Search results for "argon"
showing 10 items of 250 documents
Drift Time Measurement in the ATLAS Liquid Argon Electromagnetic Calorimeter using Cosmic Muons
2010
The ionization signals in the liquid argon of the ATLAS electromagnetic calorimeter are studied in detail using cosmic muons. In particular, the drift time of the ionization electrons is measured and used to assess the intrinsic uniformity of the calorimeter gaps and estimate its impact on the constant term of the energy resolution. The drift times of electrons in the cells of the second layer of the calorimeter are uniform at the level of 1.3% in the barrel and 2.8% in the endcaps. This leads to an estimated contribution to the constant term of (0.29-0.04+0.05)% in the barrel and (0.54-0.04+0.06)% in the endcaps. The same data are used to measure the drift velocity of ionization electrons …
The B 1Pi state of NaCs: high resolution laser induced fluorescence spectroscopy and potential construction.
2007
The lowest (1)Pi state of the NaCs molecule, the B(1)(1)Pi state, was studied using a dye laser for inducing fluorescence that was resolved by a high resolution Fourier-transform spectrometer. The presence of argon buffer gas yielded rich rotational relaxation spectra allowing to enlarge the data set for the B(1)(1)Pi state, to obtain Lambda-splittings and to reveal numerous local perturbations. 543 weakly perturbed energy levels for rotational quantum numbers from J(')=5 to 168 and vibrational quantum numbers from v(')=0 to 25, which cover about 87% of the potential well depth, were used for a direct pointwise fit of the potential energy curve applying the inverted perturbation approach me…
Measurement of the n-TOF beam profile with a micromegas detector
2004
A Micromegas detector was used in the neutron Time-Of-Flight (n_TOF) facility at CERN to evaluate the spatial distribution of the neutron beam as a function of its kinetic energy. This was achieved over a large range of neutron energies by using two complementary processes: at low energy by capture of a neutron via the 6Li(n,[alpha])t reaction, and at high energy by elastic scattering of neutrons on gas nuclei (argon+isobutane or helium+isobutane). Data are compared to Monte Carlo simulations and an analytic function fitting the beam profile has been calculated with a sufficient precision to use in neutron capture experiments at the n_TOF facility. http://www.sciencedirect.com/science/artic…
Experimental Stark broadening studies of the CI transition 3s 1 P 1o − 3p 1 S 0 at 833.5 nm
2011
AbstractExperimental Stark broadening studies of the infrared CI transition 3s 1 P 1o − 3p 1 S 0 at 833.5 nm are reported for the first time. A high-current wall-stabilized arc, operated in a mixture of helium, argon, carbon dioxide and hydrogen, was applied as the plasma source. Radiation emitted from homogeneous and optically thin plasma layers was analyzed. Stark broadening studies of the selected CI transition and the hydrogen Balmer β line were performed. As expected from theoretical considerations, the CI line width depends linearly on the electron density of the plasma. Applying theoretical Stark broadening data for the Hgb line, the measured Stark widths of the CI line were calibrat…
ag) Push-and-pull enteroscopy in the small bowel using the double-balloon technique: results of a prospective European multicenter study.
2005
BACKGROUND AND STUDY AIMS The aim of this study was to evaluate the feasibility, safety, and clinical impact of push-and-pull enteroscopy (PPE) in patients with suspected or documented small-bowel diseases, in a prospective multicenter trial in three European medical centers. PATIENTS AND METHODS A total of 100 patients (mean age 56 +/- 16 years; range 13 - 90) were included at the three institutions between July and November 2004. The leading symptoms were: acute recurrent or chronic gastrointestinal bleeding (n = 64), polyposis syndrome (n = 8), chronic abdominal pain (n = 7), chronic diarrhea (n = 7), and others (n = 14). RESULTS No major PPE-associated complications such as perforation,…
Long-term outcome after argon plasma coagulation of small-bowel lesions using double-balloon enteroscopy in patients with mid-gastrointestinal bleedi…
2011
BACKGROUND AND STUDY AIMS Vascular malformations are the most common sources of bleeding in the small bowel. They can be treated with argon plasma coagulation (APC) during double-balloon enteroscopy (DBE). This study aimed to evaluate the long-term follow-up of the effectiveness of APC for small-bowel bleeding by means of a single-center retrospective study. PATIENTS AND METHODS Between June 2003 and December 2005, APC treatment for small-bowel lesions was carried out during DBE in 63 patients with known or suspected mid-gastrointestinal bleeding. Fifty patients were included in the analysis. Main outcome measurements were comparison of hemoglobin values and blood transfusion requirements b…
Stability criteria, atomization and non-thermal processes in liquids
2008
Analyzing the first equation in the BBGKY chain of equations for an equilibrium liquid-gas system, we derived the analytical expression for the atom work function from liquid into gas. The coupling between the atom work function from liquid into vacuum and the stability criterion of liquid in limiting points of the first type was shown (using I.Z.. Fisher classification). As it turned out, Fisher's criterion corresponds to the condition of atomization. We have expressed the state equation in terms of the atom work function from liquid into vacuum and performed calculations of the limiting line of stability composed of limiting points of the first type for argon. Our model discovers an inter…
Ultraplānu bismuta selenīda nanostruktūru iegūšanas metodes
2017
Ultraplānu bismuta selenīda nanostruktūru iegūšanas metodes. Biezā K., zinātniskie vadītāji - asoc. prof., Dr. ķīm., Donāts Erts, Dr. Jana Andžāne, Maģistra darbs, 49 lappuses, 25 attēli, 9 tabulas, 30 literatūras avoti, 5 pielikumi. Latviešu valodā. Bismuta selenīds ir topoloģiskais izolators, tas ir materiāls, kura lielākā daļa tilpumā ir dielektriķis, toties ārējā virsma ir vadoša. Topoloģisko īpašību uzlabošanai un tālākam praktiskajam pielietojumam svarīgi iegūt plānas nanostruktūras ar biezumu zem 10 nm, kam, savukārt, ir liela praktiska nozīme topoloģisko izolatoru fundamentālajos pētījumos un materiāla pielietojumam kā termoelektriķim. Darbā pielietotas vairākas metodes, lai iegūtu …
Phase boundary dynamics of bubble flow in a thick liquid metal layer under an applied magnetic field
2020
Dynamic neutron radiography is used to observe the effect of a transverse magnetic field on argon bubbles rising through a thick layer of liquid gallium without interactions with the container walls.
Drift velocity of free electrons in liquid argon
1999
Abstract A measurement of the drift velocity of free electrons in liquid argon has been performed. Free electrons have been produced by photoelectric effect using laser light in a so-called “laser chamber”. The results on the drift velocity vd are given as a function of the electric field strength in the range 0.5 kV / cm ⩽| E |⩽12.6 kV / cm and the temperature in the range 87 K ⩽T⩽94 K . A global parametrization of v d (| E |,T) has been fitted to the data. A temperature dependence of the electron drift velocity is observed, with a mean value of Δ v d /( Δ T v d )=(−1.72±0.08)%/ K in the range of 87–94 K.