Cascaded Gas Electron Multipliers (GEM) allow to construct detectors for charge particles tracking with high spatial resolution and rate capability. Such detectors can withstand high background ...fluxes up to 10 super(5) particles/mm super(2)/s and determine track coordinates with precision of 50-70 micron. These remarkable features of GEM govern the use of this technology in a number of experiments at the Budker Institute of Nuclear Physics. In this paper the current status and progress in the performance studies and the development of the detectors for the tagging system of the KEDR experiment at the VEPP-4M collider and for the DEUTERON facility at the VEPP-3 storage ring will be covered. The new proposals for the upgrade of tracking and trigger system of the CMD-3 detector, the tracking detectors for the extracted beam from the VEPP-4M storage ring and the tracking detectors for the polarimeter at the VEPP-4M with the use of GEM technology will be discussed.
The size of the optic nerve head, referred to as disc area (DA), and the vertical cup-disc ratio (VCDR), are clinically relevant parameters for glaucomatous optic neuropathy. Although these measures ...have a high heritability, little is known about the underlying genes. Previously, the genes SALL1 and SIX1 were found to be genome-wide significantly associated with DA and VCDR. The purpose of the present study was to investigate whether genes encoding protein known to interact with protein encoded by SALL1 and SIX1 are also associated with either DA or VCDR.
A total of 38 candidate genes were chosen covering all known proteins interacting with SALL1 and SIX1. These were initially studied in the Rotterdam Study (RS)-I, including 5312 Caucasian subjects characterized for DA and VCDR. Positive findings were further investigated in two independent cohorts (RS-II and RS-III) and finally replicated in a fourth population (ERF). Bonferroni correction was applied to the meta-analyses.
Three loci were found to be associated with DA. The only locus significant after correcting for multiple testing is located on chromosome 11p13. Three single nucleotide polymorphisms (SNPs) in ELP4, a gene which neighbors and plays a crucial role in the expression of PAX6, show association in meta-analysis of the four cohorts yielding P values of respectively 4.79 × 10(-6), 3.92 × 10(-6), and 4.88 × 10(-6) which is below the threshold dictated by the most conservative Bonferroni correction (P = 5.2 × 10(-6)).
This study suggests that the ELP4-PAX6 region plays a role in the DA. Further research to confirm this finding is needed.
A new high precision measurement of the J/ψ- and ψ′-meson masses has been performed at the VEPP-4M collider using the KEDR detector. The resonant depolarization method has been employed for the ...absolute calibration of the beam energy. The following mass values have been obtained: MJ/ψ=3096.917±0.010±0.007 MeV,Mψ′=3686.111±0.025±0.009 MeV. The relative measurement accuracy has reached 4×10−6 for J/ψ and 7×10−6 for ψ′, approximately 3 times better than in the previous precise experiments.
Methods of dynamic imaging of explosions at a synchrotron radiation (SR) beam and small-angle X-ray scattering experiments with exploding samples are being developed in the Siberian Synchrotron ...Radiation Center (SSRC) at the Budker Institute of Nuclear Physics for more than fifteen years. The detector for imaging of explosions (DIMEX) was developed for these purposes and successfully operating at the beam line 0 at the VEPP-3 storage ring and at the beam line 8 at the VEPP-4M storage ring. The DIMEX is based on gas technology and allow to measure SR flux as a function of position and time with spatial resolution of ∼200 μm (FWHM), maximum frame rate of 2MHz and time resolution of ∼80ns. Maximum value of the SR flux that can be measured by the present detector corresponds to ∼5000 photons/(channel*bunch) (20 keV average energy, channel area 0.1x0.5 mm2, bunch revolution frequency 4MHz). Maximum number of frames that can be stored in the present detector is 32 and the number of channels with 0.1mm width is 512. In order to significantly improve the precision of data obtained by the DIMEX an upgrade of the detector has been started. The electronics of the gaseous version of the detector has been changed such that the new detector is able to operate with frame rate of 8MHz and store data in up to 100 frames. A new ASIC was developed for this purpose called DMXG64A that includes 64 channels with low noise integrator and 100 analogue memory cells in each channel. Input charge can be stored to and read out from analogue cells with maximum frequency 10MHz. This new version of the detector is called the DIMEX-G and is planned to be used at the VEPP-3 storage ring and for SAXS studies at the VEPP-4M storage ring. For imaging of explosions at the beam line 8 at the VEPP-4M storage ring, where SR flux is expected to be about 10-100 times higher than at the VEPP-3, a new detector based on Si micro-strip technology is being developed. Si micro-strip sensors with special design have been manufactured by Hamamatsu Photonics company. Each sensor contains 1024 30mm long strips with 50μm pitch. The sensor thickness is 320μm and it will be positioned at an angle of 1.7 degrees with respect to the SR beam plane in order to get effective Si thickness along the beam close to 10mm. The new detector called DIMEX-Si will have spatial resolution of 50μm (FWHM) and time resolution close to 10ns. The new ASIC is under development for this project that will allow to operate with the frame rate of 50MHz and record maximum charge that corresponds to the flux close to 106 photons/(chan*bunch), i.e. about 100 times higher than with present detector.
We report results of a search for narrow resonances in e+e− annihilation at center-of-mass energies between 1.85 and 3.1 GeV performed with the KEDR detector at the VEPP-4M e+e− collider. The upper ...limit on the leptonic width of a narrow resonance ΓeeR⋅Br(R→hadr)<120 eV has been obtained (at 90% C.L.).
The Spherical Neutral Detector (SND) is intended for study of electron–positron annihilation at the VEPP-2000 e+e− collider (BINP, Novosibirsk) in the center-of-mass energy region below 2GeV. The ...main part of the detector is a three-layer electromagnetic calorimeter based on NaI(Tl) crystals. The physics program of the SND experiment includes a high statistics study of neutron–antineutron production near threshold, for which time measurements in the calorimeter are required. In this paper we describe new shaping and digitizing calorimeter electronics, which allow to reach a time resolution of about 1ns for 100MeV signal and an amplitude resolution of about 250keV.
Spherical neutral detector for VEPP-2M collider Achasov, M.N; Aulchenko, V.M; Baru, S.E ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2000, Letnik:
449, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The Spherical Neutral Detector (SND) operates at VEPP-2M collider in Novosibirsk studying e
+e
− annihilation in the energy range up to 1.4
GeV. Detector consists of a fine granulated spherical ...scintillation calorimeter with 1632 NaI(Tl) crystals, two cylindrical drift chambers with 10 layers of sense wires, and a muon system made of streamer tubes and plastic scintillation counters. The detector design, performance, data acquisition and processing are described.
Based on numerical simulations of flight trajectories with ramjet-powered flying vehicles, it is found that all possible flight trajectories can be classified into three groups: ballistic ...trajectories, trajectories with a horizontal segment, and skipping trajectories. Trajectories of each group can be optimized, for instance, to ensure the maximum flight range under given initial conditions and constraints. Examples of optimal trajectories for a given amount of available fuel are presented as functions of the initial slope of the trajectory, angle of attack of the vehicle, instants of engine actuation, and engine operation time.
PDF
