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Hybrid Pyroelectric/nanotube LiTaO3/TiO2 X-Ray Source

Y Alivov

Y Alivov1*, M Klopfer1, V Satchouk1, S Molloi1, (1) University of California, Irvine, Irvine, CA

TU-A-218-9 Tuesday 8:00:00 AM - 9:55:00 AM Room: 218

Purpose: The purpose of this work was to fabricate and study performance of an X-ray source based on hybrid pyroelectric/nanotube LiTaO3/TiO2 system.

Methods: TiO2 nanotubes were grown via electrochemical oxidation of Ti sheets using ethylene glycol + NH4F electrolyte and anodization potential in the range 30 - 60 V. TiO2 nanotubes were attached to LiTaO3 pyroelectric crystal with conductive carbon paste. Generated x-rays from LiTaO3/TiO2 hybrid system were detected by an Ortec NaI (Tl) detector. Working vacuum level was in the range 0.03-3 mTorr. Thermal cycling to a difference of 140 ºC was provided by use of a battery-based thermostatic controller which raised the temperature at 1.2 C°/s until the desired temperature difference was achieved.

Results: The X-ray spectrum of pyroelectric of 'pure' LiTaO3 X-ray source measured ranged from 10 to 90 keV and had a maximum at 27.2 keV. After covering the Z surface of LiTaO3 pyroelectric with TiO2 nanotubes the spectrum of the hybrid TiO2/LiTaO3 system peaked at 23.5 keV and spanned from 10 to 50 keV. Photon flux from TiO2/LiTaO3 system was significantly higher than that for 'pure' LiTaO3 pyroelectric system. After increasing the pressure from 0.03 mTorr to 3.0 mTorr the peak position shifted to 18.5 keV, and photon flux dropped by about 50% due to reduced electron mean free path.

Conclusions: Pyroelectric X-ray source based on hybrid TiO2/LiTaO3 system has been fabricated and its performance was studied. It is observed that this type of X-ray source has greater X-ray emission due to electric field amplification on the nanotube tips and the spectrum has a lower energy in the range 10-50 keV.

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