High Resolution Photon Counting With MCP-Timepix Quad Parallel Readout Operating at > 1~ Frame Rates

• Published in: IEEE transactions on nuclear science 2013-04, Vol.60 (2), p.578-585
• Main Authors: Tremsin, A. S., Vallerga, J. V., McPhate, J. B., Siegmund, O. H. W., Raffanti, R.
• Format: Article
• Language: English
• Subjects: Charge measurement; Detectors; High count rate; high resolution imaging; Microchannel; photon detection; Photonics; Readout electronics; Spatial resolution
• ISSN: 0018-9499; 1558-1578
• DOI: 10.1109/TNS.2012.2223714

The unique capability of microchannel plates (MCPs) to convert a single photon/ electron/ ion/ neutron into a charge of 10 4 -10 7 electrons localized within 4-12 μm from the event position is widely used in event counting imaging detectors. The high spatial and timing resolution of MCP detectors have been demonstrated with different readout techniques. A compromise between the spatial and temporal resolution, the global/local counting rate and active area must always be made for each detector application. In this paper we present a 28 × 28 mm 2 MCP detector with 2 × 2 Timepix ASICs for readout, capable of ~ 10 μm spatial resolution at event rates up to ~ 3 MHz, and in excess of 200 MHz with ~ 55 μm pixels. This detector has a unique capability to detect multiple simultaneous events, up to several thousand with ~ 10 μm resolution and > 25000 for the 55 μm mode. The latter is enabled by the new fast readout electronics capable of readout speeds of ~ 1200 frames/sec. Despite its limitations (relatively small active area, readout dead time of 300 μs) the MCP-Timepix detector can be very attractive for applications where high spatial resolution needs to be preserved for nearly simultaneous events, e.g., time of flight measurements with pulsed sources. The low noise of the Timepix readout enables operation at gains as low as 10 4 -10 5 , which should extend the lifetime of the MCP detectors operating at high counting rates.