EFFICIENCY TESTING

 

The efficiency of your paddles should be tested once construction is complete.  Efficiency testing allows you to find out what percentage of ‘hits’ a paddle records.  The efficiency test is a comparison of the count rate of muons when they pass through the three “standard” paddles plus the one “test” paddle and when only the three “standard” paddles receive hits.  The drawing below shows the arrangement of the four paddles.

 

                                                1

                                                                                    Standard Paddles

                                2

3/4

 
 


 Test Paddle                           4

 


Top View

 
                                                  3

2

 
                                                           

 

 


The overlap area of the four paddles should be approximately 25 cm2.  The standard paddles have a small area that overlaps so that when the test paddle is put into place, the overlap area is completely covered.  If this testing mechanism is properly constructed, no cosmic rays should be able to pass through paddles 1, 2, & 3 without hitting the test paddle (4).  Ring stands and clamps are available to hold your paddles in place.

 

 

Procedure

 

  1. Set up your paddles as shown in the diagrams above.  Make sure to place the paddle that you are testing for efficiency is placed in position 4.  Make sure that the signal cable is also placed into position 4 on the board.

 

  1. Before you begin a test run, choose option 8 (Configure this program) from the menu.  Check to make sure that option “e” (Report summary of hit types, as for efficiency runs) is currently true.  If it is true, then do nothing.  Choose “x” and return to the main menu.

 

  1. If option “e” is currently false, then choose option “e” and press enter.  Option “e” should now read true and you can return to the main menu by choosing “x”.

 

  1. At the main menu, choose option 4 (Begin coincidence Run).

 

  1. In order to get enough events, these trials should be run for at least 10 minutes (when assuming a 25 cm2 overlap area).

 

  1. To calculate the efficiency of your paddle, divide the number of events striking paddles (1,2,3,4) by the sum of the events striking both paddles (1,2,3,4) and (1,2,3).

 

 

 

 

 

  

% Efficiency  = 

 

 

 

 

 

Your optimum voltage occurs when the paddle is > 95% efficient.