Sunshine Mike's Physics Archives
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J. of Physics E: Sci. Inst. 7, 789-790 (1974) Ein neuer Kristallhalter für Ramanuntersuchungen Michael Nippus Sektion Physik der Universität München, 8000 München 40, Schellingstr. 4/IV, Germany Erhalten am 6. Mai 1974, in endgültiger Fassung am 29. Mai 1974 Zusammenfassung: Es wird ein neuartiger Kristallhalter für Laser-Ramanuntersuchungen beschrieben. Der Kristall kann zur Bestimmung der Komponenten des Raman Polarisierbarkeitstensors in alle notwendigen Orientierungen hinsichtlich der Streugeometrie gedreht werden. A new crystal mounting for Raman Investigations Abstract: This paper describes a new sample holder for crystals undergoing laser-Raman investigations. The mounting of the crystal is designed to allow all possible geometries and hence components of the derived Raman polarizability tensor to be determined. |
01_Raman_Kristallhalter (249 KB).pdf |
| Optik 46 , 489-494 (1976) Die Detektivität D* von Infrarotdetektoren in Abhängigkeit von der Blendengeometrie Michael Nippus Universität München, Sektion Physik, Lehrstuhl Brandmüller Eingegangen am 19. Februar 1976 Inhalt: Das Gesichtsfeld von Infrarotdetektoren wird definiert, wenn deren Empfindlichkeit von der Umgebungsstrahlung beeinträchtigt wird. Der relative Empfindlichkeitsgewinn wird berechnet für Blendengeometrien innerhalb realistischer Abmessungen des Detektorkühlgehäuses. Abstract: The detectivity of infrared detectors depending on the geometry of blinds. The field of view (FOV) of background limited infrared photodetectors (BLIP-detectors) is defined and the gain of the detectivity D* is calculated for realistic dimensions of the detector cryostat including blinds against blackbody radiation. |
02_D-stern.pdf (299 KB) |
Z. Naturforsch. 31a, 231-235 (1976) Relative Raman-Intensitaten der Phononen von LiNbO3 Michael Nippus Universität München, Sektion Physik, Lehrstuhl J. Brandmüller, München Eingegangen am 19. Januar 1976 Abstract: Relative Raman Intensities of the Phonons of LiNbO3. In the last few years the assignment of the optical phonons of LiNbO3 to the different symmetry species was often changed. We therefore concluded that the relative intensities of the Raman lines must be re-examined. According to all elements of the Raman tensor, the fundamental spectra were recorded separately as far as possible. The relative intensities are listed within an error of 7 or 40 percent, each according to signal-to-noise-ratio and/or overlapping of nearby lines. |
03_LiNbO3_Phononen (585 KB).pdf Doctoral Thesis 1977: Ramanintensitaeten der Phonon-Polaritonen von LiNbO3(10 MB).pdf |
| J. Raman Spectroscopy 6, 2-4 (1977)
Ramanspektren im Nahen Infrarot: Ein Vergleich dreier Detektorsysteme Michael Nippus Universität München, Sektion Physik, Lehrst. Brandmüller, Schellingstr. 4/III, 8000 München 40, BRD Abstract: Raman spectra of various samples, excited by an YAG: Nd-Laser at 1064 nm, were recorded by three detection systems. A comparison was made of the detectivity of the infrared- Raman system against a visible Raman system working at 647 nm. |
04_Raman_NIR (404 KB).pdf |
Z. Naturforsch. 32a, 731-735 (1977) Wave Vector Dependent Light Scattering Intensities by Polar Modes in GaAs M. Nippus and R. Claus Sektion Physik der LM-Universität München, Schellingstr.4, 8000 München 40, FRG received June 2,1977 Abstract: Light scattering intensities by the polaritons of F2-type in GaAs have been experimentally studied. The spectra were excited by an YAG: Nd3+ laser in the infrared. When using the scattering intensities derived from the polar TO- and LO-phonons as input data for calculations, the k-dependent intensities in the polariton region could be verified within less than a few percent. The intensity variation for larger wave vectors was more precisely to be determined and verified than the frequency shifts. |
05_GaAs_Polariton (560 KB).pdf |
| Opt. Comm. 22, 318-322 (1977)
EXPERIMENTAL EVIDENCE FOR THE EXISTENCE OF SECOND ORDER POLARITONS ASSOCIATED WITH VAN HOVE SINGULARITIES AT LARGE WAVE VECTORS M. NIPPUS and R. CLAUS Sektion Physik der LM-Universität München, Schellingstr. 4, 8000 München 40. FRG Received 26 May 1977 Abstract: Light scattering experiments concerning the long wavelength totally symmetric polar transverse modes in CdS have been performed by using an Nd:YAG-Iaser. Polaritons associated with the Al (TO)-phonon at 233 cm-I show resonance couplings with two modes at 204 and 213 cm^-1. These modes have been assigned earlier to originate from second order phonon process due to two phonon density of states maxima. The recorded wave vector dependent frequencies and scattering intensities are in good agreement with calculated data. |
06_CdS_Polariton (479 KB).pdf |
| phys. stat. sol. (b) 86, 257
(1978) The Origin of the Anomalous TO-Doublet in Cubic CuCI Studied by Light Scattering K. FUKUSHI, M. NIPPUS, and R. CLAUS Sektion Physik der Universität München, Lehrstuhl J. Brandmüller Abstract: Light scattering experiments are performed concerning polaritons associated with the anomalous TO-doublet in CuCl. A quantitative description of the dispersion behaviour, recorded at liquid N2 temperature, may be obtained by taking into account coupling of the fundamental zone centered TO-phonon with second order modes due to two van Hove singularities. This description is in good agreement with recent calculations of the two-phonon density of states in CuCl. Inhalt: Es werden Lichtstreuexperimente an Polaritonen, die mit dem anomalen TO-Dublett in CuCl verknüpft sind, durchgeführt. Eine quantitative Beschreibung des Dispersionsverhaltens, das bei der Temperatur des flüssigen Stickstoffs aufgenommen wurde, wird unter Berücksichtigung der Kopplung des fundamentalen TO-Phonons im Zonenzentrum mit Moden zweiter Ordnung infolge von zwei van Hove-Singularitäten erhalten. Diese Beschreibung ist in guter Übereinstimmung mit kürzlichen Berechnungen der Zwei-Phononenzustandsdichte in CuCl. |
07_CuCl_Polariton (546 KB).pdf |
Z, Naturforschung 33a, 924-933 (1978) The Influence of Photorefractive Index Change on Raman Scattering Intensities in LiNbO3 M. Nippus and R. Claus Sektion Physik der LM-Universität München, Lehrstuhl J. Brandmüller, München received May 20,1978 Abstract: The time dependent varying shape of the laser beam within the scattering volume in Raman scattering experiments on LiNbO3 influences the recorded spectra and can be studied spectroscopically by forward-, right angle-, and backward.scattering geometries. The recorded spectra allow a time resolved insight into the microscopic local changes of the refractive index. The decay constant of the scattered phonon intensity is a well defined function of the laser power. It furthermore showed to be characteristic for the individual sample. Raman spectroscopy thus seems to provide a method to determine the concentration of Fe-impurities. We have observed that ordinary photons influence the optically damaged regions of the sample whereas undamaged regions are left almost unchanged. Damped cut-in oscillations recorded when illuminating the sample alternatingly with ordinary and extraordinary laser light seem to originate from local fluctuations of an excited cloud of impurity electrons. The observation of undamped periodic break downs of the scattering intensity from polaritons and back scattered phonons is reported. |
08_LiNbO3_Index_Change (1086 KB).pdf |
| IEEE J. of Quant. Electr. QE-16, 122
(1980) Performance of the Asterix III High Power Iodine Laser GÜNTER BREDERLOW, RAINER BRODMANN, KLAUS EIDMANN, MICHAEL NIPPUS, RAINER PETSCH, SIEGBERT WITKOWSKI, REINHARD VOLK, AND KLAUS J. WITTE Abstract: For more than 500 shots the 1 TW iodine laser Asterix III has demonstrated high reliability for light-plasma-interaction experiments. Improved laser parameters and new measurements of light pulse properties are reported. |
09_AsterixIII (628 KB).pdf |
| Opt. Comm. 33, 80-84
(1980) EVALUATION OF THE MODULATION INDEX OF THE STANDING WAVE RAMAN-NATH MODE-LOCKING DEVICE Michael NlPPUS Projektgruppe für Laserforschung der Max Planck Gesellschaft zur Förderung der Wissenschaften e. V., D-8046 Garching b. München, FRG Received 14 January 1980 Abstract: The performance of an acoustooptic standing wave Raman-Nath deflector as active mode-locking switch is evaluated and compared with theory. The time averaged intensities of the diffracted beam up to the eighth order are calculated for acoustic phase shifts up to Delta_phi=4. With fused quartz the highest attainable value of Delta_m was 6.4 at 633 nm. In the theory describing the pulse width of homogeneously broadened AM mode-locked laser oscillators the modulation index Delta_m is a parameter, given by Delta_m=2 Delta_phi. |
10_Modelock (382 KB).pdf |
PLF Report 17, 1979 Iodine Amplifier System ASTERIX: Calculations Basing on Experiments Michael Nippus Projektgruppe für Laserforschung MPI Garching May 1979 Abstract: On the basis of many experimental results delivered from iodine laser systems like PLASTERIX and ASTERIX III a model calculation is presented. It is shown that the energy extraction of an iodine amplifier can simply be described with sufficient accuracy by the well-known Frantz-Nodvik-formula. The influences of various spatial inversion- and beam profiles of extinction losses, and of the tube diameter are evaluated. The optimized physical parameters of an iodine laser system with 6 amplifiers delivering a power of 40 Terawatt in 300 ps are given in detail. All calculations are made on a HP-97. |
11_Amplific (2733 KB).pdf |
Laborpraxis 4, (1980) Computergesteuerte ICP-Sequenzanalyse Michael Nippus Kontron GmbH, Abt. Materialanalyse, 8057 Eching Inhalt: Ein computergesteuertes UV-VIS-Emissionsspektrometer zur automatischen ICP-Elementanalyse wird detailliert beschrieben. Neuartig ist die Wechselbeziehung zwischen Schrittmotorsteuerung und exakter Kontrolle der Winkelposition des Monochromator-Gitters. Komfortable Grafik-Software für die Bildschirmdarstellung von Spektren. ICP-Eichkurven, Peaksuchverfahren, zeitlichen Integrationen usw. stellt den neuesten Stand der Emissionsspektroskopie dar und erleichtert die Kontrolle des Meßablaufs durch den Analytiker. |
12_ICP_(864 KB).pdf |
| 13. Spektrometertagung . Herausgeber: K.-H. Koch, H.
Massmann @ 1981 Walter de Gruyter & Co., Berlin. New York - Printed in
Germany ATOMSPEKTROMETRISCHE MULTIELEMENT ANALYSE MIT EINEM RECHNER- GESTEUERTEN ICP SEQUENZ-EMISSIONSSPEKTROMETER M. Nippus Kontron GmbH, Abt. Materialanalyse, Oskar-van-Miller-Str. 1 D-8057 Eching, Germany Einführung: Die Automatisierung von analytischen Verfahren der Emissionsspektroskopie gewinnt in letzter Zeit immer mehr an Bedeutung, was vor allem auf die sprunghafte Entwicklung von leistungsfähigen Mikrocomputern zurückzuführen ist. Es war naheliegend, den Routineablauf der sequentiellen ICP-Atomemissionsanalyse durch eine Rechnersteuerung zu beschleunigen. Das führte KONTRON zur kommerziellen Neuentwicklung eines Automatischen Sequentiellen Spektrometers für die ICP-Analyse, genannt ASS 80. Hierbei steht die 80 sowohl für die 80er Jahre als auch für die Rechnerkapazität von 80 k Byte. |
12a_ICP (590 KB).pdf |
| Proceeding ICAMS-20, Non Crystalline Materials, Brazil
2003 Defect and Microstructural Characterisation of a-Si:H deposited by low temperature HW-CVD on paper substrates M. Härting (1)*, D. Knoesen (2), Z. Sigcau1, T.P. Ntsoane1,(3), P. Sperr (4), W. Egger (4), M. Nippus (5), D.T. Britton (1) 1. Dept. of Physics, University of Cape Town, Rondebosch 7701, South Africa 2. Dept. of Physics, University of the Western Cape, Bellville 7530, South Africa 3. Materials Research Group, iThemba LABS, Faure 7131, South Africa 4. Universität der Bundeswehr München, Institut für Nukleare Festkörperphysik, D-85577 Neubiberg, Germany 5. Huber Diffraktionstechnik GmbH & Co. KG, D-83253 Rimsting, Germany Abstract a-Si:H has been deposited on 80 g m-2 wood-free paper, with and without an intermediate metallic interlayer, using low temperature hot wire chemical vapor deposition HW-CVD. In this paper we compare the differences in microstructural properties of the two types of layer, concentrating on the influence of the substrates, including their effect on the deposition rate of the material and substrate temperature. Techniques employed in the characterisation include, X-ray diffraction to study composition, and crystallinity, positron annihilation for open-volume defects, and scanning-electron and optical microscopy. * Corresponding Author: [email protected] |
13_Charact_of_a-SiH (2088 KB).pdf |
| Nuclear Instruments and Methods in Physics Research A
551 (2005) 145–151 Fast high-resolution characterization of powders using an imaging plate Guinier camera Joseph Gal a), Dmitry Mogilanski a), Michael Nippus b), Jacob Zabicky a), Giora Kimmel a) a) Institutes for Applied Research, Ben-Gurion University of the Negev, Beer Sheva, Israel b) Huber Diffraktionstechnik GmbH & Co. KG, D-83253 Rimsting, Germany Available online 10 August 2005 Abstract: A new Huber Guinier camera G670 was installed on an Ultrax18-Rigaku X-ray rotating Cu anode source, with a monochromator (focal length B=360mm) providing pure Ka1 radiation. The camera is used for powder diffraction applying transmission geometry. An imaging plate (IP) brings about position-sensitive detection measurement. In order to evaluate this new instrumental setup, quality data were collected for some classical reference materials such as silicon, quartz, some standards supplied by NIST USA and ceramic oxides synthesized in our laboratory. Each sample was measured at 4 kW for 1–2 min at 2-theta from 0 to 100°. The results were compared with published references. The following desirable features are noted for the instrumental combination studied: production of high quality X-ray data at a very fast rate, very accurate intensity measurements, sharp diffraction patterns due to small instrumental broadening and a pure monochromatic beam, and small position errors for 2-theta from 4 to 80°. There is no evidence for extra line broadening by the IP camera detector setup. It was found that the relatively high instrumental background can be easily dealt with and does not pose difficulty in the analysis of the data. However, fluorescence cannot be filtered. |
14_Guinier_Camera_670 (250KB).pdf |