====== Photon Counter Board ======
The photon counter board is used to count the intensity count coming from the [[pmt|PMT]].
<hidden Schematic>{{:boards:photon_counter_schematic.jpg?600|photon counter board schematic}}</hidden>
<hidden Board Assembly>{{:boards:photon_counter_pcb.jpg?600|photon counter board assembly}}</hidden>
<hidden Wiring Harness>{{:boards:photon_counter_wiring_harness.jpg?600|photon counter board wiring harness}}</hidden>
===== DB9 Connector =====
The DB9 Connector going from the PMT to the photon counter board 
^DB9 Pin# Board^DB9 Pin# PMT^Use^
|1|1|Negative Signal A|
|2|2|Negative Signal B|
|3|3|Signal B|
|4|NC|NC|
|NC|4|+5V|
|5|5|Main Gate Inibit|
|6|6|Signal A|
|7|NC|NC|
|8|NC|NC|
|9|NC|NC|
|NC|7|Rate Meter Input|
|NC|8|Ground|
|NC|9|-8V|
{{ :boards:photon_counter_db9.jpg?600 |Photon Counter Board DB9 Pin numbers}}

**Note:** 
  * Pin 1/6 a twisted pair
  * Pin 2/3 is a twisted pair
  * Pin 2/3 twisted pair is the only signal wire that is actually used for counting, Pin 1/6 is not used

===== Testing The Board =====

==== Materials Required ====

  * Oscilloscope
  * Signal Generator
  * Testing Jig (Optional, but see below)

**Test Jig**\\
The test jig can be made with a male to female DB9 connector with pin 1, 2, 3, 5 and 6 connected (1/6, 2/3 should be a twisted pair). Pin 2 and 3 should be easily disconnected with something like a wago or a terminal strip.\\
Example of test jig
{{ :pictures:photon_counter_jig.jpg?600 |}}
==== Testing ====
=== Photon Counter Clock ===
  - Turn off the brewer
  - Disconnect the DB9 connector from the photon counter board
  - Hook up one of your oscilloscope lead to pin 5 of the DB9 connector
  - Turn on the brewer
  - Wait for the instrument to start up with the shutter click (It it does not, you may have to start up dosbox on the computer)
  - The signal coming out of  pin 5 of the harness which sets the clock for the PMT should be about 7.6Hgz at 87% positive duty cycle.{{ :pictures:pcb_maingate_op.jpeg?600 |Photon counter main gate signal output}}

=== Photon Counter Counting ===
  - Turn off the brewer
  - Remove the db9 connector from the photon counter board
  - Connect a signal generator to pin 1
  - Inject 3.8VDC square wave at 10Khz
  - In dosbox, enter [[mm|MM]]
  - run <key>R,0,7,1;o</key>. You should be getting about 13,000 counts across all 7 slits.

<konsole Dosbox>R,0,7,1;O  #With no lamps on and with the DB connector disconnected
 0,      0,      0,      0,      0,      0,      0,      0
R,0,7,1;O  #with injecting a 3.8VDC square wave at 10KHz onto pin 3
 2651,     2726,     2715,     2661,     2708,     2581,     2630,     2756
</konsole>
=== PMT Output ===
  - Turn off the brewer
  - Connect the test jig between the PMT and the Photon Counter board
  - Turn on the brewer
  - With your oscilloscope, measure pin 2 and pin 3. 
  - Run [[ze|ZE]][[b2|B2]]
  - The output of the oscilloscope should look something like the following {{ :pictures:pmt_lamps_on_scope.jpeg?600 |Oscilloscope output from Pin 3 and pin 2 of the PMT db9 harness with lamps on}}