Bestimmung der Driftgeschwindigkeit von Elektronen in Wasserstoff und Stickstoff bei hohem Druck

By means of a time of flight method the electron drift velocity in hydrogen and nitrogen was determined for high pressure, at which no measurements were as yet available. The values are obtained in the range fromE/p=12 toE/p=0,03 V/cm Torr with an accuracy from 1% to 1,5%. The pressure range available (up to 31000 Torr) enabled an examination of the similarity rule. The measurements show that for constantE/p, in the rangeE/p<1, the drift velocities decrease with increasing pressure.     

Eine neue Methode zur Bestimmung des Diffusionskoeffizienten von Wasserstoff in Alkalihalogeniden

The diffusion coefficient of hydrogen in KCl-, KBr- and KJ-crystals is measured by a new method, and the activation energy is evaluated by the temperature-dependence between 187 and 446 °C.     

Die Feinstruktur desL-MM-Auger-Elektronenspektrums von Argon und derK-LL-Spektren von Stickstoff,Sauerstoff und Methan

The fine structure ofL-MM Auger electron spectrum of argon andK-LL spectra of the gases N₂, O₂ and CH₄ was investigated with an electrostatical spectrometer. The ionisation was caused by the continuous X-radiation from a tungsten target. From the results of Auger electron energies measured, the binding energies of the electrons of the inner shells were calculated. The results obtained with argon agreed exactly with the known values. Further it could be shown, that the value of 400 eV for the binding energy of a 1s-electron in the N₂-molecule, so far obtained, must be replaced by the value (409,4±1,0) eV. A comparison between the relative intensities of fine structure lines and the theory of the Auger process given byAsaad andBurhop could not be carried out, because the Auger electrons, having in our experiment an angular distribution relativ to the incident X-ray beam, could only be measured between an angular range of 49,3° and 61,0°.     

Anregung von UV-Strahlung in Stickstoff und Wasserstoff durch einen Elektronenschwarm

The radiation excited in nitrogen and hydrogen by an electron swarm moving in a uniform electric field is investigated. In nitrogen the bands of the 2 ^nd positive group in the region from 3400 to 3800 Å are the dominating part of the radiation. In hydrogen the main part of the radiation is lying in the far ultraviolet (1000 to 1200 Å) due to the excitation of the state 2¹ II _u . The coefficientδ describing the intensity of the radiation is measured with a photomultiplier device as a function of the electric fieldE and the pressurep in the range from about 10 to 100 Torr. Besides the dependence ofδ onE/p a pressure dependence is found which is explained as a quenching process of the excited molecules by collisions. The pressurep ₀ for equal probability of radiating and non-radiating decay of the states involved is 60 Torr in N₂ and 20 Torr in H₂. The theoretical interpretation of the dependence onE/p supports the excitation energy of the state C³ II _u of N₂ for electron impact to be equal to the spectroscopical value of 11·04 eV and yields 0·9·10^?16 cm² for the maximum of the excitation cross section. The results of the measurements in H₂ can be described assuming a cross section of 0·55·10^?16 cm² for the excitation of the state 2¹ II _u by electron impact.     

Photoprotonen aus Kohlenstoff,Stickstoff, Sauerstoff und Neon

The energy spectra of photoprotons from carbon, nitrogen, oxygen and neon were investigated with 30·5 MeV bremsstrahlung of the Heidelberg betatron using a CsI(Tl)-spectrometer. The known resonances could be confirmed, new resonances are found in nitrogen. Yields and cross sections relative to those of the reaction C¹²(γ, n)C¹¹ are given.     

Eine neue Methode zur Bestimmung der Rauhigkeitsautokorrelationsfunktion von optischen Oberflächen

A New Method of Determining the Autocorrelation Function of Polished Optical Surfaces Starting with a general theory of light scattering a measuring procedure for determining the autocorrelation function of surface roughness of well polished substrates is deduced. In this method light intensity scattered into a fixed direction has to be measured in dependence on the dimensions of the scattering area. The results are tested for a glass surface polished by different methods.     

Eine neue Methode zur Bestimmung von L-Fluoreszenzausbeuten bei Dysprosium

In this work a new method was used to measure theL-fluorescence-yield of Dy. With the aid of a proportional-counter and an anthracene-crystal-spectrometer, theL-Xray-and the conversion-electron-spectra of Dy^165m were measured. From the intensities thus evaluated, together with the known conversion-coefficients, the meanL-fluorescence-yield was calculated. It was found to beω _L=0·14±0·02. Moreover the partial fluorescence-yield of theL _III-subshell could be evaluated:\(\omega _{L_{III} } = 0 \cdot 145 \pm 0 \cdot 055\).     

Isotopenanalyse an niederenergetischen Teilchen der Elemente Bor,Kohlenstoff, Stickstoff und Sauerstoff aus der kosmischen Strahlung in Plastik-Detektoren

In eight cellulose nitrate sheets of a plastic detector stack flown in 1968 from Ft. Churchill in 1.8 g/cm² floating altitude stopping heavy cosmic ray particles of about 100 MeV/Nuc were measured. In 0.2 m² of the 1.6 m² large stack 30 boron, 190 carbon, 83 nitrogen and 263 oxygen particles were analysed. A resolution of ΔZ=±0.1 charge units and ΔM=±0.7 mass units was obtained. Using oxygen particles for a calibration at¹⁶O the mean values of the mass distributions of the other elements are: 10.79±0.17 for boron, 12.22±0.08 for carbon, 14.61±0.12 for nitrogen.     

Das elektronische Bremsvermögen von Stickstoff und Sauerstoff für niederenergetische Protonen

The electronic stopping power of molecular oxygen and nitrogen for protons with energies between 1 keV and 30 keV has been measured using a differentially pumped stopping cell. Our results give a surprisingly good confirmation of the Lindhard-Scharff statistical theory which predicts a linear velocity dependence of the electronic stopping power at low projectile energies. Moreover our data are in fair agreement with earlier high energy (E ≧ 20 keV) measurements in other laboratories. The combination of the present measurements with theoretically calculated nuclear stopping powers yields an estimate of the atomic stopping power. This estimate leads to substantially lower atomic stopping powers at low energies compared to values derived from range measurements. This result may have interesting implications on auroral hydrogen emissions.