1. Another Straw-person SALSA Simulation Amy Connolly UCLA February 4 th, 2005 Work by A. Connolly, D. Saltzerg and D. Williams

2. Outline of the Code  Instrumented region is (2 km) 3 cube  Pick interaction position from (8 km) 3 cube beginning 500 m below the Earth’s surface  1000 dipole-like dual-polarization antennas (10 along each edge) 100-200 MHz  Calculate signal detected at each antenna  Require 4 hits, each 6 above RMS noise  Each event is weighted for prob. of atten. along ’s path length in Earth, salt Simple earth model (core, mantle, crust) Assume salt atten. length ( » 1/ =600 m at 150MHz

3. The Askaryan Signal: Electric Field  Electric field emitted at interaction:  For salt (from personal communication w/ J. Alvarez Muniz in Fall 2003) C=1.10 £ 10 -7, 0 =1300 MHz,  » 1.5  Compare to ice (J. Alvarez Muniz, astro-ph/0003315) C=2.53 £ 10 -7, 0 =1150 MHz, =1.44

4. The Askaryan Signal: Cone Width  Width of Cerenkov cone (astro- ph/9706064, astro-ph/0003315, Phys.Lett.B434,396 (1998)): Material dependence Index of refraction Shower length

5. The Signal: Cone Width (cont)  Phys.Lett.B434, 396(1998):  Beyond parameterization (>7), scaling by 7.5% per decade.  n-dependence?  Need theorists to come up with concise instructions for simulating the Askaryan signal, complete for all relevant media

6. Zenith Angle  SALSA only sensitive to down-going ’s   distribution independent of energy  Cross-section measurement seems difficult

7. Interaction Position  For E =10 19 eV, where events occur that are triggered: Vertical PlaneHorizontal Plane

8. Sensitivity

9. Conclusions  Simple simulation program written with results similar to Peter’s  How high a frequency do we need to go to  Need unified message from theorists on simulation of signal

10. Backup Slides

11. Trigger Rates  4-fold, 6 ! coincidence rate essentially zero.  4-fold, 4 ! <~ 1/year E =10 18 eV Local coincidence: 20 ns Global coincidence: 10 s