High School Cosmic Ray

Projects and TrainingBasalt High School

Math and Science Club

October 14, 2004

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

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

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:

Cosmic Ray Detector Threshold TestingSample Data:

: Data Collected

: Linear Approximations

: Calculated optimal threshold (~40mV)

Data available on www.BasaltScience.net

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

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

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

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

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