| 摘要 |
A time of flight mass analyser 1 having a drift region 2, an ion packet generator 6, first and second ion reflectors 18,19 and at least one ion detector 20 is disclosed. The drift region 2 has an axis 3, an entrance 4 and an exit 5 and provides for a place wherein ions may be temporally separated according to their mass-to-charge ratios. The ion packet generator 6 injects packets of ions into the drift region 2 at the region's entrance 4 from a beam of ions by intermittently applying an electrostatic field such that the packets of ions enter the drift region 2 in an initial direction which is inclined to the direction of said beam of ions. The first ion reflector 18 is disposed at the exit 5 of the drift region 2 to reflect back towards the entrance 4 ions which are travelling towards the reflector 18 in the drift region 2. The second ion reflector 19 is disposed in juxtaposition to the first ion reflector 18 to reflect packets of ions back towards the first ion reflector 18 through at least a portion of the drift region 2 so that the packet of ions may be reflected to and fro between said first 18 and second 19 ion reflectors and undergo a number n of reflections at the second ion reflector 19. A detector 20 is disposed to detect at least some packets of ions reflected by the first ion reflector 18 which do not enter the second ion reflector 19. The number of reflections at the second ion reflector 19 may be selected by adjustment of an inclination of the initial direction to the axis 3.
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