T. Materna

The ANCIENT CHARM project at FRM II: three-dimensional elemental mapping by prompt gamma activation imaging and neutron tomography

Journal of Analytical Atomic Spectrometry, 2013

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Detail report on the position-sensitive PGAA at the research reactor FRM-II in Garching at Munich

The new cold neutron tomography set-up at SINQ

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2002

A new cold neutron tomography set-up is operational at the neutron spallation source SINQ of the ... more A new cold neutron tomography set-up is operational at the neutron spallation source SINQ of the Paul Scherrer Institute (PSI) in Villigen, Switzerland. The detection system is based on a 6 LiF/ZnS:Ag conversion screen and a CCD camera. Several tests have been carried out to characterize the quality of the tomography system, such as homogeneity, reproducibility, L/D-ratio and spatial resolution. The high flux and the good efficiency of the detector lead to very short exposure times. Thus, a typical set of tomography scans can be performed in only 20 min. Then, 3D computed tomography objects were calculated using the filtered back-projection reconstruction method. Initial results of various samples show that cold neutron tomography can be a useful tool for industry, geology and dentistry. Furthermore, suitable applications can be found in the field of archeology. r

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New neutron imaging techniques for cultural heritage purposes

2008 IEEE Nuclear Science Symposium Conference Record, 2008

... I. INTRODUCTION Ancient artefacts and artworks that bear witness to our cultural heritage (CH... more

New features in cold neutron radiography and tomography Part II: applied energy-selective neutron radiography and tomography

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2003

The neutron attenuation coefficient drops for many solid materials quite drastically at a defined... more The neutron attenuation coefficient drops for many solid materials quite drastically at a defined cold neutron energy known as a Bragg-cut-off in the cross-section diagrams. In many cases, the drop in attenuation for the corresponding elements is significant and this behavior can be exploited to change the material contrast in radiography and tomography images by modifying the spectrum of the applied neutron beam.

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The cold neutron tomography set-up at SINQ

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2004

The cold neutron tomography station operated at SINQ (Paul Scherrer Institute, Switzerland) is re... more The cold neutron tomography station operated at SINQ (Paul Scherrer Institute, Switzerland) is reviewed. The high neutron flux together with a set-up based on a scintillator screen and a CCD camera yielded fast and effective results with resolution down to 250 mm: tomography of small samples (up to 2 cm large) could be performed in less than an hour. The use of a velocity selector improved the contrast discrimination and allows dichromatic tomography. The station is moving to the new research reactor FRM-II (Garching, Germany) where its performances will be increased by the availability of a 5-times-higher cold neutron flux.

format_quoteThe SINQ facility generates a high neutron flux of 10^14 n/cm²/s, enhancing the feasibility of neutron imaging techniques.format_quote

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On the construction of a new instrument for cold-neutron prompt gamma-ray activation analysis at the FRM-II

Journal of Radioanalytical and Nuclear Chemistry, 2005

... Materna,1 J. Jolie,1 A. Türler,2 P. Wilk,2 S. Baechler,3 Zs ... countrate measured at PSI was... more

First elemental imaging experiments on a combined PGAI and NT setup at the Budapest Research Reactor

Journal of Radioanalytical and Nuclear Chemistry, 2008

The European collaboration ANCIENT CHARM (http://ancient-charm.neutron-eu.net/ach/) aims to devel... more The European collaboration ANCIENT CHARM (http://ancient-charm.neutron-eu.net/ach/) aims to develop new non-destructive neutron techniques to image the internal composition of complex archaeological objects in order to answer various archaeological questions. Among these techniques, Prompt Gamma Activation Imaging (PGAI) and Neutron Tomography (NT) form a unique combination which can determine the 3D distribution of most elements in objects with a non-destructive procedure. A spatial resolution better than 2 mm has already been achieved in a moderately scattering matrix material.

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A new PGAI-NT setup at the NIPS facility of the Budapest Research Reactor

Journal of Radioanalytical and Nuclear Chemistry, 2008

Prompt-Gamma Activation Analysis (PGAA) is a well known tool for non-destructive bulk elemental a... more Prompt-Gamma Activation Analysis (PGAA) is a well known tool for non-destructive bulk elemental analysis of objects. The measured concentrations are only representative of the whole sample if it is homogenous; otherwise it provides only a sort of average composition of the irradiated part. In this latter case one has to scan the sample to obtain the spatial distribution of the elements. To test this idea we have constructed a Prompt-Gamma Activation Imaging -Neutron Tomograph (PGAI-NT) setup at the NIPS station of the Budapest Research Reactor, consisting of a high-resolution neutron tomograph and a germanium gamma-spectrometer. The samples are positioned relative to the intersection of the collimated neutron beam and the projection of the gamma-collimator (isocenter) by using an xyzω-moving table.

format_quoteCombining PGAI and Neutron Tomography non-destructively reveals 3D elemental distributions in complex archaeological artifacts.format_quote

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Novel Neutron Imaging Techniques for Cultural Heritage Objects

Page 1. Chapter 13 Novel Neutron Imaging Techniques for Cultural Heritage Objects C. Andreani, G.... more

FISSION FRAGMENT STUDIES AT THE MASS SEPARATOR LOHENGRIN BY GAMMA-RAY SPECTROMETRY

Capture Gamma-Ray Spectroscopy and Related Topics, 2013

MEASUREMENT OF KINETIC ENERGY DISTRIBUTIONS, MASS AND ISOTOPIC YIELDS IN THE HEAVY FISSION PRODUCTS REGION AT LOHENGRIN

Seminar on Fission VI, 2008

Mass yields and kinetic energy distribution functions for heavy mass fission products from therma... more Mass yields and kinetic energy distribution functions for heavy mass fission products from thermal neutron induced fission of 235U and 239Pu have been measured at the spectrometer Lohengrin at the high flux reactor of the Institut Laue-Langevin in Grenoble. In addition to these measurements where an ionization chamber was used for the mass identification, we also performed gamma spectrometry to quantify the isotopic and isomeric yields. This setup using Ge-detectors has been commissioned with the system 241Pu(nth,f). In order to extend the data to less abundant fission products, a proportional counter for beta detection has been constructed, allowing to reduce the background by beta-gamma coincidences.

Nuclear spins and magnetic moments of 71,73,75Cu: inversion of pi2p3/2 and pi1f5/2 levels in 75Cu

Physical review letters, Jan 2, 2009

We report the first confirmation of the predicted inversion between the pi2p3/2 and pi1f5/2 nucle... more We report the first confirmation of the predicted inversion between the pi2p3/2 and pi1f5/2 nuclear states in the nu(g)9/2 midshell. This was achieved at the ISOLDE facility, by using a combination of in-source laser spectroscopy and collinear laser spectroscopy on the ground states of 71,73,75Cu, which measured the nuclear spin and magnetic moments. The obtained values are mu(71Cu)=+2.2747(8)mu(N), mu(73Cu)=+1.7426(8)mu(N), and mu(75Cu)=+1.0062(13)mu(N) corresponding to spins I=3/2 for 71,73Cu and I=5/2 for 75Cu. The results are in fair agreement with large-scale shell-model calculations.

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Measurements of fission yields in the heavy region at the recoil ass spectrometer lohengrin

In spite of the huge amount of fission yield data available in different libraries, more accurate... more In spite of the huge amount of fission yield data available in different libraries, more accurate values are still needed for nuclear energy applications and to improve our understanding of the fission process. Thus measurements of fission yields were performed at the mass spectrometer Lohengrin at the Institut Laue-Langevin in Grenoble, France. The mass separator Lohengrin is situated at the

Indirect identification of nanosecond isomers using the fission fragment separator Lohengrin

ABSTRACT The fission fragment separator Lohengrin was used to find new nanosecond isomers in exot... more

Near-yrast structure of Cs 142 and Cs 144

Excited states in Cs142 and Cs144, populated in the spontaneous fission of Cm248 and Cf252 and in... more Excited states in Cs142 and Cs144, populated in the spontaneous fission of Cm248 and Cf252 and in thermal neutron-induced fission of U235 and Am242 were studied by means of gamma spectroscopy using the EUROGAM2 and Gammasphere multidetector Ge arrays and the LOHENGRIN fission-fragment separator, respectively. In Cs142, a band and an isomer with a half-life of T1/2=11(3) ns have been identified. Spins and parities have been proposed for excited levels in this nucleus. In Cs144 excited levels have been observed. A T1/2=1.1(1) mus isomer was found with a gamma cascade, which probably feeds this isomer. There is also an indication of a nanosecond isomer in Cs144. Quasiparticle-rotor model calculations done in this work allowed proton-neutron configurations to be proposed for levels in Cs142 and Cs144.

Development of a Gas Filled Magnet spectrometer coupled with the Lohengrin spectrometer for fission study

EPJ Web of Conferences, 2013

ABSTRACT The accurate knowledge of the fission of actinides is necessary for studies of innovativ... more ABSTRACT The accurate knowledge of the fission of actinides is necessary for studies of innovative nuclear reactor concepts. The fission yields have a direct influence on the evaluation of the fuel inventory or the reactor residual power after shutdown. A collaboration between the ILL, LPSC and CEA has developed a measurement program on fission fragment distributions at ILL in order to measure the isotopic and isomeric yields. The method is illustrated using the 233U(n,f)98Y reaction. However, the extracted beam from the Lohengrin spectrometer is not isobaric ions which limits the low yield measurements. Presently, the coupling of the Lohengrin spectrometer with a Gas Filled Magnet (GFM) is studied at the ILL in order to define and validate the enhanced purification of the extracted beam. This work will present the results of the spectrometer characterisation, along with a comparison with a dedicated Monte Carlo simulation especially developed for this purpose.

FISSION FRAGMENT STUDIES BY GAMMA-RAY SPECTROMETRY WITH THE MASS SEPARATOR LOHENGRIN

Fission and Properties of Neutron-Rich Nuclei, 2013

ABSTRACT A gamma spectrometric technique was implemented at the exit of the fission fragment sepa... more ABSTRACT A gamma spectrometric technique was implemented at the exit of the fission fragment separator of the ILL. It allows a precise measurement of isotopic yields of most important actinides in the heavy fragment region by an unambiguous identification of the nuclear charge of the fragments selected by the mass spectrometer. The status of the project and last results are reviewed. A spin-off of this activity is the identification of unknown nanosecond isomers in exotic nuclei through the observation of a disturbed ionic charge distribution. This technique has been improved to provide an estimation of the lifetime of the isomeric state.

$Research paper thumbnail of In-source laser spectroscopy of ^{75,77,78}Cu: Direct evidence for a change in the quasiparticle energy sequence in ^{75,77}Cu and an absence of longer-lived isomers in ^{78}Cu$

In-source laser spectroscopy of ^{75,77,78}Cu: Direct evidence for a change in the quasiparticle energy sequence in ^{75,77}Cu and an absence of longer-lived isomers in ^{78}Cu

Physical Review C, 2011

U. Köster,1 NJ Stone,2,3 KT Flanagan,4,* J. Rikovska Stone,2,3 VN Fedosseev,5 KL Kratz,6 BA Marsh... more

Isomers in Fission Fragments

AIP Conference …, 2009

... R. Orlandi, JF Smith, I. Ahmad. Abstract. The structure of neutron‐rich nuclei produced as se... more

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