The newly sequenced mitochondrial genomes of 107 Asian swamp buffalo (Bubalus bubalis carabensis) allowed the reconstruction of the matrilineal divergence since ~900 Kya. Phylogenetic trees and ...Bayesian skyline plots suggest a role of the glacial periods in the demographic history of swamp buffalo. The ancestral swamp-buffalo mitogenome is dated ~232 ± 35 Kya. Two major macro-lineages diverged during the 2
Pleistocene Glacial Period (~200-130 Kya), but most (~99%) of the current matrilines derive from only two ancestors (SA1'2 and SB) that lived around the Last Glacial Maximum (~26-19 Kya). During the late Holocene optimum (11-6 Kya) lineages differentiated further, and at least eight matrilines (SA1, SA2, SB1a, SB1b, SB2a, SB2b, SB3 and SB4) were domesticated around 7-3 Kya. Haplotype distributions support an initial domestication process in Southeast Asia, while subsequent captures of wild females probably introduced some additional rare lineages (SA3, SC, SD and SE). Dispersal of domestic buffaloes created local population bottlenecks and founder events that further differentiated haplogroup distributions. A lack of maternal gene flow between neighboring populations apparently maintained the strong phylogeography of the swamp buffalo matrilines, which is the more remarkable because of an almost complete absence of phenotypic differentiation.
An assembly line for the construction of ultra-radio-pure detectors Buccheri, E.; Capodiferro, M.; Morganti, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2014, Letnik:
768
Journal Article
Recenzirano
Odprti dostop
The 19 towers constituting the CUORE detector are an assembly of ultra-radio-pure components made of copper and PTFE plus tellurium dioxide crystals for a total of more than 10,000 pieces. A ...dedicated assembly line is mandatory to handle and assemble those parts and to minimize the risk of recontamination induced by external agents both during their construction and during their storage prior to installation inside the cryostat. The assembly strategy and the tool design proposed in this paper and developed for CUORE offer solutions that can be extended to the construction of similar-size detectors with strict requirements regarding contamination.
High-speed optical links are often used in trigger and data acquisition systems of High Energy Physics (HEP) experiments for data transfer, trigger and fast control distribution. Many experiments ...prefer the use of commercial off-the-shelf components (COTS) if possible, in order to avoid the non-recurrent engineering (NRE) costs and risks associated with the design of application specific integrated circuits. For the mentioned reason, static random access memory-based field programmable gate arrays (SRAM-based FPGAs) are usually deployed. However they are mostly used off-detector, where little or no radiation is present, since single event upsets in the configuration memory may alter the design functionality. In order to benefit from SRAM-based FPGAs also in radiation environments expected on-detector, suitable soft-error mitigation strategies must be adopted. In this work we evaluate the design trade-offs between performance and radiation-tolerance in a high-speed fixed-latency link based on a Virtex-5 SRAM-based FPGA. We evaluate different radiation mitigation strategies. Moreover, we experimentally verify some custom-developed placement and routing rules aimed at improving the FPGA firmware robustness against configuration upsets.
The upgrade of the KLOE detector at DAFNE, the Φ-factory at the Laboratori Nazionali di Frascati, foresees the insertion of an Inner Tracker around the interaction region, composed of four layers ...with diameters from 26cm to 41cm and an active length of 70cm. Each layer is realized as a cylindrical triple-GEM detector, a solution that allows to keep the total material of the Inner Tracker below 2% of a radiation length, which is of utmost importance to limit the multiple scattering of low-momentum tracks and to minimize dead spaces, thus maximizing the detector's active area. The peculiar read-out pattern with X and V strips provides a spatial resolution of about 200μm and 400μm for azimuthal and longitudinal coordinates, respectively.
After 2 years, the construction of the Inner Tracker has been completed and the detector is ready to be inserted in the KLOE apparatus for a next data-taking run. The details of the manufacturing procedure as well as the results of validation tests are reported.
Gas detector development is one of the pillars of the research in fundamental physics. Since several years, a new concept of detectors, called Micro Pattern Gas Detector (MPGD), allowed to overcome ...several problems related to other types of commonly used detectors, like drift chamber and micro strips detectors, reducing the rate of discharges and providing better radiation tolerance. Among the most used MPGDs are the Gas Electron Multipliers (GEMs). Invented by Sauli in 1997, nowadays GEMs have become an important reality for particle detectors in high energy physics. Commonly deployed as fast timing detectors and triggers, their fast response, high rate capability and high radiation hardness make them also suitable as tracking detectors. The readout scheme is one of the most important features in tracking technology. Analog readout based on the calculation of the center of gravity technique allows to overcome the limit imposed by digital pads, whose spatial resolution is limited by the pitch dimensions. However, the presence of high external magnetic fields can distort the electronic cloud and affect the performance. The development of the micro-TPC reconstruction method brings GEM detectors into a new prospective, improving significantly the spatial resolutionin presence of high magnetic fields. This innovative technique allows to reconstruct the 3-dimensional particle position, as Time Projection Chamber, but within a drift gap of a few millimeters. In these report, the charge centroid and micro-TPC methods are described in details. We discuss the results of several test beams performed with planar chambers in magnetic field. These results are one of the first developments of micro-TPC technique for GEM detectors, which allows to reach unprecedented performance in a high magnetic field of 1 T.
A new inner tracker based on a cylindrical gas electron-multiplier detector is under development to replace the current inner drift chamber of the BES III spectrometer. The BES III experiment is ...carried out at the BEPC II e
+
e
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collider in Beijing at center-of-mass energies in the tau-charm region with a design luminosity of 1.0
x
10
33
cm
-2
s
-1
. The new inner tracker consists of three cylindrical layers of triple GEM surrounding the interaction point, covering 93% of solid angle. To fulfill physics requirements, a spatial resolution of 130 μm must be achieved. Both planar and cylindrical prototypes have been built and tested. A custom ASIC using UMC 110-nm technology has been designed to provide charge and time measurements—the first prototype is in testing. Notable and innovative aspects of the new inner tracker and the performance of the detector prototypes and readout ASIC are reported here.
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