can be achieved by searching for the nano-second radio pulses that are emitted when a particle interacts in Earth's moon with current and future radio telescopes. In this contribution we present the design of an online analysis and trigger pipeline for the detection of nano-second pulses with the LOFAR radio telescope. The most important steps of the processing pipeline are digital focusing of the antennas towards the Moon, correction of the signal for ionospheric dispersion, and synthesis of the time-domain signal from the polyphased-filtered signal in frequency domain. The implementation of the pipeline on a GPU/CPU cluster will be discussed together with the computing performance of the prototype.Comment: Proceedings of the 22nd International Conference on Computing in High Energy and Nuclear Physics (CHEP2016), US

G0^0 Electronics and Data Acquisition (Forward-Angle Measurements)

The G$^0$ parity-violation experiment at Jefferson Lab (Newport News, VA) is designed to determine the contribution of strange/anti-strange quark pairs to the intrinsic properties of the proton. In the forward-angle part of the experiment, the asymmetry in the cross section was measured for $\vec{e}p$ elastic scattering by counting the recoil protons corresponding to the two beam-helicity states. Due to the high accuracy required on the asymmetry, the G$^0$ experiment was based on a custom experimental setup with its own associated electronics and data acquisition (DAQ) system. Highly specialized time-encoding electronics provided time-of-flight spectra for each detector for each helicity state. More conventional electronics was used for monitoring (mainly FastBus). The time-encoding electronics and the DAQ system have been designed to handle events at a mean rate of 2 MHz per detector with low deadtime and to minimize helicity-correlated systematic errors. In this paper, we outline the general architecture and the main features of the electronics and the DAQ system dedicated to G$^0$ forward-angle measurements.Comment: 35 pages. 17 figures. This article is to be submitted to NIM section A. It has been written with Latex using \documentclass{elsart}. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment In Press (2007

A low power and low signal 4 bit 50MS/s double sampling pipelined ADC for Monolithic Active Pixel Sensors

International audienceA 4 bit very low power and low incoming signal analog to digital converter (ADC) using a double sampling switched capacitor technique, designed for use in CMOS monolithic active pixels sensor readout, has been implemented in 0.35μm CMOS technology. A non-resetting sample and hold stage is integrated to amplify the incoming signal by 4. This first stage compensates both the amplifier offset effect and the input common mode voltage fluctuations. The converter is composed of a 2.5 bit pipeline stage followed by a 2 bit flash stage. This prototype consists of 4 ADC double-channels; each one is sampling at 50MS/s and dissipates only 2.6mW at 3.3V supply voltage. A bias pulsing stage is integrated in the circuit. Therefore, the analog part is switched OFF or ON in less than 1μs. The size for the layout is 80μm*0.9mm. This corresponds to the pitch of 4 pixel columns, each one is 20μm wide

Local Simulation Algorithms for Coulomb Interaction

Long ranged electrostatic interactions are time consuming to calculate in molecular dynamics and Monte-Carlo simulations. We introduce an algorithmic framework for simulating charged particles which modifies the dynamics so as to allow equilibration using a local Hamiltonian. The method introduces an auxiliary field with constrained dynamics so that the equilibrium distribution is determined by the Coulomb interaction. We demonstrate the efficiency of the method by simulating a simple, charged lattice gas.Comment: Last figure changed to improve demonstration of numerical efficienc

A low power and low signal 4 bit 50MS/s double sampling pipelined ADC for monolithie active pixel sensors

A 4 bit very low power and low incoming signal analog to digital converter (ADC) using a double sampling switched capacitor technique, designed for use in CMOS monolithic active pixels sensor readout, has been implemented in 0.35μm CMOS technology. A non-resetting sample and hold stage is integrated to amplify the incoming signal by 4. This first stage compensates both the amplifier offset effect and the input common mode voltage fluctuations. The converter is composed of a 2.5 bit pipeline stage followed by a 2 bit flash stage. This prototype consists of 4 ADC double-channels; each one is sampling at 50MS/s and dissipates only 2.6mW at 3.3V supply voltage. A bias pulsing stage is integrated in the circuit. Therefore, the analog part is switched OFF or ON in less than 1μs. The size for the layout is 80μm*0.9mm. This corresponds to the pitch of 4 pixel columns, each one is 20μm wide