Abstract: A quadrupole ion trapping device has a ring electrode (11) and two end-cap electrodes (12, 13). Ions are introduced into a trapping region (15) of the ion trapping device via a hole (14) in a first of the end-cap electrodes (12) and are retarded by application of a DC retarding voltage to the second of the end-cap electrodes (13). The retarding voltage is removed when the retarted ions are about to change their direction of motion towards the first end-cap electrode (12), and an ion trapping field is established by applying a radio frequency voltage to the ring electrode (11) when the ions are inside the ion trapping device.

Abstract: A cathode lens is formed between a gun electrode (8) and a specimen (9). An electron probe (11), produced as part of an electron column and suitably focused by lenses (1, 2 and 3) and scanned by suitable deflector/stigmator electrodes (2), is decelerated within the cathode lens field and its final landing energy is finely adjustable by the specimen negative bias. Emitted secondary electrons are re-accelerated within the same field and due to uniformity of this field, they increase their axial velocity only so that they are collimated into a narrow signal beam. The collimated signal beam passes mostly through an aperture (18) of electrode (8), where it enters the gun and a final lens consisting of a central earthed electrode (6) surrounded by two earthed electrodes (7) and (8). The signal beam approaches a special mirror electrode (4), the field of which decelerates and deflects the electrons further off the axis and returns them back towards the specimen (9).

Abstract: A method of fast start and/or fast termination of a radio frequency resonator, which has a coil, a capacitor and two switches with internal resistance wherein one end of the switches is connected to a junction of the coil and the capacitor where a RF voltage is provided, and another end of each switch is connected to high voltage power supplies with opposite polarities, a fast start being achieved by closing one of the switches for a short period of time for fast start, and a fast termination being obtained by closing both switches for a while.

Abstract: A time-of-flight mass spectrometer includes a gridless dual-stage ion reflector (10) having a high-field first stage (18) and a low-field second stage (19). The ratio of the electric field strength in the low-field second stage (19) to the electric field strength in the high-field first stage (18) is 0.55, and may be in the range 0.35 to 0.07.

Abstract: A time-of-flight spectrometer comprises a quadrupole ion trap (10) as an ion source, a drift tube (11) defining a field-free drift space, an ion reflector (12) and an ion detector (13). The quadrupole ion trap (10) has two end-cap electrodes (22, 23) and a ring electrode (21). End-cap electrode (22) has a central hole (24) through which ions to be extracted can pass. High voltage power supplies (34, 35) and associated switching devices (32, 33) are provided to supply extraction voltages to the end-cap electrodes (22, 23). The extraction voltage supplied to end-cap electrode (22) has the opposite polarity to the extraction voltage supplied to the other end-cap electrode (23) being respectively negative and positive voltages for positive ion extraction and respectively positive and negative voltages for negative ion extraction. The magnitude of the extraction voltage supplied to electrode (23) is in the range from 0.5 to 0.8 that of the extraction voltage supplied to electrode (22).