MoEDAL is designed to identify new physics in the form of stable or pseudostable highly ionizing particles produced in high-energy Large Hadron Collider (LHC) collisions. Here we update our previous ...search for magnetic monopoles in Run 2 using the full trapping detector with almost four times more material and almost twice more integrated luminosity. For the first time at the LHC, the data were interpreted in terms of photon-fusion monopole direct production in addition to the Drell-Yan-like mechanism. The MoEDAL trapping detector, consisting of 794 kg of aluminum samples installed in the forward and lateral regions, was exposed to 4.0 fb^{-1} of 13 TeV proton-proton collisions at the LHCb interaction point and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges equal to or above the Dirac charge are excluded in all samples. Monopole spins 0, ½, and 1 are considered and both velocity-independent and-dependent couplings are assumed. This search provides the best current laboratory constraints for monopoles with magnetic charges ranging from two to five times the Dirac charge.
The PICASSO dark matter search experiment operated an array of 32 superheated droplet detectors containing 3.0 kg of C4F10 and collected an exposure of 231.4 kgd at SNOLAB between March 2012 and ...January 2014. We report on the final results of this experiment which includes for the first time the complete data set and improved analysis techniques including acoustic localization to allow fiducialization and removal of higher activity regions within the detectors. No signal consistent with dark matter was observed. We set limits for spin-dependent interactions on protons of σpSD = 1.32 × 10−2 pb (90% C.L.) at a WIMP mass of 20 GeV/c2. In the spin-independent sector we exclude cross sections larger than σpSI = 4.86 × 10−5 pb (90% C.L.) in the region around 7 GeV/c2. The pioneering efforts of the PICASSO experiment have paved the way forward for a next generation detector incorporating much of this technology and experience into larger mass bubble chambers.
MoEDAL is designed to identify new physics in the form of long-lived highly ionizing particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors and aluminium ...trapping volumes provide two independent passive detection techniques. We present here the results of a first search for magnetic monopole production in 13 TeV proton-proton collisions using the trapping technique, extending a previous publication with 8 TeV data during LHC Run 1. A total of 222 kg of MoEDAL trapping detector samples was exposed in the forward region and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges exceeding half the Dirac charge are excluded in all samples and limits are placed for the first time on the production of magnetic monopoles in 13 TeV pp collisions. The search probes mass ranges previously inaccessible to collider experiments for up to five times the Dirac charge.
The MoEDAL trapping detector consists of approximately 800 kg of aluminum volumes. It was exposed during run 2 of the LHC program to 6.46 fb^{-1} of 13 TeV proton-proton collisions at the LHCb ...interaction point. Evidence for dyons (particles with electric and magnetic charge) captured in the trapping detector was sought by passing the aluminum volumes comprising the detector through a superconducting quantum interference device (SQUID) magnetometer. The presence of a trapped dyon would be signaled by a persistent current induced in the SQUID magnetometer. On the basis of a Drell-Yan production model, we exclude dyons with a magnetic charge ranging up to five Dirac charges (5g_{D}) and an electric charge up to 200 times the fundamental electric charge for mass limits in the range 870-3120 GeV and also monopoles with magnetic charge up to and including 5g_{D} with mass limits in the range 870-2040 GeV.
The unified linear variant of the general mathematical description of stability conditions for a girder with a bluff cross-section under the influence of wind flow is presented. A double ...degree-of-freedom model for the heave and pitch self-excited motion is used. The properties of the response located at the stability limits and the tendencies of the response in their vicinity are analyzed by means of the Routh–Hurwitz theorem. The respective stability conditions are depicted in the frequency plane delimited by the frequencies of two principal aero-elastic modes. Conditions for flutter onset and divergence are identified as special cases of the general theory. The results can be used as an explanation of several experimentally observed effects. The application of this method to real bridges is presented and compared with existing results from other approaches.
► Linear variant description of aeroelastic stability of bluff cross-sections is presented. ► Stability conditions are analyzed in frequency plane delimited by principal aero-elastic modes. ► The flutter and divergence conditions are identified as special cases of general description. ► Results can be used as phenomenological explanation of several experimentally observed effects. ► Application of this method to real bridges is presented and compared with other approaches.
A
bstract
The MoEDAL experiment is designed to search for magnetic monopoles and other highly-ionising particles produced in high-energy collisions at the LHC. The largely passive MoEDAL detector, ...deployed at Interaction Point 8 on the LHC ring, relies on two dedicated direct detection techniques. The first technique is based on stacks of nucleartrack detectors with surface area ~18m
2
, sensitive to particle ionisation exceeding a high threshold. These detectors are analysed offline by optical scanning microscopes. The second technique is based on the trapping of charged particles in an array of roughly 800 kg of aluminium samples. These samples are monitored offline for the presence of trapped magnetic charge at a remote superconducting magnetometer facility. We present here the results of a search for magnetic monopoles using a 160 kg prototype MoEDAL trapping detector exposed to 8TeV proton-proton collisions at the LHC, for an integrated luminosity of 0.75 fb
–1
. No magnetic charge exceeding 0:5
g
D
(where
g
D
is the Dirac magnetic charge) is measured in any of the exposed samples, allowing limits to be placed on monopole production in the mass range 100 GeV≤ m ≤ 3500 GeV. Model-independent cross-section limits are presented in fiducial regions of monopole energy and direction for 1
g
D
≤ |
g
| ≤ 6
g
D
, and model-dependent cross-section limits are obtained for Drell-Yan pair production of spin-1/2 and spin-0 monopoles for 1
g
D
≤ |
g
| ≤ 4
g
D
. Under the assumption of Drell-Yan cross sections, mass limits are derived for |
g
| = 2
g
D
and |
g
| = 3
g
D
for the first time at the LHC, surpassing the results from previous collider experiments.
Data acquisition and processing software package for Medipix2 Holy, T.; Jakubek, J.; Pospisil, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2006, Letnik:
563, Številka:
1
Journal Article
Recenzirano
The semiconductor pixel detector Medipix2 1 (256×256 square pixels, 55×55
μm
2 each) is a superior imaging device in terms of spatial resolution, linearity and dynamic range. This makes it suitable ...for various applications such as radiography, neutronography, and micro–tomography. The software package for acquisition and data processing has been developed to control and manage complex measurements. The solution features an open and very flexible modular architecture with custom made plugin support. Plugins can control parts of the acquisition system as well as perform real-time data processing and use these results as feedback for controlling further steps of measurements. This allows us to control, e.g. data acquisition, position and rotation of the sample (stepper motors), source parameters, temperature, etc. in a synchronized way. An example is the adaptive tomography plugin which adaptively controls the measurement and benefits from preprocessing performed by other plugins such as the beam-hardening correction of measured projections.
Thermal neutron measurements by Timepix detector in H4IRRAD at CERN Biskup, B.; Brugger, M.; Calviani, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2019, Letnik:
944
Journal Article
Recenzirano
Timepix, a pixel detector, was installed in the H4IRRAD irradiation area at CERN to study its response to a mixed radiation field. The measured data were compared to Monte Carlo simulations performed ...by the FLUKA code. This paper focuses on thermal neutron fluence measurement and simulation studies. The observed disagreement between the measured and simulated thermal neutron fluence of a factor 2.6 is discussed and the influence of the shielding material composition on this disagreement is studied.
This paper presents the results of in-orbit commissioning of the first Czech technological CubeSat satellite of VZLUSAT-1. The 2U nanosatellite was designed and built during the 2013 to 2016 period. ...It was successfully launched into Low Earth Orbit of 505 km altitude on June 23, 2017 as part of international mission QB50 onboard a PSLV C38 launch vehicle. The satellite was developed in the Czech Republic by the Czech Aerospace Research Centre, in cooperation with Czech industrial partners and universities. The nanosatellite has three main payloads. The housing is made of a composite material which serves as a structural and radiation shielding material. A novel miniaturized X-Ray telescope with lobster-eye optics and an embedded Timepix detector represents the CubeSat’s scientific payload. The telescope has a wide field of view. VZLUSAT-1 also carries the FIPEX scientific instrument as part of the QB50 mission for measuring the molecular and atomic oxygen concentration in the upper atmosphere.
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