With the existence of a time sensitive pixellated chip like "Timepix" a digital imaging option is available for the time of flight mass spectrometry (ToF), see ref. 1. In contrast to the classical method of mico probing or spatial scanning with a point like laser spot (MALDI process) the new method offers the advantage of parallel observation of ions release from a sample of extended surface provided the illumination of the laser is spatially extended and the ions are guided by an imaging electrode system onto the detector. A sizable reduction of date taking speed results from this new device.
First prove of principle with a MCP-Timepix
detector in a ToF with ion optics has been published in 2010
(ref. 2). Later a similar readout system
has been employed in a comercially available instrument (Physical Electronics, TRIFT series).
An increase of sensitivity has been observed here compared with micro probing (ref. 3). An essential feature of the Timepix is the front end digitisation resulting in a speedy readout option (up to 4 kHz ideally). Another feature is the possibility of seamless arrangements of up to 6 chips.
It is mounted on a PCB board of size 50x70 mm2. The readout is provided with a detachable flat cable of 200mm length which leads from UHV vacuum to the readout box in normal enviroment. The readout box (ref. 4) is interfaced with a USB2 to the aquisition computer.
Possible use of Timepix3 is envisioned allowing drastic improvement of the acquisition speed, since in this case the readout during data taking is restricted to the area of hit pixels.