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Cosmic Rays: Ever Present and Useful Anthony Gillespie Denbigh High School Mentor: Dr. Douglas Higinbotham Cosmic Rays Using the Cosmic Rays Current Research Finding the Angular Distribution Detector Construction Cosmic rays are not only useful in experiments such as this. There are experiments going on around the world involving cosmic rays, such as: These particles constantly bombard the earth Interaction with other particles in the atmosphere create particle showers Known to come from a variety of sources including: solar flares, black holes, neutron stars, quasars, supernovae and radio galaxies Most of the particles that reach the earth’s surface are muons and neutrinos Some believe cosmic rays have a large impact on our weather: playing a large role in the creation of clouds and guiding the path of lightning Cosmic rays affect communications with satellites especially those from solar flares Incident Rays (%) Two new layers are being added to the already existing neutron detector to be used in an upcoming Hall A experiment 24 new scintillator bars were built and tested using cosmic rays The bars are comprised of a piece of scintillator plastic 100x25x10cm, two light guides and two PMTs The always present cosmic rays were used in our experiment to test the performance of the new scintillator detectors we built The rays were also used to calibrate the gains of the photomultiplier tubes allowing us to determine the optimum voltage for each tube We took the testing of the scintillator detectors a step further and used them to find the angular distribution of the cosmic rays Two rows of three bars were stacked on top of one another,, then one bar was placed laying down on top to act as a trigger for our data acquisition system We used the time it took each signal to reach each PMT to calculate exactly where each particle had passed We wrote a basic program in ROOT, a data analysis system, that we used to analyze a run containing over 1 million events The result of that analysis was this histogram illustrating the angular distribution of cosmic rays. ABSTRACT In the study of sub atomic particles, it is essential to have highly accurate detectors. One such detector is the scintillator detector. This type of detector is made up of bars of scintillating plastic with light guides that direct the light to Photomultiplier Tubes (PMTs). The PMTs can take an input of only a few photons and transform it into a measurable electrical signal. These detectors measure the light produced as charged particles pass through, or as neutral particles cause charged particles within the plastic to move, thus producing light. Because these detectors measure light, the interior of the detector must be shielded from all external sources of light, which is done by way of wrapping each bar in several layers of black electrical tape. However, one must ensure that the detectors are working properly. To do this we used a very reliable and consistent source of charged particles, cosmic rays. The flux of cosmic rays is widely known and documented as around 100 particles per m 2 per second. By comparing our results of around 20 particles per second obtained by our scintillator detectors (with an area of .25m 2 ) to the known cosmic ray flux, it was possible to determine the accuracy of our detectors. Thus we determined that our detectors were functioning properly and ready to be assembled into an array. Passing this cosmic ray test means that these detectors are one step closer to being used in an upcoming Jefferson Lab experiment. I would like to thank: Douglas Higinbotham, Or Chen, Dominik Wermus, David Abbott, Eliazer Piasetzky, Moshe Zilka, Brad Sawatzky as well as my fellow interns for all their help, instruction and for making my experience here at Jefferson Lab very enjoyable. Conclusion Cosmic rays can be extremely useful and are the focus of many cutting edge experiments. There is still much we can learn about these particles, their effects, and where they come from. Testing for light leaks Each PMT has its own specific voltage The setup we used to calibrate the gains of the PMTs We’re adding another two layers behind the existing 4 The veto layer allows the detector to filter out protons and electrons 90% 9% 1% Incident Rays (%) Protons Alpha Particles Electrons Neutrinos are extremely penetrating, almost mass less particles , and so are extremely hard to detect, one way to do this is by using the earth as a giant detector Neutrinos travelling through the earth will occasionally crash into a proton or neutron, creating a muon These muons produce Cherenkov light as they pass from the earth into the ocean (or into the ice caps) This light can be picked up by Photomultiplier Tubes (PMTs) and used to determine the speed and direction of the original neutrino Neutrino Telescopes High Energy Particle Detection Extremely high energy particles (10^19 eV) only arrive once per sq Km per year. The Auger Observatory in Argentina has covered an area the size of the state of Rhode Island with a hybrid detection system looking specifically for high energy particles ANTARES, a neutrino telescope off the coast of France The Hybrid Detection System

Cosmic Rays: Ever Present and Useful Anthony Gillespie Denbigh High School Mentor: Dr. Douglas Higinbotham Cosmic Rays Using the Cosmic Rays Current Research

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Page 1: Cosmic Rays: Ever Present and Useful Anthony Gillespie Denbigh High School Mentor: Dr. Douglas Higinbotham Cosmic Rays Using the Cosmic Rays Current Research

Cosmic Rays: Ever Present and UsefulAnthony Gillespie

Denbigh High SchoolMentor: Dr. Douglas Higinbotham

Cosmic Rays

Using the Cosmic Rays

Current ResearchFinding the Angular Distribution

Detector Construction

Cosmic rays are not only useful in experiments such as this. There are experiments going on around the world involving cosmic rays,

such as:

These particles constantly bombard the earthInteraction with other particles in the atmosphere create particle showersKnown to come from a variety of sources including: solar flares, black holes, neutron stars, quasars, supernovae and radio galaxiesMost of the particles that reach the earth’s surface are muons and neutrinosSome believe cosmic rays have a large impact on our weather: playing a large role in the creation of clouds and guiding the path of lightningCosmic rays affect communications with satellites especially those from solar flares

Incident Rays (%)

Two new layers are being added to the already existing neutron detector to be used in an upcoming Hall A experiment 24 new scintillator bars were built and tested using cosmic rays The bars are comprised of a piece of scintillator plastic 100x25x10cm, two light guides and two PMTs

The always present cosmic rays were used in our experiment to test the performance of the new scintillator detectors we builtThe rays were also used to calibrate the gains of the photomultiplier tubes allowing us to determine the optimum voltage for each tube

We took the testing of the scintillator detectors a step further and used them to find the angular distribution of the cosmic raysTwo rows of three bars were stacked on top of one another,, then one bar was placed laying down on top to act as a trigger for our data acquisition systemWe used the time it took each signal to reach each PMT to calculate exactly where each particle had passedWe wrote a basic program in ROOT, a data analysis system, that we used to analyze a run containing over 1 million eventsThe result of that analysis was this histogram illustrating the angular distribution of cosmic rays.

ABSTRACT In the study of sub atomic particles, it is essential to have highly accurate detectors. One such detector is the scintillator detector. This type of detector is made up of bars of scintillating plastic

with light guides that direct the light to Photomultiplier Tubes (PMTs). The PMTs can take an input of only a few photons and transform it into a measurable electrical signal. These detectors measure the light produced as charged particles pass through, or as neutral particles cause charged particles within the plastic to move, thus producing light. Because these detectors measure

light, the interior of the detector must be shielded from all external sources of light, which is done by way of wrapping each bar in several layers of black electrical tape. However, one must ensure that the detectors are working properly. To do this we used a very reliable and consistent source of charged particles, cosmic rays. The flux of cosmic rays is widely known and documented as

around 100 particles per m2 per second. By comparing our results of around 20 particles per second obtained by our scintillator detectors (with an area of .25m2) to the known cosmic ray flux, it was possible to determine the accuracy of our detectors. Thus we determined that our detectors were functioning properly and ready to be assembled into an array. Passing this cosmic ray test

means that these detectors are one step closer to being used in an upcoming Jefferson Lab experiment.

I would like to thank: Douglas Higinbotham, Or Chen, Dominik Wermus, David Abbott, Eliazer

Piasetzky, Moshe Zilka, Brad Sawatzky as well as my fellow interns for all their help, instruction and for

making my experience here at Jefferson Lab very enjoyable.

ConclusionCosmic rays can be extremely useful and are the focus of many cutting edge experiments. There is still much we can learn about these particles, their effects, and where they come

from.

Testing for light leaks

Each PMT has its own specific voltage

The setup we used to calibrate the gains of the PMTs

We’re adding another two layers behind the existing 4

The veto layerallows the detector to filter out protons and

electrons 90%

9%

1%

Incident Rays (%)

Protons

Alpha Particles

Electrons

Neutrinos are extremely penetrating, almost mass less particles , and so are extremely hard to detect, one way to do this is by using the earth as a giant detectorNeutrinos travelling through the earth will occasionally crash into a proton or neutron, creating a muonThese muons produce Cherenkov light as they pass from the earth into the ocean (or into the ice caps) This light can be picked up by Photomultiplier Tubes (PMTs) and used to determine the speed and direction of the original neutrino

Neutrino Telescopes

High Energy Particle DetectionExtremely high energy particles

(10^19 eV) only arrive once per sq Km per year.The Auger Observatory in Argentina has covered an area the size of the state of Rhode Island with a hybrid detection system looking specifically for high energy particles

ANTARES, a neutrino telescope off the coast of

FranceThe Hybrid Detection System