PTB Braunschweig Research Articles

THREE DIMENSIONAL REFERENCE STRUCTURES FOR CONFOCAL MICROSCOPY

International Journal of Computational Engineering ScienceVol. 04, No. 03, pp. 605-608 (2003) Poster PapersNo AccessTHREE DIMENSIONAL REFERENCE STRUCTURES FOR CONFOCAL MICROSCOPYA. H. FOITZIK, M. SCHÄFER, R. STEIN, L. VOLLMER, and G. SCHUSTERA. H. FOITZIKUniversity of Applied Sciences Esslingen, Department for Mechatronics, Robert-Bosch-Str. 1, D-73037 Goeppingen, Germany Search for more papers by this author , M. SCHÄFERUniversity of Applied Sciences Esslingen, Department for Mechatronics, Robert-Bosch-Str. 1, D-73037 Goeppingen, Germany Search for more papers by this author , R. STEINUniversity of Applied Sciences Esslingen, Department for Mechatronics, Robert-Bosch-Str. 1, D-73037 Goeppingen, Germany Search for more papers by this author , L. VOLLMERUniversity of Applied Sciences Esslingen, Department for Mechatronics, Robert-Bosch-Str. 1, D-73037 Goeppingen, Germany Search for more papers by this author , and G. SCHUSTERUniversity of Applied Sciences Esslingen, Department for Mechatronics, Robert-Bosch-Str. 1, D-73037 Goeppingen, Germany Search for more papers by this author https://doi.org/10.1142/S1465876303001861Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractApplying thin film MEMS technologies threedimensional reference structures for spatially high resolving optical imaging and spectroscopy techniques were manufactured containing non-transparent defects of different lateral and axial extention and being located in various heights within the samples. This special manufacture was enabled using thin films of resist as layers in between the defects layers, as well as applying a modified "single mask process", the geometrical arrangement of the defects being distributed on different quadrants of the "mask" according to their axial height in the subsequent reference structure. Minimal distances of about 600 nm in between two defect layers could be achieved.Keywords:Four or Five KeywordsSeparated by Semicolon References http://www.cs.ubc.ca/spider/ladic/confocal.html . Google Scholar R. J. Lehnert, Renishaw plc, personal communication . Google ScholarR. J. Lehnert, G.I.T. Laborator Journal — Bioforum International 2, (2000). Google Scholar D.A. Smith, S. Webster, M. Ayad, S.D. Evans, D. Fogherty and D.N. Batchelder: "Development of a scanning near-field optical probe for localised Raman Spectroscopy (SNOM)", Ultramicroscopy 61, 1995, p.247 . Google Scholar Dr. H. Bauch, Zeiss Vision GmbH, personal communication . Google Scholar W. Mirandé, PTB Braunschweig, personal communication . Google Scholar PTB Braunschweig, proc., "BCR Photomask Linewidth Standard", not dated . Google Scholar C.K. Lee, S. Arkhipov, W. Kaese, M. Schäfer and A.H. Foitzik, "Low Cost Manufacturing of MEMS for Educational Purposes", proc. MicroTec 2000, Hannover, VDE-Verlag Berlin Offenbach, (2000), pp. 597-601 . Google Scholar W. Kaese, C.K. Lee, R.J. Lehnert and A.H. Foitzik, "Low Budget Manufacturing of Reference Structures for Raman Spectroscopy", proc. MicroTec 2000, Hannover, VDE-Verlag Berlin Offenbach, (2000) pp. 603-608 . Google Scholar A. Foitzik, "Dreidimensionale Messstandards für konfokale Mikroskopieverfahren", Final Report to the Ministry for Education, Research and Arts of the State of Baden-Wuerttemberg, in German, (2000) . Google Scholar A. Foitzik et al., to be published . Google Scholar FiguresReferencesRelatedDetails Recommended Vol. 04, No. 03 Metrics History KeywordsFour or Five KeywordsSeparated by SemicolonPDF download

State of the art of electronic personal dosimeters for neutrons

Despite a widely recognised need, electronic devices for personal dosimetry of neutrons or mixed neutron–photon fields are still far less established than systems for photon or beta radiations. A large research project is in progress to evaluate different methods currently used or under development for electronic personal dosimetry in mixed neutron–photon fields. The study includes testing in calibration fields as well as in representative workplaces of the nuclear industry. This paper describes the commercial and laboratory systems under investigation and their response characteristics. These were determined so far with measurements using ISO standard monoenergetic beams up to 19MeV at the PTB in Braunschweig, Germany.

Determination of light output function and angle dependent correction for a stilbene crystal scintillation neutron spectrometer

In addition to liquid NE213 scintillators also stilbene solid crystals are applied traditionally for fast neutron spectrometry. A proper evaluation of experimental data provides a precise determination of the nonlinear light output function for the given scintillator/photomultiplier combination, and for stilbene additionally an adequate correction of the anisotropy effect. Calibration experiments with monoenergetic neutrons (1.2, 2.5, 5.0, 13.95, 14.8, 19.0 MeV) and various neutron incidence angles were carried out at the accelerator facility of the PTB Braunschweig for two cylindrical scintillators (∅30 mm×25 mm, ∅10 mm×10 mm). An improved analytic light output function as well as an adequate angle dependent correction function were derived.

Study of the Radiation Environment Caused by Galactic Cosmic Rays at Flight Altitudes, at the Summit of the Zugspitze and at PTB Braunschweig

The high energy Monte Carlo codes MARS and FLUKA are compared as applied to calculations of neutron spectra in the atmosphere resulting from interactions of primary galactic cosmic rays (GCR) with the nuclei in the atmosphere. The calculational strategies of either code are discussed. The primary galactic spectrum at the top of the atmosphere and the model used for the atmosphere are presented in detail. MARS is used to calculate neutron energy spectra which before had been calculated with FLUKA and measured with Bonner spheres. The comparison shows acceptable agreement. Therefore, MARS is used to provide new data for the analysis of dosimetric measurements at flight altitudes. The new data encompass calculated angular distributions and energy spectra of neutrons, protons, photons and pions for the geographical position of Braunschweig and the Zugspitze. In addition, the influence of aluminium layers on these spectra is studied. These new data are expected to provide valuable support in the analysis of dosimetric measurements at flight altitudes. Throughout the paper, emphasis is placed on the discussion of the main sources of variance for these calculations.

Interlaboratory beta source calibration using TL and OSL on natural quartz

Laboratories using luminescence methods for dose reconstruction have to make interlaboratory source calibrations—initially this will be a single isotope beta or gamma source using one particular reference material. The procedure requires not only the administration of exact doses to the material but also the uniform handling of the dosimetric material and standardization of the procedures. An interlaboratory calibration of an Sr-90 beta source was recently carried out by our five laboratories which are involved in a retrospective project. The reference material was quartz but there were difficulties finding sufficient suitable quartz. Five different batches were obtained from the Merck company and tested for sensitivity, linearity and stability of the 340°C peak, the 1992 batch was found to be the most appropriate. The irradiations were performed at the Secondary Standard Dosimetry Laboratory at GSF using a Co-60 source as well as the in situ measurements with an ionization chamber, calibrated to the primary standards of PTB Braunschweig. Irradiated and unirradiated quartz was distributed to the five laboratories and although different procedures were used for thermoluminescence and optically stimulated luminescence, the source calibrations for the different laboratories agreed within ±3% compared to the previous calibrations of the laboratories.

A collimator system for fast neutron scattering experiments

A multichannel collimator system for fast neutrons which is part of a new time-of-flight facility at the PTB in Braunschweig is described. Five flight paths, each about 10 m long, are shielded by asymmetrically designed collimators which were optimized by means of Monte Carlo calculations. The optimum shape of the collimator channels and the optimum shielding material for 10 MeV neutrons are discussed.

Neutron energy dependence of different track etch detectors

Abstract The paper discusses the neutron energy dependence and the threshold energy of various track etch detectors as a function of neutron energy in the range 0.57–19 MeV. The neutron detectors were irradiated with monoenergetic neutrons during two European intercalibration experiments at PTB Braunschweig and GSF Neuherberg. In this study three different counting techniques were applied: 1. microscopic counting of recoil tracks in LR-115 cellulose nitrate 2. jumping spark counting of 237Np and 232Th fission fragment tracks in thin Makrofol foils and 3. counting of electrochemically etched recoil tracks in thick Makrofol foils with a microfiche reader.

Traffic Noise in West Germany, Evaluation of Noise Levels and Experience in Noise Control

In 1932, Bakos and Kagan first attempted to measure traffic noise in Berlin. Later in 1938, Kösters and collaborators formed a “Map of Loudness” for Charlottenburg. At that early date they used a sound-level meter with weighting curves having frequency characteristics recommended by the German Acoustic Committee in 1937 and the logarithmic graphic level recorder of Braünmuhl. Many years later the PTB in Braunschweig and the Acoustics Laboratory in Düsseldorf began new traffic noise studies. In Düsseldorf we published a Map of Loudness for the city and tried to obtain acoustical statistics for all vehicles. The map of loudness so obtained in 1938, 1951, 1952, and 1955 showed successively an increase in the occurrence of levels over 80 db. For the purpose of evaluation, the levels at three points have been found useful in psychoacoustical work and for expert testimony. These are: (1) level of background, (2) average level (by a planimeter), and (3) median peaks per minute. These will be illustrated by an example. Many ways are possible for reducing traffic noise. One of the best is proper construction of the vehicles. Noise control now is known by town planning boards. Two projects are presented to show organized planning in Germany.