| 1. |
- Penttila, H., et al.
(författare)
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Independent Isotopic Product Yields in 25 MeV and 50 MeV Charged Particle Induced Fission of U-238 and Th-232
- 2014
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Ingår i: Nuclear Data Sheets. - : Elsevier BV. - 0090-3752 .- 1095-9904. ; 119, s. 334-337
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Tidskriftsartikel (refereegranskat)abstract
- Independent isotopic yields for most elements from Zn to La in 25-MeV proton-induced fission of U-238 and Th-232 have been determined at the IGISOL facility in the University of Jyvaskyla. In addition, isotopic yields for Zn, Ga, Rb, Sr, Zr, Pd and Xe in 50-MeV proton-induced fission of U-238 and for Zn, Ga, Rb, Sr, Cd and In in 25-MeV deuterium-induced fission of U-238 have been measured. The utilised technique recently developed at the University of Jyvaskyla, is based on a combination of the ion guide technique and the ability of a Penning trap to unambiguously identify the isotopes by their atomic mass. Since the yields are determined by ion counting, no prior knowledge beyond the mass and half-life of the isotopes was needed for the measurements.
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| 2. |
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| 3. |
- Gorelov, D., et al.
(författare)
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Developments for neutron-induced fission at IGISOL-4
- 2016
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier BV. - 0168-583X .- 1872-9584.
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Tidskriftsartikel (refereegranskat)abstract
- Abstract At the IGISOL-4 facility, neutron-rich, medium mass nuclei have usually been produced via charged particle-induced fission of natural uranium and thorium. Neutron-induced fission is expected to have a higher production cross section of the most neutron-rich species. Development of a neutron source along with a new ion guide continues to be one of the major goals since the commissioning of IGISOL-4. Neutron intensities at different angles from a beryllium neutron source have been measured in an on-line experiment with a 30 MeV proton beam. Recently, the new ion guide coupled to the neutron source has been tested as well. Details of the neutron source and ion guide design together with preliminary results from the first neutron-induced fission experiment at IGISOL-4 are presented in this report.
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| 4. |
- Gorelov, D., et al.
(författare)
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Measuring independent yields of fission products using a penning trap
- 2015
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Ingår i: Bulletin of the Russian Academy of Sciences: Physics. - 1062-8738. ; 79:7, s. 869-871
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Tidskriftsartikel (refereegranskat)abstract
- A new method for determining independent fission products is used in an experiment at the Accelerator Laboratory of the University of Jyväskylä. The method combines the chemical universality of the ion guide technique and the unique properties of the Penning trap. A beam of charged particles is formed by stopping fission products in gaseous helium. The Penning trap is employed as a highly accurate filter to identify particles by their mass. The yields of fission products are determined by the ion count downstream of the trap. The setup’s mass resolving power is on the order of 105 with a radio frequency excitation time of 400 ms. Such high mass resolution occasionally allows us not only to separate nuclides but to separate the isomeric and ground states of nuclei as well. Independent yields of fission products are measured in the fission reaction of the 232Th isotope by protons with an energy of 25 MeV. A short description of the method ae nd soexperimental data are supplememnted by the results fro theoretical calculations.
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| 5. |
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| 6. |
- Rakopoulos, Vasileios, et al.
(författare)
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First isomeric yield ratio measurements by direct ion counting and implications for the angular momentum of the primary fission fragments
- 2018
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Ingår i: Physical Review C. - : AMER PHYSICAL SOC. - 2469-9985 .- 2469-9993. ; 98:2
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Tidskriftsartikel (refereegranskat)abstract
- We report the first experimental determination of independent isomeric yield ratios using direct ion counting with a Penning trap, which offered such a high resolution in mass that isomeric states could be separated. The measurements were performed at the Ion Guide Isotope Separator On-Line (IGISOL) facility at the University of Jyvaskyla. The isomer production ratios of Ge-81, Y-96,Y-97 Sn-128(,1)30, and Sb-129 in the 25-MeV proton-induced fission of U-na(t) and Th-232 were studied. Three isomeric pairs (Ge-81, Y-96, and Sb-129) were measured for the first time for the U-na(t)(p, f) reaction, while all the reported yield ratios for the Th-232(p, f) reaction were determined for the first time. The comparison of the experimentally determined isomeric yield ratios with data available in the literature shows a reasonable agreement, except for the case of Sn-130 for unspecified reasons. The obtained results were also compared with the GEF model, where good agreement can be noticed in most cases for both reactions. Serious discrepancies can only be observed for the cases of Y-96(,)97 for both reactions. Moreover, based on the isomeric yield ratios, the root-mean-square angular momenta (J(r)(ms)) of the fission fragments after scission were estimated using the TALYS code. The experimentally determined isomeric yield ratios, and consequently the deduced J(rms), for Sn-130 are significantly lower compared to Sn-128 for both fissioning systems. This can be attributed to the more spherical shape of the fragments that contribute to the formation of Sn-130, due to their proximity to the N = 82 shell closure. The values of J(rms) for Sb-129 are higher than Sn-128 for both reactions, despite the same neutron number of both nuclides (N = 78), indicating the odd-Z effect where fission fragments with odd-Z number tend to bear larger angular momentum than even-Z fragments. The isomer production ratio for the isotopes of Sn is more enhanced in the U-na(t)(p, f) reaction than in Th-232(p, f). The opposite is observed for Y-96 and Y-97. These discrepancies might be associated to different scission shapes of the fragments for the two fission reactions, indicating the impact that the different fission modes can have on the isomeric yield ratios.
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| 7. |
- Tuboltsev, Yu. V., et al.
(författare)
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A CAMAC-USB crate controller
- 2010
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Ingår i: Instruments and experimental techniques (New York). - 0020-4412 .- 1608-3180. ; 53:1, s. 79-83
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Tidskriftsartikel (refereegranskat)abstract
- 79-83A controller providing communication between a computer and a CAMAC crate via the USB bus is described. For this purpose, the controller includes a DLP-USB245M module, which allows a programmer to work with the controller through a virtual COM port and, at the same time, provides all the advantages of the USB standard. We consider versions of interactions of the DLP-USB module with controller registers on a programmable logic array and on the microcontroller.
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| 8. |
- Bevilacqua, Riccardo, et al.
(författare)
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Light-Ion Production in the Interaction of 175 MeV Neutrons with Iron and Bismuth
- 2011
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Ingår i: Journal of the Korean Physical Society. - : Korean Physical Society. - 0374-4884 .- 1976-8524. ; 59:2, s. 1701-1704
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Tidskriftsartikel (refereegranskat)abstract
- We have measured double-differential (angle and energy) cross sections for light-ion (p, d, t, (3)He, and a) production in the interaction of quasi-monoenergetic 175 MeV neutrons with iron and bismuth. Measurements have been performed at the The Svedberg Laboratory, Uppsala (Sweden), using the Medley setup which allows low-energy thresholds and wide energy and angular ranges. Medley is a spectrometer system consisting of eight three-element telescopes placed at angles from 20 degrees to 160 degrees, in steps of 20 degrees. Each telescope is composed of two silicon surface barrier detectors and a CsI(Tl) scintillator, to perform particle identification, fully stop the produced light-ions and measure their kinetic energy. The time-of-flight was used to reduce the contribution from the low energy tail in the accepted incident neutron spectrum. We report double-differential production cross sections for protons, deuterons, tritons, (3)He and alpha particles and compare them with model calculations with TALYS-1.2.
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| 9. |
- Bevilacqua, Riccardo, et al.
(författare)
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Neutron induced light-ion production from iron and bismuth at 175 MeV
- 2010
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Ingår i: RADIATION MEASUREMENTS. - : Elsevier BV. ; 45:10, s. 1145-1150
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Konferensbidrag (refereegranskat)abstract
- We have measured light-ion (p, d, t, He-3 and alpha) production in the interaction of 175 MeV neutrons with iron and bismuth with low-energy thresholds and for a wide angular range (from 20 degrees to 160 degrees, in steps of 20 degrees). Measurements have been performed with the Medley setup, semi-permanently installed at the The Svedberg Laboratory, Uppsala (Sweden), where a quasi-monoenergetic neutron beam is available and well characterized. Medley is a conventional spectrometer system and consists of eight telescopes, each of them composed of two silicon surface barrier detectors, to perform particle identification, and a CsI(Tl) scintillator to fully measure the kinetic energy of the produced light-ions. We report preliminary double-differential cross sections for production of protons, deuterons and tritons in comparison with model calculations using TALYS-1.0 code. These show better agreement for the production of protons, while the theoretical calculations seem to overestimate the experimental production of deuterons and tritons.
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| 10. |
- Gorelov, D., et al.
(författare)
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Isomeric Yield Ratios of Fission Products Measured with the Jyfltrap
- 2014
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Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 45:2, s. 211-216
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Tidskriftsartikel (refereegranskat)abstract
- Experimental methods to determine isomeric yield ratios usually apply gamma-spectroscopic techniques. In such methods, ground and isomeric states are distinguished by their decays. In the present work, several isomeric yield ratios of fission products have been measured by utilizing capabilities of the double Penning-trap mass spectrometer JYFLTRAP, where isomeric and ground state were separated by their masses. To verify the new experimental technique, the results were compared to those from gamma-spectroscopy measurements.
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