Transcript SALSA Simulation at UCLA

Another Straw-person
SALSA Simulation
Amy Connolly
UCLA
February 4th, 2005
Work by A. Connolly, D. Saltzerg and
D. Williams
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
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
The Askaryan Signal: Cone Width

Width of Cerenkov cone (astroph/9706064, astro-ph/0003315,
Phys.Lett.B434,396 (1998)):



Material dependence
Index of refraction
Shower length
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

Zenith Angle
SALSA only sensitive to down-going ’s
  distribution independent of energy
 Cross-section measurement seems difficult

Interaction Position

For E=1019 eV, where events occur that
are triggered:
Vertical Plane
Horizontal Plane
Sensitivity
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

Backup Slides
Trigger Rates
E=1018 eV
Local coincidence: 20 ns
Global coincidence: 10 s
4-fold, 6 ! coincidence rate essentially
zero.
 4-fold, 4 ! <~ 1/year
