SECONDARY-ELECTRON EMISSION FROM BORON-DOPED DIAMOND UNDER ION IMPACT- APPLICATIONS IN SINGLE-ION DETECTION

The secondary electron emission from a 2 mu m thick boron-doped diamon d film under ion (4.6-7.7 MeV He+)impact is reported. The yield under ions impact is found to be remarkably high, stable over a period of ma ny months, and independent of which side of the film (i.e., growth or substrate side) is exposed to the ion flux. By taking advantage of the high secondary-electron yield, the passage of each ion through the fi lm could be detected with an efficiency of close to 100%, which to the best of our knowledge is the highest efficiency recorded to date for any thin-film window. This finding has an immediate application in sin gle-ion irradiation systems where a thin vacuum window is required to allow extraction of an ion beam from the vacuum into air and at the sa me time offer 100% efficiency for the detection of the passage of the ion through the window. (C) 1997 American Institute of Physics.