Spice Model for PMT

Do you need all 14 pins modelled, or just the photon->anode current response?

Even if it's just the anode current, PMTs vary greatly in transit time, transit time spread, afterpulses, and so on--you can get pulse widths of

Cheers,

Phil Hobbs

www-boone.fnal.gov/publicpages/detector_tdr.ps.gz

Page 82 has some simple models.

Best regards, Spehro Pefhany

Just photon->anode current

...Jim Thompson

Thanks!

...Jim Thompson

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Not a spice model, but perhaps, some data that will help you build one. A few years ago, I came up with a functional fit between total supply voltage and gain for an Hamamatsu R928 stage side view multiplier:

The function I pulled out of my but and fit to the data sheet curve is:

gain(a,b,v,N)=(a*(v/(N+1))^b)^N Where N=9 successive internal gain stages, a=0.185, b=0.755, and v = the total voltage applied across the voltage divider socket type E717-21, shown at the end of the above data sheet.

Add propagation delay and capacitance and I think you are close, if this is the sort of PMT.

R928.pdf

Don't try and pull too much current out of the tube though. There are at least eight different sources of photomultiplier non-linearity, starting with space charge in the photo-cathode to first dynode space.

Space charge between the last two dynodes (which are usually on either side of the anode) and the anode usually limits the anode current to less than 100mA (unless you use fairly high voltages across the last few dynodes).

There was a rather dire Spice simulation of a PMT in IEEE Trans. Electron Devices vol.36 (9) 2005-2010 (Sept 1989) and my comment on it was published in 1991."Comment on 'Computer aided simulation study of photomultiplier tubes'", IEEE Transactions on Electron Devices, ED-38

It lists a bunch of papers on photomultiplier non-linearity. The best of them - by Sauerbrey - is in Applied Optics, but in German. I've got a translation somewhere.

-- Bill Sloman, Nijmegen

Thanks!

...Jim Thompson

multiplier:

Thanks, Bill!

...Jim Thompson