Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

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FaNGaS: a New Instrument for Fast Neutron Gamma Spectroscopy at FRM II Research Reactor at Garching

For the identication and quantication of actinides in radioactive packages,the non-destructive method of Prompt-Gamma Activation Analysis (PGAA)is applied. To investigate the inelastic (n; n0) scattering, a new instrumen-tation was installed at the FRM II research reactor. It is designed to exploitthe 108 cm2s1 neutrons at an average neutron energy of 1:9 MeV deliveredby the SR10 beam line. The outgoing prompt -rays are measured utilizinga 50% eciency HPGe detector. Since the cross sections are expected to below for such a process, two related factors had to be taken into account for thedesign of the instrumentation: the high beam intensity at the sample positionand the high signal-to-background ratio seen by the detector. Eventual lowenergy neutrons due to the multiple scatterings through the beam line can beminimized using collimators in the beam tube. This has also an eect to a priorneutrons and photons background reduction of the experimental environment.A higher eciency of the counting can be achieved by the lowering of back-ground at the detector. In this case, a heavy shielding for both neutrons andphotons, is designed around the detector while optimizing the sample-detectordistance. Monte-Carlo simulation studies were conducted to eectively designthe fast neutron beam collimators and the detector shield. A detailed descrip-tion of the setup characterization and results from simulations and experimentalmeasurements will be discussed through this contribution

Development and Test of a Neutron Imaging Setup at the PGAA Instrument at FRM II

We report on the developments of a neutron tomography setup at the instrument for prompt gamma-ray activation analysis (PGAA) at the Maier-Leibnitz Zentrum(MLZ). The recent developments are driven by the idea of combining the spatial information obtained with neutron tomography with the elemental information determined with PGAA, i.e. to further combine both techniques to an investigative technique called prompt gamma activation imaging (PGAI).At the PGAA instrument, a cold neutron flux of up to 6 x 1010 cm-2 s-1 (thermal equivalent) is available in the focus of an elliptically tapered neutron guide. In the reported experiments, the divergence of the neutron beam was investigated, the resolution of the installed detector system tested, and a proof-of-principle tomography experiment performed. In our study a formerly used camera box was upgraded with a better camera and an optical resolution of 8 line pairs/mm was achieved. The divergence of the neutron beam was measured by a systematic scan along the beam axis. Based on the acquired data, a neutron imaging setup with a L/D ratio of 200 was installed. The resolution of the setup was testedin combination with a gadolinium test target and different scintillator screens. The test target was irradiated at two positions to determine the maximum resolution and the resolution at the actual sample position. The performance of the installed tomography setup was demonstrated bya tomography experiment of an electric amplifier tube

Prompt and delayed inelastic scattering reactions from fission neutron irradiation—first results of FaNGaS

A new instrument for fast neutron gamma spectroscopy has been installed and tested at the Forschungsneutronenquelle Heinz Maier-Leibnitz of the MLZ in Garching. A beam with the flux of about 108 cm−2 s−1 fission neutrons is available to irradiate small samples to study inelastic neutron scattering reactions in materials. A number of relevant elements have been investigated and new gamma lines were identified in comparison to existing data libraries. The method seems to be linear with respect to measurement time and sample mass. A particular advantage of fast neutron PGAA compared to thermal neutron PGAA appears in the analysis of materials with high thermal capture cross sections

In-beam activation analysis facility at MLZ, Garching

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 upgraded facility has been demonstrated to be applicable for both PGAA and neutron activation analysis using in-beam activation and decay counting in the low-background counting chamber

Fission Neutron PGAA from inelastic scattering reactions – first results of FaNGaS

A beam of fission neutrons extracted at the SR10 beam line of the FRM II Research Reactor in Garching has been used to study inelastic scattering reactions and related product nuclei with a new instrument Fast Neutron Gamma Spectroscopy (FaNGaS). Complimentary to cold neutron PGAA, with FaNGaS (n,n’) reactions induced by fission neutrons can be studied. Prompt Gamma lines from inelastic scattering reactions up to now have been rarely studied and no adequate compilation of the emitted gamma energies exist. In developing non-destructive analytical techniques using neutron generator based PGAA such data are badly needed for quantification of heavy metals and actinides in e.g. nuclear waste, hazardous materials, or safeguards samples.A number of elements and relevant actinides have been irradiated in the fast neutron beam SR10 at the FRM II reactor in Garching, Germany. A heavily shielded 50% eff. HPGe detector perpendicular to the beam is looking at the samples exposed to ≈ 108 cm-2s-1 fission neutrons. Prompt and delayed gamma spectra have been taken and evaluated using the available data in scattered reports. Additional gamma lines have been detected and are being compiled to create a data base for (n,n’) reactions. Particular emphasis is given on actinides including 238U, as well as on shielding materials such as Cd, W and Pb. Some examples will be given and first results will be discussed in this contribution

FaNGaS: A new instrument for (n,n′γ)\left({\mathrm{n,n}}^{\prime }\mathrm{\gamma }\right) reaction measurements at FRM II

The FaNGaS instrument was set up at the research reactor FRM II, Garching. It performs measurements of (n,n′γ)(n,n′γ) reactions based on the γ-ray spectroscopy technique within the fission neutrons energy region. The optimization studies of the experimental setup were carried out using MCNP simulations. A full characterization of the detector system and the neutron beam is presented. The determination of the neutron energy spectrum was done using the foil activation method. An average neutron energy of about 2 MeV and a neutron flux of View the MathML source108cm−2·s−1 were measured

Prompt and delayed inelastic scattering reactions from fission neutron PGAA – first results of FaNGaS

The new instrument Fast Neutron Gamma Spectroscopy (FaNGaS) has been installed at the SR10 beam line of the FRM II Research Reactor in Garching and tested successfully. Complimentary to cold neutron PGAA, with FaNGaS inelastic scattering reactions induced by fission neutrons can be studied. Prompt Gamma lines from (n,n’) reactions up to now have been rarely studied and no adequate compilation of the emitted gamma energies exist. In developing non-destructive analytical techniques using neutron generator based PGAA such data are badly needed for quantification of heavy metals and actinides in e.g. nuclear waste or safeguards samples.A number of elements and relevant actinides have been irradiated in the fast neutron beam SR10 at the FRM II reactor in Garching, Germany. A heavily shielded 50% eff. HPGe detector perpendicular to the beam is looking at the samples exposed to 2.3E8 cm-2s-1 fission neutrons. Prompt gamma spectra have been taken and evaluated using the available data in scattered sources. Additional gamma lines have been detected and are being compiled to create a data base for (n,n’) reactions. Particular emphasis is given on actinides including 238U, 232Th, 237Np, 242Pu and 241Am. Some examples will be given and first results will be discussed in this contribution