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

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

Incoming cosmic ray Atmosphere collisional debris SPASE Surface Antarctic Ice AMANDA

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

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

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

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

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!”

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

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!

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

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

Cosmic Ray Energy Spectrum: the Knee

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