Geiger counter

  
Inside:
Repository
This experiment has two main objectives. First, we will become familiar with the characteristics of the Geiger-MG ller (GM) tube, including the properties of threshold, starting and operating voltages, GM plateau region and plateau slope. Then we will use the GM tube to perform a simple statistical experiment for the purpose of studying some of th
Geiger counter - schematic

e techniques of statistical analysis. The basic GM circuit diagram is shown in Figure1. The power supply and counter are one unit. The GM tube itself consists of a cylindrical outer shell which serves as a cathode and is grounded. In the center it has a coaxially mounted wire serving as anode. The cylinder is filled with an inert gas (typically Argon) at low pressure plus a small amount of ``quenching`` gas (e. g. ethyl alcohol). A DC power supply provides a voltage across the tube in the range of a few hundred to over a thousand Volts depending on the requirements of the particular tube. Caution: The front window of the tube is very thin and delicate and should not be touched. Radiation entering the tube can ionize some of the gas atoms, thereby freeing electrons which are accelerated towards the central wire by the electric field and gaining enough energy to cause further ionization. The result is a ``cascade`` or ``avalanche`` effect which produces a current pulse through the tube. This current pulse causes a voltage pulse across resistor R, which is used to trigger a counting device that records the number of pulses. We are thus able to count the number of ionizing particles entering the tube. There is, however, no information about the initial particle energy. An oscilloscope is connected to the system to allow us to visually observe the pulses from the tube. The purpose of the quenching additive to the gas is to...



Leave Comment

characters left:

New Circuits

.