| 1. |
- Abdel, Naseem, et al.
(författare)
-
Fabrication and Characterization of Ultra-Thin PIN Silicon Detectors for Counting the Passage of MeV Ions
- 2013
-
Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499. ; 60:2, s. 1182-1188
-
Tidskriftsartikel (refereegranskat)abstract
- This paper describes the fabrication and initial characterization of an ultra-thin silicon PIN detector using a new technique in silicon nanotechnology. In collaboration with the Nuclear Physics Division and the Lund Nano Lab at Lund University, we have developed and manufactured ultra thin Delta E-detectors for spectroscopic applications. The fabrication process has been carried out using a double-polished silicon substrate n-type wafer and locally thinning by means of a 10:1 solution of 25% tetramethyl ammonium hydroxide (TMAH) with Isopropyl alcohol. More than 100 detectors of different thicknesses, down to 5 mu m with active areas ranging from 0.71 to 0.172 mm(2), have been fabricated. The main design considerations of our thin detectors were a very low leakage current below 12 nA and a low full depletion voltage at a reverse bias less than 1.5 V. Finally, most of our thin detectors offer an energy resolution (FWHM) as low as 31 keV for 5.487 MeV alpha particles from a Am-241 source.
|
|
| 2. |
- Akselsson, Roland, et al.
(författare)
-
PIXE Analysis Research in Lund
- 1979
-
Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499. ; NS-26:1, s. 1358-1362
-
Tidskriftsartikel (refereegranskat)abstract
- Protons or a-particles from a 3 MV tandem Pelletron are used to induce characteristic x-rays, which are detected by a Si(Li)-detector. To optimize the quality and speed of data taking we use an absorber with a hole, pile-up rejection and on-demand beam. Forty samples may be entered simultaneously into the vacuum, and their positioning is operated by pushbuttons. The system is prepared for minicomputer steering. PIXE is combined with analysis of backscattered particles and in some cases γ-ray detection from a 19F(p,αγ) 160-reaction. At different stages of development we have a bent-chrystal spectrometer, microbeam and facilities to extract the beam from vacuum. In the introduction of PIXE to applied fields, it is important, that physicists take part in identifying, planning and performing suitable projects e.g. experiments where rapid multielemental analysis of many samples is crucial. In Lund we investigate the elemental composition of size-fractionated airborne particles from work environments and ambient air. The objectives are then to learn about sources, transport and deposition of particles and to contribute to the understanding of relations between exposure and health effects. We are also developing procedures for trace elemental analysis of water. Detection limits in the range of 0.1 ppb have been demonstrated. In other projects in progress biological and mineralogical samples are analysed.
|
|
| 3. |
- Akselsson, Roland
(författare)
-
PIXE in 1980: Summary of the Second International Conference on Particle Induced X-Ray Emission and its Analytical Applications
- 1981
-
Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499. ; NS-28:2, s. 1369-1373
-
Tidskriftsartikel (refereegranskat)abstract
- The Second International Conference on Particle Induced X-ray Emission (PIXE) and its analytical applications was held in Lund, Sweden, June 9-12, 1980. About a hundred papers were presented, including seven invited talks (PIXE and particle scattering, microbeam analysis (2), applications to aerosols (2) and biological samples (2)). The main impression left by the conference was that both the PIXE method and its applications are in a phase of fast development. Considerable effort has successfully been devoted to optimizing the basic PIXE technique. Also the great advantage of simultaneously getting information about lighter elements and sample mass was reported to have been successfully employed in routine analyses. PIXE, which was initially considered to be a method mainly for thin samples, has also been shown to be competitive for a variety of thick samples. Consequently there were several papers dealing with problems characteristic of thick sample analysis. In this context, external beam analysis was also thoroughly discussed. Charged particle microprobes seem to be very attractive and several investigators reported progress on microprobe development and very interesting results of applied work. It is gratifying to note the increasing interest shown by non-physicists in using PIXE. These activities have greatly contributed to the fact that PIXE has now in a few areas left the phase of feasibility tests. E.g. an imposing amount of data from aerosol studies was presented. With the PIXE method, it is feasible to perform series of measurements over a long period of time, many samples in parallel and/or samples from sites of poor accessibility. However, the advantages of PIXE may be further exploited in aerosol investigations and some promising lines of sampler development were reported. Sample preparation techniques are crucial for applications to biological samples and several laboratories are engaged in such developmental work,. However, it was also evident that PIXE us already giving significant contributions to research in biology and medicine.
|
|
| 4. |
- Allison, J, et al.
(författare)
-
Geant4 developments and applications
- 2006
-
Ingår i: IEEE TRANSACTIONS ON NUCLEAR SCIENCE. - 0018-9499. ; 53:1, s. 270-278
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 5. |
- Andreou, Charalambos M., et al.
(författare)
-
Single Event Transients and Pulse Quenching Effects in Bandgap Reference Topologies for Space Applications
- 2016
-
Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 63:6, s. 2950-2961
-
Tidskriftsartikel (refereegranskat)abstract
- An architectural performance comparison of bandgap voltage reference variants, designed in a 0.18 mu m CMOS process, is performed with respect to single event transients. These are commonly induced in microelectronics in the space radiation environment. Heavy ion tests (Silicon, Krypton, Xenon) are used to explore the analog single-event transients and have revealed pulse quenching mechanisms in analogue circuits. The different topologies are compared, in terms of cross-section, pulse duration and pulse amplitude. The measured results, and the explanations behind the findings, reveal important guidelines for designing analog integrated circuits, which are intended for space applications. The paper includes an analysis on how pulse quenching occurs within the indispensable current mirror, which is used in every analog circuit.
|
|
| 6. |
- Anelli, A., et al.
(författare)
-
Measurement and simulation of the neutron response and detection efficiency of a Pb-scintillating fiber calorimeter
- 2008
-
Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 55:3, s. 1409-1412
-
Tidskriftsartikel (refereegranskat)abstract
- We have measured the overall detection efficiency to neutrons of a small prototype of the KLOE Pb-scintillating fiber calorimeter in the kinetic energy range [5,175] MeV. using the neutron beam facility of The Svedberg Laboratory, TSL, Uppsala. The measurement of the neutron detection efficiency of a NE110 scintillator provided a reference calibration. At the lowest trigger threshold, the overall calorimeter efficiency ranges from 28% to 33%. This value largely exceeds the estimated similar to 8% expected if the response were proportional only to the scintillator equivalent thickness. A detailed simulation of the calorimeter and of the TSL beamline has been performed with the FLUKA Monte Carlo code. The simulated response of the detector to neutrons is presented together with first data to Monte Carlo comparison. The results show an overall neutron efficiency of about 35%. The reasons for such an efficiency enhancement, in comparison with the typical scintillator-based neutron counters, are explained, opening the road to a novel neutron detector.
|
|
| 7. |
- Argume, A., et al.
(författare)
-
NOAA Image Data Acquisition to Determine Soil Moisture in Arequipa - Perú
- 2021
-
Ingår i: IEEE Transactions on Nuclear Science. - : IEEE. - 0018-9499 .- 1558-1578. ; 68:8, s. 1933-1936
-
Tidskriftsartikel (refereegranskat)abstract
- In recent years, irrigations have been built on dry areas in Majes-Arequipa. Over time, the irrigations water forms moist areas in lower areas, which can have positive or negative consequences. Therefore, it is important to know in advance where the water from the new irrigation will appear. The limited availability of real-time satellite image data is still a hindrance to some applications. Data from environmental satellites NOAA (National Oceanic and Atmospheric Administration) are available fee and license free. In order to receive data, users must obtain necessary equipment. In this work we present a satellite data acquisition system with an RTL SDR receiver, two 137-138 Mhz designed antennas, Orbitron, SDRSharp, WXTolmag and MatLab software. We have designed two antennas, a Turnstile Crossed dipole antenna with Balun and a quadrifilar helicoidal antenna. The antennas parameter measurements show very good correspondence with those obtained by simulation. The RTL SDR RTL2832U receiver, combined with our antennas and software, forms the system for recording, decoding, editing and displaying Automatic Picture Transmission (APT) signals. The results show that the satellite image receptions are sufficiently clear and descriptive for further analysis.
|
|
| 8. |
- Arredondo, I., et al.
(författare)
-
Adjustable ECR Ion Source Control System: Ion Source Hydrogen Positive Project
- 2015
-
Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499. ; 62:3, s. 903-910
-
Tidskriftsartikel (refereegranskat)abstract
- ISHP (Ion Source Hydrogen Positive) project consists of a highly versatile ECR type ion source. It has been built for several purposes, on the one hand, to serve as a workbench to test accelerator related technologies and validate in-house made developments, at the first stages. On the other hand, to design an ion source valid as the first step in an actual LINAC. Since this paper is focused on the control system of ISHP, besides the ion source, all the hardware and its control architecture is presented. Nowadays the ion source is able to generate a pulse of positive ions of Hydrogen from 2 mu s to a few range with a repetition rate ranging from 1 Hz to 50 Hz with a maximum of 45 mA of current. Furthermore, the first experiments with White Rabbit (WR) synchronization system are presented.
|
|
| 9. |
- Aykac, M., et al.
(författare)
-
Timing performance of Hi-Rez detector for time-of-flight (TOF) PET
- 2006
-
Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 53:3, s. 1084-1089
-
Tidskriftsartikel (refereegranskat)abstract
- Positron emission tomography (PET)-based on time-of-flight (TOF) is desired to enhance the image quality by improving the noise variance in the reconstruction. This benchtop study evaluates the timing performance of the current Hi-Rez detector which is based on a 13/spl times/13 LSO array of 4 mm/spl times/4 mm/spl times/20 mm crystals and not optimized for TOF PET applications. A Hamamatsu R9779, fast, 51-mm-diameter PMT was used for some experiments in this study as a reference PMT and its time resolution was measured to be 160 ps with a plastic scintillator. The average crystal time resolution of two Hi-Rez detectors, coupled to a 2/spl times/2 array of Hamamatsu 25-mm-diameter R8619 PMTs at +1050 V, in coincidence was measured to be 733 ps. The average crystal energy resolutions for two detectors were measured 13.1% and 13.2%. The average crystal time resolution of two Hi-Rez detectors improved from 733 ps to 642 ps when the PMT voltage was increased to +1300 V. The Hi-Rez detector was originally optimized for good energy resolution to reduce scatter and high packing fraction to obtain high sensitivity and improved spatial resolution for clinical PET.
|
|
| 10. |
- Badel, Xavier, et al.
(författare)
-
Metallized and oxidized silicon macropore arrays filled with a scintillator for CCD-based X-ray imaging detectors
- 2004
-
Ingår i: IEEE Transactions on Nuclear Science. - : IEEE. - 0018-9499 .- 1558-1578. ; 51:3, s. 1001-1005, s. 1006-1010
-
Tidskriftsartikel (refereegranskat)abstract
- Silicon charge-coupled devices (CCDs) covered with a scintillating film are now available on the market for use in digital medical imaging. However, these devices could still be improved in terms of sensitivity and especially spatial resolution by coating the CCD with an array of scintillating waveguides. In this paper, such waveguides were fabricated by first etching pores in silicon, then performing metallization or oxidation of the pore walls and finally filling the pores with CsI(TI). The resulting structures were observed using scanning electron microscopy and tested under X-ray exposure. Theoretical efficiencies of macropore arrays filled with CsI(TI) were also calculated, indicating that the optimal pore depth for metallized macropore arrays is about 80 mum while it is around 350 mum for oxidized ones. This result, together with the roughness of the metal coating, explains why lower SNR values were measured with the metallized macropores. Indeed, the macropore arrays had depths in the range of 210-390 mum, which is favorable to oxidized structures.
|
|
