I have been working on the design for the driver boxes for the last week. The general design is pretty well laid out now and we can begin finding the necessary components for construction. I also finished testing for noise generated by the LED boards when mounted near the PMT and found that the small amount of noise originally present can be eliminated by wrapping the LED boards in aluminum foil.
I finished the LED pulse width testing and the results still show that a 6ns pulse can be produced. LED Pulsing results
I have been examining the PMT pulses produced by various numbers of photoelectrons. The results show that a PMT pulse of ~6ns is attainable with ~100 photoelectrons. Slightly smaller pulses can be obtained with fewer photoelectrons but the pulse width increases dramatically as the number of photoelectrons increases above 100.
I just finished my study on single photoelectron areas. The results show that a single photoelectron produces an area under the PMT voltage curve of ~1.2E-10Vs area +/- ~2.2E-11Vs with PMT at 1800V, ~2.2E-10Vs area +/- ~2.3E-11Vs with PMT at 1900V, and ~8.5E-11Vs area +/- ~2.9E-11Vs with PMT at 2000V. Here is a link to the data and results: SPE area data/results. I will now look again at the minimum pulse width that can be generated by an led.
I have temporarily postponed the minimum pulse width studies to pursue investigation of single photoelectrons. Preliminary results yield around a 200pVs area for a single photoelectron with the PMT at 1900V.
I am currently trying to determine the minimum pulse width that can be generated by an led.
Hey Chris, this is Andrew. If you want to update your site just write in the date and a little something and then save it as a website. Whenever you create a new entry do it at the top of the list so the most recent entry is the first one seen.