| 1. |
- Ideguchi, E., et al.
(author)
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Orbifold projection in supersymmetric QCD at N(f) ≤ N(c)
- 2000
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 492:3-4, s. 369-375
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Journal article (peer-reviewed)abstract
- Supersymmetric orbifold projection of N = 1 SQCD with relatively small number of flavors (N(f) ≤ N(c)) is considered. The purpose is to check whether orbifolding commutes with the infrared limit. On the one hand, one considers the orbifold projection of SQCD and obtains the low-energy description of the resulting theory. On the other hand, one starts with the low-energy effective theory of the original SQCD, and only then performs orbifolding. It is shown that at finite N(c) the two low-energy theories obtained in these ways are different. However, in the case of stabilized run-away vacuum these two theories are shown to coincide in the large N(c) limit. In the case of quantum modified moduli space, topological solitons carrying baryonic charges are present in the orbifolded low-energy theory. These solitons may restore the correspondence between the two theories provided that the soliton mass tends to zero in the large N(c) limit. (C) 2000 Elsevier Science B.V.
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| 2. |
- Bergenius, S., et al.
(author)
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Proton irradiation response of CsI(Tl) crystals for the GLAST calorimeter
- 2003
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In: 2003 IEEE Nuclear Science Symposium Conference Record. - : IEEE Press. - 0780382579 ; , s. 1096-1099
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Conference paper (peer-reviewed)abstract
- The electromagnetic calorimeter of the Gamma-Ray Large Area Space Telescope (GLAST) consists of 16 towers of CsI(Tl) crystals. Each tower contains 8 layers of crystals (each 326.0x26.7x19.9 mm3) arranged in a hodoscopic fashion. The crystals are read out at both ends with photodiodes. Crystals produced by Amcrys-H (Ukraine) are used. A full size crystal was irradiated with a 180 MeV proton beam and the radiation induced attenuation was measured. The induced radioactivity of the crystal was also studied. In this paper we will discuss the damage due to proton irradiation and compare this with the expected in-orbit background flux.
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| 3. |
- Bergenius, S., et al.
(author)
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Radiation hardness tests of CSI(Tl) crystals for the GLAST electromagnetic calorimeter
- 2003
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In: Proceedings of 28th International Cosmic Ray Conference. ; , s. 2787-2790
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Conference paper (peer-reviewed)abstract
- The electromagnetic calorimeter of the Gamma ray Large Area Space Telescope(GLAST) consists of 16 towers of CsI(Tl) crystals. Each tower contains 8layers of crystals (each 326.0×26.7×19.9 mm3) arranged in a hodoscopic fashion.The crystals are read out at both ends with PIN photodiodes. Crystals producedby Amcrys-H (Ukraine) are used. As a part of the quality control procedureduring crystal production, samples from the uncut boules are systematically irradiatedwith gamma rays from a 60Co source. Studies have also been carried outto verify the correspondence between the post-irradiation properties of the boulesamples and the full size crystals which are subsequently cut from the boule. Thefull size crystals have also been irradiated with a 180 MeV proton beam and theradiation induced attenuation measured.
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| 4. |
- Ideguchi, Eiji, et al.
(author)
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Superdeformation in 91Tc
- 2000
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In: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 492:3-4, s. 245-253
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Journal article (peer-reviewed)abstract
- A high-spin rotational band with 11 gamma -ray transitions has barn observed in Tc-91. The dynamical moment of inertia as well as the transition quadrupole moment of 8.1(-1.4)(+1.9) eb measured for this band show the characteristics of a superdeformed band. However, the shape is more elongated than in the neighbouring A = 80-90 superdeformed nuclei. Theoretical interpretations of the band within the cranked Strutinsky approach based on two different Woods-Saxon potential parameterisations are presented. Even though an unambiguous configuration assignment proved difficult, both calculations indicate a larger deformation and at least three additional high-N intruder orbitals occupied compared to the lighter SD nuclei. (C) 2000 Elsevier Science B.V. All rights reserved.
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| 5. |
- Klamra, Wlodzimierz, et al.
(author)
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High-spin multiparticle-hole excitations in Eu-148
- 2001
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In: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 10:1, s. 11-12
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Journal article (peer-reviewed)abstract
- Studies by means of 155 MeV Al-27 bombardment on a Te-130 target revealed in Eu-148 high-spin structures up to spin 31 (n) over tilde, in addition to a cascade extended to the 11088.1 keV excitation. The observed levels are tentatively assigned as complex multiparticle-hole proton and neutron configurations.
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| 6. |
- Moszynski, A., et al.
(author)
-
Intrinsic energy resolution and light yield nonproportionality of BGO
- 2004
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In: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 51:3, s. 1074-1079
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Journal article (peer-reviewed)abstract
- The intrinsic energy resolution and nonproportionality of the light yield as a function of gamma ray energies, in the energy range of 14 keV to 1.33 MeV, were studied for small BGO (Bi4Ge3O12) crystals at room and liquid nitrogen (LN2) temperatures. The study showed that the intrinsic resolution of BGO and the light yield nonproportionality, as a function of energy do not depend on the crystal temperature. High light outputs of 14000 +/- 300 electron-hole pairs and energy resolution of 6.5% +/- 0.2% for 662 keV gamma rays were measured with the 9 mm diameter, 4 mm thick crystals, coupled to large area avalanche photodiodes and cooled down to LN2 temperature. Special attention was paid to analyzing the energy resolution of the escape peaks, which were well separated from the full-energy peaks due to the good energy resolution of BGO at LN2 temperatures and the energy of bismuth KX-rays. The intrinsic energy resolution of the BGO crystal for escape peaks does not show deviations from analysis of total energy absorption photopeaks. This is in spite of the fact that the contributions of X-rays and Auger electron cascade in creation of escape peaks are much smaller than in full-energy peaks. In the small volume crystal, mainly electrons produced in the photoelectric absorption create the escape peaks.
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| 7. |
- Moszynski, M., et al.
(author)
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Application of large area avalanche photodiodes to study scintillators at liquid nitrogen temperatures
- 2003
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In: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 504:03-jan, s. 307-312
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Journal article (peer-reviewed)abstract
- Properties of Large Area Avalanche Photodiodes (LAAPDs) at liquid nitrogen (LN2) temperatures in application to study pure NaI, CsI and BGO scintillators are presented. All the tested crystals exhibited excellent performance at LN2 temperatures reflected by a high light output and very good energy resolution. The study showed that the LAAPD operating at LN2 temperatures is an excellent light readout device for testing different scintillators at low temperatures.
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| 8. |
- Moszynski, M., et al.
(author)
-
Energy resolution and light yield non-proportionality of pure NaI scintillator studied with large area avalanche photodiodes at liquid nitrogen temperatures
- 2002
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In: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 486:02-jan, s. 13-17
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Journal article (peer-reviewed)abstract
- The pure NaI crystal has been studied using a Large Area Avalanche Photodiode (LAAPD) at near liquid nitrogen (LN2) temperatures. The study showed a high light output of 44000+/-4000 photons/MeV (ph/MeV), the energy resolution of 5.9 +/- 0.2% for 661.6 keV gamma-rays from a Cs-137 source and a good proportionality of the light yield versus gamma-ray energy. It has been shown also that a cooled LAAPD is an excellent photodetector to study scintillators at near LN2 temperatures.
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| 9. |
- Moszynski, M., et al.
(author)
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Intrinsic energy resolution of pure NaI studied with large area avalanche photodiodes at liquid nitrogen temperatures
- 2003
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In: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 505:02-jan, s. 63-67
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Journal article (peer-reviewed)abstract
- The energy resolution and non-proportionality of the light yield vs gamma-ray energy of pure NaI scintillators directly coupled to Large Area Avalanche Photodiodes (LAAPDs) and cooled down to the liquid nitrogen temperatures have been studied. Large improvements of energy resolution and nearly proportional light yield response have been obtained at very long shaping time constants. Energy resolution of 3.8+/-0.1% for 662 keV gamma-rays from a Cs-137 source was recorded at 50 mus integration time. The intrinsic resolution of the crystal vs energy of gamma-rays has been estimated by measurements of the number of primary electron-hole pairs generated in LAAPD by scintillation light.
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| 10. |
- Moszynski, M., et al.
(author)
-
Study of pure NaI at room and liquid nitrogen temperatures
- 2003
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In: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 50:4, s. 767-773
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Journal article (peer-reviewed)abstract
- Three pure NaI crystals grown in different batches by Scionix (The Netherlands) were studied at room and liquid nitrogen temperatures. The room temperature studies performed with photomultiplier readout covered measurements of emission spectra, photoelectrons yield and energy resolution. Moreover, the scintillation light poises were measured by single photon method. Two crystals showed the photoelectron yield of about 1000 phe/MeV measured at room temperature with an XP2020Q photomultiplier. The energy resolution of the 662 keV photopeak was measured to, be about 16% and was limited mainly by a low number of photoelectrons and a large nonproportionality of the light yield. The fast light pulse had the main decay time components of 1 and 5 ns. The high initial photon intensity of the tested NaI crystals revealed a good timing. resolution of about 140 ps obtained for Co-60 gamma-rays. At. liquid nitrogen temperatures the measurements of light yield and energy resolution were performed using An Advanced Photonix, Inc. avalanche photodiode readout A high light output above 80 000 ph/MeV was measured for the best of the tested crystals. The energy resolutions of the 662 kAV photopeak of the three crystals differ a lot, varying from an excellent value of 3.8% to 6.2%. This suggests that the measured, pies energy resolutions depend on the purity of the scintillator samples reflected in the emission spectral The studies that were performed demonstrate the attractive properties of pure NaI at both room and LN2 temperature.
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