| dc.description.abstract | Our group studies the high energy physics. My professor and classmates analyze the data collected by the CMS (Compact Muon Solenoid) detector in LHC (Large Hadron Collider). Therefore, in the NCU (National Central University) laboratory, we don′t have any experimental devices to show the visitors. We think that if we can show the particles to them directly, the introduction will be more attractive to them. Maybe more people will be interested in high energy physics. To show the particles, we need a particle detector. There are many particle detectors that have the different properties. We think the spark chamber is the good choice for our purpose. Spark chamber can show the particle track with the spark, the discharge in the air, so we can see the particle track by our eyes directly. It is very instinctive and impressive. Another reason is that the spark chamber doesn’t have any complex machinery structure. It is driven by electronic circuit, so it is easy to manufacture from nothing. In fact, we have the scintillator device for the trigger detector, so my project is to manufacture the high speed trigger circuit and the chamber. The breakdown voltage in the air is about 30kV/cm, so first we need change the air to reduce the breakdown voltage. The noble gas is contributive for spark chamber. However, it still needs about 10kV/cm to break. Because the gap in my chamber design is 8mm, the breakdown voltage is about 8kV. Therefore, I need to amplify the signal from -0.8V to 6~8kV even if I use the noble gas (the helium). I use the operational amplifier, insulated-gate bipolar transistor, transformer and spark plug to amplify the trigger signal step by step. To show the particle track, the total delay time can’t be larger than 500ns. The circuit part is the most difficult and important part in manufacture of the spark chamber. Success or failure almost depends on the circuit. Finally, my circuit can amplify the signal from -0.8V to -8kV and discharge pulse signal in about 500ns. It makes my spark chamber work properly. | en_US |