1. High School Cosmic Ray Projects and Training Basalt High School Math and Science Club October 14, 2004

2. Cosmic Ray Detector Threshold Testing Detectors detect flashes of light caused by internal fluors, which scintillate when hit by a high-energy particle. The detector emits a voltage spike upon being hit, which is picked up by the data acquisition card and recorded as a hit. The size of the spike is proportional to the energy of the particle. The question: What is the threshold voltage for detecting and recording cosmic ray hits? How big should should the spike have to be to trigger the counter? Right: Voltage spikes from detector

3. Cosmic Ray Detector Threshold Testing Optimal threshold voltage is different for each detector, so each detector must be tested individually. Threshold is set in 10 mV increments on data acquisition card. Using CROPDAQ data acquisition program, detection runs are initiated for a given time per increment. Procedure: Discriminator threshold adjust Data Acquisition Card

4. Cosmic Ray Detector Threshold Testing Data collected should be plotted with tested threshold voltage along one axis, and number of hits along the other. At low threshold, we expect to be dominated by noise, which plummets rapidly with threshold. Its exponential drop should ideally look like a straight line on a logarithmic plot. At high threshold, the background noise should be pretty much eliminated, and any additional increase in threshold will actually start cutting into the real signal. When plotted on a logarithmic scale, both processes appear approximately linear. The optimum threshold voltage can be found at the intersection of these two lines Data Analysis:

5. Cosmic Ray Detector Threshold Testing Sample Data: : Data Collected : Linear Approximations : Calculated optimal threshold (~40mV) Data available on www.BasaltScience.net

6. High School Cosmic Ray Projects/Training Threshold scanning was one preparation to make cosmic ray detectors ready for data collection Other preparations include light-testing and efficiency testing Following these preparations, detectors were brought to Henderson Mine, where they are currently collecting data

7. High School Henderson Mine Trip On September 28, 2004, students from Basalt, Roaring Fork, Aspen, Lake County and Clear Creek High Schools met in Empire at the Henderson Mine. Purpose of visit:  Familiarize students with the Henderson location  Cosmic ray detector installation and data acquisition training

8. High School Henderson Mine Trip Students were given a tour of the mine to familiarize them with the mine atmosphere and to get a feel for the proposed location of the laboratory

9. High School Henderson Mine Trip Additionally, students were trained in data collection techniques including:  Underground placement of cosmic ray detectors  Data logging and media replacement

10. High School Henderson Mine Trip Cosmic ray detectors are currently collecting data at the surface of Henderson Mine, and 2000 feet underground. In the future, groups will revisit Henderson approx every two weeks to log data, check detectors, and change detector position. Eventually, data will be compared to baseline data to determine ideal placement for proposed underground laboratories. Future: Right: Surface data collection station Note: This presentation is available online at basaltscience.net