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Neutrons contribute to the background of low radioactivity measurements, especially with detectors in large lead shields above ground, and to a lower extent in underground laboratories of medium depth. We measured the natural neutron flux in the energy region of fission by commercial 3He filled proportional counters at different places above ground and in an underground laboratory, which is covered by 47 m of rock, and demonstrated the drastic reduction of the neutron flux in the underground and the influence of the materials of the environment.

George de Hevesy has founded Radioanalytical Chemistry and Nuclear Medicine, discovered the element hafnium and first separated stable isotopes. For all these different important achievements he was nominated for the Nobel Prize. On occasion of his discovery of activation analysis 70 years ago his life and work will be illustrated.

For the investigation of flooding processes in uranium mines, Ra and Th nuclides as well as 238U and 227Ac activities in waters were simultaneous analyzed by gamma-ray spectrometry. The activities of 227Ac and 228Th, not directly determinable by gamma-ray spectrometry, can be calculated from two consecutive measurements (approximately 25 d delay) of the progeny 227Th and 224Ra. For the short-lived radionuclides 234Th, 227Th, 223Ra and 224Ra a correction of the results to the sampling date is necessary.

A chamber with a shield of steel and lead of a total surface density of 365 g cm −2 for low-level measurements has been installed within a cave at an old brewery named ‘Felsenkeller’ in the Weisseritz-valley near Dresden. In the 45 m deep underground laboratory 98% of cosmic muons are shielded by the rock. Low detection limits are necessary for the measurement of different kinds of water and biological samples. The use of γ-spectrometry reduces the need for complex chemical separation procedures.

Long-lived isotopes of corrosion products are very important for the disposal of low-level radioactive wastes. These nuclides serve for risk calculations of accidents. Their determination needs the radiochemical separation from high active main nuclides. Supervision of waste vessels is done by direct non-destructive γ-spectrometry of the key nuclide60Co for corrosion products. The activity ratios of the long-lived nuclides to the key nuclides are called scaling factors. We have determined such factors radiochemically in evaporation residues of power water and cooling water. They are used for activity calculations of long-lived nuclides in the waste vessels. In case of59Ni the obtained scaling factor was compared with a literature value and values calculated on the basis of nuclear data. Our value was in a good agreement with the calculated one. Due to the fact, that we have used low-level measurement techniques, we could perform the necessary chemical separations in a laboratory not exceeding the 10-fold free-level limit.

Long-lived isotopes of lanthanides and actinides are very important for the disposal of low-level radioactive wastes. These nuclides serve for risk calculations of accidents. Their determination requires radiochemical separation from high activity main nuclides. Supervision of waste vessels is done by direct non-destructive γ-spectrometry of the key nuclides:60Co for corrosion products and137Cs as for fission products as for transuranic elements. The activity ratios of the long-lived nuclides to the key nuclides are called scaling factors. They have to be determined radiochemically in the laboratory in representative samples of each waste type. They are used for activity calculations of long-lived nuclides in the waste vessels. The scaling factors determined are of the order of magnitude of 10−6 and due to the fact that we have used low-level measurement techniques, we could performe the necessary chemical separations in a laboratory not exceeding the 10-fold free-level limit.

3D integration through silicon technology of integrated circuits challenges non‐destructive testing methods. 3D x‐ray methods are the techniques of choice to localize defects in interconnects. The development of high‐power x‐ray sources enabled the use of x‐ray microscopy in laboratory tools. Those devices are able to resolve features down to 40 nm in an acceptable measurement time. However, the field of view is very limited to 16 μm in high‐resolution mode and to 65 μm in large‐field‐of‐view mode. To record tomography data, the size of the samples must not exceed the field of view to circumvent specific artifacts. Semiconductor samples usually do not fulfill the condition mentioned above since they have the shape of flat sheets. Therefore limited‐angle tomography is typically used. The missing angles cause typical capping artifacts and poor signal‐to‐noise ratio. We present a modified scanning geometry that overcomes some of the artifacts and yields a better image quality. The geometry and potential appl...

Mantle-derived magmatites from the Saxonian Granulite Massif have been investigated by instrumental und radiochemical NAA. Pd, Ir and Pt were separated after irradiation by extraction with DDTC and DBDTO. Cs was precipitated by sodium tetraphenyl borate, the REE were isolated by cation exchange and the activation products of thorium and uranium by extraction with TOPO. The Lower-Riphean and Upper-Riphean magmatites contain sequences of partial melting and fractionated crystallization. They start from ultramafic garnet serpentinites with the composition of primary earth mantle. The contents of platinum group elements in garnet serpentinites amount to about 1% those of Cl chondrites. In depleted serpentinites, which are residues of partial melting, the concentration of Pd is reduced by a factor of 4.5.

During a five-year period, the International Atomic Energy Agency supported a Coordinated Research Programme (CRP) to investigate the quantitative relationship between internal body burdens of a number of elements of environmental health significance and their respective concentrations in hair. The use of nuclear-related analytical techniques, such as neutron activation analysis, X-ray fluorescence, particle-induced X-ray emission and radiotracers, was emphasized. One aspect of the CRP focused on studies in man, using autopsy cases, of mineral distribution in five tissues, i.e. liver, kidney, lung, brain and bone in addition to hair, and the elements of primary importance were As, Cd, Cu, Hg, Pb, Se and Zn. Emphasis was placed on analytical quality assurance. Hair and internal tissue samples were obtained from subjects from Bulgaria, China, the former German Democratic Republic, Hungary, Japan, Norway and Sweden.

A force‐sensor technique was developed to determine small forces in‐situ in a scanning electron microscope (SEM), enabling to investigate elastic and plastic deformation modes and corresponding critical strains in single silicon lamellae. Large elastic deformations were obtained, matching with modeling of the Si deformation behavior by finite element analysis. This technique is shown to be applicable also to copper structures obtained after filling of the space between the Si lamellae and subsequent etching. The obtained mechanical properties of the structures on a nanoscale are important for the design of present and next‐generation microprocessors.

With this article we remember the discovery of solid and liquid scintillators 50 years ago.H. Kallmann andL. Herforth found out that aromatic hydrocarbons are suitable to convert the absorbed energy of nuclear radiation especially from β-particles into light. They found the quenching of impurities, the reduced photon yield of α-emitters and the different fluorescent decay time of α- and β-particles.

Based upon extensive data on the elemental and isotopic compositions of Kupferschiefer of the Sangerhausen basin and according to results of trace-element and structural investigations of bitumen extracts trends of lateral and vertical distribution of various elements and genetic assertions are presented. Irregular positions of F, V, Se, Au and U in the correlation diagram, peculiarities of the lateral distribution of these elements, abnormally high elemental concentrations in the rocks and in the bituminous extracts as well as alterations discovered in the composition of hydrocarbon groups and their structures support the idea of an influx of oxidizing, metalrich waters moving through the “Rote Faule” from the Rotliegendes basin into the Kupferschiefer sediment. Isotope geochemical investigations (carbon, nitrogen and oxygen of organic, carbonate and silicate fractions were carried out in order to characterize more precisely the conditions of sedimentation and the regime of diagenesis. The contrary δ 13 C curves of PbZn facies and “Rote Faule” facies and the 13 C enrichment in the organic matter of “Rote Faule” can be explained by different redox conditions during sedimentation and/or diagenesis. Furthermore the decreasing δ 18 O-values of carbonates of the Rote Faule also suggest an influx of meteoric waters. The results oppose a final syngenetic to early diagenetic fixation of the metal contents in Kupferschiefer areas in the vicinity of Rote Faule. The established model of influx of metalliferous fluids, which arose from the Rotliegendes, is of local interest for element input and element redistribution.

In the meteorites trace elements have been determined by instrumental and radiochemical N.A.A. and the cosmogenic radioactivity of 22Na, 26Al, 48V, and 54Mn are measured by low-level gamma spectrometry in the two meteorites Hohenlangenbeck and Trebbin fallen November 1985 and March 1988 onto the territory of the GDR. The contents of Rb and Cs in the meteorite Hohenlangenbeck are relatively high indicating a low condensation temperature. Becuase of the small activity ratio of 22Na/26Al a lower particle flux in its orbit during the last five years is assumed.

The paper presents actual data from investigations of the soil-plant transfer of the primordial radionuclides 40K, 238U, 226Ra, 210Pb and 227Ac for tomatoes growing at soils from former uranium mining areas. The analysis were carried out using low-level gamma-ray spectrometry in a 47 m deep underground laboratory. For tomato fruits transfer factors of (0.0007 +/- 0.0006) for 235U, (0.0021 +/- 0.0017) for 226Ra, (0.0015 +/- 0.0009) for 210Pb and (0.0018 +/- 0.0012) for 227Ac were obtained. The investigation of the soil-plant transfer by low-level gamma-ray spectrometry is often limited by the Compton-continuum from the always present high-energy gamma-ray emitter 40K.

In the underground laboratory 'Felsenkeller' in Dresden a new iron shielded counting room is installed. In the paper the laboratory is described and examples of application of low-level counting techniques are presented. Long-lived radionuclides in low-level wastes from a power station are corrosion products, fission products, and actinides. They have been radiochemically separated and measured by alpha, beta, and gamma spectrometry. Natural radionuclides in soil samples, water and plants from the vicinity of an uranium mining plant are measured by gamma and by alpha spectrometry. Geochemical and technological processes cause important changes of the radioactive equilibrium, for example in the activity ratio of 223Ra and 226Ra.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The first measurements of the fluorescence of liquid organic compounds after excitation with nuclear radiation were published 1948 in a thesis of L Herforth and a paper by Herforth and Kallmann (1949).

Long-lived isotopes of lanthanides and actinides are important components in low-level radioactive wastes. Their determination requires radiochemical separation from the predominant highly active nuclides. Control of waste vessels containing fission products and transuranic elements is achieved by direct non-destructive γ-spectrometry of the key nuclide 137Cs. The activity ratios of the long-lived nuclides to the key nuclides, called scaling factors, have to be determined radiochemically in the laboratory in representative samples of each waste type. The scaling factors are in the order of magnnitude of 10−6. By using low-level measurement techniques in an underground laboratory, the chemical separations can be performed with small sample quantities.

After publication of an article about the discovery of organic scintillators by H. KALLMANN and L. HERFORTH more details came to the authors knowledge which point to the need to add I. BROSER to the discoverers of organic scintillators.

With the help of NAA a number of trace elements were determined in ultrabasic rocks, xenolithes of alkali basalts, basalts, phonolites and pyroxene inclusions in phonolites from the South of the GDR. The formation of the investigated magmatites were explained by metasomatism, partial melting and fractionated crystallization in the earth mantle.

Es wird eine automatische Auswertung von Ge(Li)-Gammaspektren mittels elektronischer Rechenmaschine vorgestellt. Sie besteht aus Peaksuche, Peakparameterbestimmung, Nuklididentifizierung sowie Aktivitāts- und Elementgehaltsbestimmung.

In einigen Organen und Tumoren der Ratte wurde der Gehalt an Spurelehmenten, insbesondere an Kupfer, Zink und Arsen, durch Neutronenaktivieruntjsanalyse bestimmt. Die Organe der Halle enthalten sehr viel Arsen, welches besonders in den Erythrozyten angereichert ist. Die hohen Konzentrationen verbunden in it der geringen Streuung der Arsengehalte weisen auf eine ausgezeichnete Rolle dieses Elementes in der Ratte hin.

Teile von Leberbiopsieproben des Menschen von etwa 0,4 mg Masse werden auf ihren Gehalt an Mangan, Kupfer und Zink untersucht. Die Proben werden gefriergetrocknet und in Quarzrohrchen im Rossendorfer Forschungsreaktor bei einem Fluβ thermischer Neutronen von 2 · 1013 n cm−2 s−1 aktiviert. Nach chemischer Auftrennung an einem Anionenaustauscher werden die Aktivitaten von 56Mn, 64Cu und 69mZn im NaJ(Tl)-Szintillationsdetektor gemessen. In jeder Probe wird gesondert der Leber-Triglyzeridgehalt bestimmt. 20 Proben von Normalpersonen mit kontrolliertem Kohlenhydrat- und Fettstoffwechsel wiesen 6,3 ppm Mn, 30 ppm Cu und 164ppm Zn, bezogen auf Trockenmasse, auf. Diese Konzentrationen stimmen mit Literaturangaben etwa uberein. Bei Fettleber und Hypertriglyzeridamie waren die Metallkonzentrationen verringert. Es wurden zwischen den Metallkonzentrationen untereinander positive Korrelationen und zwischen Metall- und Triglyzerid-konzentrationen negative Korrelationen festgestellt.

The installation of a multi-sample beta-gamma coincidence spectrometer in an underground laboratory with a rock covering of 47 m yielded further background reduction by factors of between 10 (at 2 MeV) and about 4 (below 1 MeV). In silicon samples Fe can be measured by neutron activation analysis with a detection limit of 40 pg.

A survey of problems connected with the activation analysis of extremely pure materials is given. The treatment of the surface of the samples influences the results. The detection limit of counting radiochemically pure nuclides are determined by efficiency, background and counting interval. The background, which usually is reduced by selected construction materials, large shields and anticoincidence techniques also may be reduced by the βγ-coincidence technique. It is possible to arrange several small β-ray detectors closely to one large γ-ray detector. Several samples are measured at the same time with a long counting interval without interferences. The method was applied to the analysis of semi-conductor silicon.

In an interlaboratory comparison four samples of monocrystalline silicon were analyzed sequentially by INAA in four laboratories. The results obtained demonstrate the possiblity of repeated use of silicion samples for interlaboratory comparisons. *** DIRECT SUPPORT *** A0653052 00003

Es wurden einige k0-Faktoren fur die Standandisierung der Multielement-Neutronenaktivierungsanalyse bestimmt und mit Werten verglichen, die aus Kerndaten berechnet bzw. von anderen Antoren bestimmt wurden.

NAA and CPAA are the most sensitive analytical tools for the determination of residual impurities in semiconductor silicon. Extremely small detection limits are found by measuring the activity in an underground laboratory. The accuracy and reliability of the methods were checked by several comparisons: interlaboratory comparison on NAA, another CPAA with IR-spectrometry as well as comparison of NAA-results, obtained instrumentally and by chemical separation.

Methods of separation of uranium and plutonium from irradiated nuclear fuels by extraction and ion exchange are described as well as methods of the determination of the element concentration or isotopic composition by spectrophotometry, coulometry, potentiometric titration, mass spectrometry, alpha spectroscopy and liquid scintillation counting. Advantages and disadvantages of the methods are discussed.

In order to investigate the behaviour of elements during the progressive regional metamorphosis 28 elements have been determined by radiochemical and instrumental NAA. The concentrations are determined in different stages of metamorphosis. The results enable us to classify the elements.

Die Gehalte an F, Al, Cl, Cr, Fe, Co, Cu, Zn, Se, Ag, I und Au sind im Haar aktivicrungsanalytisch bestimmt und mit Werten aus der Literatur verglichen worden. Dabei fanden wir einen relativ niedrigen Se-Gehalt (0,3 ppm). Wir erhielten, erhohte Konzentrationen an Cr und Mn im Haar von Schweisern und hohe Werte fur F bei Personen, die mit Fluorverbindungen arbeiten. Frauen mit einem Mamma- bzw. Schilddrusenkarzinom zeigten erhohte Zn-Werte und Struma-patienten erniedrigte I-Gehalte im Haar.

Primary coolant samples from a research have been analyzed for239,240Pu,238Pu,238U,237Np and239Np. The determination of237Np and238U was carried out with the help of isotope dilution neutron activation analysis with239Np or238Np as tracer. For determination of239,240Pu and238Pu alpha spectroscopic isotope dilution analysis with238Pu as tracer was used.239Np was determined with the help of isotope dilution analysis using238Np as tracer. Nuclides were isolated by chemical separation on anionite resin. Before measurement, Pu isotopes were electrolytically deposited on stainless steel plates. Activity ratios referred to238U were reported. They are helpful for identification of the sources of actinide activity in reactor effluents.

Durch Altivierungsanalyse mit 6,75-MeV-Protonen des Rossendorfer Zylclotrons U-120 wurde Stickstoff in Silizium uber die Kernreaktion 14N(p, α)11C bestimmt. Die 11C-Aktivitat wurde durch einen oxydativen Aufschluβ von der Matrix abgetrennt und in einer γ, γ–Koinzidenzanordnung gemessen. Die erreichte Nachweisempfindlichkeit belragt 1 ppb. Bor stort die Bestimmung.

For89Sr and90Sr determination in grass samples neutron activation analysis was employed as an advantageous method for yield measurements during the separation process. From the activity ratio found conclusions on the source of radioactivity are possible taking into consideration the dependence on reactor operating time.

Mg, Ti, Ni and Zn have been determined in semiconductor silicon by deuteron activation analysis using radiochemical separation and coincidence spectrometric methods. Detection limits under the experimental conditions are 15, 3, 0.7, and 14 ppb, respectively.

The underground laboratory of the CINR with 125 metres water equivalent (mwe) is used mainly for activation analysis of pure materials. Background spectra of NaI(Tl) and Ge(Li) detectors are discussed in comparison with those of other underground laboratories. Detection limits are calculated as disintegration rates to about 15 mBq as well as masses detectable by neutron activation analysis for some 50 elements, most of them below pg.

A multiple beta - single gamma detector assembly offers the low background necessary for the coincidence technique and the possibility to measure several samples simultaneously with only one gamma-ray detector of good efficiency and high resolution. Detection and pulse processing, as well as the decrease of the total counting time consumption and the cross-talk probabilities of the arrangement are dealt with.

An underground laboratory has been installed under 47 m rock covering (125 metres water equivalent), where the cosmic radiation ist diminished more than 40-fold. The massive laboratory building, 6 × 3.5 m2 by 3.4 m height, was erected on a foundation of 0.8 m serpentinite with a framework of old steel, forming walls and ceiling with 0.7 m thickness, filled with serpentinite. A Ge(Li)-detector of 75 m3 and 9.1% efficiency ist shielded by lead of 10 cm thickness. The background spectra are comparable with those of anticoincidence devices described in the literature. Detection limits for small samples amount to 0.025 Bq; for natural radioactivities of 1000 g samples to 0.15 ppm Th, 0.03 ppm U and 0.011% K2O for 12 h-measurements.

7 days after the fall of a stony meteorite its γ-spectrum has been measured on a Ge/Li/-detector installed in an underground laboratory. The activity of22Na,26Al,40K,48V, and54Mn has been determined.

The determination of impurities in semiconductor silicon by nondestructive and destructive NAA is described. To improve the detection limit, a multiple beta—single gamma detector assembly is used. It is shown that24Na is also produced from silicon by a (n, αp) reaction with reactor neutrons. The cross-section with fission neutrons is 1.8·10−9 barn.

In tertiary mugmatites from the south of GDR the contents of Na, Fe and 20 trace elements are determined by INAA. For 9 phonolithes and other basaltic rocks mean values and concentration intervals uf the elements determined are represented. Comparison of some results determined parallel with optical analytical methods give average deviations for Fe and Na of approximately 3% and for Ba, Cr and Ni of about 20%. The results of U- and Th-determination are compared by measurements of natural radioactivity. Average deviations run to 10%. The use of Cr, Sc and Th as indicator elements of magmalic differentiation is discussed.

Using a layer etching technique impurity profiles of Cu and Fe in silicon samples are measured by n.a.a. Radiation enhanced diffusion of Cu and Fe impurities from the surface into the bulk material has been observed. The samples were etched before irradiation to remove the impurity profiles caused by the sampling procedures.

NAA, TEM, DLTS, and EBIC investigations of Cu-contaminated CzSi with an intrinsic-gettering procedure realized by a multistep heat tretament demonstrate the efficiency of intrinsic gettering concerning redistribution to volume defects for Cu-contamination up to 1016 cm−3. The Cu-precipitation at the surface can still be suppressed for such contamination due to volume defects. However, in this case the concentration of contamination induced deep level centers at the surface is independent of the volums defect density. Only for Cu-contamination of about 1015 cm−3 the gettering effect is strong enough to prsrent the introduction of contamination induced deep levels at the surface. Die Untersuchung von Cu-kontaminiertem CzSi nach einer fur die Intrinsic-Getterung typischen Mehrstufen-Warmebehandlung mittels Naa, TEM, DLTS und EBIC demonstriert die Wirksamkeit der Intrinsic-Getterung hinsichtlich Umverteilung zu den Volumendefekten bis zu einer Cu-Kontamination von 1016 cm−3. Die Ca-Prazipitation an dsr Oberflache kann infolge der Getter-wirksamkeit von Volumendefekten fur diese Kontamination noch unterdruckt werden. Die Konzentration kontaminationsinduzierter tiefer Storstellen an der Oberflache wird aber in diesem Fall schon nicht mehr reduziert. Nur fur eine Cu-Kontamination um 1015 cm−3 konnen infolge Mehrstufen-Warmebehandlung keine kontaminationsinduzierten tiefen Storstellen an der Oberflache mehr nachgewiesen werden.

Die Diffusion von Kupfer aus der Oberflache in das Innere von Siliciumproben ist abhangig von der Bestrahlungszeit und der Behandlung der Proben von der Bestrahlung. Nach 120 h Bestrahlung im Reaktor sind bis zu 40% des Kupfers aus der Oberflache tiefer als 20 μn in die Probe gewandert.

In oxygen rich silicon wafers profiles with defined defects in the volume are produced by different heal treatment procedures. They are compared with concentration profiles of Fe and Cu. Characteristic differences in gettering efficiency of the defect types are seen. A large content of secondary defects are due to gettering. The electrical activity of Cu is determined by defect profils.

In einer bestrahlten Kernbrennstofflosung wurde die Plutoniumaktivitat mit Hilfe der Isotopenverdunnungsanalyse bestimmt. Dabei wurde 238Pu als Tracerisotop verwendet. Die Abtrennung des Plutoniums wurde durch Extraktion und die Aktivitatsmessung mit Hilfe der Alphaspektrometrie unter Verwendung von Si-Halbleiterdetektoren vorgenommen. Die Storung durch 241Am wurde durch gammaspektrometrische Messung berucksichtigt. Die Genauigkeit der 238Pu-Aktivitatsmessung und die der Messung der Gesamtaktivitat betragt ungefahr 1,5%. Die Bestimmung des 239Pu zu 240Pu Verhaltnisses war nur mit einem groβen Fehler moglich, entsprechend der nahezu gleichen Alphaenergien dieser Isotope und der komplizierten Peakform. 241Pu wurde durch alphaspektrometrische Differenzmessung der nachgebildeten 241Am Aktivitat bestimmt. In irradiated nuclear fuel solution plutonium isotops were determined with the help of isotope dilution analysis. 238Pu was used as a tracer isotope. Plutonium was separated by extraction and the activity was...

A radiochemical neutron activation method for the determination of rare earth elements (REE) in periodolitic rocks is presented. The procedure involves a post irradiation sample solution with a mixture of H2F2, HNO3, IHClO4 and HCl and the selective sorption of REE by cation exchange. Most of the elements which will interfere with their precise determination are separated before the REE arc cluted. 88Y-Tracer is used to monitor the chemical yield. The procedure is capable of providing precise REE data for La, Ce, Sm, Nd, Eu, Tb, Yb and Lu. The advantage of the radiochemical method is demonstrated by comparison of BEE-contents and their standard deviations by radiochemical and instrumental neutron activation analysis.

Die Komparatormethode hat sich in der Reaktoraktivierungsanalyse [1, 2] zur Standardisierung sowie zur kritisehen Einschatzung der Literaturwerte fur thermische Wirkungsquerschnitte, Resonanzintegrale und absolute γ-Intensitaten [3 –5] bewabrt.

A sensitive method of carbon determination in silicon by activation with deuterons and3He particles followed by chemical separation of the measured nuclides13N and11C has been developed. Aside from the etch removal after irradiation, it is essential for a low detection limit to avoid too much thermal exposure of the target surface during the irradiation process, or else microflaw formation and diffusion on the surface have to be anticipated. The ion current must have an optimal rather than a maximum value.