Alan Stummer
Research Lab Technologist

"PhotonFinish2" Sub-nS Heptal Coincidence Timer

I am curious who uses what.  Are these webpages a waste of time, or are they any help to others?  Are the circuits, software and utilities appearing in other labs?  Please send your comments or suggestions or what you have used (or not) or schematics of your version or pictures or anything!   Email me, or be creative and send a postcard! I want to hear from the vacuum!

NOTICE: This webpage and associated files is provided for reference only.  This is not a kit site!  It is a collection of my work here at the University of Toronto in the Physics department. If you are considering using any schematics, designs, or anything else from here then be warned that you had better know something of what you are about to do.  No design is guaranteed in any way, including workable schematic, board layout, HDL code, embedded software, user software, component selection, documentation, webpages, or anything.

All that said, if it says here it works then for me it worked. To make the project work may have involved undocumented additions, changes, deletions, tweaks, tunings, alterations, modifications, adjustments, waving of a wand while wearing a pointy black hat, appeals to electron deities and just plain doing whatever it takes to make the project work.


Originally for Xingxing Xing, Lee Rozema and Dylan Mahler in Aephraim's lab, started Nov 2010.  A new and improved version of the original Coincidence Timer - PhotoFinish which had 2 channels and 50pS resolution, this one has 7 channels with 250pS resolution.

Timing is done with Acam's TDC-GPX series of time-to-digital converters. Seven external TTL inputs from APDs are time logged with 250nS resolution over hours or days. The unit reports each photon arrival time to the host computer which determines coincidences.

Details to follow...

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