7,450 research outputs found
The first version Buffered Large Analog Bandwidth (BLAB1) ASIC for high luminosity collider and extensive radio neutrino detectors
Future detectors for high luminosity particle identification and ultra high
energy neutrino observation would benefit from a digitizer capable of recording
sensor elements with high analog bandwidth and large record depth, in a
cost-effective, compact and low-power way. A first version of the Buffered
Large Analog Bandwidth (BLAB1) ASIC has been designed based upon the lessons
learned from the development of the Large Analog Bandwidth Recorder and
Digitizer with Ordered Readout (LABRADOR) ASIC. While this LABRADOR ASIC has
been very successful and forms the basis of a generation of new, large-scale
radio neutrino detectors, its limited sampling depth is a major drawback. A
prototype has been designed and fabricated with 65k deep sampling at
multi-GSa/s operation. We present test results and directions for future
evolution of this sampling technique.Comment: 15 pages, 26 figures; revised, accepted for publication in NIM
The Modern FPGA as Discriminator, TDC and ADC
Recent generations of Field Programmable Gate Arrays (FPGAs) have become
indispensible tools for complex state machine control and signal processing,
and now routinely incorporate CPU cores to allow execution of user software
code. At the same time, their exceptional performance permits low-power
implementation of functionality previously the exclusive domain of dedicated
analog electronics. Specific examples presented here use FPGAs as
discriminator, time-to-digital (TDC) and analog-to-digital converter (ADC). All
three cases are examples of instrumentation for current or future astroparticle
experiments.Comment: 7 pages, v3 minor JINST editorial correction
A Monolithic Time Stretcher for Precision Time Recording
Identifying light mesons which contain only up/down quarks (pions) from those
containing a strange quark (kaons) over the typical meter length scales of a
particle physics detector requires instrumentation capable of measuring flight
times with a resolution on the order of 20ps. In the last few years a large
number of inexpensive, multi-channel Time-to-Digital Converter (TDC) chips have
become available. These devices typically have timing resolution performance in
the hundreds of ps regime. A technique is presented that is a monolithic
version of ``time stretcher'' solution adopted for the Belle Time-Of-Flight
system to address this gap between resolution need and intrinsic multi-hit TDC
performance.Comment: 9 pages, 15 figures, minor corrections made, to appear as JINST_008
Predicting Violent Crime
This research works to predict the likelihood that an individual is going to participate in a violent crime. The predictors were taken from several bodies of work and synthesized into a survey format, which can be distributed to the desired population. These measures operate on the hypothesis that certain characteristics increase the likelihood of, but do not predict with certainty, an individual\u27s propensity to participate in violent crime. The work also serves as a manual for how to interpret the selected data sets as well as how to break down the statistical correlations of each question to their predictive power
Multiyear measurements of ebullitive methane flux from three subarctic lakes
Ebullition (bubbling) from small lakes and ponds at high latitudes is an important yet unconstrained source of atmospheric methane (CH4). Small water bodies are most abundant in permanently frozen peatlands, and it is speculated that their emissions will increase as the permafrost thaws. We made 6806 measurements of CH4 ebullition during four consecutive summers using a total of 40 bubble traps that were systematically distributed across the depth zones of three lakes in a sporadic permafrost landscape in northernmost Sweden. We identified significant spatial and temporal variations in ebullition and observed a large spread in the bubbles\u27 CH4 concentration, ranging from 0.04% to 98.6%. Ebullition followed lake temperatures, and releases were significantly larger during periods with decreasing atmospheric pressure. Although shallow zone ebullition dominated the seasonal bubble CH4 flux, we found a shift in the depth dependency towards higher fluxes from intermediate and deep zones in early fall. The average daily flux of 13.4 mg CH4 m−2 was lower than those measured in most other high‐latitude lakes. Locally, however, our study lakes are a substantial CH4 source; we estimate that 350 kg of CH4 is released via ebullition during summer (June–September), which is approximately 40% of total whole year emissions from the nearby peatland. In order to capture the large variability and to accurately scale lake CH4 ebullition temporally and spatially, frequent measurements over long time periods are critical
The PRO1 ASIC for Fast Wilkinson Encoding
Wilkinson conversion of stored samples in large Switch Capacitor Array (SCA)
ASICs, such as used for high speed waveform sampling, has many benefits in
terms of compactness, no missing output codes, low power requirements and
robustness. However such Analog-to-Digital conversions are relatively slow,
limited by the encoder clock speed. By repeating the same fast sampling
technique used by the SCA, combined with a fast priority encoder, significantly
faster conversion is demonstrated for a prototype ASIC designated PRO1. For
8-10 bits of resolution, this technique is compact and requires far fewer
system resources.Comment: 10 pages, 11 figure
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