CXO Project Science: Ion Studies

• HEG substrate + OBF + ACIS Gate Structure: 190 keV
• MEG substrate+ OBF + ACIS Gate Structure: 140 keV
• OBF-I + ACIS Gate Structure: 90 keV
• OBF-S+ ACIS Gate Structure: 80 keV
• OBF-I: 30 keV
• OBF-S: 20 keV

• Assuming no-damage-with-HETG-in was because of HETG shielding implies that damaging radiation is primarily between 80 and 190 keV.
   
• Scattering through HETG support structure is a factor in diluting flux and leads to a higher upper limit. The effective transmission is 50% at 600 keV when dilution because of scattering is included.
   

   
   

• HEG substrate + OBF + ACIS Gate Structure: TBD (>1 MeV)
• MEG substrate+ OBF + ACIS Gate Structure: 850 keV
• OBF-I + ACIS Gate Structure: 400 keV
• OBF-S+ ACIS Gate Structure: 350 keV
• OBF-I: TBD (approx. 200 keV)
• OBF-S: TBD (approx. 150 keV)

Proton transmission through OBF-I only
OBF-I: 130 nm Al; 200 nm polyimide (1.34 g/cm^3); 30 nm Al

Proton transmission through OBF-S + ACIS-FI gate structure
OBF-S: 90 nm Al; 200 nm polyimide (1.34 g/cm^3); 30 nm Al
ACIS Gate Structure: 300 nm Si; 300 nm SiO₂; 40 nm Si₃N₄

Proton transmission through OBF-I + ACIS-FI gate structure
OBF-I: 130 nm Al; 200 nm polyimide (1.34 g/cm^3); 30 nm Al
ACIS Gate Structure: 300 nm Si; 300 nm SiO₂; 40 nm Si₃N₄

HEG: 20 nm Au; 5 nm Cr; 1000 nm polyimide (1.34 g/cm^3)
OBF-S: 90 nm Al; 200 nm polyimide (1.34 g/cm^3); 30 nm Al
ACIS Gate Structure: 300 nm Si; 300 nm SiO₂; 40 nm Si₃N<sub>4

Proton transmission through MEG substrate+OBF+ACIS-FI gate structure
MEG: 20 nm Au; 5 nm Cr; 500 nm polyimide (1.34 g/cm^3)</sub>
OBF-S: 90 nm Al; 200 nm polyimide (1.34 g/cm^3); 30 nm Al
ACIS Gate Structure: 300 nm Si; 300 nm SiO₂; 40 nm Si₃N₄

_{Proton transmission through HEG substrate}

• _{Scattering through HETG is a factor in diluting flux and leads to a higher upper limit. The scatter dilution factor plotted above is the fraction of total transmitted flux which scatters less than 1°.}
• _{If we assume that damaging radiation which is scattered more than 1° misses the ccds while that which is scattered less than 1° can still hit ACIS, then the 50% transmission point increases to about 600 keV.}
• _{This transmission combined with another 50% reduction because of the grating bars, suggests that the HETG has an effective transismission of only 25% at 600 keV. This significantly weakens the significance of the suggestion of no damage with HETG inserted during the rad. pass.}

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Oxygen ion transmission through OBF-S + ACIS-FI gate structure
OBF-S: 90 nm Al; 200 nm polyimide (1.34 g/cm^3); 30 nm Al
ACIS Gate Structure: 300 nm Si; 300 nm SiO₂; 40 nm Si₃N₄

Oxygen ion transmission through OBF-I + ACIS-FI gate structure
OBF-I: 130 nm Al; 200 nm polyimide (1.34 g/cm^3); 30 nm Al
ACIS Gate Structure: 300 nm Si; 300 nm SiO₂; 40 nm Si₃N₄

ACIS Gate Structure: 300 nm Si; 300 nm SiO₂; 40 nm Si₃N₄

Oxygen ion transmission through MEG substrate+OBF+ACIS-FI gate structure
MEG: 20 nm Au; 5 nm Cr; 500 nm polyimide (1.34 g/cm^3)
OBF-S: 90 nm Al; 200 nm polyimide (1.34 g/cm^3); 30 nm Al
ACIS Gate Structure: 300 nm Si; 300 nm SiO₂; 40 nm Si₃N₄

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