Untagged gamma-ray and tagged-neutron yields from AmBe andPuBe mixed-field sources have been measured. Gamma-ray spectroscopy measurements from 1 to 5MeV were performed in an open environment using a CeBr detector and the same experimental conditions for both sources. The shapes of the distributions are very similar and agree well with previous data. Tagged-neutron measurements from 2 to 6MeV were performed in a shielded environment using a NE-213 liquid-scintillator detector for the neutrons and a YAP(Ce) detector to tag the 4.44MeVgamma-rays associated with the de-excitation of the first-excited state of C. Again, the same experimental conditions were used for both sources. The shapes of these distributions are also very similar and agree well with previous data, each other, and the ISO recommendation. OurPuBe source provides approximately 2.6 times more 4.44MeVgamma-rays and 2.4 times more neutrons over the tagged-neutron energy range, the latter in reasonable agreement with the original full-spectrum source-calibration measurements performed at the time of their acquisition.

We present the development of a specialized concrete for neutron shielding at neutron research facilities, based on the addition of hydrogen atoms in the form of polyethylene and also B 4 C for enhancing the neutron capture properties of the concrete. We show information on the mechanical properties of the concrete and the neutronics, in particular it's relevance to modern spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden. The new concrete exhibits a 15% lower mass density, a compressible strength of 50% relative to a standard concrete and a significant increase in performance of shielding against MeV neutrons and lower energies. The concrete could find application at the ESS in for example common shielding components, individual beamline shielding and instrument caves.Initial neutronic tests of the concrete, carried out at Lund University, have also verified the performance in the MeV neutron energy range and the results are presented.

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New high-flux and high-brilliance neutron sources demand a higher count-rate capability in neutron detectors. In order to achieve that goal, the Solid-State Neutron Detector (SoNDe) project is developing a scintillation-based neutron detector. It will be capable of fully exploiting the available flux at small-angle neutron scattering (SANS) instruments at high brilliance sources, such as SKADI at the European Spallation Source (ESS). The read-out of the scintillator is based on a pixelized multi-anode PMT (MaPMT), where each pixel is treated separately. In addition to enabling higher achievable count-rates, one of the design goals was to develop a modular and scalable solution that can also be used in other instruments or even contexts, such as for laboratory setups. This has been achieved by combining the complete read-out electronics along with the MaPMT into modules that can be controlled and read-out individually via a network without additional any infrastructure. An overview of the present state of development and current test results is presented, highlighting the results of previously published project reports.

Coincidence and time-of-flight measurement techniques are employed to tag fission neutrons emitted from a Cf source sealed on one side with a very thin layer of Au. The source is positioned within a gaseousHe scintillator detector. Together with α particles, both light and heavy fission fragments pass through the thin layer of Au and are detected. The fragments enable the corresponding fission neutrons, which are detected in a NE-213 liquid-scintillator detector, to be tagged. The resulting continuous polychromatic beam of tagged neutrons has an energy dependence that agrees qualitatively with expectations. We anticipate that this technique will provide a cost-effective means for the characterization of neutron-detector efficiency in the energy range 1-6MeV.