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After several months of operation, many photovoltaic (PV) modules develop a discolouration defect called snail trails which appear as irregular dark traces across the cells. These traces are caused by silver nanoparticles accumulating within the encapsulation foil directly above the grid finger. In this work we systematically investigate combinations of encapsulation and back-sheet foils with respect to their susceptibility for snail trails. We can show that certain additive compositions within the encapsulation and back sheet foils are critical for the formation of the discolouring silver nanoparticles. We suggest a reaction model explaining the formation of snail trails from a chemical point of view. This fundamental understanding allows the rapid testing of foils for their snail trail sensitivity as well as the special design of resistant foils.

In view of the proposed redefinition of the kilogram, in 2005, 2007 and 2010 the CCM adopted recommendations and conditions to be met before the redefinition is implemented. Some of these conditions concern the uncertainty by which the kilogram will be realized after the redefinition. This uncertainty has become a point of discussion in other committees, because the needs for this value were not sufficiently transparent. Here, examples of the realization of the new kilogram with different uncertainties, along with the experimental results available from the Avogadro and watt balance experiments, the uncertainties of mass determinations and their propagation with reasonable assumptions are presented, in order to compare possible realization uncertainties with the requirements in practice. It turned out that the CCM conditions are reasonable, if major changes in the dissemination chain of the kilogram are to be avoided.

An experiment is described for determining the atomic mass constant by accumulating ions from an ion beam up to a weighable mass. It establishes a link between the international prototype of the kilogram, the realization of the associated SI unit and an atomic mass. The items necessary for such an experiment are a high-current ion source, an ion optical system with high transmission, a suitable ion collector and a vacuum balance. With the most recent measurement, a mass of more than 320 mg of bismuth was accumulated and its atomic mass was determined with a relative standard uncertainty of 9.4 × 10−5. Special emphasis is placed on determining the mass loss of the accumulated ions caused through sputter effects in the ion collector.Although work on this experiment at the PTB has now been stopped, we conclude with a number of suggestions that could lead to much smaller relative uncertainty in a future experiment.

Measurements of air density determined gravimetrically and by using the CIPM-81/91 formula, an equation of state, have a relative deviation of 6.4 ? 10?5.This difference is consistent with a new determination of the mole fraction of argon xAr carried out in 2002 by the Korea Research Institute of Standards and Science (KRISS) and with recently published results from the LNE. The CIPM equation is based on the molar mass of dry air, which is dependent on the contents of the atmospheric gases, including the concentration of argon. We accept the new argon value as definitive and amend the CIPM-81/91 formula accordingly. The KRISS results also provide a test of certain assumptions concerning the mole fractions of oxygen and carbon dioxide in air. An updated value of the molar gas constant R is available and has been incorporated in the CIPM-2007 equation. In making these changes, we have also calculated the uncertainty of the CIPM-2007 equation itself in conformance with the Guide to the Expression of Uncertainty in Measurement, which was not the case for previous versions of this equation. The 96th CIPM meeting has accepted these changes.

The influence of the working gas pressure on the extraction behavior of ion beams out of a cold or hot reflex discharge ion source was investigated using xenon ions in the energy range from 17 to 30 keV. Optimal extraction conditions were achieved by transmission measurements through a 90 doubly focusing dipole magnet. The measured currents obtained at the optimized transmission reproduce the Child-Langmuir equation. The results are compared with IGUN simulations of the extraction system.

An experiment for the direct measurement of the atomic mass unit is under way by accumulating ions from an ion beam up to a weighable mass. In the first experiment, a mass of more than 38 mg of bismuth was accumulated, and the atomic mass unit was reproduced with a relative deviation of 9 × 10−4 from the CODATA value. Details of the experimental setup and accumulation process are presented.

In the comparison in air of mass standards having different volumes, the major source of uncertainty arises from the determination of the density of moist air (buoyancy correction). The method being commonly used is the application of a recommended equation of state (CIPM 81/91 formula); a second method developed and used by only a few laboratories is based on two special artefacts having the same mass and surface area but very different volumes. Comparisons carried out by weighing the artefacts in air and in vacuum revealed a relative discrepancy of 6.4 × 10−5 between air density as measured by the artefacts and by the CIPM formula. Additional measurements were carried out at the BIPM in dry nitrogen. The comparison of the gas density obtained by the two methods confirmed the discrepancy already obtained for moist air but showed a much smaller discrepancy for dry nitrogen. These results reinforce the hypothesis that the accuracy of the air density using the CIPM formula is limited by the estimation of its composition, in particular the mole fraction of argon which may be underestimated. To test this hypothesis, an alternative value for the mole fraction of argon in air, arising from a recent redetermination, has been considered for use in the CIPM 81/91 formula. Modification of the CIPM 81/91 formula to include the recent argon determination would remove the discrepancy between the two methods of determining the density of moist air.

Unwanted magnetic effects must be minimized and quantified in precision weighing and mass metrology. To this end, methods of measuring magnetic fields and of characterizing the magnetic properties of bodies such as weights are reviewed. The results of comparisons between weights made of ferromagnetic and weakly magnetic materials as well as modelling the magnetic forces between weight and balance are reported. Finally, the impact of the magnetic properties of the weights on regulations in legal metrology is discussed.

A value for the Avogadro constant, NA, was derived from new measurements of the lattice parameter, the density and the molar mass of a silicon single crystal. The result NA = 6.022 135 3 × 1023 mol−1 has a relative measurement uncertainty and is in excellent agreement with other published data based on the x-ray crystal density molar mass method, indicating the high repeatability of these experiments. The value differs significantly from the Committee on Data for Science and Technology's most recent recommended value of 6.022 141 99 × 1023 mol−1 by more than 1 × 10−6 NA.

Proliferation of breast and endometrial cells is under the control of ovarian steroid hormones (SHs) such as oestrogen and progesterone. They mediate diverse physiological functions via interaction with nuclear-localised steroid hormone receptors (HRs). The SH receptor complex modifies the expression of SH-regulated genes by binding to conserved binding sites in their promoter region or through cross-talk with other transcription factors. In non-malignant tissues, HRs are in balance with other factors regulating proliferation, differentiation and apoptosis. While dysfunction of the regulatory mechanisms is a part of malignant transformation, functional SH receptors can promote growth of SH-responsive tumours. Therefore, anti-hormones that block the interaction of steroid hormones with the SH receptor are useful tools for the treatment of SH-responsive carcinomas. However, a portion of ER-positive breast cancers and most endometrial cancers do not respond to anti-oestrogens and continued treatment results in hormone resistance, mostly without loss of the ER. This review focuses on the mechanisms of action of hormones and anti-hormones in breast and endometrial carcinomas.

Thermal accommodation of 1 kg and 50 kg weights to ambient air under different storing conditions and change of apparent mass due to temperature differences between weight and air have been measured. Physical models taking account of different heat transfer processes and of convective forces of flowing air acting on the weight have been developed for describing the measurement results. Finally, the models are used to extrapolate the results and predict the change of apparent mass and waiting times for given residual deviations of apparent mass and residual temperature differences for weights of similar shape but other nominal values.

Berichtet wird ein Fall einer Patientin mit attackenformigen neuropathischen Schmerzen nach Unterarmverletzungen mit wiederholter Atemdepression und Bewusstlosigkeit nach mehreren adaquat dosierten Analgetikagaben zur Anfallkupierung. Die Leser sind anhand der klinischen Untersuchung aufgefordert, eine Diagnose zu stellen und online mit anderen Kollegen zu diskutieren (http://www.blogs.springer.com/DerSchmerz). Die Diskussion und Auflosung des Falls werden in der Folgeausgabe dargestellt.

After some months of operation, a number of PV modules develop a discolouration defect called “snail trails”, or “snail traces”, which appear as irregular dark stripes across the cells. Whereas these traces were soon identified as discoloured silver contacts along the cell edges or at micro cracks, the chemical and mechanistic reasons for this phenomenon have not yet been resolved in detail. In this work we show that silver nanoparticles accumulating within the encapsulation foil cause the brownish discolouration, and that certain additives of encapsulation and back sheet foils trigger the formation of these nanoparticles.

In this contribution, a new method to determine the crystal orientation with the example of chemical treated silicon wafers by means of optical microscopy has been demonstrated. The introduced procedure represents an easy method to obtain all relevant parameters to describe the crystal structure of the investigated material, i.e., the crystal grain orientation and the grain boundary character. The chemical treatment is a standard mono-texture for solar cells, well known in the solar industry. In general, this concept can also be applied to other crystalline materials, i.e., GaAs, SiC, etc., the only thing that needs to be adjusted is the texturing method to reveal specific crystal planes and the calculation model. In conclusion, an application of this method is shown with the example of the defect classification of recombination active defects in mc-Si solar cell. The introduced method demonstrates a simple and quick opportunity to improve the crystallization process and the quality of electronic devices by means of an optical microscope and a chemical treatment of the material.

Apparent mass differences due to free convection were measured for 1 kg mass standards. The observed temperature dependence was analysed, also that of some 20 g artefacts reported earlier. A model based on estimates of the convective heat transfer rate and the overall average velocity of the convective air current was used to interpret the experimental results.

On the basis of economical importance of mass determination of material streams, especially in agriculture, the radiometric measuring principle was proved as the priority solution for estimation of the transported masses. Optimal arrangements of sources and detectors with a minimum influence of material cross distribution on the weighing processes were found by theoretical and experimental studies. This radiometric conveying mass gauge was subjected to a serial of tests under research and agricultural conditions. The influence of various factors (e.g. moisture content, crude ash content, kind of agricultural material) was studied.

The density of ambient air has been determined by a straightforward experimental method. The apparent masses of two artefacts having about the same mass and surface, but different well-known volumes, have been compared by using a 1 kg balance in vacuum and in air. The differences of apparent masses and volumes yield the air density with a relative uncertainty (1σ) of 5 × 10-5. From measurements made using a third artefact, surface sorption effects caused by the change between vacuum and air conditions gave a coefficient of about 0,2 μg cm-2.

The change of the apparent mass of 20-g masses and tubes that are not in thermal equilibrium with ambient air has been observed. Buoyancy, adsorption and convection influences are discussed. Quantitative comparisons show that, under such conditions, it is predominantly free convection forces which change the apparent mass.

The present applications of nuclear techniques in agriculture of the GDR are reviewed. An estimation of the future application potential is given. Der gegenwartige Anwendungsumfang radiometrischer Meβtechnik in der Landivirtschaft der DDR wird dargestellt und eine Einschatzung der zukunftigen Entwicklung gegeben.

In order to show equivalence of mass standard determination among NMIs of CIPM member countries, key comparisons of mass standards have been carried out under the auspices of the CCM. At each NMI, mass standards are derived from one kilogram by means of the multiples and submultiples methods. The pilot laboratory, NMIJ, prepared five sets of transfer standards. Any set of transfer standard consists of five pairs of mass standards with nominal values of 200 mg, 1 g, 50 g, 200 g and 2 kg. The nominated twenty participants have been divided into four groups and the corresponding four sets of transfer standards have been circulated within the groups simultaneously while the remaining set has been kept at the pilot laboratory for the stability evaluation. The pilot laboratory measured the volumes, the centres of gravity and the magnetic properties, susceptibilities or magnetism, of the standards before the circulation and has reported these values to the participants. The pilot laboratory has also verified the stability of all travelling standards in advance. Nineteen laboratories have reported final results to the pilot. Nine participants belong to EURAMET, three belong to COOMET but two of them also belong to EURAMET, four belong to SIM, and five belong to APMP. Table 2 shows all the results associated with their uncertainties reported by the participants. As shown in table 3 the majority of the instabilities of the transfer standards during their circulation were less than the claimed uncertainties of the participants except for few standards of small mass, 1 g and 200 mg. These instabilities are considered for uncertainty evaluation within the group. All reported results among different groups have been linked based on the average values of transfer standards before and after the circulation. Figures 3 to 7 show the comparison results of all the participants for five nominal mass values respectively. The plotted results are expressed in relation to the median as reference values. Tables 10 to 19 show the differences and associated expanded uncertainties referred to a confidence level of 95% between any combination of the laboratories in the form of matrices. They show a few outliers, one at 2 kg and 200 g, three at 50 g, and two at 200 mg. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Mass as a physical quantity and its measurement are described. After some historical remarks, a short summary of the concept of mass in classical and modern physics is given. Principles and methods of mass measurements, for example as energy measurement or as measurement of weight forces and forces caused by acceleration, are discussed. Precision mass measurement by comparing mass standards using balances is described in detail. Measurement of atomic masses related to 12C is briefly reviewed as well as experiments and recent discussions for a future new definition of the kilogram, the SI unit of mass.

We report a key comparison of 1 kg stainless steel mass standards carried out between February 1995 and October 1997. Organized within the Consultative Committee for Mass and Related Quantities (CCM), the participants included 14 national metrology institutes (NMIs) and the BIPM, with the BIPM serving as pilot laboratory. The 14 NMIs were divided into two groups, each of which determined the mass of two cylindrical travelling standards. In preliminary measurements, the pilot laboratory had determined the important physical properties of the four travelling standards and had monitored their mass stability over time. Measurements within the two groups then proceeded in parallel, with the four travelling standards returning several times to the pilot laboratory in order to monitor their stability. One of the present authors (MG) shows in appendix 3 how to treat comparisons among participants in different 'loops'. As shown in appendix 4, the mass reported by each NMI was derived indirectly from the mass of its national prototype, introducing a significant correction for air buoyancy during this step. The median of all results was taken to be the reference value for this key comparison. The degrees of equivalence are shown in tables 3?5 and summarized graphically in figure 7. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the Mutual Recognition Arrangement (MRA).

The editors of this book are well qualified for the immense task they have undertaken. Both have acquired great expertise during their distinguished careers at the Physikalisch-Technische Bundesanstalt. The word `comprehensive', which appears in the title, is certainly well chosen. Scarcely any topic has been overlooked. The diverse subjects which together comprise the untidy story of mass metrology have here been organized and presented in sufficient depth to make this book an essential reference in every science library. Quite simply, I know of no other book like this available in English. Comprehensive Mass Metrology, aside for some updated material, is essentially a translation of Massebestimmung, which appeared in 1997. It is evident on most pages, alas, that the English version has been translated from a foreign language (e.g. `inert mass' instead of `inertial mass' throughout); but the meaning is always clear enough. Abundant references are given in each chapter. I wish this book, or one like it, had been available to me the first time I was called upon (as a postdoctoral fellow) to make an accurate mass measurement. After hours of searching in the library and talking to busy colleagues, I found (but still did not fully grasp) that, even when properly calibrated, balances display only the `apparent' mass of the object on the pan; that the apparent mass is usually close to something called the `conventional' mass; and that neither the apparent mass nor the conventional mass is quite what is meant by mass in the Newtonian sense, which was what I needed. This book covers all these topics in great depth. The book begins at the beginning with a brief definition of mass, followed by a thorough discussion of the unit of mass (the kilogram). As most readers of this journal will be aware, the kilogram is the last remaining base unit of the International System (SI) still defined by an artefact: a cylinder of platinum alloy. One of the exciting areas of mass metrology consists of attempts, all of them clever and experimentally demanding, to replace the artefact definition by a definition linked directly to a physical constant. Conceptual elegance is desirable in any new definition. However, it must also be practical to realize with sufficient accuracy. This, of course, is the real challenge. The relevant chapter, which appears early on, provides a careful introduction to this fascinating subject. Among the diversity of other topics treated in the book, I was pleased to find an excellent and authoritative chapter on vacuum weighing. The various contributions, having been written by several different authors, are largely self-contained. Consequently, similar material is sometimes presented in slightly different ways. For instance, one chapter gives an approximate equation for the density of distilled water near room temperature. The formula is abstracted from a 1975 reference (with temperatures given in terms of the IPTS-68 temperature scale) despite the fact that an Appendix in the book gives another table (based on the ITS-90 temperature scale). Minor quibbles aside, this book is indeed comprehensive and authoritative. I highly recommend it. R S Davis

A He-Ne laser at λ = 612 nm, stabilized to saturated absorption features of 127I2 in an external cell [and with no cell inside the laser cavity] is presented. The successive-2-sample deviation for an averaging time of 10 s is not larger than 0.15 kHz or 3 × 10-13 of the laser frequency. The uncertainty of the laser frequency due to variations of the laser power or of the beam geometry is less than 5 kHz. But dramatic frequency shifts occur when the returning beam touches an obstacle. Single and multiple linear-regression analyses of the pressure and modulation dependence seem to offer a measure of the reproducibility and of technical or physical perturbations. Linewidth and asymmetry of the peaks have been studied, and the frequency differences of 9 hyperfine components have been determined.

Auf der Grundlage theoretischer und experimenteller Untersuchungen wurde uberpruft, inwieweit 83Kr durch 133Xc als Tracer bei Stromungs-, Volumenstrom-, Gasaustausch- und Vermischungsmessungen ersctzt werden kann. Insbesondere wurde die Effektivitat verschiedener Detektortypen und der Empfangsradius in Luft gegenuber der Strahlung dieser Radionuklide ermittelt. Es zeigte sich, daβ trotz Einsatz des effektivsten, betaempfindlichen Zahlrohrtyps zur Erzielung vergleichbarer Impulsdichten ein hoherer Aktivitatseinsatz bei 133Xe im Vergleich zu 85Kr erforderlich ist. Der Einsatz von Szintillationsmeβsonden erhoht die Effektivitat, allerdings auf Kosten der raumlichen Auflosung. On the basis of theoretical and experimental investigations the possibility of substituting the radionuclide 85Kr by the radionuclide 133Xe as tracer for flow-, hold-up time (residual time)-, exchange rate- and mixing measurements in gases was tested. Especially the efficiency of several different counters and the range of the radiation...

We have investigated the properties of He-Ne lasers stabilized to saturated absorption features of either 127I2 or 129I2 at 612 nm. Using 129I2 we observe 25 strong, not yet reported, saturated absorption signals which are preliminarily attributed to hyperfine structure (HFS) components of the P(110) 10-2 transition of 129I2. Linewidths of 5.5 MHz fulwidth half medium (FWHM) and 1.2 MHz have been observed with I2 cells positioned inside and outside the laser cavity, respectively. Using intralaser cavity I2 cells the frequency difference of our lasers, stabilized independently to the 127I2 components o or r was 2.10-11?.

Die zunehmende Industrialisierung der landwirtschaftlichen Production bei hoheren Qualitatsanforderungen verlangt objective und hochempfindliche Kontrollverfahren. Zur zerstorungsfreien Ermittlung innerer Qualitatsmangel an Fruchten, z.B. Kartoffelknollen, konnen lichtoptische Verfahren wegen der starken Streuung nicht umfassend eingesetzt werden. Deshulb wurde unter Einsatz weicher Gammastrahlung (241 Am) versucht, “trockene” Hohlstellen, insbesondere bedingt durch Hohlherzigkeit, in Kartoffelknollen zu erkennen. Es konnte gezeigt werden, daβbei einem Erkennungsfehler von etwa 13% diese Mangel (ab ca. 5 mm Durchmenser) zu erkennen sind, auch wenn die Knollen nur in einer durch die Knollenmitte verlaufenden Ebene durchstrahlt werden.

Das ursprunglich fur die Ascheanteilsbestimmung in Braunkohle entwickelte Komplexe Radiometrische Analysen-system KRAS-2“, das auf der Grundlage des Zwei-Gammaenergie-Transmissionsverfahrens arbeitet und zur Eliminierung von Dichte- und Schichtdickenschwankungen des Meβgutes ein auf einem Mikroprozessor basierendes Datenver-arbeitungssystem enthalt, wurde hinsichtlich seiner Eignung fur die Messung des Anteils mineralischer Beimengungen in Erntegutern getestet. Die on-line-Messungen an einer Kartoffel-Einlagerungsstrecke einer Praxis-Anlage wahrend der Erntekampagne bestatigten die Ergebnisse aus vorausgegangenen Abschatzungen und Laborexperimenten, daβ der Beimengungsanteil mit einem Fehler von unter 3 Masseprozent bestimmbar ist. The 2-energy transmission gauge KRAS-2 applying a microprocessorbased on-line date processing for eliminating surface density variations – originally developed for ash content determination in raw lignite – has been checked for its applicability to measuring the content of mine...

The 690 nm absorption change reflecting the turnover of the reaction center chlorophyll of System II, chlorophyll a II , (see Doring, G., Renger, G., Vater, J. and Witt, H. T. (1969) Z. Naturforsch. 31c, 712–721 and Glaser, M., Wolff, Ch., Buchwald, H. E. and Witt, H. T. (1974) FEBS. Lett. 42, 81–85) has been investigated as a function of pH of the chloroplast suspension. It was found: 1. (1) In the range 6.0 ⩽ pH ⩽ 8.0 the amplitude of the measured chlorophyll a II absorption change, ΔA 0 (chlorophyll- a II ), markedly declines with increasing pH, whereas the average oxygen yield per flash remains nearly unaffected. 2. (2) The dependency on actinic flash intensity of the amplitudes ΔA 0 (chlorophyll- a II ) at pH 6.0 closely resembles that for the amplitudes of the chlorophyll a I absorption change. On the contrary, at pH 7.5 a higher flash intensity is required for half saturation of ΔA 0 (chlorophyll- a II ), whereas the corresponding curve for ΔA 0 (chlorophyll- a I ) is practically invariant to pH. 3. (3) Addition of ionophores at concentrations sufficiently high for a complete collaps of proton gradients across the thylakoid membrane shifts the pH-dependence of ΔA 0 (chlorophyll- a II ) by more than 2 units towards the acidic range. On the basis of a hypothesis presented very recently (Glaser, M., Wolff, Ch. and Renger, G. (1976) Z. Naturforsch. 31c, 712–721) it is assumed, that the reduction in the dark of photooxidized chlorophyll a II + is regulated by the proton concentration in the inner thylakoid space. At lower pH the reaction proceeds predominantly via the well known 35 μs kinetics, whereas at higher pH a very rapid kinetics (⩽ 1 μs ), too fast to be resolvable by our measuring device, additionally contributes to a significant degree to the overall reduction of chlorophyll a II + . Furthermore, on the basis of Lavorels model (Lavorel, J. (1975) in Bioenergetics of Photosysthesis (Govindjee, ed.), pp. 223–317, Academic Press, New York) the close interrelationship between ΔA 0 (chlorophyll- a II ) and delayed fluorescence intensity in the μs range is shown to be interpretable mainly by kinetical rather than by energetical effects.

Es wird eine radiometrische Forderbandwaage nach dem Prinzip der Gammastrahlungsschwachung beschrieben. Sie arbeitet netzunabhangig und ist fur den nichtstationaren Einsatz geeignet. Als Strahlungsquelle wird Casium-137 eingesetzt, der Strahlungsnachweis erfolgt mit einer speziellen Anordnung von Halogenzahlrohren und einfachen Zāhlgeraten. Erste Erprobungen unter Feldbedingungen erfolgten zum Zwecke der Bestimmung der Uberlaufmasse (Kartoffeln und Erdreich) zur Feststellung der Absiebleistung bei Forschungsvarianten an Kartoffelkombines. Der maximal mogliche Durchsatz liegt bei 180th−1. Kartoffeln und Erdreich in der Groβenordnung von 2 t sind mit dieser Wageeinrichtung mit einem relativen Fehler von ±3,5% bestimmbar.

A new dye laser spectrometer utilizing a non-tunable reference resonator is described. The resonator consists of two Zerodur mirrors optically contacted to a Zerodur spacer. Frequency scanning of the laser is provided by acoustooptic modulation. Residual drifts of the resonator frequency — measured on line — are compensated automatically by corresponding corrections of the modulation frequency. The stability during several hours and the resettability of the dye laser frequency are±2.5 kHz and±10 kHz, respectively.

Es wird eine radiometrische Bandwaage zur Koksaustragsmengen-Messung in BHT-Kokereien beschrieben. Voranstellend werden einige analytische Ausdrucke zur theoretischen Behandlung dieses Bandwaagentyps mitgeteilt. Die Waage zeichnet sich durch hohe Stabilitat der Anzeige, durch die Moglichkeit des routinemasigen Umsetzens von Messtelle zu Messtelle innerhalb kurzer Zeit und durch einen relativ kleinen Wagefehler (Mesunsicherheit ≦ 2,9%) aus. Die Signalaufbereitung innerhalb der Elektronik erfolgt durchgangig digital unter Verwendung eines Rechnerschaltkreises.

A procedure is suggested for compensating the broadening due to the quadratic Doppler effect and for band shifts caused by phase mismatch in the observation of a Ramsey signal in an atomic calcium beam. The relative error in the frequency stabilized by this method is estimated to be 2 × 10− 12.

Es wird eine radiometrische Fullstandsmeβsonde mit linearer Anzeige beschrieben. Sie besteht aus einem Salz Quellen ionisierender Kernslrahlung (z. B. von 137Cs) quadratischer Aktivitatsabstufung, die in einem schlanken Rohr untergebracht sind, einem Szintillationszahlrohr und der Nachfolgeelektronik. Sondenrohr, Quellen und Szintillationszahler stellen eine kompakte, leicht transportable und besonders in schwer zuga;nglichen, schmalen und undurchsichtigen Behaltern einsetzbare Sonde dar. Das beschriebene Gerat erganzt die Palette der Fullstandsmeβgerate um eine weitere, fur viele Falle der Praxis geeignete Variante.

The assumptions made in a correction theory developed by Kramers for the counting rate of Geiger-Muller counters were tested experimentally. The results obtained for Vakutronik-GM counters (containing organic quenching vapour) require the introduction of a new quantity for the calculation of the correction-factors, the minimal dead-time. A function is given for the envelope of the peaks of the pulses, which appear during the recovery-period.

Eine Korrekturformel fur die Zahlrate von Geiger-Muller-Zāhlrohren wird angegeben und experimentell gepruft. Die Formel wurde auf der Grundlage der Kramersschen Korrekturtheorie und experimenteller Ergebnisse des Autors entwickelt. Sie isfur Geiger-Muller-Zāhlrohre mit relativ empfindlicher Nachfolgelektronik geeignet, die selbst als nichtblockierende (non paralyt sable) Zāhler mit konstanter Sperrzeit arbeitet.