Christoph Genreith

Forschungszentrum Jülich · Institute of Energy and Climate Research (IEK)

The beam port SR10 at the neutron source FRM II of Heinz Maier-Leibnitz Zentrum (MLZ) is equipped with a moveable assembly of two uranium plates, which can be placed in front of the entrance window of the beam tube via remote control. With these plates placed in their operating position the thermal neutron spectrum produced by the neutron source FR...

The neutron-capture reaction is fundamental for identifying and analyzing the γ-ray spectrum from an unknown assembly because it provides unambiguous information on the neutron-absorbing isotopes. Nondestructive-assay applications may exploit this phenomenon passively, for example, in the presence of spontaneous-fission neutrons, or actively where...

In the framework of the OECD/NEA WPEC subgroup 41, ways to improve neutron induced capture cross sections for 241Am and 237Np are being sought. Decay data, energy dependent cross section data and neutron spectrum averaged data are important for that purpose and were investigated. New time-of-flight measurements were performed and analyzed, and cons...

The reconstruction of the prompt gamma activation analysis facility and the construction of the new low-background counting chamber at MLZ, Garching is presented. The improvement of the shielding and its effect on the radiation background is shown. The setting up and the fine-tuning of the electronics and their characterization are also discussed....

The instrument MEDAPP Medical Applications), operated by the Technische Universität München, and the respective irradiation position are located at the world-wide unique fast neutron beam tube SR10 to which a uranium converter is attached. Thus, the instrument is operated with unmoderated fission neutrons and can be used for a broad variety of appl...

The methodology to derive cross-section data from measurements in a cold neutron beam was studied. Mostly, capture cross-sections at thermal energy are derived relative to a standard cross-section, e.g. the cross-section of the 1 H(n,γ), 14 N(n,γ), or 197 Au(n,γ) reaction, and proportionality between the standard and the measured cross-section, eva...

The need for accurate nuclear reaction data of actinides is well documented and several initiatives from international organizations for improvement have been initiated in the past. This need, particularly in view of method development for non-destructive assay of nuclear waste, has generated a joint effort to use prompt and delayed neutron activat...

With the high-intensity cold neutron flux available at the Prompt Gamma Activation Analysis (PGAA) instrument of the research reactor FRM II at the Heinz Maier-Leibnitz Zentrum (MLZ), samples with a weight of 1 mg or even less can be investigated for their elemental compositions using the (n,γ) capture reaction. In such cases, the typical sample pa...

Radioactive waste has to undergo a process of quality checking in order to check its conformance with national regulations prior to its transport, intermediate storage and final disposal. Within the quality checking of radioactive waste packages non-destructive assays are required to characterize their radio-toxic and chemo-toxic contents. The Inst...

Accurate cross section data of actinides are crucial for criticality calculations of GEN IV reactors and transmutation but also for analytical purposes such as nuclear waste characterization, decommissioning of nuclear installations and safeguard applications. Tabulated data are inconsistent and sometimes associated with large uncertainties. Neutro...

The Evaluated Gamma-ray Activation File (EGAF) is the result of a 2000–2007 IAEA Coordinated Research Project to develop a database of thermal, prompt γ-ray cross sections, , for all elemental and selected radioactive targets. No previous database of this kind had existed. EGAF was originally based on measurements using guided neutron beams from th...

Segmented γγ-scanning (SGS) is the most widely applied technique to non-destructively reconstruct the isotope specific activity content in radioactive waste drums. Around 25% of all radioactive waste drums at the Forschungszentrum Jülich exhibit a homogeneous matrix distribution and activity distribution. Due to these conditions, a numerical method...

Several samples of 237Np and 242Pu were irradiated in the guided cold neutron beam of the prompt gamma activation analysis facility at the Budapest Research Reactor. The thermal neutron capture cross sections of 237 Np and 242Pu were evaluated from the obtained prompt and delayed gamma ray data. The thermal neutron capture cross sections for 237Np(...

A sample of 237Np was irradiated in the guided cold neutron beam of the PGAA-NIPS facility at the Budapest Research Reactor to acquire data on its characteristic prompt γ-rays such as energies and relative intensities. A first evaluation of the obtained data showed significant differences from data reported in the evaluated nuclear structure data f...