共查询到20条相似文献,搜索用时 31 毫秒
1.
X. Aslanoglou M.N. Bakirci S. Cerci A. Cyz D. d’Enterria E. Gladysz-Dziadus L. Gouskos A. Ivashkin C. Kalfas P. Katsas A. Kuznetsov Y. Musienko A.D. Panagiotou E. Vlasov 《The European Physical Journal C - Particles and Fields》2007,52(2):495-506
We present results of the performance of the second prototype of the CASTOR quartz–tungsten sampling calorimeter, to be installed
in the very forward region of the CMS experiment at the LHC. The energy linearity and resolution, as well as the spatial resolution
of the prototype to electromagnetic and hadronic showers are studied with E=20–200 GeV electrons, E=20–350 GeV pions, and
E=50, 150 GeV muons from beam tests carried out at CERN/SPS in 2004. The responses of the calorimeter using two different
types of photodetectors (avalanche photodiodes APDs, and photomultiplier tubes PMTs) are compared. 相似文献
2.
V. Batusov J. Budagov J. C. Gayde J. Khubua C. Lasseur M. Lyablin N. Russakovich A. Sissakian N. Topilin 《Physics of Particles and Nuclei Letters》2007,4(1):92-95
The influence of a turbulent air medium on a laser beam space localization precision was studied experimentally. For a helium-neon
one-mode laser LGN-302 and for a solid-state multimode laser DS-670, the laser ray coordinate measurement uncertainties were
determined with 1 m step for the distances up to 9 m from the laser source. It was found that the σ values at 9 m distance
are equal to σ(DS-670) = 21 μm and σ(LGN-302) = 12 μm. To reduce the turbulent air medium influence on the laser ray space
localization precision, the laser beam was positioned inside a heat-isolating tube. Very significant decrease of σ values
was achieved at 9 m from the source: σ*(DS-670) = 2 μm and σ*(LGN-302) = 2.5 μm. The work is made within a framework of a
preparation to the creation of a high-precision large-distance laser metrology to be possibly used for long linear collider
component alignment.
The text was submitted by the authors in English.
On leave from the Institute of High Energy Physics and Informatization, Tbilisi, Georgia. 相似文献
3.
V. A. Bezzubov I. A. Vasil’ev V. N. Goryachev S. P. Denisov V. N. Evdokimov S. V. Erin A. V. Kozelov A. V. Levin V. V. Lipaev D. A. Stoyanova A. A. Shchukin 《Physics of Particles and Nuclei》2018,49(1):17-20
In this work, the results of the measurements of characteristics of 40-cm and 2-m scintillation counters irradiated by a particle beam with a momentum of 7 GeV/c from the accelerator of the Institute for High Energy Physics are presented. The scintillators used in counters are BC-404 and BC-408 scintillators. The counters are viewed from both ends by R1828-01 photomultiplier tubes. The PMT signal spectra are well described by a convolution of the Landau and Gaussian distributions. Their width is determined mainly by fluctuations of ionization energy losses. The time distributions of the signals obey the Gaussian law. For the 40-cm counter, the time resolution is σ(T) = 88 ps; for the 2-m counter, it varies from 120–160 ps in its center to ~100 ps near the end. 相似文献
4.
A. M. Galper S. V. Borisov V. G. Zverev C. I. Suchkov N. P. Topchiev M. O. Farber M. I. Fradkin Yu. T. Yurkin 《Bulletin of the Lebedev Physics Institute》2011,38(7):191-197
When designing devices of modern gamma astronomy, one of the most important problems is achieving the maximum possible angular
resolution. This study is devoted to the method for reconstructing the arrival direction of primary gamma-rays with energies
E
γ > 10 GeV in the GAMMA-400 satellite experiment. By the example of the GAMMA-400 gamma telescope, the possibility of improving
the angular resolution of gamma telescopes incorporating a “converter + calorimeter” system is shown. The dependence of the
angular resolution on the step of silicon strips used to determine the coordinates of incident particles in the converter
and calorimeter and the distance between the converter and calorimeter is analyzed. 相似文献
5.
In the detectors currently being developed for experiments on the next-generation lepton colliders, highly granular calorimeters are to be used. In particular, the hadron calorimeter is planned to be assembled from scintillation cells with direct readout of light by silicon photomultipliers. According to the results of experimental measurements of the light collection in a cell developed for the CALICE prototype hadron calorimeter, when detecting minimum ionizing particles, an estimate of the detector effects was obtained. The detector effect on the resolution of the ILD hadron calorimeter was studied by modeling the response of the detector to single neutral kaons. It was shown that the contribution of experimentally measured detector effects to the resolution for single particles is on the order of 0.5–1% in the range of hadron energy of 5–60 GeV. 相似文献
6.
I. F. Larin 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(10):1481-1486
The main parameters and technical features of the PrimEx experiment conducting in Jefferson Lab (USA) are presented. One of
the main parts of the PrimEx setup-electromagnetic calorimeter is described in details. Value of π0 meson decay width into two γ-quanta, obtained from PrimEx 2004 year data is Γ(πo → 2γ) = 7.82 eV 2.2% (stat.) 2.1% (syst.) 相似文献
7.
K. G. Trouni V. R. Kocharyan G. R. Grigoryan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2012,47(2):87-92
The problem of Borrmann absorption (anomalous absorption) of X-rays in weakly deformed crystals is considered on the basis
of Takagi’s approach to the dynamical theory. Using wave function considerations, the attenuation of rays is represented by
exp(−σl) where the attenuation factor σ includes a parameter of the lattice deformation field. The possibility of cases σ = 0 and
even σ < 0 is discussed. 相似文献
8.
S. Ba?e?mez D. d’ Enterria L. Gouskos I. Katkov P. Katsas L. Khein for the CMS collaboration 《Indian Journal of Physics》2010,84(12):1689-1693
We present preliminary results of the performance of prototype III of the CASTOR quartz-tungsten sampling calorimeter, to
be installed in the very forward region of the CMS experiment at the LHC. The energy linearity and resolution, as well as
the spatial resolution of the prototype to electromagnetic and hadronic showers are studied with E= 10−200 GeV electrons,
E= 20−350 GeV pions, and E= 50, 150 GeV muons in beam tests carried out at CERN/SPS in 2007. 相似文献
9.
K. Uzelac Z. Glumac O. S. Barišić 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,63(1):101-108
We present numerical investigations of the short-time dynamics at criticality in the 1D Potts model with power-law decaying
interactions of the form 1/r1+σ. The scaling properties of the magnetization, autocorrelation function and time correlations of the magnetization are studied.
The dynamical critical exponents θ' and z are derived in the cases q=2 and q=3 for several values of the parameter σ belonging
to the nontrivial critical regime. 相似文献
10.
This paper is concerned with properties of the wave speed for the stochastically perturbed Fisher–Kolmogorov–Petrovsky–Piscunov
(FKPP) equation. It was shown in the classical 1937 paper by Kolmogorov, Petrovsky and Piscunov that the large time behavior
of the solution to the FKPP equation with Heaviside initial data is a travelling wave. In a seminal 1995 paper Mueller and
Sowers proved that this also holds for a stochastically perturbed FKPP equation. The wave speed depends on the strength σ
of the noise. In this paper bounds on the asymptotic behavior of the wave speed c(σ) as σ→0 and σ→∞ are obtained. 相似文献
11.
V. V. Varlamov B. S. Ishkhanov V. N. Orlin V. A. Chetvertkova 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(6):833-841
A combined analysis of experimental data on total and partial photoneutron reaction cross sections, obtained using bremsstrahlung
γ-radiation and quasi-monoenergetic annihilation photon beams, was performed for nine Sn isotopes. The partial reactions σeval(γ, nX) and σeval(γ, 2nX) cross sections were evaluated using an approach free of the shortcomings of experimental neutron multiplicity sorting methods.
This approach involves calculations within the photonuclear reaction model, based on Fermi gas densities and considering the
effects of nucleus deformation, the isospin splitting of its giant dipole resonance (GDR), and experimental data on the total
photoneutron cross sections σexp(γ, xn) = σexp(γ, nX) + 2σexp(γ, 2nX) = σexp(γ, n) + σexp(γ, np) + … + 2σexp(γ, 2n) + 2σexp(γ, 2np) + …. The evaluated σeval(γ, nX) and σeval(γ, 2nX) reactions cross sections were obtained using the introduced transition multiplicity functions F
theor = σtheor(γ, 2nX)/σtheor(γ, xn) = σtheor(γ, 2nX)/[σtheor(γ, nX) + 2σtheor(γ, 2nX) + …]; and σeval.(γ, 2nX) = F
theor.σexp.(γ, xn) = σeval(γ, nX) = (1 − 2F
theor)σexp(γ, xn). The evaluated partial reaction cross sections were used to assess the total photoneutron reaction cross sections σeval(γ, sn) = σeval(γ, nX) + σeval(γ, 2nX) + … as functions of the mass number A. The GDR features of 112, 114, 116, 117, 118, 119, 120, 122, 124Sn isotopes were studied and are discussed here. 相似文献
12.
Mark A. Thomson 《Pramana》2007,69(6):1101-1107
One of the most important requirements for a detector at the ILC is good jet energy resolution. It is widely believed that
the particle flow approach to calorimetry is the key to achieving the goal of 0.3/√E(GeV). This paper describes the current performance of the PandoraPFA particle flow algorithm. For 45 GeV jets in the Tesla TDR detector concept, the ILC jet energy resolution goal is reached.
At higher energies the jet energy resolution becomes worse and can be described by the empirical expression: σ
E
/E ≈ 0.265/√E(GeV) + 1.2 × 10−4
E(GeV).
相似文献
13.
In this work, the problem of separating the contribution of a strange quark to the proton spin in the process
is studied. Measurements of the quantities Δσ
K
and Δσ±, where Δσ
M
=dσ
M
(+ +) -dσ
M
(+ -) at small z, and the use of definite combinations of them allow important information on the proton-spin structure to
be obtained.
M. A. Rasulzade Baku State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 21–25, January,
2000. 相似文献
14.
V. V. Varlamov B. S. Ishkhanov V. N. Orlin S. Yu. Troshchiev 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(6):842-849
The results from experimental and theoretical studies of the total and partial cross sections of photoneutron reactions on
the 197Au isotope were analyzed. The cross sections for reactions σ(γ, nX) = σ(γ, n) + σ(γ, np) + … + σ(γ, 2nX) = σ(γ, 2n) + σ(γ, 2np) + … were evaluated in the energy range 7 ≤ E
γ ≤ 30 MeV using an approach free of the shortcomings of experimental photoneutron multiplicity sorting methods. The total
photoneutron reaction cross sections σexp(γ, xn) = σexp(γ, nX) + 2σexp(γ, 2nX) + … = σexp(γ, n) + σexp(γ, np) + 2σexp(γ, 2n) + 2σexp(γ, 2np) + … were used as the initial experimental data. The contributions from the cross sections σ(γ, nX) and σ(γ, 2nX) to the cross sections σexp(γ, xn) were separated using the multiplicity transition functions F
1
theor = σtheor(γ, 1nX)/σtheor(γ, xn) and F
2
theor = σtheor(γ, 2nX)/σtheor(γ, xn), calculated within an updated version of the pre-equilibrium model of photonuclear reactions. New evaluated data for both
partial reaction cross sections, i.e., σeval (γ, 1nX) = F
1
theorσexp(γ, xn) and σeval(γ, 2nX) = F
2
theorσexp(γ, xn), were obtained. The cross sections σeval(γ, nX) and σeval.(γ, 2nX) evaluated using the theoretically calculated functions F
1,2theor are consistent with the Livermore data, but substantially contradict the Saclay data. 相似文献
15.
V. E. Shebalin A. V. Anisenkov V. M. Aulchenko N. S. Bashtovoy D. A. Epifanov L. B. Epshteyn A. A. Grebenuk F. V. Ignatov A. L. Erofeev O. A. Kovalenko A. N. Kozyrev A. S. Kuzmin I. B. Logashenko K. Yu. Mikhailov G. P. Razuvaev A. A. Ruban B. A. Shwartz A. A. Talyshev V. M. Titov Yu. V. Yudin 《Physics of Atomic Nuclei》2015,78(13):1544-1551
The structure of the barrel calorimeter of the CMD-3 detector is presented in this work. The procedure of energy calibration of the calorimeter and the method of photon energy restoration are described. The distinctive feature of this barrel calorimeter is its combined structure; it is composed of two coaxial subsystems: a liquid xenon calorimeter and a crystalline CsI calorimeter. The calorimeter spatial resolution of the photon conversion point is about 2 mm, which corresponds to an angular resolution of ~6 mrad. The energy resolution of the calorimeter is about 8% for photons with energy of 200 MeV and 4% for photons with energy of 1 GeV. 相似文献
16.
A. Ozawa 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):163-167
Recent experimental results concerning interaction cross-sections ( σI) are reviewed. The σI values were measured by a transmission method using the fragment separator at GSI. The σI values for B, C, N, O and F isotopes and the recently measured σI for Ar are presented. As related topics, an analysis by the recently developed Glauber model for a few-body system is introduced.
By using this analysis, the effective density distributions for light neutron-rich nuclei can be deduced. The recently shown
magic number N = 16 near to the neutron drip line is also discussed.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
17.
M. Weis P. Bartsch D. Baumann J. Bermuth A. M. Bernstein K. Bohinc R. Böhm M. Ding M. O. Distler I. Ewald J. M. Friedrich J. Friedrich M. Kahrau M. Kohl K. W. Krygier A. Liesenfeld H. Merkel P. Merle U. Müller R. Neuhausen M. M. Pavan Th. Pospischil M. Potokar G. Rosner H. Schmieden M. Seimetz S. Širca A. Wagner Th. Walcher 《The European Physical Journal A - Hadrons and Nuclei》2008,38(1):27-33
The differential cross-sections σ0 = σT + εσL , σLT , and σTT of electroproduction from the proton were measured from threshold up to an additional center-of-mass energy of 40MeV, at a value
of the photon four-momentum transfer of Q
2 = 0.05 GeV2/c2 and a center-of-mass angle of θ = 90° . By an additional out-of-plane measurement with polarized electrons σLT' was determined. This showed for the first time the presence of an imaginary part of the s -wave above the threshold, which is usually interpreted as a unitary cusp. The predictions of the Heavy Baryon Chiral Perturbation Theory
(HBChPT) are in disagreement with these data. On the other hand, the data are somewhat better predicted by the MAID phenomenological
model and are in good agreement with the dynamical model DMT. 相似文献
18.
J.-P. Rieu Y. Sawada 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,27(1):167-172
Using a two dimensional experimental geometry, we study hydrodynamics and cell motion during the rounding-up of three kinds
of hydra aggregates (ectodermal, endodermal and mixed). The relaxation of initially elongated aggregates toward a circular shape is
exponential and the relaxation time is proportional to the aggregate size as expected from hydrodynamics laws. As for viscous
liquids, aggregate rounding is driven by tissue surface tensions σ and resisted by tissue viscosity η. The ratio η/σ is the
same for the three kinds of aggregates. With a reasonable value σ = 1 mN/m, we obtain an estimate larger than 104 Pa s for the tissue viscosity. Cell motion during rounding is strongly cooperative and cell displacements exhibit some specific
patterns in each aggregate. These results point out the role of adhesive bonds in the observed kinetics.
Received 21 December 2001 相似文献
19.
The fundamental properties of the AlN and GaN compounds with a wurtzite structure under external hydrostatic pressure, uniaxial
mechanical stress σ⊥ along the hexagonal axis, and biaxial mechanical stress σ⊥ in the basal plane of the unit cell have been considered in terms of first-principles calculations in the frame-work of the
density functional theory. The pressures of the phase transitions from the structures of wurtzite and zinc blende to the structure
of rock salt have been obtained. The behavior of the structural parameters, interband transitions, and positions of the charge
neutrality level has been investigated. The calculated pressure coefficients of the band gap are as follows: ∂E
g
/∂p = 40.9 meV/GPa, −∂E
g
/∂σ
| = −4.2 meV/GPa, and −∂E
g
/∂σ
⊥ = 45.2 meV/GPa for AlN and ∂E
g
/∂p = 33.0 meV/GPa, −∂E
g
/∂σ
| = 23.6 meV/GPa, and −∂E
g
/∂σ
⊥ = 9.6 meV/GPa for GaN. The pressure coefficients of the charge neutrality level in almost all cases are substantially smaller
than the corresponding values obtained for the band gap E
g
. 相似文献
20.
U. Siodlaczek P. Achenbach J. Ahrens H.-J. Arends R. Beck R. Bilger H. Clement V. Hejny J.D. Kellie M. Kotulla B. Krusche V. Kuhr R. Leukel J.C. McGeorge V. Metag R. Novotny V. Olmos de León F. Rambo M. Schepkin A. Schmidt H. Ströher G.J. Wagner Th. Walcher J. Weiß F. Wissmann M. Wolf 《The European Physical Journal A - Hadrons and Nuclei》2000,9(3):309-311
The reaction γd↦π0
X has been measured with TAPS at MAMI in the energy range E
γ = 140-300 MeV. Using the Glasgow tagging spectrometer a photon energy resolution of 0.8 MeV was achieved. The energy excitation
functions of integral and differential total cross-sections show no structures of statistical significance > 2σ. Upper limits
for the production of narrow isoscalar or isovector dibaryons with masses m? 2100 MeV/c2 were deduced. They are in the range 2-5 μb averaged over the 0.8 MeV energy resolution.
Received: 25 October 2000 / Accepted: 24 November 2000 相似文献