Erik Strub

University of Cologne | UOC · Institute of Nuclear Chemistry

Latterly, PIXE using high-energy protons has been applied effectively for the qualitative analysis of archaeological and art objects, providing information from deep inside the object. This is due to the high cross-sections for the excitation of K-lines of heavy elements together with the large penetration depth of high-energy protons, resulting in...

Three different coatings layers have been found in a feasibility study as potential candidates of certified reference materials for the determination of hydrogen concentration by GD OES i electroplated zinc, ii carbon rich coatings and iii amorphous silicon layers

Tungsten disulfide WS2 is a layer-type semi-conductor with an energy band gap and an absorption coefficient making it suitable as an absorber for thin film solar cells. In the article [1] WS2–x films were pre-pared by reactive magnetron sputtering from a metallic tungsten target in Ar–H2S atmospheres. The cover figure shows in situ energy-dispersiv...

The number of crystal structures of pertechnetates derived from aqueous solutions has been expanded from seven to over 30. We report the conversion of NH4TcO4 to aqueous HtcO4 via acidic cation exchange. This is followed by the synthesis and structural elucidation of pertechnetate salts of alkaline earth (AE), transition metal I and lanthanoids (Ln...

Losses of soil organic matter (SOM) from arable land poses a serious threat to soil fertility and crop yields, and thwarts efforts to conserve soils as carbon sinks to mitigate global warming. Wind erosion can be a major factor in the redistribution of soil fines including SOM, but assessments of its impact have typically been limited by short obse...

Auf der Jagd nach im Periodensystem fehlenden Elementen gab es einige Irrungen und Wirrungen – selbst Nobelpreisträger lagen falsch. Und auch, wenn das von den Entdeckern vorgeschlagene Kürzel dasselbe ist: Np sollte ursprünglich Nipponium heißen, nicht Neptunium.

In this manuscript we evaluate the X‐ray structure of five new pertechnetate derivatives of general formula [M(H2O)4(TcO4)2], M=Mg, Co, Ni, Cu, Zn (compounds 1–5) and one perrhenate compound Zn(H2O)4(ReO4)2 (6). In these complexes the metal center exhibits an octahedral coordination with the pertechnetate units as axial ligands. All compounds exhib...

Prompt gamma rays of terbium emitted after (n,nʹγ) inelastic scattering reactions induced by irradiation of a terbium(III) hexahydrate (TbCl 3 ·6H 2 O) sample with a beam of fission neutrons were investigated with the instrument FaNGaS (Fast Neutron-induced Gamma-ray Spectrometry) at an angle of 90° between neutron beam and detector. At sample posi...

he Cover Feature shows a 3D view of the single-crystal structure of K3[MO4][MO3N] with M=Tc, Re together with the Raman spectrum of K3[ReO4][ReO3N]. Both compounds were synthesized using a highly alkaline KOH hydroflux. Since single-crystal X-ray diffraction does not prove the presence of nitrogen within the (MO4)-tetrahedra unambiguously, Raman an...

The reactions of ammonium perrhenate and pertechnetate in highly alkaline medium led to the isotypic mixed anionic nitridotrioxidorhenate and ‐technetate k3[MO4][MO3N] (M= Tc, Re). Both compounds occur as colorless crystals, which were investigated by single crystal X‐ray diffraction. Furthermore, K3[ReO4][ReO3N] has been studied by means of X‐ray...

Prompt gamma rays of cerium and chlorine were investigated with the FaNGaS (Fast Neutron-induced Gamma-ray Spec-trometry) instrument operated at the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching. The gamma radiation was emitted from (n,n'), (n,p) and (n,α) reactions induced by the irradiation of a cerium(III) chloride (CeCl 3) sample with a beam o...

The autoreduction of ammonium pertechnetate in solutions of trifluoromethanesulfonic acid (triflic acid, TfOH) and trifluoromethanesulfonic anhydride (triflic anhydride, TfOTf) results, in the presence of sodium ions, in the formation of the complex Na 2 [(Tc V O)(OTf) 5 ] · 2(TfOH). Its structure has been determined by single-crystal X-ray diffrac...

For the final disposal of reactor graphite a quantitative characterization of its radioactivity is needed. In this work an emphasis is placed on the isotope ¹⁴C, an isotope accessible to AMS measurements. Reactor graphite can be highly activated and therefore difficult to measure without the risk of contaminating the AMS setup. Using an Elemental A...

The release of nuclear facilities from regulatory control is commonly addressed by demonstrating that contaminations are below ‘clearance values’. AMS is commonly too laborious for a large number of samples, especially if nuclide vectors have been established, but it might be of interest for the release of a so-called ‘small facility’. For this cas...

Emission of prompt gamma rays following (n,n’), (n,p) and (n,α) reactions induced by irradiation of a calcium carbonate (CaCO 3 ) sample with a beam of fission neutrons was investigated with a modified version of the FaNGaS (Fast Neutron-induced Gamma-ray Spectrometry) instrument operated at the Heinz Maier-Leibnitz Zentrum (MLZ) in Garching. The n...

An advanced radio-frequency quadrupole (RFQ) ion cooler was developed for accelerator mass spectrometry to use element-selective laser photodetachment and ion-molecule reactions for isobar suppression. The system will be installed as a central part of the new Anion Laser Isobar Separator (ALIS) at the 6 MV AMS system of CologneAMS. The new RFQ desi...

The preparation of novel technetium oxides, their characterization and the general investigation of technetium chemistry are of significant importance, since fundamental research has so far mainly focused on the group homologues. Whereas the structure chemistry of technetium in strongly oxidizing media is dominated by the TcO4- ${{\left[{\rm { Tc}}...

Zum 9. Mal fand in diesem Jahr am Department Chemie der Universität Köln die „Carnival Conference Session“ (CCS‐2022) mit etwa 50 Teilnehmer:innen statt. Corona hatte den ursprünglich karnevalistischen Termin dieses Jahr in den Sommer verschoben. Zur CCS werden aufstrebende Forscher:innen aus allen Bereichen der Chemie nach Köln eingeladen. Die Vor...

Fire‐gilding is a historic technique for the application of golden layers on a number of different base materials by utilizing a gold‐amalgam. This technique leaves a significant amount of Hg in the golden layer, giving archeometrists a reliable indicator to identify fire‐gildings. Recent findings on presumably fire‐gilded objects showed in several...

Annual Report 2020/21 of the Working Group of Analytics and Basic Nuclear Chemistry Division of Nuclear Chemistry at the University of Cologne

Ammonium pertechnetate reacts in mixtures of trifluoromethanesulfonic anhydride and trifluoromethanesulfonic acid under final formation of ammonium pentakis(trifluoromethanesulfonato)oxidotechnetate(V), (NH4)2[TcO(OTf)5]. The reaction proceeds only at exact concentrations and under the exclusion of air and moisture via pertechnetyl trifluoromethane...

Ammonium pertechnetate reacts in mixtures of trifluoromethanesulfonic anhydride and trifluoromethanesulfonic acid to ammonium penta­kis(tri­fluoro­methane­sulfonato)oxido­technetate(V), (NH 4 ) 2 [TcO(OTf) 5 ]. The reaction proceeds only at exact concentrations under the exclusion of air and moisture via the formation of pertechnetyl trifluorometha...

In this paper, the excitation function utilizing the nuclear reaction Vnat(p,X) Ti44 was determined. The seven investigated metallic vanadium disks were proton irradiated within an energy range of 111–954 MeV between 1995 to 1996. The experiments' cross sections were validated using two independent measurements by combining γ spectrometry with both...

This work is focused on the nat Pb(p,xn) ²⁰⁷ Bi reaction to extend earlier works on proton induced reactions for the determination of cross sections of residual nuclides. ²⁰⁷ Bi decay (half-life 31.55 years) was measured by γ-ray spectrometry in 42 lead foils which had been irradiated by high proton fluxes 20 years ago. Since then, all short-lived...

The aim of this study is the development of a separation technique for geological samples, namely bismuthinites, with the goal to isolate Tl from excess amounts of Bi. This will enable an isotopic measurement of the Tl content on the ultra-trace level to identify a possible signature of Bi α-decay. The separation of Tl from other elements like e.g....

ISBN 978-3-947685-75-2

Annual Report of the Working Group of Analytics and Basic Nuclear Chemistry Division of Nuclear Chemistry at the University of Cologne

Zum achten Mal fand in diesem Jahr am Department Chemie der Universität Köln die Carnival Conference Session (CCS‐2020) statt, traditionell am Mittwoch vor Karneval. Das Konzept der CCS: Auf Einladung der Nachwuchsgruppen des Departments finden Vorträge statt, die die Breite des Faches Chemie widerspiegeln und sich an Arbeitsgruppen und Studierende...

In the field of nuclear waste management is the determination of difficult to measure isotopes important for the isotopic nuclide inventory in disposal material. Accelerator mass spectrometry propose a new precise and reliable way for the quantification of the radioactive material by the means of direct atom counting. For the radiological character...

An automated CO 2 gas handling and injection system was developed. It is designed to dilute CO 2 samples with blank gas in a mixing volume. The system is intended to be used for the characterization and quantification of ¹⁴ C content in reactor graphite with accelerator mass spectrometry. A 100 kV accelerator system was developed to measure samples...

We report on systematic γ-γ fast-timing measurements by using four cylindrical 1.5′′×1.5′′ LaBr3(Ce) scintillator detectors which were installed in compact geometry around the focal plane of the Lohengrin fission-fragment separator at the Institut Laue–Langevin in Grenoble, France. Unconventional γ-ray sources as ¹⁸⁵Os and ¹⁸⁷W were produced by the...

Annual Report Working Group of Analytics and Basic Nuclear Chemistry Division of Nuclear Chemistry at the University of Cologne

Zum siebten Mal fand in diesem Jahr am Department Chemie der Universität Köln die Carnival Conference Session statt, traditionell am Mittwoch vor Karneval. Konzept der CCS: Auf Einladung der Nachwuchsgruppen des Departments halten Nachwuchswissenschaftler Vorträge, die die ganze Breite der Chemie widerspiegeln und sich sowohl an Arbeitsgruppen als...

Als wir uns kennenlernten, das Element 104 und ich, da hieß es noch gar nicht Rutherfordium. 298 Begegnungen später waren wir gute Bekannte.

Traditionell fand am Mittwoch vor Karneval am Department für Chemie der Universität Köln die „Carnival Conference Session“ (CCS‐2018) statt, zum sechsten Mal seit 2012. Konzept der CCS ist es, dass auf Einladung der Nachwuchsgruppen des Departments Nachwuchswissenschaftler vortragen, die aus möglichst unterschiedlichen Teilbereichen der Chemie komm...

A new multi-isotope plutonium standard for isotopic ratio measurements with Accelerator Mass Spectrometry (AMS) was created by gravimetric mixing of different single-isotope standards provided by IRMM (Pu-239, Pu-240, Pu-242, Pu-244). This standard material has been measured at the AMS facilities at Canberra (Australia), Cologne (Germany), Caserta...