Pressure dependence of X-rays produced by an LiTaO3 single crystal over a wide range of pressure

The energy spectra of X-rays produced by an LiTaO3 single crystal have been measured at the pressures of 8 x 10(-4) - 4 Pa. The energy spectra showed that the endpoint energy steadily increased with decrease of pressure at 2-4 Pa and gradually decreased with decrease of pressure at 0.1-2 Pa, and became almost constant below 0.1 Pa. The amount of X-rays steadily increased with decrease of pressure at 2-4 Pa and almost saturated below 0.5 Pa. The change off X-rays produced by the LiTaO3 single crystal was compared with the previous works and discussed in relation to the distance between the crystal surface and the target.