Turnov, Czech Republic
Turnov, Czech Republic

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Tous J.,CRYTUR Ltd. | Blazek K.,CRYTUR Ltd. | Kucera M.,Charles University | Nikl M.,ASCR Institute of Physics Prague | Mares J.A.,ASCR Institute of Physics Prague
Radiation Measurements | Year: 2012

Very thin scintillator imaging plates have recently become of great interest. In high resolution X-ray radiography, very thin scintillator layers of about 5-20 μm are used to achieve 2D-spatial resolutions below 1 μm. Thin screens can be prepared by mechanical polishing from single crystals or by epitaxial growth on single-crystal substrates using the Liquid Phase Epitaxy technique (LPE). Other types of screens (e.g. deposited powder) do no reach required spatial resolutions. This work compares LPE-grown YAG and LuAG scintillator films doped with different rare earth ions (Cerium, Terbium and Europium). Two different fluxes were used in the LPE growth procedure. These LPE films are compared to YAG:Ce and LuAG:Ce screens made from bulk single crystals. Relative light yield was detected by a highly sensitive CCD camera. Scintillator screens were excited by a micro-focus X-ray source and the generated light was gathered by the CCD camera's optical system. Scintillator 2D-homogeneity is examined in an X-ray imaging setup also using the CCD camera. © 2012 Elsevier Ltd. All rights reserved.


Tous J.,Crytur Ltd. | Blazek K.,Crytur Ltd. | Nikl M.,ASCR Institute of Physics Prague | Mares J.A.,ASCR Institute of Physics Prague
Journal of Physics: Conference Series | Year: 2013

Very thin scintillator imaging plates have recently become of great interest. In high resolution X-ray projection imaging, very thin scintillators of about 5-20 micrometres are used to achieve high spatial resolution. Such thin screens are mainly used in micro-CT and nano-CT systems with either micro-focus X-ray tubes or with synchrotron sources. This work deals with a high resolution CCD camera in connection with an optical system and different single crystal scintillators in application for low energy X-ray micro-radiography. The thin screens used were prepared by mechanical polishing from Y3Al5O12 or Lu3Al5O12 single crystals. The screens can be used in equipment for the detection of different kinds of radiation and particles (UV, VUV, electrons or ions or their beams, X- or gamma-rays). A high resolution open type micro-focus X-ray tube was used to achieve the high resolution. The results show that the single crystal plates exhibit high spatial resolution and high sensitivity to low energy X-rays resulting in high image contrast. The use of the plates is highly suitable for light weight (low Z) material X-ray radiography. The resolution achieved is demonstrated using a test grid. Several light weight objects are imaged using the thin plates.


Tous J.,Crytur Ltd. | Horodysky P.,Crytur Ltd. | Blazek K.,Crytur Ltd. | Nikl M.,ASCR Institute of Physics Prague | Mares J.A.,ASCR Institute of Physics Prague
Journal of Instrumentation | Year: 2011

A high resolution X-ray camera for micro-radiography is described and presented, consisting of a CCD detector and precise thin YAG:Ce or LuAG:Ce single crystal screens. Different applications and various results are described. The 2D-spatial resolution of an X-ray or other ionizing radiation imaging systems is one of the critical parameters in non-destructive microradiography and radiation beam inspection. The main goal of this work was to use the 2D-imaging system with different scintillation screens, and to compare the 2D-resolution in the micrometer range and sensitivity for low energy microradiography. These imaging systems can use various scintillation detectors. Specifically, thin YAG:Ce or LuAG:Ce single crystal screens are compared. Finally, the use of an X-ray CCD camera in imaging of small, light-weight biological objects is presented. © 2011 IOP Publishing Ltd and SISSA.


Fibrich M.,Czech Technical University | Sulc J.,Czech Technical University | Jelinkova H.,Czech Technical University | Nejezchleb K.,Crytur Ltd. | Skoda V.,Crytur Ltd.
Optics Letters | Year: 2010

We report the cw blue generation of Pr:YAP laser emission at room temperature, which has been achieved by intracavity frequency doubling of the near-IR-emitting Pr:YAP laser operating at a fundamental wavelength of 747 nm. For active medium pumping, a GaN laser diode providing up to 1W of output power at ∼448 nm was used. With beta barium borate crystal employed as a nonlinear medium, 12.3 mW of output power at 373.5 nm has been obtained. © 2010 Optical Society of America.


Fibrich M.,Czech Technical University | Jelinkova H.,Czech Technical University | Sulc J.,Czech Technical University | Nejezchleb K.,Crytur Ltd. | Skoda V.,Crytur Ltd.
Optics Letters | Year: 2010

A cw Pr : YAlO3 microchip-laser operation in the near-IR spectral region is reported. A microchip resonator was formed by dielectric mirrors directly deposited on the Pr:YAlO3 crystal surfaces. For active medium pumping, a GaN laser diode providing up to 1 W of output power at ∼448 nm was used. 139 mW of laser radiation at 747 nm wavelength has been extracted from the microchip-laser system. Slope efficiency related to the incident pumping power was ∼25%. © 2010 Optical Society of America.


Jelinkova H.,Czech Technical University | Fibrich M.,Czech Technical University | Cech M.,Czech Technical University | Nejezchleb K.,Crytur Ltd | Skoda V.,Crytur Ltd
Laser Physics Letters | Year: 2010

In this contribution we report on blue generation of Pr:YAP laser under flash-lamp pumping at room temperature. Stimulated emission at 373.5 nm has been reached by intracavity frequency doubling of the red-emitting Pr:YAP laser operating in Q-switched pulsed regime at a fundamental wavelength of 747 nm. For Q-switching, electro-optical modulator based on LiNbO3 Pockels cell in quarter-wave configuration was used. Employing BBO crystal as a nonlinear medium for second harmonic generation, blue radiation with a pulse energy and length of 380 μJ and 38 ns, respectively, were generated. The red-to-blue conversion efficiency was determined to be more than 31%. © 2010 by Astro Ltd.


Fibrich M.,Czech Technical University | Sulc J.,Czech Technical University | Jelinkova H.,Czech Technical University | Nejezchleb K.,Crytur Ltd. | Skoda V.,Crytur Ltd.
Laser Physics Letters | Year: 2010

In the present work we report on two wavelength generation of Pr:YALO3 laser reached by Lyot filter tuning at room temperature. Laser emission at two transitions in the visible part of the electromagnetic spectrum (747 nm and 720 nm) has been demonstrated employing the broadband laser resonator mirrors in connection with the tuning element (Lyot filter). As a pumping source, GaN laser diode designed for operation around 448 nm wavelength and providing an output power of up to 1 W was utilized. © 2010 by Astro Ltd.


Fibrich M.,Czech Technical University | Jelinkova H.,Czech Technical University | Sulc J.,Czech Technical University | Nejezchleb K.,Crytur Ltd. | Skoda V.,Crytur Ltd.
Laser Physics Letters | Year: 2011

A continuous-wave Pr:YAlO 3 microchip laser operation at 662 nm is reported. Microchip resonator was formed by dielectric mirrors directly coated on the Pr:YAlO 3 crystal front surfaces. GaN laser diode providing up to 1 W of output power at ~448 nm was used as a pumping source. Output characteristics were investigated at different active medium temperature within the range of 11-35°C. The best result 27.4 mW of output power has been reached at 11°C at 680 mW of pumping power. The slope efficiency related to the incident pumping power was ~9%. © 2011 by Astro Ltd., published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA.


Fibrich M.,Czech Technical University | Jelinkova H.,Czech Technical University | Sulc J.,Czech Technical University | Nejezchleb K.,Crytur Ltd. | Skoda V.,Crytur Ltd.
Laser Physics Letters | Year: 2011

Spectroscopic properties and laser output results of Pr-doped YAlO 3 material under 1-W GaN-laser-diode pumping at various resonator arrangement (linear, V-folded, and microchip configuration) are reviewed and compared. Continuous output power of up to 140 mW in the near-infrared spectral range at 747 nm wavelength as well as 45% slope efficiency (with respect to absorbed pump power) and intracavity frequency doubling resulting in 12.3 mW blue emission is reported. © 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA.


Fibrich M.,Czech Technical University | Jelinkova H.,Czech Technical University | Nejezchleb K.,Crytur Ltd. | Skoda V.,Crytur Ltd.
Laser Physics Letters | Year: 2012

Spectroscopic properties and laser results of GaN-diode pumped Pr,Ce:YAlO 3 crystal at room temperature are reported. Pr:YAlO 3 laser-host co-doped by Ce 3+-ions is intended for crystal-property improvement in the UV region from the solarization point of view. The polarization-resolved absorption and emission spectra have been recorded and the decay time of 3P 0 manifold has been measured. The concentration of Pr 3+ and Ce 3+ ions in YAlO 3 (YAP) matrix were 0.6 and 0.1 at.%, respectively. Output power of 30 mW at 747 nm wavelength with slope efficiency of 7% with respect to the absorbed power has been demonstrated. © 2012 by Astro Ltd.

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