June,18,2007 Teachers in lab
Experimenters:
- Jenette Briggs
- Keith Quigley
- Bettie Keetch
- Tony Forest
Monday, June 18, 2007
Out Quarknet Teachers had their first seesion experimenting with a coscmic ray test stand made up of two scintillators. Each scintillator was attached to a single PMT. A voltage of -900 Volts was applied and signals were observed using an oscilloscope.
First Cosmic ray scope pictures using PMT + Scintillator
First scope picture on a single detector
now look for a coincidence signal between two PMT detectors
Tuesday , June 19, 2007
Today our team of experimenters setup a discriminator (LeCroy Model 821) to determine which of the PMT outputs would be used to define the presence of a charged particle passing through the scintillator.
The discriminator takes a signal from the PMT that is above the threshold (-30mV to -9V)and returns a voltage of -lV square pulse.
The voltage for each channel was set so that the trigger rates from the discriminator were the same (about 21 pulse/second).
Channel A voltage -1057V, Discriminator threshold -30mV,
Channel B voltage -1001V, Discriminator threshold -30mV.