Nanoparticulate Coatings Enhance Ion Detection

Project Summary
A new thin film deposition technique for increasing the gain and sensitivity of existing
microchannel ion detectors was proven in a previously completed NIH phase I. An increased
Secondary Electron (SE) yield from these films was found to improve with ion doses of helium
up to rt 100 Coulombs/cm2 while the electron yield from the uncoated detector first surface
decreased after 1 Coulombs/cm2. A NIH Phase II will use these films to vary elemental
composition and morphology of the first surface to increase the first hit SE yield and to prolong
the deposited layer lifetime. Detector testing will proceed with in-house ion and electron
sources.
Methods for putting these thin film coatings onto the sidewalls of the MCP (in addition to
covering the front detector surface) should increase the detector gain and substantially prolong
the detector lifetime of commercially available MCPs.
We will emphasize use of the Zeiss Orion helium ion microscope at Rutgers to perform
accelerated lifetime testing of the MCP pulse height, gain and first surface secondary electron
yield from individual pores. Elemental composition change in the first hit area of the
microchannel pore will also be determined by Nanoscale Rutherford backscattering within the
Orion and will be correlated with the lifetime and yield measurement. The combination of the
Zeiss Orion configured with the Ionwerks NanoRBS spectrometer should prove to be a crucial
tool in detector physics. In addition the overall performance of the NanoRBS will improve when
this spectrometer is retrofitted with newly enhanced MCPs from this phase II effort.
.