Barrier-discharge excilamp on a mixture of krypton and molecular bromine and chlorine

Spectral and energy characteristics of a barrier-discharge excilamp on a mixture of krypton with bromine and chlorine molecules that emits in the range 200–300 nm are presented. The radiation spectrum contains the bands of the B → X transitions of the KrCl* (222 nm) and KrBr* (207 nm) molecules and the band of the D′ → A′ transition of the Br*₂ molecule (291 nm). It is demonstrated that the bromine content must be higher than the chlorine content in the triple (Kr?Cl₂?Br₂) mixtures that are optimal with respect to the radiant power. A radiant power of 0.7 W and an efficiency of 3% are realized. A multiband barrier-discharge excilamp based on the triple mixture exhibits a potentially long lifetime.     

Density and dielectric constant of dense argon and krypton mixtures

The density and the dielectric constant of three dense argon-krypton mixtures have been measured at 25°C and up to 8000 bar. For density measurements a constant volume method is used. The dielectric constant is determined by a capacitance measurement. The polarizability of the three mixtures is studied as a function of density.     

Emission characteristics of an ultraviolet emitter based on mixtures of krypton with low-aggressive halogen carriers pumped by a barrier discharge

The emission characteristics of a pulse-periodic excilamp with three dielectric barriers based on the 222-nm KrCl(X-B) and 248-nm KrF(X-B) emission bands have been investigated. The working gases of the lamp were mixtures of krypton with low-aggressivity halogen carriers (SF₆, CCl₄). Optimal compositions of Kr-SF₆ and Kr-CCl₄ mixtures for obtaining the maximum intensity of the system of 222-nm KrCl(X-B) and 248-nm KrF(X-B) bands have been determined. The results of lamp optimization depending on the parameters of the source of pulse-periodic short-duration barrier discharge are presented.     

Excitation Transfer for K2 in High-Lying States by N2

A K-N2 mixture is irradiated in a glass fluorescence cell with pulses of 710hm radiation from an OPO laser, populated K2 （^1∧g） state by two-photon absorption. The cross section for ^1∧g →^3∧g transfer in K2 is determined using molecular fluorescence spectrometry. The cell temperature is kept constant at 553K. The N2 pressure is varied between 40 Pa and 400 Pa. The effects of K2-K collisions could not be neglected. These effects are subtracted out by using the results of the pure K experiment. The cross sections are （3.8 ± 1.5） ×10^-15 cm^2 for K2 （^1∧g） ＋ N2 → K2（^3∧g） ＋N2 and （8.9 ± 3.5） × 10^-15 cm^2 for K2 （^3∧g） collisions with N2.     

Preliminary results on the 2p levels of krypton obtained by the Hanle effect

Using Hanle experiments in a discharge, the radiative lifetimes of 7 out of the ten 2p-levels of krypton have been studied as well as the cross-sections for the destruction of alignment in these levels by collisions with ground-state krypton atoms. The limitations of the present experimental method are emphasized and plans for future improvements are formulated.     

Simulation of the transition radiation detection conditions in the ATLAS TRT detector filled with argon and krypton gas mixtures

Performance of the Transition Radiation Tracker (TRT) at the ATLAS experiment with argon and krypton gas mixtures was simulated. The efficiency of transition radiation registration, which is necessary for electron identification, was estimated along with the electron identification capabilities under such conditions.     

Energy degradation of electrons in krypton

The problem of energy degradation of electrons in krypton has been investigated using the Monte Carlo method. The results are presented as the probability distributions of the number of ionizations, the Fano factor, the mean energy per ion pair and the degradation spectra for source energies up to 4 keV.     

Emission characteristics of plasma of a transverse volume discharge in mixtures of helium, argon, and krypton with sulfur hexafluoride

The emission characteristics of the plasma of repetitively pulsed spontaneous UV-VUV radiation sources on the basis of ArF* (193 nm) and KrF* (249 nm) molecules, and the products of decomposition of sulfur hexafluoride molecules pumped by a transverse volume discharge in a mixture of inert gases with sulfur hexafluoride molecules have been investigated. The discharge emission spectra in the range of 190–780 nm at the low-current and high-current stages of the transverse discharge, the time characteristics of the voltage across the electrodes, the pump current, and the emission of excimer molecules and the products of decomposition of sulfur hexafluoride have been studied. It is shown that, in the gas-static operation mode of the radiator at the number of discharge pulses smaller than 10³, the 193-nm ArF* and 249-nm KrF* bands are main in the emission spectrum. Upon further operation of the radiator, a spectral continuum is formed on the basis of sulfur molecular bands in the range 260–550 nm.     

Excitation of the isoscalarE2 resonance in12C by proton inelastic scattering

Proton inelastic excitation spectra of¹²C have been measured imposing a coincidence with alpha decay to⁸Be_g.s. and⁸Be_2.9MeV. In plane angular correlations have been obtained for the main structures observed in the spectra. Comparison with DWBA correlation functions permits a 2⁺ assignment for all the groups in the 20–30MeV excitation range. The percentage of theE2-EWSR exhausted in the same range is in agreement, within the uncertainties indicated, with that derived from the inelastic scattering of other particles.     

纳秒光场下原子团簇产生高离化Kr离子的激光波长效应

利用不同波长和光强的纳秒激光,对Kr原子团簇进行了激光电离的飞行时间质谱研究,观察到Kr高价离子价态显著地依赖于激光波长,当分别用波长为1064,532,355和266 nm的激光照射Kr原子团簇时,可分辨的离子最高价态分别为+17,+11,+4和+2价;然而离子价态与激光功率密度的依赖关系并不明显。实验结果支持多光子电离-逆轫致吸收加热-电子碰撞电离三步电离模型,表明电子碰撞电离是高价离子产生的主要途径。     

Excitation dynamics during the multiphoton absorption in SF6+buffer-gas mixtures

A detailed analysis of the total average number of absorbed photons 〈n〉_total during Infrared multiphoton absorption processes in mixtures of SF₆-Ar, N₂ and CH₄ buffer gases is presented. The results for 〈n〉_total are deduced using pulsed photoacoustic technique in collisional regime. Complete analysis is based on the theoretical generalized coupled two-level model (GCT) and its application to different gas mixtures. Evaluation of partial 〈n〉_coll. values is presented too, obtained using the results from time-resolved optoacoustic (TROA) and time-resolved absorption (TRA) methods for V-T relaxation times (τ_V-T) and the saturable absorber (SA) method for R,R-T relaxation times (τ_rot.-rel.), and applying them directly to the GCT model. All methods (TROA and SA) and the GCT model use the same photoacoustic results from our experiment under identical experimental conditions.     

纳秒光场下原子团簇产生高离化Kr离子的激光波长效应

利用不同波长和光强的纳秒激光,对Kr原子团簇进行了激光电离的飞行时间质谱研究,观察到Kr高价离子价态显著地依赖于激光波长,当分别用波长为1064,532,355和266 nm的激光照射Kr原子团簇时,可分辨的离子最高价态分别为+17,+11,+4和+2价;然而离子价态与激光功率密度的依赖关系并不明显。实验结果支持多光子电离-逆轫致吸收加热-电子碰撞电离三步电离模型,表明电子碰撞电离是高价离子产生的主要途径。