Microchannel plates: recent advances in performance

Abstract

Microchannel plates have, because of their adaptability to various size and configuration formats, allowed a wide range of devices to be realized in astronomical applications for X-ray, UV and visible sensing, employing many different forms of readout techniques and photocathode types. Two essential performance issues are the quantum detection efficiency, and the uniformity of response over the detector field of view. In both of these areas microchannel plates have had issues, both in the consistency of high quantum detection efficiency, and in fixed pattern noise introduced by fabrication processes for microchannel plates. We show that recent work has improved the consistency of obtaining high quantum detection efficiency, and has virtually eliminated the causes of fixed pattern noise due to fabrication issues.

Gallium nitride photocathode development for imaging detectors

“…CsTe is also highly sensitive to, and irreversibly damaged by, gas exposure. Recent studies performed by our group 4,5,6,7,8 as well as other reports 9 -17 indicate that Cs activated GaN cathodes can be more robust and may possibly achieve >50% QDE from the MgF 2 window cutoff to ~350 nm. An attractive feature of GaN photocathodes is their ability to be tuned with respect to the long wavelength cutoff.…”

Microchannel plate imaging photon counters for ultraviolet through NIR detection with high time resolution

“…Visible features such as dark spots are caused by defects on the mesh and MCPs. Faint hexagonal features are also seen, which correspond with the multifibers of the MCP 15 . Distortions of the MCP pore shape at the multifiber boundaries cause slight variations in the MCP gain and deflect the charge cloud trajectory causing this effect.…”

“…Distortions of the MCP pore shape at the multifiber boundaries cause slight variations in the MCP gain and deflect the charge cloud trajectory causing this effect. However, the effect is now minimal as a result of considerable advances in MCP fabrication technology 15 . Some faint residual “striping” in Y is due to strip to strip charge modulation that has not been fully corrected by the centroid algorithm.…”

Large-format high-spatial resolution cross-strip readout MCP detectors for UV astronomy

“…This more clearly shows the 60 m wide mesh wires and a few spots (both "hot" and "dead") which can be used to measure spatial resolution. It is also possible to see faint hexagonal features which correspond with the multifibers of the MCP 16 . The multifiber boundaries cause slight variations in the MCP gain and deflect the charge cloud trajectory approximately 25 microns causing this effect.. …”