| 1. |
- Knyazev, A., et al.
(författare)
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Tl concentration and its variation in a CsI(Tl) crystal for the CALIFA detector
- 2020
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 975
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Tidskriftsartikel (refereegranskat)abstract
- One of the factors that can contribute to the resolution of long, doped inorganic scintillators used for nuclear spectroscopy is the variation of the dopant concentration over the length the detector crystal. In this work an investigation of such potential variations in one of the CsI(Tl) scintillators used in the calorimeter, CALIFA, of the R3B experiment at FAIR, has been performed using particle induced X-ray emission. No statistically significant gradient in doping level was found along the long axis of the investigated sample crystal and the mean value of the Tl concentration was measured to be 0.0839(38)% by weight. This corresponds to a light output of 97.3−1.7 +1.3% relative to the maximum attainable light output according to previously published work. By taking the ±1σ bounds, the 3% statistical spread in the relative light output provides a good reference value of the minimum light-output non-uniformity observed for the CALIFA crystals. If the relative light output is estimated pointwise from a set of Tl concentration measurements a light-output non-uniformity of 4.6(2.4)% results. For a γ-ray energy of 662 keV the deduced variation in Tl concentration contributes with 0.48(6)% to the typical resolution of 7.74(6)% measured with a collimated source along the crystal main axis. The result is of interest for the characterization of the detector system performance and for realistic simulations of the light collection process in detector systems that are used for nuclear spectroscopy and calorimetry.
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| 2. |
- Rofors, E., et al.
(författare)
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Response of a Li-glass/multi-anode photomultiplier detector to focused proton and deuteron beams
- 2020
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 984
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Tidskriftsartikel (refereegranskat)abstract
- The response of a position-sensitive Li-glass based scintillation detector being developed for thermal-neutron detection with 6 mm position resolution has been investigated using focused beams of 2.5MeV protons and deuterons. The beams were scanned across the detector in 0.5 mm horizontal and vertical steps perpendicular to the beams. Scintillation light was registered using an 8 × 8 pixel multi-anode photomultiplier tube. The signal amplitudes were recorded for each pixel on an event-by-event basis. Several pixels generally registered considerable signals at each beam location. To optimize planned detector operation at the European Spallation Source, the number of pixels above set thresholds was investigated, with the maximization of the single-hit efficiency over the largest possible area as the primary goal. For both beams, at a threshold of ∼50% of the mean of the full-deposition peak, ∼80% of the events were registered in a single pixel, resulting in an effective position resolution of ∼5 mm in X and Y. Lower thresholds resulted in higher pixel multiplicities. These events could also be localized with the same effective position resolution.
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| 3. |
- Frost, R. J.W., et al.
(författare)
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One detector, all the light elements – Low-background NRA, RBS and ERDA for the quantification of elements from hydrogen to fluorine
- 2021
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 494-495, s. 34-45
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Tidskriftsartikel (refereegranskat)abstract
- Presented is a review of the accomplishments, of the light-element program, conducted at the Lund Ion-Beam Analysis Facility. A detailed account is given of the current experimental setup at the total Ion-Beam Analysis Chamber, which is equipped with two Double-Sided Silicon Strip Detectors for charge particle detection, a silicon drift detector for PIXE analysis, an electrostatic deflection system for charge measurement and implements a Nuclear Micro-Probe. A summary of the work conducted to date on the quantification of low Z elements is presented on a case by case basis. Details of the current work efforts and an overview of the advances which are intended in the near future are given.
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| 4. |
- Frost, R. J.W., et al.
(författare)
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The prototyping of a high-resolution neutron activation analysis system - Based on a Pelletron accelerator and fast pneumatic sample-transport
- 2022. - 1
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 2326
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Konferensbidrag (refereegranskat)abstract
- A new neutron activation analysis system is currently being designed at Lund University. The design incorporates a compact accelerator driven neutron source, based on a 3 MV Pelletron accelerator and a pneumatic sample conveyor to transport samples from the neutron source to a measurement station consisting of an array of high-purity Ge γ-ray detectors. A prototype for this new station is currently in operation, with a Genie 16 SODERN neutron generator used in place of the compact accelerator driven neutron source. Preliminary results from the prototype system are presented, alongside qualitative analysis supported by simulations performed in FISPACT-II. The system has been tested with the measurements of Al and In foils, using a PLA sample holder. The results demonstrate that activation products with half-lives of as little as 2 s can be measured. γ-rays from the 2 s isomer, 116n In are clearly observed providing the irradiation and measurement times are appropriately chosen.
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| 5. |
- Frost, R. J. W., et al.
(författare)
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A compact accelerator driven neutron source at the Applied Nuclear Physics Laboratory, Lund University
- 2023
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Ingår i: EPJ TECHNIQUES AND INSTRUMENTATION. - : Springer Nature. - 2195-7045. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- The Applied Nuclear Physics Group at Lund University has constructed a CANS (Compact Accelerator-driven Neutron Source). The CANS is based around a 3 MV, single-ended, Pelletron accelerator, which is used to impinge a 2.8 MeV deuterium beam into a beryllium target. The anticipated neutron production will be on the order of 10(10) n/s in 4 pi sr, with future upgrades expected to increase neutron production to 10(11) n/s. Neutron energy will be up to 9 MeV with peak emission at similar to 5 MeV. Shielding and moderation will be provided by a large water tank surrounding the target, with exit ports to allow moderated neutrons to be directed to experiments. The thermal-neutron flux at the exit of the extraction ports is anticipated to be up to 10(6) n/cm(2)/s. The CANS will be used to forward the activities of the group in the area of neutron-activation analysis, in addition to a broader range of neutron related applications.
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| 6. |
- Frost, R. J.W., et al.
(författare)
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Automating the setup and control of the pre-sample charge measurement system at the Lund Ion-beam Analysis Facility
- 2020
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 464, s. 84-88
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Tidskriftsartikel (refereegranskat)abstract
- In many IBA applications the aim is to obtain quantitative figures characterising the sample, usually requiring a reliable measurement of the beam current for normalisation. To avoid the drawbacks associated with on-sample and post-sample charge measurement systems a pre-sample measurement system can be used. In this work an upgrade to the pre-sample charge measurement system at the Lund Ion-beam Analysis Facility is presented, in which a custom built control module based around a Teensy 3.2 micro-controller has been added to the existing system. The new control module allows for remote handling and monitoring of the deflection system, operated via USB connection to a PC running a graphical user interface. Details of the control modules functionality, design and programming are given, as well as the functionality of the user interface. An example of how the new control module can be used for automated calibration of the deflection system is also presented.
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| 7. |
- Pallon, Jon, et al.
(författare)
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Presence of microorganisms in children with pharyngotonsillitis and healthy controls: a prospective study in primary healthcare
- 2021
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Ingår i: Infection. - : Springer Science and Business Media LLC. - 0300-8126 .- 1439-0973. ; 49:4, s. 715-724
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Most studies on paediatric pharyngotonsillitis focus on group A streptococci. This study, however, analyses a broad spectrum of bacteria and viruses related to paediatric pharyngotonsillitis and evaluates their associated clinical symptoms and courses. Methods This observational prospective study in primary healthcare includes 77 children aged < 15 with a sore throat and 34 asymptomatic children, all of whom were sampled from the tonsils with an E-swab(R) for analysis with culture and PCR for 14 bacteria and 15 viruses. Patients were evaluated clinically, and their symptoms recorded in diaries for 10 days. Participants were followed up for 3 months by reviewing medical records. Results A pathogen was detected in 86% of patients and in 71% of controls (P = 0.06). Bacteria were found in 69% of patients and 59% of controls (P = 0.3), and viruses in 36% and 26%, respectively (P = 0.3). Group A streptococci was the most common finding, with a prevalence of 49% and 32%, respectively (P = 0.1). Clinical signs were not useful for distinguishing pathogens. None of the controls and 16% of the patients reconsulted for a sore throat within 3 months. Conclusion Bacteria were more common than viruses in both study groups. The high rate of pathogens in asymptomatic children interferes with diagnoses based on aetiology.
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