·      Connecting Phototubes to the Board

 

·      Plug green signal cables into the connector on the base.

 

 

 

 

 

 

 

 

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

 

 

 

 

 

 

 

 

·      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

2.31

 

1125 V

2.88

925 V

2.37

 

1150 V

2.95

950 V

2.44

 

1175 V

3.01

975 V

2.50

 

1200 V

3.08

1000 V

2.57

 

1225 V

3.14

1025 V

2.63

 

1250 V

3.21

1050 V

2.70

 

1275 V

3.27

1075 V

2.76

 

1300 V

3.33

1100 V

2.82

 

 

 

 

·      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.

 

 

 

 

 

 

 

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).