Difference between revisions of "Test Stand at FSU"
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##The 50 Ohm terminations at the PMTs were removed and linear FAN IN/OUT are introduced. The signals from the PMTs are directly connected to individual linear FAN IN/OUT channels. Each of these channels has its DC offset adjusted to be zero or slightly negative. One output of each linear FAN IN/OUT is connected to a JLAB VME discriminator and a second output is connected over delay cables to a CANE VME charge integrating ADC. The 4 PMTs from the trigger paddles from a 4-fold coincidence to generate a trigger signal. This trigger signal is set into coincidence with a DAQ latch level and the inverted BUSY signal from the TI. | ##The 50 Ohm terminations at the PMTs were removed and linear FAN IN/OUT are introduced. The signals from the PMTs are directly connected to individual linear FAN IN/OUT channels. Each of these channels has its DC offset adjusted to be zero or slightly negative. One output of each linear FAN IN/OUT is connected to a JLAB VME discriminator and a second output is connected over delay cables to a CANE VME charge integrating ADC. The 4 PMTs from the trigger paddles from a 4-fold coincidence to generate a trigger signal. This trigger signal is set into coincidence with a DAQ latch level and the inverted BUSY signal from the TI. | ||
##Picture of the detectors in the test stand:<br>[[Image:test_stand_detectors.gif|200px|degree=90]] | ##Picture of the detectors in the test stand:<br>[[Image:test_stand_detectors.gif|200px|degree=90]] | ||
| − | ##The HV for the two TOF PMTs are set to provide average signal amplitudes of about 300mV with the trigger paddles located at the center of the TOP paddle. The HV of the right PMT is 1400V and 1600V for the left PMT. The gain of the right PMT at 1750 was measured to be 4.6e6 while the left PMT gain a 1750V is found to be 1.3e6. Here a screen shot of the scope and similarly if the trigger paddles are moved 17" from the right PMT. At this location the signal of the left PMT reduced to about 200mV while the signal from the right PMT increased to about 600mV:<br>[[Image:tof_paddle_signals_average.gif|200px]] [[Image:tof_paddle_signals_trig_17inch_from_right.gif|200px]] | + | ##The HV for the two TOF PMTs are set to provide average signal amplitudes of about 300mV with the trigger paddles located at the center of the TOP paddle. The HV of the right PMT is 1400V and 1600V for the left PMT. The gain of the right PMT at 1750 was measured to be 4.6e6 while the left PMT gain a 1750V is found to be 1.3e6. Here a screen shot of the scope and similarly if the trigger paddles are moved 17" from the right PMT. At this location the signal of the left PMT reduced to about 200mV while the signal from the right PMT increased to about 600mV(yellow):<br>[[Image:tof_paddle_signals_average.gif|200px]] [[Image:tof_paddle_signals_trig_17inch_from_right.gif|200px]] |
Revision as of 10:30, 6 December 2011
Cosmic ray test stand at FSU
- Sketch of the electronics setup and trigger circuit.
- The Test Stand
- 2 Trigger paddle 3/4" thick, 6cm wide and 40cm long with PMTs on both ends are located above and below the TOF paddle which is 252cm long 6cm wide nad 1" thick. Also the TOF paddle is read out on both ends with PMTs.
- The 50 Ohm terminations at the PMTs were removed and linear FAN IN/OUT are introduced. The signals from the PMTs are directly connected to individual linear FAN IN/OUT channels. Each of these channels has its DC offset adjusted to be zero or slightly negative. One output of each linear FAN IN/OUT is connected to a JLAB VME discriminator and a second output is connected over delay cables to a CANE VME charge integrating ADC. The 4 PMTs from the trigger paddles from a 4-fold coincidence to generate a trigger signal. This trigger signal is set into coincidence with a DAQ latch level and the inverted BUSY signal from the TI.
- Picture of the detectors in the test stand:
- The HV for the two TOF PMTs are set to provide average signal amplitudes of about 300mV with the trigger paddles located at the center of the TOP paddle. The HV of the right PMT is 1400V and 1600V for the left PMT. The gain of the right PMT at 1750 was measured to be 4.6e6 while the left PMT gain a 1750V is found to be 1.3e6. Here a screen shot of the scope and similarly if the trigger paddles are moved 17" from the right PMT. At this location the signal of the left PMT reduced to about 200mV while the signal from the right PMT increased to about 600mV(yellow):
