Transcript PMT and preamps

Information for the assembly of the test board w/ PMT and preamps
• the ORIGINAL/UNMODIFIED schematic of the board is given
separately as a pdf document, also the gerber files used for the
board fabrication
• the ACTUAL two-stage preamp schematic is here (on 2nd page),
with illustration of how to fit it on the board on the 3rd page
• the board has been modified as necessary, and fitted with pin
sockets, capacitors for the PMT, and the LMH6629 chips
• I would strongly suggest the use of rosin RMA flux if possible,
tin/lead solder if possible. No-clean flux is not good for these circuits
(at least, not around the high voltage points). If using water-soluble
flux excellent cleaning is needed, promptly after soldering. Rosin
flux may be left uncleaned it will have no detrimental effects.
Schematic of the amplifier channel that you should build (if you
want essentially same as is proposed for real detector). See next
page for a picture illustrating component placement on the
modified printed circuit board.
I suggest leave this open for optimal
timing results, but you may load
~10pF to simulate the effect of IRSX
input capacitance on the amplifier
to see the pulse shape in that case.
Also install R49=237 Ohms, R50=95.3 Ohms to provide VREF = 1.0V,
and install some tantalum capacitors at C36, C41, C42.
Use +3.6 V power supply for the amplifiers (VPP) at point “W1”, and
+5V and -5V for the output buffer (at “W3” and “W4”).
This shows only the two-stage amplifer not the output buffer
(which involves no modifications to the printed circuit board).
Also please note the power supply series resistors are on the
bottom of the board.
GND
GND
Overall top & bottom view of the PMT & preamp area of the test board
Note: I took this picture first, then realized I had forgotten to delete these pads. So the picture is not exactly
right. But in the detailed picture on previous page it is correct. Sorry.
Overall top & bottom view of the PMT & preamp area of the test board
Please note, the circuit biases the anode input to VREF. If this is not
ok for some reason, you can of course AC couple it.
Do not forget that all anodes must be connected to something, and
ideally all should be at the same voltage. Use the resistor locations
on the board to connect unused anodes to VREF, ideally with about
a 70 Ohm resistor (but direct connection might be ok).
I did not load any of these components since I don’t know if you
intend to do anything different with the other 14 anodes that are
not connected to the preamp channels here.