1. Cosmic Ray Composition: Preparation for an Analysis of 2002 AMANDA Data
Amanda Heffner-Wong
Wichita State University
Wichita, KS
Mentor: Dr. Katherine Rawlins
REU Final Presentation
University of Wisconsin – Madison
August 7, 2003

2. Cosmic Rays Why study them? high-energy particle nuclei from space
What are they?
high-energy particle nuclei from space
routinely enter our atmosphere
Why study them?
go beyond particle accelerator energies
most from outside solar system; some from beyond galaxy
around the “knee,” power-law changes slope
What is unknown?
composition
origins

3. Incoming cosmic ray
Atmosphere
collisional debris
SPASE
Surface
Antarctic Ice
AMANDA

4. Preparation Steps Cross Talk cleaning (strings 5-10)
2002 Data
first cosmic ray study to use AMANDA-II
we're the first to use 2002 data
Cross Talk cleaning (strings 5-10)
signal from one detector “leaks”...
... causes “fake” signal in another detector
must clean out fake signals

5. Preparation Steps Cross Talk cleaning amplitude (mV)
time over threshold (ns)

6. Preparation Steps Cross Talk cleaning amplitude (mV)
time over threshold (ns)

7. Preparation Steps
Ice Properties – dust layers affect light propagation
dust in ice

8. Preparation Steps Monte Carlo – simulates the process
in actual data, cosmic ray is unknown
need known initial conditions to “check” AMANDA
Monte Carlo provides known initial cosmic ray
“Preliminary!”

9. Preparation Steps Theory
have mathematical function to predict AMANDA response
fit theory to data (here, Monte Carlo)
how does data compare?
function
“Preliminary!”

10. Preparation Steps 2002 Data coming soon! will fit theory to 2002 data
just delivered two days ago
will fit theory to 2002 data
will compare to Monte Carlo
check back in a few days to see how real data looks!

11. And Then...? Complete analysis of AMANDA combine with SPASE data
reach better understanding of “knee” region
work towards understanding origins of cosmic rays

12. Many, Many Thanks to: The National Science Foundation
University of Wisconsin – Madison
The AMANDA Collaboration
Dr. Katherine Rawlins
Dr. Robert Benjamin
“Drew and Lucy”
Tzu Tshin Wong

13. Cosmic Ray Energy Spectrum: the Knee

14. Cross Talk: Pulse Shapes and ADC vs. TOT Plots
Threshold
ADC
Cherenkov photon pulse
Threshold
cross talk pulse