Nonproportional response of LaBr₃:Ce and LaCl₃:Ce scintillators to synchrotron x-ray irradiation

Abstract

The nonproportional scintillation response of LaBr 3 doped with 5% Ce 3+ and of LaCl 3 doped with 10% Ce 3+ was measured using highly monochromatic synchrotron irradiation. To estimate the photon response, pulse height spectra at many finely spaced energy values between 9 and 100 keV were measured. The experiment was carried out at the X-1 beamline at the Hamburger Synhrotronstrahlungslabor (HASYLAB) synchrotron radiation facility in Hamburg, Germany. Special attention was paid to the x-ray fluorescence escape peaks as they provide us with additional information about photon response in the range 1.2-14.5 keV for LaBr 3 :Ce and 2.0-11.6 keV for LaCl 3 :Ce. A rapid variation of the photon response curve is observed near the lanthanum K-electron binding energy for both scintillators. A dense sampling of data was performed around this energy and those data are used to apply a method, which we call K-dip spectroscopy. This method allows us to derive the electron response curves of LaBr 3 :Ce and LaCl 3 :Ce down to energies as low as 0.1 keV.

Energy dependence of the relative light output of YAlO3:Ce, Y2SiO5:Ce, and YPO4:Ce scintillators

“…By the nonproportionality of the relative light output is meant the nonlinear dependence of the number of light pho tons produced in the scintillator, on the absorbed radi ation energy. Serious attempts have recently been made to reveal the mechanism of the nonproportion ality and develop the theoretical model capable of pre dicting both the nonproportionality scale and the energy resolution of scintillation materials [15][16][17][18][19][20]. However, most of the models existing today can only describe available experimental data, but are incapable of predicting the behavior of new scintillators.…”

“…Since the energy resolution of all the scintillation materials used in this study was inad equate for unfolding the K α and K β peaks (Fig. 2), as had been done for the other scintillators in [17,31], the energy carried away by the X ray fluorescence photon E esc was assumed to be the weighted average energy of all five transitions. Applying Eq.…”

Luminescence of LaBr3: Ce,Hf crystals under photon excitation in the ultraviolet, vacuum ultraviolet, and X-ray ranges

“…The mechanism of the formation of scintillation pulses in these crystals has been studied in sufficient detail due to investigations of the luminescence under excitation of different types, as well as due to research in electronic excitation energy transfer to Ce 3+ impu rity centers [4][5][6][7]. At present, the main problem is to investigate the energy nonproportionality of the light yield in the gamma ray spectral range and, especially, in the X ray region of the spectrum [8,9]. In [8], this dependence was studied using synchrotron radiation (SR) in the X ray spectral range (1.4-100 keV).…”

“…At present, the main problem is to investigate the energy nonproportionality of the light yield in the gamma ray spectral range and, especially, in the X ray region of the spectrum [8,9]. In [8], this dependence was studied using synchrotron radiation (SR) in the X ray spectral range (1.4-100 keV). The d f photoluminescence (PL) of Ce 3+ ions and self trapped excitons (STEs) in LaBr 3 : Ce under photon excitation in the ultraviolet (UV) and vacuum ultravi olet (VUV) ranges was investigated only in [4,5].…”

Time-resolved luminescence of LaBr3-Ce scintillation crystals upon selective UV-VUV-XUV excitation

“…At present, the main problem is studying the energy nonproportionality of the photon yield, espe cially in the X ray spectral range. Such a dependence was studied in [4] using synchrotron radiation (SR) in the X ray range of 1.4 to 100 keV. The d → f lumines cence of the Ce 3+ ions in LaBr 3 -Ce upon ultraviolet (UV) and vacuum ultraviolet (VUV) excitation was studied in [5], in which the edge of fundamental absorption and the energy of interband transitions (E g = 5.9 eV at Т = 10 K) were determined.…”