Pixel Imaging Mass Spectrometry with fast and intelligent Pixel detectors

Abstract

We report on 'proof of concept' experiments in Pixel Imaging Mass Spectrometry (PImMS) using an ultra-fast frame-transfer CCD camera and also describe an intelligent CMOS sensor which is being developed for this application by the PImMS collaboration in the UK. PImMS is a combination of traditional TOF mass spectrometry and ion imaging. Information provided by the ion imaging gives access to valuable structural information of the molecule under investigation, in addition to the normal mass spectrum. Recording of the 2D spatial information of the arriving ions allows to reconstruct the ion velocity distributions for separate ion masses and to correlate them to each other. The new PImMS sensor will be capable of time stamping up to four arriving ions per pixel during the 200 µsec acquisition cycle with 100 nsec resolution which should meet the demanding requirements of complete recording of mass spectra of complex organic molecules.

Coulomb-explosion imaging using a pixel-imaging mass-spectrometry camera

“…Ion events imaged on the phosphor screen were recorded using the PImMS camera [22][23][24][25]: a pixelated photon-sensitive event-counting sensor. The PImMS sensor comprises a 2D array of 72 × 72 pixels, each of which can store the time stamps of up to four events per acquisition cycle.…”

Dynamic Stark Control of Torsional Motion by a Pair of Laser Pulses

“…The cationic fragments, notably Br þ and F þ ions, from the Coulomb explosion were collected in a velocity map imaging system enclosing the interaction region and the velocity focused onto a position sensitive detector consisting of a microchannel plate assembly and a P47 phosphor screen. The phosphor screen was backed by a pixel imaging mass spectrometry (PIMMS) camera [23,24] To image the torsional motion we follow the strategy from previous works [11,13,25] and determine the dihedral angle directly by measuring the angle between the fragmenting Br þ ions and F þ ions. Assuming axial recoil, this is the angle between the Br-and F-substituted benzene rings when the molecule is viewed along the long axis.…”

Using laser-induced Coulomb explosion of aligned chiral molecules to determine their absolute configuration

“…In practice, all cationic ions created by the probe pulse were accelerated by a three-electrode ion optics assembly, optimized to effect velocity-map ion imaging [19], and focused onto a detector consisting of a pair of microchannel plates and a P47 phosphor screen. The phosphor screen was backed by a pixel imaging mass spectrometry (PImMS) camera [20][21][22].…”