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PACS. 79.70 -Field emission and field ionization.Abstract. -We have observed ion emission from electrochemically etched tungsten tips at field strengths below the level of field ion microscopy. The tip potential-dependent emission curve is peaked at a field strength of about 2 V/nm. The temporal behaviour includes periodic outbursts of ions, the period being of the order of half an hour. Besides this, the system shows flickernoise at frequencies between and 0.1Hz.

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