1. 1 55 Fe Simulations under the divine guidance of Sauli’s “Bible” Jason for the SB Tent Crew Mar 11, 2008

2. 2 55 Fe Simulation 55 Fe source 55 Fe γ Simulation… γ is emitted from 55 Fe determine γ angle φ φ mesh top GEM readout pad note: not to scale Incidentals: Source sits 1 cm from mesh Drift Gap: 1.5 mm pad radius: 1.5 cm RB collection region: 150 μ Drift Gap

3. 3 55 Fe Simulation 55 Fe source 55 Fe γ Simulation… γ is emitted from 55 Fe determine γ angle φ determine conversion length where for CF4, λ ~8.5cm conversion length φ mesh top GEM readout pad pe note: not to scale Incidentals: Source sits 1 cm from mesh Drift Gap: 1.5 mm pad radius: 1.5 cm RB collection region: 150 μ Drift Gap

4. 4 55 Fe Simulation 55 Fe source 55 Fe γ Simulation… γ is emitted from 55 Fe determine γ angle φ determine conversion length where for CF4, λ ~8.5cm determine pe emission θ follows a sin 2 dist conversion length θ φ mesh top GEM readout pad pe note: not to scale Incidentals: Source sits 1 cm from mesh Drift Gap: 1.5 mm pad radius: 1.5 cm RB collection region: 150 μ Drift Gap

5. 5 55 Fe Simulation 55 Fe source 55 Fe γ Simulation… γ is emitted from 55 Fe determine γ angle φ determine conversion length where for CF4, λ ~8.5cm determine pe emission θ follows a sin 2 dist determine primary charge deposited by pe (poisson, 109) conversion length θ φ mesh top GEM readout pad pe note: not to scale Incidentals: Source sits 1 cm from mesh Drift Gap: 1.5 mm pad radius: 1.5 cm RB collection region: 150 μ Drift Gap

6. 6 55 Fe Simulation 55 Fe source 55 Fe γ Simulation… γ is emitted from 55 Fe determine γ angle φ determine conversion length where for CF4, λ ~8.5cm determine pe emission θ follows a sin 2 dist determine primary charge deposited by pe (poisson, 109) dist traversed by e’s (E<300keV) R p = 0.71xE 1.72 (E in MeV, R p in g/cm 2 ) in CF 4 at 5.9 keV, R p ~286μ conversion length θ RpRp φ mesh top GEM readout pad pe note: not to scale Incidentals: Source sits 1 cm from mesh Drift Gap: 1.5 mm pad radius: 1.5 cm RB collection region: 150 μ Drift Gap

7. 7 55 Fe Simulation 55 Fe source 55 Fe γ Simulation… γ is emitted from 55 Fe determine γ angle φ determine conversion length where for CF4, λ ~8.5cm determine pe emission θ follows a sin 2 dist determine primary charge deposited by pe (poisson, 109) dist traversed by e’s (E<300keV) R p = 0.71xE 1.72 (E in MeV, R p in g/cm 2 ) in CF 4 at 5.9 keV, R p ~286μ for each of 109 e’s, determine position along track conversion length θ RpRp φ mesh top GEM readout pad pe note: not to scale Incidentals: Source sits 1 cm from mesh Drift Gap: 1.5 mm pad radius: 1.5 cm RB collection region: 150 μ Drift Gap

8. 8 55 Fe Simulation 55 Fe source 55 Fe γ Simulation… γ is emitted from 55 Fe determine γ angle φ determine conversion length where for CF4, λ ~8.5cm determine pe emission θ follows a sin 2 dist determine primary charge deposited by pe (poisson, 109) dist traversed by e’s (E<300keV) R p = 0.71xE 1.72 (E in MeV, R p in g/cm 2 ) in CF 4 at 5.9 keV, R p ~286μ for each of 109 e’s, determine position along track If e is over our readout pad && Forward Bias if e is inside drift gap, avalanche it. Reverse Bias if e is within 150μ, avalanche it. conversion length θ RpRp φ mesh top GEM readout pad pe note: not to scale Incidentals: Source sits 1 cm from mesh Drift Gap: 1.5 mm pad radius: 1.5 cm RB collection region: 150 μ Drift Gap

9. 9 Simulated 55 Fe Spectra The FB bias spectrum is very similar to what we see in the gain test box. After the 10 th stack is installed, we’ll hook Maestro up to the “pre-CsI” box and measure RB spectra for comparison. Actual Spectrum