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61.
U. Werling Wan Chong-Yi K. F. Renk 《International Journal of Infrared and Millimeter Waves》1985,6(6):449-457
The tuning characteristics of a uv preionized 20-atmospheres gas discharge CO2 laser with a novel and simple preionization scheme have been investigated. Continuous tunability in all branches of the 9.4 m and 10.4 m band with a total tuning range of more than 60 cm–1 without frequency pulling is demonstrated. Additionally, a study of the laser pulse behaviour was performed. 相似文献
62.
T. Tillert P. Zimnas K. F. Renk 《International Journal of Infrared and Millimeter Waves》1996,17(6):1011-1021
Using a continously tunable pulsed 20-atmosphere CO2 laser as a pump source, we generated pulses of mid-infrared radiation, partly tunable in frequency intervals in the range between 200 and 900 cm–1 via stimulated Raman scattering in gaseous ammonia. As a Raman cell we used a multiple pass cell. We observed for14NH3 and15NH3 laser lines at 52 different frequencies with 39 lines observed for the first time. Tuning ranges up to 150 GHz and peak powers of several MW were achieved. The quantum efficiency reached 40 %. 相似文献
63.
L. Bertanza A. Bigi P. Calafiura M. Calvetti R. Carosi M. C. Carrozza R. Casali C. Cerri R. Fantechi I. Mannelli V. M. Marzulli A. Nappi G. M. Pierazzini L. Tassi G. D. Barr P. Buchholz D. Coward D. Cundy N. Doble L. Gatignon P. Grafström R. Hagelberg H. Wahl K. J. Peach T. Beier H. Blümer R. Heinz K. Kleinknecht B. Panzer-Steinde B. Renk H. Rohrer J. Scheidt J. Staeck A. Wagner E. Augé D. Fournier L. Iconomidou-Fayard O. Perdereau A. C. Schaffer L. Serin M. Holder A. Kreutz R. Werthenbach 《Zeitschrift fur Physik C Particles and Fields》1997,73(4):629-632
A precision measurement of the K S mean lifetime has been performed by comparing, in the same experimental setup, the distributions of two-pion decays of neutral kaons produced by high energy proton-beryllium interactions in two targets at a relative distance variable between 112 and 160 m. The value obtained combining the results from π+π? and π0π0 decays is τs = (0.8971 ± 0.0021) 10?10 s. 相似文献
64.
The NA60 experiment has measured low mass muon pair production in In-In collisions at 158A GeV with unprecedented precision. We show that these data are reproduced very well by a dynamical model with parameters scaled from fits to measurements of hadronic transverse mass spectra and Hanbury Brown-Twiss correlations in Pb-Pb and Pb-Au collisions at the same energy. The data are consistent with in-medium properties of rho and omega mesons at finite temperature and density as deduced from empirical forward-scattering amplitudes. Inclusion of the vacuum decay of the rho meson after freeze-out is necessary for an understanding of the mass and transverse momentum spectrum of dimuons with M less similar 0.9 GeV/c(2). 相似文献
65.
P. T. Lang I. Leipold W. J. Knott A. D. Semenov G. N. Gol'tsman K. F. Renk 《Applied physics. B, Lasers and optics》1991,53(4):207-212
In this paper we report on the detection of new far-infrared laser lines from CH3Cl and CH3Br optically pumped with a continuously tunable high pressure CO2 laser. We found 80 new lines for CH3Cl and 9 new lines for CH3Br in the frequency region between 16 cm–1 and 41 cm–1, all due to stimulated Raman scattering. For the Raman gain regions bandwidths up to about 700 MHz were found. We also observed high intensity short far-infrared laser pulses of durations in the nanosecond regime.Permanent address: Physics Department, State Pedagogical University, SU-119435 Moscow, USSR 相似文献
66.
Anatoly A. Ignatov E. Schomburg J. Grenzer K. F. Renk E. P. Dodin 《Zeitschrift für Physik B Condensed Matter》1995,98(2):187-195
We report on a theoretical analysis of terahertz (THz-) field induced nonlinear dynamics of electrons in a semiconductor superlattice that are capable to perform Bloch oscillations. Our results suggest that for a strong THz-field a dc voltage should be generated. We have analyzed the real-time dynamics using a balance equation approach to describe the electron transport in a superlattice miniband. Taking account of both Bloch oscillations of electrons in a superlattice miniband and dissipation, we studied the influence of a strong THz-field on currently available superlattices at room temperature. We found that a THz-field can lead to a negative conductance resulting in turn in a THz-field induced dc voltage, and that the voltage per superlattice period should show, for varying amplitue of the THz-field, a form of wisted plateaus with the middle points being with high precision equal to the photon energy divided by the electron charge. We show voltage to the finite voltage state, and that in the finite voltage state dynamic localization of the electrons in a miniband occurs. 相似文献
67.
H. Abramowicz G. Hansl-Kozanecki J. May P. Palazzi A. Para F. Ranjard A. Savoy-Navarro D. Schlatter J. Steinberger H. Taureg W. von Rüden H. Wahl S. Whitaker J. Wotschack H. Blümer P. Buchholz J. Duda F. Eisele K. Kleinknecht J. Knobloch H. Lierl B. Pszola B. Renk F. Dydak J. G. H. de Groot T. Flottmann C. Geweniger V. Hepp J. Królikowski K. Tittel P. Debu C. Guyot J. P. Merlo P. Perez B. Peyaud J. Rander J. P. Schuller R. Turlay 《Zeitschrift fur Physik C Particles and Fields》1984,25(1):29-43
The CDHS neutrino detector has been used to measure events originating in a tank of liquid hydrogen and in the iron of the detector. Total cross-sections, differential cross-sections, and structure functions are given for hydrogen and compared with those in iron. The measurements are in agreement with the expectations of the quark parton model. No significant differences indicative of nuclear binding effects in corresponding structure functions of protons and iron are observed. This may be of special interest in the case of the sea structure functions, since large differences are expected in some models. 相似文献
68.
69.
Redox-Studies on lodoboranes. XVI. Formation of Boron-Carbon Compounds: 1,2,5-Thiadiborolene, Cyano- and Phenylethynylboranes The redox reaction of 3-iodo-4-dijodborylhexen-3 mit Trijodborthiin leads in 46% yield to the diiodo derivative of 1,2,5-thiadiborolene. Some of the properties of this new heterocyclic compound are reported. Redox reactions of iodoboranes with iodocyan and phenyliodoacetylene yield under elimination of iodine cyano- and phenylethynylboranes. 相似文献
70.
The NA60 experiment has studied low-mass muon pair production in In–In collisions at 158 A GeV with unprecedented precision. With these results there is hope that the in-medium modifications of the vector meson spectral
function can be constrained more thoroughly than before. We investigate in particular what can be learned about collisional
broadening by a hot and dense medium and what constraints the experimental results put on in-medium mass shift scenarios.
The data show a clear indication of considerable in-medium broadening effects but disfavor mass shift scenarios where the
ρ-meson mass scales with the square root of the chiral condensate. Scaling scenarios which predict at finite density a dropping
of the ρ-meson mass that is stronger than that of the quark condensate are clearly ruled out since they are also accompanied
by a sharpening of the spectral function.
PACS 25.75.-q 相似文献