ICE Vs SALT GeV Electron Showers Shahid Hussain Shahid Hussain University of Kansas
ICE Vs SALT---- Chemical composition: Ice (H2O): Hydrogen: A=1.01, Z=1 Oxygen: A=16, Z=8 Salt (NaCl): Chlorine: A=35.45, Z=17 Sodium: A=22.99, Z=11 salt has larger e- and nucleon density
ICE Vs SALT---- Some Properties: Dens. g/cm^3 n C.Ang (deg) Radlen (cm) E_th (e) (KeV) Ice Salt I have used E_th (kinetic) smaller than 50KeV for both Ice and salt.
Simulation Results for 100 GeV 100 Showers average for electron initiated showers
Charge ratio at shower max. Ice/salt =0.63
Charge ratio at shower max. Ice/salt =0.69
ICE: SALT: Tracklengths: z is along the shower axis; r is the total track. Ice/salt=2.96 ‘+’ is for +ive charges ‘-’ is for –ive charges
Expect for field strength: Ice/salt = 0.63*2.96 = 2.0
Ice/salt=1.82 (at few GHz) Ice is even better below 1GHz.
Field strength: Ice/salt = 2.3 (at 1.3 GHz) 2.4 (at 0.8 GHz) 2.6 (at 0.3 GHz) Area under the curve: Ice/salt = 1.35 (at 1.3 GHz) 1.29 (at 0.8 GHz) 1.34 (at 0.3 GHz)
ICE: SALT: z is 43% of r z is 62% of r Lateral spread: Larger lateral spread in Salt
COMMENTS Lateral spread larger in salt (not satisfied; need to check this carefully with a more powerful test). Shower depth larger in ice (compare to theory using radlens for ice and salt).
COMMENTS…… Around 1 GHz, R|E|_ice/R|E|_slat=2 (approx.) is consistent with (q_exc*trackl.)_ice/(q_exc*tracll.)_salt =2. At lower frequencies, ice is even better as expected. At higher freqs., the field strength ratio (ice/salt ) reduces to 1.8. Pulse width is larger for salt.
SUGGESTION A detailed study is needed for a detailed comparison (ice vs. salt) and scaling to higher energies: 1. Need to do more tests on lateral- spread comparison. 2. Simulate some higher energy em and hadronic showers to check energy scaling implied by theory.
Finally, the pulse strength and width do not tell the whole story of ice –salt comparison; salt will gain a factor of 2.22/0.92 in event rates; ice will gain from larger attenuation lengths.
The End
MAGIC NUMBERS: Ice: 43*0.62=26.66 Salt: 62*0.43=26.66 Isn’t it fun!