This instrument will allow for ultrafast, high throughput mass spectrometry imaging. Unlike standard probe-based sampling approaches, this offers vast improvements in imaging throughput.
This novel instrument is a stigmatic mode (microscope mode) TOF SIMS imaging instrument and has the potential to provide rapid imaging of the many chemical constituents present at a surface. However, the requirement for a detection system that can acquire large numbers of images with nanosecond resolution on a timescale of tens to hundreds of microseconds has proved to be a significant bottleneck in the development of the technique.
The PImMS (Pixel Imaging Mass Spectrometry) sensor developed at the University of Oxford aims to overcome this limitation. A standard dual microchannel plate/phosphor screen ion imaging detector is capable of creating an optical image of arriving ions. However, it provides no means of capturing and storing the ions time of arrival. The PImMS sensor is event-triggered and has an array of pixels each equipped with four timestamp memories. When the PImMS camera is focused on the phosphor screen of an ion imaging detector, the sensor records the arrival position and time of each detected ion with ns time resolution. The resulting data set can be used to reconstruct time-of-flight mass spectra by integrating over the spatial coordinates of the data, or to reconstruct images for each mass by selecting out spatially-resolved data corresponding to the arrival time of the ion(s) of interest.
Project team at The Franklin:
- University of Oxford