Posted by
Zdenek Svindrych-2 on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Upgrading-Leica-MP-PMTs-to-HyD-or-Ga-As-tp7585036p7585046.html
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Hi Ethan,
my guess is:
surely it is possible, everything is possible (not very helpful, I know).
And surely it'll be difficult (not very helpful either)...
With a lot of engineering and reverse engineering (where to get control
voltage aka gain; where to inject the signal, what amplitude and impedance
matching) you may achieve the goal, you may even use some liquid light guide
if the detector does not fit into the scanhead, but is it worth the effort?
Remember that Leica HyDs are not APDs! APDs are (typically) silicon
detectors (good response in near IR, up to 900 nm) and fast APDs (for photon
counting, aka SPADs) have very small active area (maybe 1000x smaller than a
PMT, so it may not be possible to integrate them). HyDs, on the other hand
(as far as I know), have GaAsP photocatode, so the spectral response is
similar to other GaAsP PMTs (these work up to 700 - 750 nm only).
Overcurrent protection: even regular PMT detector modules usually have some
protection. So do GaAs and other detector modules ... unless you want to
build the power source and amplifier yourself - then it's really big project
(and not necessary cheaper, depending on how many bare detectors get fried
during the process :-).
Also, not only the electric current may damage the detector, it may be the
light itself (the noise of a PMT may increase, sometimes permanently). APDs
should not be too susceptible (no warranty).
Good luck breathing new life into an old SP2!
zdenek
---------- Původní zpráva ----------
Od: Ethan Cohen <
[hidden email]>
Komu:
[hidden email]
Datum: 12. 4. 2016 20:57:54
Předmět: Upgrading Leica MP PMTs to HyD or Ga/As
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I am wondering if it is possible to upgrade a SP2 vintage scanhead PMT to
either HyD (APDs) or Ga/As PMTs?
I have a Hammatsu Ga/As H7421 sitting around, and wonder if it would be
difficult to integrate it into the scan head on a channel (limited of
course).
The PMTs sit in a black box near the front bottom of the scan head
(according to the Leica cartoon).
Do HyD also need overcurrent protection like Ga/As heads?
Ethan Cohen, Ph.D.
CDRH/FDA labs."