Chandra
Ion Path Parameters

From outside to inside the path includes:
HRMA PreCollimator
Parabolic Shells
Central Apertures
Hyperbolic Shells
PostCollimator
Grating substrate
Magnetic Broom
ACIS Optical Blocking Filter
ACIS Chips


HRMA PreCollimator
x (mm) : distance from telescope focus along x-axis (optical axis)
inner r (mm) : inner aperture radius from x-axis
outer r (mm) : outer aperture radius from x-axis

type

x

shell #

outer r

inner r
Precollimator 1

aperture

11573

1

622.16

579.58

3

499.39

466.97

4

439.87

412.61

6

327.01

308.9
Precollimator 2

aperture

10963

1

618.57

583.43

3

498.78

469.01

4

440.96

413.41

6

329.08

305.91



Mirror Surface Composition
density (g/cm^3) : material density
Zerodur specific resistivity: 2*10+13 ohm-cm at room temperature
Zerodur dielectric constant: 7.4 at low frequency
shell #

layer #

material

density

thickness

1

1

Ir

22.4

32.5 nm

2

Cr

7.2

10.0 nm

3

Zerodur Glass Ceramic

2.53

2.36 cm

3

1

Ir

22.4

32.5 nm

2

Cr

7.2

10.0 nm

3

Zerodur Glass Ceramic

2.53

1.83 cm

4

1

Ir

22.4

32.5 nm

2

Cr

7.2

10.0 nm

3

Zerodur Glass Ceramic

2.53

1.65 cm

6

1

Ir

22.4

32.5 nm

2

Cr

7.2

10.0 nm

3

Zerodur Glass Ceramic

2.53

1.59 cm




Parabolic Shells
r (mm) =10*Sqrt(rh^2+2*k*(x-xm)-p*(x-xm)^2) : nominal prescription
r (mm) = cone approx : cone appoximation to nominal prescription
xmin, xmax (mm) : shell-end x-positions
length (cm) : shell lengths
shell #

cone approx

xmin

xmax

xm

length

p

k

rh

1

452.143+0.0147213 x

10086.5

10928.7

1050.762

84.2215

-0.00177977166

-0.8933311353

60.686080964

3

363.673+0.0118623 x

10096.6

10938.9

1051.775

84.2208

-0.00115323958

-0.57939624154

48.846244216

4

321.044+0.0104735 x

10100.3

10942.5

1052.139

84.2208

-0.00089864417

-0.45165799274

43.126225933

6

238.601+0.00778562 x

10105

10938.9

1052.612

84.2209

-0.00049625996

-0.24957050467

32.056977726




Central Apertures
x (mm) : distance from telescope focus along x-axis (optical axis)
inner r (mm) : inner aperture radius from x-axis
outer r (mm) : outer aperture radius from x-axis

type

x

shell #

outer r

inner r
Shell 6 baffle

aperture

10421.78

6

n/a

315.37
Center Aperture Plate 1

aperture

10081.04

1

605.54

581.3

3

488.17

466.71

4

431.58

411.42

6

322.09

304.47
Center Aperture Plate 2

aperture

10031.13

1

605.54

585.87

3

488.17

471.28

4

431.58

415.99

6

322.09

309.04




Hyperbolic Shells
r (mm) =10*Sqrt(rh^2+2*k*(x-xm)-p*(x-xm)^2) : nominal prescription
r (mm) = cone approx : cone appoximation to nominal prescription
xmin, xmax (mm) : shell-end x-positions
length (cm) : shell lengths
shell #

cone approx

xmin

xmax

xm

length

p

k

rh

1

148.481+0.0449262 x

9180.73

10022.9

-960.182

84.2192

0

-2.6050603441

57.98901584

3

119.412+0.0361668 x

9178.93

10021.1

-960.002

84.2197

0

-1.6875942398

46.664379784

4

105.392+0.0319265 x

9179.1

10021.3

-960.021

84.2225

0

-1.3150318066

41.191935912

6

78.2667+0.023726 x

9180.72

10022.9

-960.182

84.22

0

-0.72620248153

30.609851669




PostCollimator
x (mm) : distance from telescope focus along x-axis (optical axis)
inner r (mm) : inner aperture radius from x-axis
outer r (mm) : outer aperture radius from x-axis

type

x

shell #

outer r

inner r

Postcollimator 1

aperture

9025.4

1

558.94

520.34

3

450.7

417.69

4

398.45

368.21

6

297.41

272.42

Postcollimator 2

aperture

8808.2

1

548.83

504.3

3

442.49

404.78

4

391.23

356.83

6

292.07

263.99



Grating substrate (HETG)
density (g/cm^3) : material density
thickness (nm, unless otherwise noted) : layer thickness
x

shell #

layer #

material

density

thickness

8632.7

1, 3

1

Au

17

20

2

Cr

7.2

5

3

C_22 H_10 N_2 O_5

1.34

500

4, 6

1

Au

17

20

2

Cr

7.2

5

3

C_22 H_10 N_2 O_5

1.34

1000



Grating is retractable
50% is substrate: 50% is substrate + 500 nm Gold grating bars


Magnetic Broom
x (mm) : distance from telescope focus along x-axis (optical axis)
magnet r (mm) : magnet radius from x-axis
magnet dipole strength (kG cm^3)
x

magnet dipole strength

magnet r

magnet #

azimuthal position

dipole orientation

5851

45

504.5

1

0(+z)

+z

2

45

+y

3

90(+y)

-z

4

135

-y

5

180

+z

6

225

+y

7

270

-z

8

315

-y




ACIS Optical Blocking Filter
density (g/cm^3) : material density
thickness (nm, unless otherwise noted) : layer thickness
x

chip ID

layer #

material

density

thickness

16

S-Array

1

Al

2.7

90

2

C_22 H_10 N_2 O_5

1.34

200

3

Al

2.7

30

I-Array

1

Al

2.7

130

2

C_22 H_10 N_2 O_5

1.34

200

3

Al

2.7

30




ACIS Chips
density (g/cm^3) : material density
thickness (nm, unless otherwise noted) : layer thickness
x

shell #

layer #

material

density

thickness

0

Front Illuminated

1

Si

2.3

300

2

Si O_2

2.2

300

3

Si_3 N_4

3.4

40

4

Si

2.3

525000

Back Illuminated

1

Si O_2

2.2

35

2

Si

2.3

45000

3

Si_3 N_4

3.4

40

4

Si O_2

2.2

300

5

Si

2.3

300

6

Si O_2

2.2

24000