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The Mini Labyrinth experiment is a simple neutron and gamma shielding experiment developed at Slovak University of Technology (STU), inspired by the ALARM-CF-AIR-LAB-001 ICSBEP benchmark. Compared to the original Labyrinth, which was made from concrete blocks and had dimension of several meters, the STU Mini Labyrinth is approximately ten times smaller and consists of NEUTRONSTOP shielding blocks. So far, several versions and modifications of the Mini Labyrinth have been investigated, currently the V2-25-L version is used for code evaluation. This version uses a PuBe neutron source loaded in the entrance of the Mini Labyrinth, a plastic tank filled with light water moderator and the NuDET plastic scintillation neutron detector, which can be placed around the experimental workplace. This detector has a significant role in the experiment since it is a calibration apparatus and provides real time data on the rates of ambient dose equivalents of neutron radiation. On the other hand, as it is a certified commercial product, the response function of this detector is unknow, which makes a significant challenge of verifying the measured data with computer codes. This paper presents a result of a series of measurements with the NuDET detector performed at STU and discusses the options, how to verify the experimental results by the SCALE6 system in the most effective way.

6H-SiC samples have been implanted by 4 MeV C and Si ions in the (0001) channeling direction to the sets of multiple implantation fluences. These samples were analyzed via Elastic Backscattering Spectroscopy in the channeling mode (EBS/C) using 1.725 MeV proton beam, from which SiC amorphization depth profiles and averaged integral 6H-SiC amorphization have been obtained. The averaged integral 6H-SiC crystal amorphization vs implanted fluence dependence has been determined for both types of implanted ions. From these dependences, the 6H-SiC integral crystal amorphization vs. implanted fluence/type of implanted atom assessment model have been proposed.

One of the most effective ways of gaining user experience and minimizing user effects on modelling and simulation is benchmarking. Currently (2022) a new experimental workplace, the so called 'Mini Labyrinth' is being developed at Slovak University of Technology in Bratislava (STU). It is a simple neutron and gamma shielding benchmark, inspired by the ALARM-CF-AIR-LAB-001 ICSBEP experiment. The latest V2 setup consists of a PuBe neutron source, several NEUTRONSTOP C5 shielding blocks, H2O filled polylactic acid (PLA) tank, plastic source holder and detectors placed inside and outside the Mini Labyrinth. This paper is focused on the monitoring of the radiation doses around the workplace using the NuDET neutron detector and on the comparison of the measured quantities with ones simulated by SCALE 6 MONACO. The influence of the size of the model and the definition of the detector is studied in this analysis. The achieved results are presented and some discussions on further needed development are also included.

Neutron activation measurement using set of thin foils from highly pure materials is a method known for decades. Using shielding materials like cadmium might add an extra information about neutron field which causes the activation. We very often use relation of activity of bare foil to the activity of the same foil covered by cadmium, and call it cadmium ratio or cadmium spectral index. We could use the same way to define another spectral indices like gadolinium ratio, hafnium ratio, boron ratio, etc. Manipulation with some specific materials like pure gadolinium, samarium, dysprosium or even boron is difficult, sometimes impossible. We introduce and tested method of ion implantation of neutron shielding material directly to the activation foil, and thus redefine spectral index as a ratio between activity of foil without implanted absorber to the activity with implanted absorber. For thicker layers of absorber another method, a vapor deposition, was used and tested. Activities are tested in systems with different neutron spectra, and compared with theoretical models and MCNP simulations.

During the ion implantation process, regardless if it was attentional or not, amorphization will be introduced into the crystal structure. Depending on the chosen ions, different quantities of the amorphization will be introduced for the same applied fluences. In order to estimate the total amorphization of the SiC crystal for different ions and fluences combination, an assessment model was proposed. For this purpose, 4 MeV carbon and silicon ions with multiple fluences were implanted in the [0001] axial direction of a 6H-SiC single crystal. The amorphization depth distributions were obtained by Elastic Backscattering Spectroscopy/channeling spectra analysis via Channeling SIMulation (CSIM) phenomenological computer code. As a result, relation of the total induced amorphization and implantation fluences for carbon and silicon ions were obtained. Based on these experimental results, a total amorphization assessment model for different ions (energy of 4 MeV) and fluences combination was established.

Due to its unique material properties, such as extreme hardness and radiation resistance, silicon carbide has been used as an important construction material for environments with extreme conditions, like those present in nuclear reactors. As such, it is constantly exposed to energetic particles (e.g., neutrons) and consequently subjected to gradual crystal lattice degradation. In this article, the 6H-SiC crystal damage has been simulated by the implantation of 4 MeV C3+ ions in the (0001) axial direction of a single 6H-SiC crystal to the ion fluences of 1.359 1015 cm-2, 6.740 1015 cm-2, and 2.02 1016 cm-2. These implanted samples were subsequently analyzed by Rutherford and elastic backscattering spectrometry in the channeling orientation (RBS/C & EBS/C) by the usage of 1 MeV protons. Obtained spectra were analyzed by channeling simulation phenomenological computer code (CSIM) to obtain quantitative crystal damage depth profiles. The difference between the positions of damage profile maxima obtained by CSIM code and one simulated with stopping and range of ions in matter (SRIM), a Monte Carlo based computer code focused on ion implantation simulation in random crystal direction only, is about 10%. Therefore, due to small profile depth shifts, the usage of the iterative procedure for calculating crystal damage depth profiles is proposed. It was shown that profiles obtained by iterative procedure show very good agreement with the ones obtained with CSIM code. Additionally, with the introduction of channeling to random energy loss ratio the energy to depth profile scale conversion, the agreement with CSIM profiles becomes excellent.

The Mini Labyrinth experiment is a neutron and gamma shielding experiment currently being developed at the Slovak University of Technology, Bratislava (STU). The STU Mini Labyrinth consists of NEUTRONSTOP shielding blocks, water tank, PuBe neutron source, and graphite prism. This article describes the second construction version of the Mini Labyrinth experiment and presents the newest results of the neutron and gamma fields’ simulation and measurement. The PuBe neutron source with the emission rate of 1.06E7 $\textn\cdot \texts^-1$ was used in the experiment. The measurement of gamma ambient dose equivalent H*(10) and neutron count rates is performed by the Thermo Scientific RadEye portable survey meter and the SNM-11 BF3-filled corona detector. The simulation part was carried out using the state-of-the-art MCNP6 and SCALE6 MONACO stochastic calculation tools, considering the detailed geometry of the Mini Labyrinth and a combined neutron and gamma source of particles. The comparisons were performed between codes and the experiment. The propagation of cross-sectional uncertainties was investigated through the shielding analysis. Almost perfect agreements between simulation codes were achieved. The comparison with measurement suggests the further needs of room effect assessment.

The Mini Labyrinth experiment is a simple neutron and gamma shielding experiment developed at STU, inspired by the ALARM-CF-AIR-LAB-001 ICSBEP benchmark experiment. The STU Mini Labyrinth is approximately ten times smaller and consists of NEUTRONSTOP shielding blocks. This paper describes the second version of the Mini Labyrinth experiment and presents the results of the neutron and gamma fields simulation and measurement. The PuBe neutron source with the emission rate of 1.0E7 n/s was utilized in the experiment. The measurement of gamma ambient dose equivalent H*(10) and neutron count rates is performed by the Thermo Scientific RadEye portable survey meter. The simulation part was carried out using the state-of-the-art MCNP6 and SCALE6 MONACO stochastic calculation tools taking into account the detailed geometry of the labyrinth and combined neutron and gamma source of particles. The comparisons were performed between codes and experiment, based on the dose rate in the unique detection positions and using a 2D map of neutron and photon fluxes. The propagation of cross-section uncertainties was investigated through shielding analysis. Partial agreement between codes and measurement was achieved, however serious discrepancies near the PuBe source were identified.