[en] The set of Mo and (Mo,Y) doped PbWO₄ scintillating crystals was irradiated 30 min by a homogeneous gamma-radiation field, produced in the irradiation of tungsten target by 21 MeV electron beam from the microtrone accelerator. The induced absorption spectra were measured on-line, i.e. during the irradiation and after switching-off the machine with a sampling rate of 10 s for the dose rates of about 0.17 Gy/min. The results show a clear effect of the doped ions in PWO crystals on the spectra and kinetics of both colour centres formation and recovery processes. The induced absorption build-up and recovery time dependences at fixed wavelength are approximated by a simple model and quantitative parameters are extracted and discussed

[en] A hybrid photomultiplier (HPMT) was used to study the scintillation response {N_phels(E) photoelectron and L.Y.(E) light yields and energy resolutions} of various known or newly developed scintillators--namely, Ce-doped crystals (perovskites or garnets), CsI(Tl) and the intrinsic BGO crystal--at different energies in the range 8 keV-1.33 MeV. Detailed comparative studies of the scintillation properties of these crystals are presented. A newly developed fast and heavy LuAG:Ce scintillator is characterized by about a 50% higher L.Y. compared to that of well-known and popular BGO (roughly 12 500 ph/MeV against 8080 ph/MeV, respectively)

[en] We investigated Czochralski-grown YAG:Pr single crystal as a potential novel scintillator. Optical characteristics including photoluminescence, radioluminescence, scintillation decay, radiation damage and thermoluminescence were measured. Their dependence on the dopant concentration was studied. The radiation damage results show that with increasing concentration of Pr the radiation damage reduces. Thermoluminescence above room temperature shows the dominant glow curve peak around 250 C. Comparing to YAG:Ce scintillator an advantage of YAG:Pr is its much faster scintillation decay (16-17 ns at room temperature) and an absence of slow components in the decay. Therefore YAG:Pr appears as potentially interesting scintillator material. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

[en] In this paper we present the photoluminescence (PL) and scintillation response of Pr³⁺-doped Y₃Al₅O₁₂ (YAG:Pr) single crystals grown by the Czochralski method with different Pr³⁺ concentrations of 0.16, 0.33, and 0.65 mol%. PL spectra and decay curves were measured for both the fast 5d → 4f and slow 4f → 4f emissions. The PL decay times were evaluated which evidence concentration quenching especially in ¹D₂ → ³H₄ emission for the highest Pr³⁺ concentration. Light yield (LY) of 15,600 photons per MeV and energy resolution of 6.4% at 662 keV γ-rays were obtained with the YAG:Pr (0.33%) crystal. The LY non-proportionality and energy resolution versus γ-ray energy were measured and the intrinsic resolution was calculated. A good proportionality of the LY was found within 7% over the energy range from 1274.5 keV down to 32 keV. The estimated photofraction in the pulse height spectra of 320 and 662 keV γ-rays was also determined and compared with the theoretical one calculated using WinXCom program. -- Highlights: •Pr-concentration dependence of light yield in YAG:Pr crystals is studied. •Concentration quenching is revealed in 4f–4f emission spectra and decays. •Light yield of 15,600 ph/MeV and energy resolution of 6.4% @662 keV are evaluated. •Photofraction in pulse height spectra of 320 and 662 keV γ-rays is determined

[en] The scintillation properties of Lu₃Al₅O₁₂:Pr³⁺ (LuAG:Pr) single crystal grown by the Czochralski method with praseodymium concentration of 0.19 mol% were investigated. For a comparison, a good quality Bi₄Ge₃O₁₂ (BGO) single crystal grown by Bridgman method was also studied. The light yield and energy resolution were measured using photomultiplier tube (XP5200B PMT) readout. Moderate light yield of 15,900 photons per MeV was measured for the LuAG:Pr(0.19%) crystal. For 662 keV gamma rays (¹³⁷Cs source), an energy resolution of 6.5% obtained for LuAG:Pr(0.19%) is much better than that of 9.0% obtained for BGO. The light yield non-proportionality and energy resolution versus energy of gamma rays were measured and the intrinsic resolution of the crystals was determined after correcting the measured energy resolution for PMT statistics. The LuAG:Pr(0.19%) showed a good proportionality of the light yield within 5% over the energy range from 1274.5 keV down to 32 keV, which is much better than that of 14% for BGO. The photofraction was determined at 320 and 662 keV for both crystals and compared with the ratio of the cross-sections for the photoelectric effect to the total one calculated using WinXCOM program.

[en] The wavelength tunability of a diode-pumped laser, based on Yb³⁺ -doped mixed garnet Gd₃Ga_5−xAl_xO₁₂ (Yb:GGAG, , 4.25% Yb/Gd, 2.7 mm thick) crystal was investigated. Absorption and emission spectra together with fluorescence decay time were measured. The longitudinally diode-pumped Yb:GGAG laser was continuously tuned over  ∼47 nm (from 1019 nm up to 1066 nm). The maximum output power amplitude of 1.6 W was obtained at wavelength 1042 nm with an absorbed pump power amplitude 6.9 W. The corresponding tunable laser slope efficiency was 30%. (paper)

[en] Scintillation response [N_phels(E) and LY(E) yields and energy resolutions] of well-defined and efficient Ce³⁺-doped aluminium perovskite (YAP) and garnets (YAG and LuAG) was investigated using the experimental set-up with HPMT multiplier. Possibilities of increasing scintillation response with growth of mixed (Y,Lu) crystals or with suitable co-doping are presented and also the influence of re-absorption of Ce³⁺ emission