55 Fe Simulations under the divine guidance of Sauli’s “Bible”

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

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

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

4. 55Fe Simulation • Incidentals: • Source sits 1 cm from mesh • Drift Gap: 1.5 mm • pad radius: 1.5 cm • RB collection region: 150 μ • Simulation… • γ is emitted from 55Fe • determine γ angle φ • determine conversion length • where • for CF4, λ ~8.5cm • determine pe emission θ • follows a sin2 dist conversion length top GEM mesh pe 55Fe γ 55Fe source θ readout pad φ Drift Gap note: not to scale 4

5. 55Fe Simulation • Incidentals: • Source sits 1 cm from mesh • Drift Gap: 1.5 mm • pad radius: 1.5 cm • RB collection region: 150 μ • Simulation… • γ is emitted from 55Fe • determine γ angle φ • determine conversion length • where • for CF4, λ ~8.5cm • determine pe emission θ • follows a sin2 dist • determine primary charge deposited by pe (poisson, 109) conversion length top GEM mesh pe 55Fe γ 55Fe source θ readout pad φ Drift Gap note: not to scale 5

6. 55Fe Simulation • Incidentals: • Source sits 1 cm from mesh • Drift Gap: 1.5 mm • pad radius: 1.5 cm • RB collection region: 150 μ • Simulation… • γ is emitted from 55Fe • determine γ angle φ • determine conversion length • where • for CF4, λ ~8.5cm • determine pe emission θ • follows a sin2 dist • determine primary charge deposited by pe (poisson, 109) • dist traversed by e’s (E<300keV) Rp = 0.71xE1.72 (E in MeV, Rp in g/cm2) in CF4 at 5.9 keV, Rp ~286μ conversion length top GEM mesh pe 55Fe γ 55Fe source θ readout pad φ Rp Drift Gap note: not to scale 6

7. 55Fe Simulation • Incidentals: • Source sits 1 cm from mesh • Drift Gap: 1.5 mm • pad radius: 1.5 cm • RB collection region: 150 μ • Simulation… • γ is emitted from 55Fe • determine γ angle φ • determine conversion length • where • for CF4, λ ~8.5cm • determine pe emission θ • follows a sin2 dist • determine primary charge deposited by pe (poisson, 109) • dist traversed by e’s (E<300keV) Rp = 0.71xE1.72 (E in MeV, Rp in g/cm2) in CF4 at 5.9 keV, Rp ~286μ • for each of 109 e’s, • determine position along track conversion length top GEM mesh pe 55Fe γ 55Fe source θ readout pad φ Rp Drift Gap note: not to scale 7

8. 55Fe Simulation • Incidentals: • Source sits 1 cm from mesh • Drift Gap: 1.5 mm • pad radius: 1.5 cm • RB collection region: 150 μ • Simulation… • γ is emitted from 55Fe • determine γ angle φ • determine conversion length • where • for CF4, λ ~8.5cm • determine pe emission θ • follows a sin2 dist • determine primary charge deposited by pe (poisson, 109) • dist traversed by e’s (E<300keV) Rp = 0.71xE1.72 (E in MeV, Rp in g/cm2) in CF4 at 5.9 keV, Rp ~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 top GEM mesh pe 55Fe γ 55Fe source θ readout pad φ Rp Drift Gap note: not to scale 8

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