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| 2. |
- Hueyuek, Tayfun, et al.
(författare)
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Conceptual design of the early implementation of the NEutron Detector Array (NEDA) with AGATA
- 2016
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Ingår i: European Physical Journal A. - : Springer-Verlag New York. - 1434-6001 .- 1434-601X. ; 52:3
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Tidskriftsartikel (refereegranskat)abstract
- The NEutron Detector Array (NEDA) project aims at the construction of a new high-efficiency compact neutron detector array to be coupled with large gamma-ray arrays such as AGATA. The application of NEDA ranges from its use as selective neutron multiplicity filter for fusion-evaporation reaction to a large solid angle neutron tagging device. In the present work, possible configurations for the NEDA coupled with the Neutron Wall for the early implementation with AGATA has been simulated, using Monte Carlo techniques, in order to evaluate their performance figures. The goal of this early NEDA implementation is to improve, with respect to previous instruments, efficiency and capability to select multiplicity for fusion-evaporation reaction channels in which 1, 2 or 3 neutrons are emitted. Each NEDA detector unit has the shape of a regular hexagonal prism with a volume of about 3.23 l and it is filled with the EJ301 liquid scintillator, that presents good neutron-gamma discrimination properties. The simulations have been performed using a fusion-evaporation event generator that has been validated with a set of experimental data obtained in the Ni-58 + Fe-56 reaction measured with the Neutron Wall detector array.
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| 3. |
- Javier Egea, Francisco, et al.
(författare)
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Design and Test of a High-Speed Flash ADC Mezzanine Card for High-Resolution and Timing Performance in Nuclear Structure Experiments
- 2013
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 60:5, s. 3526-3531
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Tidskriftsartikel (refereegranskat)abstract
- This work describes new electronics for the EX-OGAM2 (HP-Ge detector array) and NEDA (BC501A-based neutron detector array). A new digitizing card with high resolution has been designed for gamma-ray and neutron spectroscopy experiments. The higher bandwidth requirement of the NEDA signals, together with the necessity for accuracy, require a high sampling rate in order to preserve the shape for real-time Pulse Shape Analysis (PSA). The PSA is of paramount importance for the NEDA to discriminate between neutrons and gamma-ray signals. Both high resolution and high speed parameters are often difficult to achieve in a single electronic unit. These constraints, together with the need to build new digitizing electronics to improve performance and flexibility of signal analysis in nuclear physics experiments, led to the development a new FADC mezzanine card. In this work, the design and development are described, including the characterization procedure and the preliminary measurement results.
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| 4. |
- Khaplanov, Anton, et al.
(författare)
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A gamma-ray polarimeter based on a single segmented planar HPGe detector
- 2008
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 593:3, s. 459-465
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Tidskriftsartikel (refereegranskat)abstract
- The polarization sensitivity of a segmented planar HPGe detector has been measured. For this purpose 662 keV photons from a Cs-137 source which were Compton scattered at approximate to 90 degrees in a coaxial germanium detector were utilized as a source of partially linearly polarized gamma radiation of the energy; approximate to 288 keV. The detector has a 50 x 50 x 21 mm sensitive volume and 5 x 5 electrical segmentation of the cathode contact. The degree of linear polarization is determined through the analysis of the directions of Compton scatterings inside the detector. The locations of the Compton scattering interactions and of the subsequent photo-absorption interactions have been determined with the help of pulse shape analysis (PSA), provided that these interactions are in two different segments of the planar detector. A comparison with a polarization analysis using the position resolution defined by the physical segmentation (without the use of PSA) was also performed. It is demonstrated that the use of PSA enables a much higher polarization sensitivity for events where the 288 keV photons scatter between adjacent pixels. Such events constitute 90% of the data for the 288 keV photons and are even more important for gamma-rays of lower energies.
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| 5. |
- Rolla, Dorota Tomaszewska, et al.
(författare)
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Mid-infrared optical frequency comb spectroscopy using an all-silica antiresonant hollow-core fiber
- 2024
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Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 32:6, s. 10679-10689
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Tidskriftsartikel (refereegranskat)abstract
- We present the first mid-infrared optical frequency comb spectrometer employing an absorption cell based on self-fabricated, all-silica antiresonant hollow-core fiber (ARHCF). The spectrometer is capable of measuring sub-mL sample volumes with 26 m interaction length and noise equivalent absorption sensitivity of 8.3 × 10−8 cm−1 Hz−1/2 per spectral element in the range of 2900 cm−1 to 3100 cm−1. Compared to a commercially available multipass cell, the ARHCF offers a similar interaction length in a 1000 times lower gas sample volume and a 2.8 dB lower transmission loss, resulting in better absorption sensitivity. The broad transmission windows of ARHCFs, in combination with a tunable optical frequency comb, make them ideal for multispecies detection, while the prospect of measuring samples in small volumes makes them a competitive technique to photoacoustic spectroscopy along with the robustness and prospect of coiling the ARHCFs open doors for miniaturization and out-of-laboratory applications.
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| 6. |
- Söderström, Pär-Anders, et al.
(författare)
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Interaction position resolution simulations and in-beam measurements of the AGATA HPGe detectors
- 2011
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 638:1, s. 96-109
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Tidskriftsartikel (refereegranskat)abstract
- The interaction position resolution of the segmented HPGe detectors of an AGATA triple cluster detector has been studied through Monte Carlo simulations and in an in-beam experiment. A new method based on measuring the energy resolution of Doppler-corrected γ-ray spectra at two different target to detector distances is described. This gives the two-dimensional position resolution in the plane perpendicular to the direction of the emitted γ-ray. The γ-ray tracking was used to determine the full energy of the γ-rays and the first interaction point, which is needed for the Doppler correction. Five different heavy-ion induced fusion-evaporation reactions and a reference reaction were selected for the simulations. The results of the simulations show that the method works very well and gives a systematic deviation of in the FWHM of the interaction position resolution for the γ-ray energy range from 60 keV to 5 MeV. The method was tested with real data from an in-beam measurement using a 30Si beam at 64 MeV on a thin 12C target. Pulse-shape analysis of the digitized detector waveforms and γ-ray tracking was performed to determine the position of the first interaction point, which was used for the Doppler corrections. Results of the dependency of the interaction position resolution on the γ-ray energy and on the energy, axial location and type of the first interaction point, are presented. The FWHM of the interaction position resolution varies roughly linearly as a function of γ-ray energy from 8.5 mm at 250 keV to 4 mm at 1.5 MeV, and has an approximately constant value of about 4 mm in the γ-ray energy range from 1.5 to 4 MeV.
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| 7. |
- Tomaszewska-Rolla, Dorota, et al.
(författare)
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Mid-IR optical frequency comb Fourier transform spectroscopy using an antiresonant hollow-core fiber
- 2023
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Ingår i: 2023 conference on lasers and electro-optics Europe & European quantum electronics conference (CLEO/Europe-EQEC). - : IEEE. - 9798350345995 - 9798350346008
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Konferensbidrag (refereegranskat)abstract
- Optical frequency combs (OFCs) enable high resolution, sensitivity, and speed in spectroscopic measurements. An efficient way of generating an optical frequency comb in the mid-infrared (mid-IR) is the difference frequency generation (DFG) process, which involves the interaction of two input waves in a non-linear crystal, resulting in the generation of a third wave with a frequency that is the difference in frequency of the two input beams [1]. The classical way of extending the path of light-gas interaction in spectroscopic measurements, thus increasing the sensitivity, is to use multi-pass cells (MPC). However, MPCs have disadvantages related to the difficulty of aligning laser light into the cell or optical fringes. An alternative approach is to use the so-called antiresonant hollow-core fibres (ARHCF) [2]. ARHCFs are characterized by a wide low-loss transmission range in the mid-IR, high quality of the delivered beam, and their air core can be filled with the target gas sample, which makes them well suited for laser-based gas sensing.
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