http://myais.fsktm.um.edu.my/987/ Effect of X-ray from a small plasma focus on colorless synthetic corundum Mongkolnavin, R. Ngamrungroj, D. Leeviriyalard, C. Wong, C. S. Q Science, Computer Science A preliminary investigation on effect of X-ray on colorless synthetic corundum has been carried out. The X- ay used was generated from a small 3 kJ UNU/ICTP Plasma Focus device. The X-ray produced by the focusing plasma was measured by using four channels PIN diode spectrometer. The spectral content of the X-ray and the plasma electron temperature were obtained by a ratio method. The electron temperature was deduced to be 1.9 keV. The color of the corundum changed to yellow-brown after an exposure with the X-ray. The intensity of the color varied with the number of focusing and non-focusing shot applied to the samples. UV-VIS-NIR Spectrometer was used to test the photo-absorption of the treated corundum. The experimental results show that the color change is not caused by a known Rayleigh’s scattering process. This color change is non-permanent and can be reverted to its initial state by thermal annealing process. Malaysian Institute of Physics (IFM) 2004 Journal PeerReviewed http://eprints.ictp.it/222/; http://eprints.ictp.it/222/01/JFMv25-87.pdf Mongkolnavin, R. and Ngamrungroj, D. and Leeviriyalard, C. and Wong, C. S. (2004) Effect of X-ray from a small plasma focus on colorless synthetic corundum. Jurnal Fizik Malaysia, 25 (3 & 4). pp. 87-91. ISSN 0128-0333 http://myais.fsktm.um.edu.my/987/