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The scintillation properties of La[Cl.sup.3] doped with different [Ce.sup.3+] concentrations studied by means of optical, [Gamma]-ray, and [Gamma]-ray excitation are presented. Under optical and [Gamma]-ray excitation, [Ce.sup.3+] emission is observed peaking at 330 and 352 nm. For La[Cl.sup.3] doped with 2%, 4%, 10%, and 30% [Ce.sup.3+] and pure Ce[Cl.sup.3], we measured a light yield of 46 000 [+ or -] 3000 photons per MeV of absorbed [Gamma]-ray energy. The scintillation decay curve can be described by three decay components: short ([Tau] = 25 ns), intermediate ([Tau] = 200 - 800 ns), and long ([Tau] = 0.8-14 [micro]s). The contribution of the short decay component to the total light yield increases with [Ce.sup.3+] concentration: ranging from 10% for La[Cl.sup.3]: 2% [Ce.sup.3+] to 69% for pure Ce[Cl.sup.3]. An energy resolution (full-width half-maximum over peak position) for the 662-kev full energy peak of 3.5 [+ or -] 0.4%, 3.5 [+ or -] 0.4%, 3.1 [+ or -] 0.3%, 3.3 [+ or -] 0.3%, and 3.4 [+ or -] 0.3%, respectively, was observed for La[Cl.sup.3]: 2%, 4%, 10%, 30% [Ce.sup.3+] and pure Ce[Cl.sup.3]. Index Terms--Energy resolution, Gamma-detection, La[Cl.sup.3]:Ce, PACS: 29.40 Mc; 2930 Kv; 78.55 Hx, rare-earth trihalides, scintillators.

In this paper we report on the optical and scintillation properties of Cs2LiYCl6 : Ce3+ and Cs2LiYCl6 : Pr3+ crystals. Crystals of Cs2LiYCl6 doped with different Ce and Pr3+ concentrations were grown and studied under optical, X-ray, gamma ray, and thermal neutron excitation. These scintillators exhibit core-valence and self-trapped exciton luminescence in addition to fast emission from Ce3+ and Pr3+ Efficient thermal neutron detection was observed for both scintillators. The position of the neutron peak in the pulse height spectra was found at about 5 times the channel number of the position of the 137Cs 662 keV gamma peak. [ABSTRACT FROM AUTHOR]

In this communication, we investigate the scintillation properties of LaBr3 :Ce as a function of Ce concentration. We have studied crystals nominally doped with 0.5%, 5%, 10%, 20%, and 30% Ce (by mole). Previous reports suggest that as the Ce content increases, there is a decrease in light output and little or no change in decay time constants. These results show that the light output does not change with Ce concentration up to 30% and depends mostly on the crystal quality. On the other hand we have found the timing properties to be a strong function of Ce concentration. As the Ce content increases, the principal decay time constant of scintillation decreases from 26 ns for 0.5%Ce to 17 ns for crystals with > 5% Ce. Moreover, there is a significant change in rise time constants. The rise time measured for a sample doped with 0.5% Ce is up to 9 ns, whereas for samples doped with > 10% Ce it is less than 0.5 ns. The change of rise time has a major effect on the timing properties of this scintillator, with timing resolution improving from 361 Ps to less than 100 PS (full width at half maximum). [ABSTRACT FROM AUTHOR]

The 4 f 11 energy levels of Er 3+ in LiYF 4 in the spectral region 39 000-65 000 cm -1 have been studied. The agreement between experimental energy levels, obtained from luminescence excitation spectra, and calculated energy levels is good. Luminescence originating from high-lying energy levels has been investigated. Emission from the states 4 D 1/2 (∼47 200 cm -1 ), 2 F(2) 7/2 (∼54 700 cm -1 ) and 2 F(2) 5/2 (∼63 300 cm -1 ) is observed. 2 F(2) 5/2 emission occurs for Er 3+ in LaF 3 , where the 2 F(2) 5/2 level is situated just below the lowest 4 f 10 5 d state, but also for Er 3+ in LiYF 4 , where it lies in between the two lowest 4 f 10 5 d states. [ABSTRACT FROM AUTHOR]

Presents a study that measured the electron and photon response of an aluminum canned LaCl[sub3]:10% Ce&sup3+; crystal using the Compton Coincidence Technique (CTT). Overview of the theoretical photon response calculation; Features of the CTT; Description of the response.

In undoped and Ce 3+ -doped LaCl 3 EPR has been detected in the X-ray luminescence (XL-EPR) in K-band (25 GHz) at 1.5 K. Two excited triplet states with different EPR parameters and spectral shapes could be separated, both triplet states have been attributed to "out-of-plane" self-trapped excitons (STE) in LaCl 3 . No EPR signals of V K centres (self-trapped holes) could be detected in undoped or Ce 3+ -doped LaCl 3 after X-irradiation at low temperatures. X-irradiation of undoped LaCl 3 creates also an EPR spectrum which can be tentatively attributed to F-type defects. The scintillation mechanism is discussed. [ABSTRACT FROM AUTHOR]

Presents a study on the optical and scintillation properties of LaCl...crystals doped with different Ce...concentrations under X-ray and y-ray excitation. Discovery of scintillating materials; Details of the experiment; Results and discussion.

The scintillation properties of LaBr[sub 3] doped with 0.5% Ce[sup 3+] are presented. Under optical and gamma ray excitation, Ce[sup 3+] emission is observed to peak at 356 and 387 nm. The scintillation light output is 61 000±5000 photons/MeV at 662 keV. More than 90% is emitted with a decay time of 35 ns. An energy resolution (full width at half maximum over the peak position) of 2.85%±0.05% was observed for the 662 keV full absorption peak. A time resolution of 385 ps was obtained using BaF[sub 2] as second scintillator and gamma rays of [sup 60]Co. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The scintillation properties of LaCl[sub 3] doped with 10% Ce[sup 3+] are presented. Under optical and gamma ray excitation, Ce[sup 3+] emission is observed to peak at 330 and 352 nm. The scintillation light output is 46 000±1000 photons/MeV at 662 keV. Forty percent is emitted with a decay time of 26 ns, 30% with 210 ns, and 30% with about 1000 ns. An energy resolution (full width at half maximum over the peak position) of 3.3±0.3% was observed for the 662 keV full absorption peak. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]