Absolute ion detection efficiencies of microchannel plates and funnel microchannel plates for multi-coincidence detection

Abstract

Modern momentum imaging techniques allow for the investigation of complex molecules in the gas phase by detection of several fragment ions in coincidence. For these studies, it is of great importance that the single-particle detection efficiency ε is as high as possible, as the overall efficiency scales with ε n , i.e., the power of the number of detected particles. Here we present measured absolute detection efficiencies for protons of several micro-channel plates (MCPs), including efficiency enhanced "funnel MCPs." Furthermore, the relative detection efficiency for two-, three-, four-, and five-body fragmentation of CHBrClF has been examined. The "funnel" MCPs exhibit an efficiency of approximately 90%, gaining a factor of 24 (as compared to "normal" MCPs) in the case of a five-fold ion coincidence detection.

Angular streaking in strong field ionization of chiral molecules

“…A symmetric cold target recoil ion momentum spectroscopy [12] spectrometer was built consisting of two identical arms (21 cm acceleration length and E = 119 V/cm electric field). Both sides of the spectrometer were equipped with a detector [Photonis multichannel plate (MCP); open area ratio (OAR) specified 60%, slightly used, electron detector]/Hamamatsu MCP (OAR specified 90%, recoil detector [13]), and a second MCP for further amplification followed by a hexagonal delay-line anode [14] for position decoding. The main chamber was baked for 1 wk at 90°C, resulting in a residual gas pressure without a gas jet of 1 × 10 −10 mbar.…”

“…It should be noted that when calculating the normalized differences as displayed in Figs. 3 and 4, many systematic errors such as a nonuniform detection efficiency of the MCP (e.g., a "hole" in the detector or different angles of incidence relative to the MCP pores [13]) do not influence the final result, as they are normalized element by element. This is not the case for the Gaussian fits performed in Figs.…”

Dissociation of multiply charged ICN by Coulomb explosion

“…The key point where instrumental improvement would benefit research on Auger cascades would be the development of detectors with higher detection e ciency than the MCP plates used in this thesis. Recent detector developments have resulted in a new type of MCP plates with reported detection e ciencies up to 90% [65]. Upgrading the detector e ciency from about 50 to 90 % detection e ciency would significantly reduce the acquisition time required for multi-particle coincidence studies and would have a drastic, positive e ect in reducing the influence of mixed coincidences.…”

Extreme Ultraviolet to Visible Dispersed Single Photon Detection for Highly Sensitive Sensing of Fundamental Processes in Diverse Samples

“…The channel density at the surface is an important quantity influencing the overall detection efficiency of the detector. Recently, MCPs with funnel-shaped channels have been developed to increase [ 10 ]. An evenly distributed potential at each surface must be ensured by a conductive coating.…”