Instructions for Assembly and Operation of Rochester PARTICLE Cosmic Ray Telescopes


Cable Connections (all equipment should be off before you start!)


        Connect board to computer via the gray serial cable with the blue connectors.


        Plug into the connector on the board



        and into the port on the computer.




        Plug the cable from power adapter into connector on the board.




        Plug the power adapter into the wall. 




        Check to be sure that both of the green power LEDs on the board are on.



v   Connecting Phototubes to the Board


       Plug green signal cables into the connector on the base.










       Plug other ends of the green cables into the inputs on the board


v   Providing power to the base.


       Plug the power supply cord into the base.









       Plug the power supply into an outlet.










       Before placing the phototube into the base, insert two probes from a voltmeter into the bases test points










       Turn the base on.









       Dial up the correct voltage using the conversion chart.











Actual Voltage

Voltmeter Voltage Reading


Actual Voltage

Voltmeter Voltage Reading

900 V



1125 V


925 V



1150 V


950 V



1175 V


975 V



1200 V


1000 V



1225 V


1025 V



1250 V


1050 V



1275 V


1075 V



1300 V


1100 V






       Once the correct voltage has been obtained, lock the voltage into place by flipping on the lock.










       Turn off the base.










       Insert the phototube into the base.







       To provide power to two or three bases, you need to “daisy chain” the power cords.

       Plug one end of the back power cord into the base that is plugged into the wall and the other end in the next base.

       For three bases, plug one end of the power cord into the second base and the other end into the third base. The third base will only have one black cable coming off of it, but the first and second will have two.



v  Adjusting Thresholds of your Board


Although the default threshold of 30mV is probably fine for more applications, you may wish to increase the threshold if your tube has a high count rate at a low voltage (1000V) or decrease your threshold if it has a low count rate at a high voltage (1500V).


       The procedures for adjusting the threshold are documented in the "electronics instructions".

       The tools that you will need are: a flat head screwdriver for removing top of the board case, a board with power available, a digital voltmeter with probes, and a jeweler’s screwdriver. 








       Remove the top of the board housing with power off.







       Read the threshold voltage (reads 10x actual threshold) as voltage between ground on PMT input connector and a test point.








       Adjust the blue potentiometer with jeweler's screwdriver until you reach the desired threshold (probably between 10 and 50mV).