| 摘要 |
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). |
