Oštećenja u aluminiju proizvedena zračenjem iz CO2 i Nd:YAG lasera

The change in the electrical properties of pure aluminium (Al 99.999%) after exposure to CO2 (energy = 2.5 J/pulse, wavelength = 10.6 µm, pulse duration = 200 nsec) and Nd:YAG (energy = 10 mJ/pulse, wavelength = 1.06 µm and pulse duration = 12 nsec) laser radiation is investigated. The samples were exposed to laser radiations for different numbers of pulses. The change in electrical characteristics of Al is studied under different ambient conditions, after irradiating the samples in air, vacuum and hydrogen at different pressures. After exposure, the electrical conductivity of Al is measured by the four probe method. The electrical conductivity decreases with increasing number of pulses. The damage in air and in hydrogen is more pronounced than in vacuum which can be attributed to collisionnal sputtering of Al by plasma ions of air molecules and hydrogen, respectively. The change in the conductivity in hydrogen is pressure-dependent. Some theoretical considerations are also made, e.g. the phonon speed in Al during the photon interaction, minimal melting and evaporation energy per volume, damage threshold energy, penetration depth, the mass of heated volume and average temperature rise at the Al surface during laser irradiation.Proučavamo promjene električnih svojstava čistog aluminija (Al 99.999%) nakon obasjavanja CO2 (energija = 2.5 J/puls, valna duljina = 10.6 µm, trajanje pulsa = 200 nsec) i Nd:YAG (energija = 10 mJ/puls, valna duljina = 1.06 µm, trajanje pulsa = 12 nsec) laserima. Uzorci su izloženi različitim brojevima pulseva. Proučavali smo promjene električne vodljivosti Al s uzorcima u zraku, vakuumu i u vodiku. Nakon obasjavanja mjerili smo električnu vodljivost metodom četiriju spojišta. Električna se vodljivost smanjuje nakon povećanog broja pulseva. Oštećenja u zraku i vodiku veća su nego u vakuumu, što se pripisuje sudarnom rasprašivanju Al ionima molekula zraka odnosno vodika u plazmi. Promjena vodljivosti uzoraka obasjanih u vodiku ovisna je o tlaku. Razmotrili smo neke teorijske rezultate, npr. fononsku brzinu u Al tijekom obasjavanja, minimalnu energiju taljenja i isparavanja po jedinici volumena, energijski prag oštećenja, dubinu prodiranja, masu zagrijanog volumena i prosječno povećanje temperature površine Al tijekom obasjavanja

Oštećenja u aluminiju proizvedena zračenjem iz CO2 i Nd:YAG lasera

The change in the electrical properties of pure aluminium (Al 99.999%) after exposure to CO2 (energy = 2.5 J/pulse, wavelength = 10.6 µm, pulse duration = 200 nsec) and Nd:YAG (energy = 10 mJ/pulse, wavelength = 1.06 µm and pulse duration = 12 nsec) laser radiation is investigated. The samples were exposed to laser radiations for different numbers of pulses. The change in electrical characteristics of Al is studied under different ambient conditions, after irradiating the samples in air, vacuum and hydrogen at different pressures. After exposure, the electrical conductivity of Al is measured by the four probe method. The electrical conductivity decreases with increasing number of pulses. The damage in air and in hydrogen is more pronounced than in vacuum which can be attributed to collisionnal sputtering of Al by plasma ions of air molecules and hydrogen, respectively. The change in the conductivity in hydrogen is pressure-dependent. Some theoretical considerations are also made, e.g. the phonon speed in Al during the photon interaction, minimal melting and evaporation energy per volume, damage threshold energy, penetration depth, the mass of heated volume and average temperature rise at the Al surface during laser irradiation.Proučavamo promjene električnih svojstava čistog aluminija (Al 99.999%) nakon obasjavanja CO2 (energija = 2.5 J/puls, valna duljina = 10.6 µm, trajanje pulsa = 200 nsec) i Nd:YAG (energija = 10 mJ/puls, valna duljina = 1.06 µm, trajanje pulsa = 12 nsec) laserima. Uzorci su izloženi različitim brojevima pulseva. Proučavali smo promjene električne vodljivosti Al s uzorcima u zraku, vakuumu i u vodiku. Nakon obasjavanja mjerili smo električnu vodljivost metodom četiriju spojišta. Električna se vodljivost smanjuje nakon povećanog broja pulseva. Oštećenja u zraku i vodiku veća su nego u vakuumu, što se pripisuje sudarnom rasprašivanju Al ionima molekula zraka odnosno vodika u plazmi. Promjena vodljivosti uzoraka obasjanih u vodiku ovisna je o tlaku. Razmotrili smo neke teorijske rezultate, npr. fononsku brzinu u Al tijekom obasjavanja, minimalnu energiju taljenja i isparavanja po jedinici volumena, energijski prag oštećenja, dubinu prodiranja, masu zagrijanog volumena i prosječno povećanje temperature površine Al tijekom obasjavanja

MICE: the Muon Ionization Cooling Experiment. Step I: First Measurement of Emittance with Particle Physics Detectors

The Muon Ionization Cooling Experiment (MICE) is a strategic R&D project intended to demonstrate the only practical solution to providing high brilliance beams necessary for a neutrino factory or muon collider. MICE is under development at the Rutherford Appleton Laboratory (RAL) in the United Kingdom. It comprises a dedicated beamline to generate a range of input muon emittances and momenta, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. The emittance of the incoming beam will be measured in the upstream magnetic spectrometer with a scintillating fiber tracker. A cooling cell will then follow, alternating energy loss in Liquid Hydrogen (LH2) absorbers to RF cavity acceleration. A second spectrometer, identical to the first, and a second muon identification system will measure the outgoing emittance. In the 2010 run at RAL the muon beamline and most detectors were fully commissioned and a first measurement of the emittance of the muon beam with particle physics (time-of-flight) detectors was performed. The analysis of these data was recently completed and is discussed in this paper. Future steps for MICE, where beam emittance and emittance reduction (cooling) are to be measured with greater accuracy, are also presented

The design, construction and performance of the MICE scintillating fibre trackers

This is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2011 ElsevierCharged-particle tracking in the international Muon Ionisation Cooling Experiment (MICE) will be performed using two solenoidal spectrometers, each instrumented with a tracking detector based on diameter scintillating fibres. The design and construction of the trackers is described along with the quality-assurance procedures, photon-detection system, readout electronics, reconstruction and simulation software and the data-acquisition system. Finally, the performance of the MICE tracker, determined using cosmic rays, is presented.This work was supported by the Science and Technology Facilities Council under grant numbers PP/E003214/1, PP/E000479/1, PP/E000509/1, PP/E000444/1, and through SLAs with STFC-supported laboratories. This work was also supportedby the Fermi National Accelerator Laboratory, which is operated by the Fermi Research Alliance, under contract No. DE-AC02-76CH03000 with the U.S. Department of Energy, and by the U.S. National Science Foundation under grants PHY-0301737,PHY-0521313, PHY-0758173 and PHY-0630052. The authors also acknowledge the support of the World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan

MICE: The muon ionization cooling experiment. Step I: First measurement of emittance with particle physics detectors

Copyright @ 2011 APSThe Muon Ionization Cooling Experiment (MICE) is a strategic R&D project intended to demonstrate the only practical solution to providing high brilliance beams necessary for a neutrino factory or muon collider. MICE is under development at the Rutherford Appleton Laboratory (RAL) in the United Kingdom. It comprises a dedicated beamline to generate a range of input muon emittances and momenta, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. The emittance of the incoming beam will be measured in the upstream magnetic spectrometer with a scintillating fiber tracker. A cooling cell will then follow, alternating energy loss in Liquid Hydrogen (LH2) absorbers to RF cavity acceleration. A second spectrometer, identical to the first, and a second muon identification system will measure the outgoing emittance. In the 2010 run at RAL the muon beamline and most detectors were fully commissioned and a first measurement of the emittance of the muon beam with particle physics (time-of-flight) detectors was performed. The analysis of these data was recently completed and is discussed in this paper. Future steps for MICE, where beam emittance and emittance reduction (cooling) are to be measured with greater accuracy, are also presented.This work was supported by NSF grant PHY-0842798

CMS physics technical design report : Addendum on high density QCD with heavy ions

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First Dark Matter Search Results from the LUX-ZEPLIN (LZ) Experiment

The LUX-ZEPLIN (LZ) experiment is a dark matter detector centered on a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility in Lead, South Dakota, USA. This Letter reports results from LZ's first search for Weakly Interacting Massive Particles (WIMPs) with an exposure of 60 live days using a fiducial mass of 5.5 t. A profile-likelihood ratio analysis shows the data to be consistent with a background-only hypothesis, setting new limits on spin-independent WIMP-nucleon, spin-dependent WIMP-neutron, and spin-dependent WIMP-proton cross-sections for WIMP masses above 9 GeV/c$^2$. The most stringent limit is set at 30 GeV/c$^2$, excluding cross sections above 5.9$\times 10^{-48}$ cm$^2$ at the 90\% confidence level.Comment: 9 pages, 6 figures. See https://tinyurl.com/LZDataReleaseRun1 for a data release related to this pape