SAO Development of adjustable grazing incidence x-ray optics Paul B. Reid 1, William Davis 1, Daniel...

SAO

Development of adjustable grazing incidence x-ray opticsDevelopment of adjustable grazing incidence x-ray optics

Paul B. Reid1, William Davis1, Daniel A. Schwartz1, Sang Park1,

Susan Trolier-McKinstry2, Rudeger (Derek) H. T. Wilke2,

and Brian Ramsey3

AXRO2009, Prague, Czech Republic

1 Smithsonian Astrophysical Observatory

2 Pennsylvania State University

3 NASA Marshall Space Flight Center

Paul B. Reid1, William Davis1, Daniel A. Schwartz1, Sang Park1,

Susan Trolier-McKinstry2, Rudeger (Derek) H. T. Wilke2,

and Brian Ramsey3

AXRO2009, Prague, Czech Republic

1 Smithsonian Astrophysical Observatory

2 Pennsylvania State University

3 NASA Marshall Space Flight Center

SAO

pbr 12/2009 2 AXRO2009, Prague, December 2009

How many astronomers does it take to change a light bulb?

SAO



Ten.

One to change the bulb…

SAO



Ten.

One to change the bulb …

and nine to argue about the color.

SAO


Why adjustable optics? Gen-X

Introduction

– 50 m2 effective area at 1 keV– 0.1 arcsec HPD at 1 keV– Subject of two NASA studies PI’d at SAO

•NASA Visions Mission Study (2004-2005)•NASA Advanced Mission Concept Study (2008-2009)

– Follows IXO and builds upon IXO technology– 60 m focal length using an extensible boom– Mirror unfolds to ~ 16 m diameter– Launch on Ares V launch vehicle

SAO


Introduction: bi-morph mirrors

Develop bi-morph mirrors

– Thin film (1 – 5 um) piezoelectric actuators deposited on back surface of thin (0.2 – 0.4 mm) thermally formed glass mirror

– Strain direction of piezo is parallel to mirror surface– Energizing piezo produces bending in the surface (similar to bi-metallic

bending)– Calibrate the piezo responses (impulse functions) for use in correcting mirror

figure on-orbit, but use a feedback loop for correction

SAO


Adjustable Optics

Finite element modeling of impact of mirror mounting (support constraints, or boundary conditions) on influence functions

– SAO

Development of thin piezo film deposition on thermally formed thin glass sheets and thin electroplated metal optics

– PSU

Fabrication of thin Ni/Co electroplated mirrors

– NASA MSFC

SAO


Finite Element Modeling – Mounting Constraints

Kinematic mount 5 point mount each end 5 point mount each end + 1 point each side

SAO


Finite Element Modeling – Mounting Constraints

SAO


Crystallization of PZT in Perovskite Phase

20 25 30 35 40 45 500

1

2

3

4

5

Pyr

och

lore

(2

22

)

PZT (100)

52/48: 500 oC

52/48: 550 oC

30/70: 500 oC

30/70: 550 oC

WL

WL

lo

g (c

ount

s) (

a.u.

)

2 (o)

Pt (111)Cu

K PZT (111)

• Single layer films: spun on at 1500 rpm and pyrolized at 225 oC, 400 oC for 4 minutes• Crystallization step performed in box furnace (1 hour hold at temp)• Can crystallize in PbZr0.30Ti0.70O3 in perovskite phase at 550 oC

SAO


Deposition of PbZr0.52Ti0.48O3 on PbZr0.30Ti0.70O3

15 20 25 30 35 40 45 500

2

4

6

8

Pyr

och

lore

(2

22

)

PZ

T (

10

1)

PZ

T (

20

0)

CuK

WL P

ZT

(1

11

)

PZT (100)

lo

g (c

ount

s) (

a.u.

)

2 (o)

3 Layers - No RTA 3 Layers - w/ RTA 6 Layers - No RTA 6 Layers - w/ RTA P

t (1

11

)

• PZT 30/70 seed layer used for all samples• 3 and 6 layers of PZT 52/48 deposited on seed layer under different conditions• No RTA = 1 hour crystallization in furnace @ 550 oC after 3 layers• w/RTA = 3 minutes @ 550 oC in RTA after pyrolysis of each layer plus box furnace heat treatment after 3 layers

SAO


Deposition of PZT Films on 1x1 inch Substrates

PZT film

Spin-coat solution:1500 rpm for 40 sec

Pyrolysis 1: 225 °C for 4 min

Pyrolysis 2: 400 °C for 4 min

Crystallization at 550 °C for 3 min in RTA

Crystallization at 550 °C for 1 hour in Box Furnace

• PZT 30/70 seed layer is deposited with same flow but with crystallization done after single layer

SAO


Films crystallized using RTA/Box furnace approach (6, 9, 12 layers of 52/48 on 30/70 seed layer)

Crystallizes in perovskite structure – no evidence of pyrochlore

Films Grown up to thickness of 1 µm

15 20 25 30 35 40 45 500

1

2

3

4

5

PZT (100)

PZ

T (

10

1)

CuK

WL

PZ

T (

11

1)

Pt

(11

1)

PZT (200)

log

(cou

nts)

(a.

u.)

2 (o)

0.65 m 0.88 m 1.06 m

SAO


Development of Adjustable Optics – test optic

SAO


Development of Adjustable Optics – test optic

SAO


Films on 1x1 inch Substrate: Electrical Properties

Relative permitivity (average of two samples) is 785 @ 10 kHz for 1.06 µm thick film (Films on Si are ~1000 @ 10 kHz)

Hysteresis loops show low levels of imprint (loops shifted ~15 kV/cm)

Pr~ 30-34 µC/cm2, Ec~55-70 kV/cm (Films on Si: 25 µC/cm2, 45 kV/cm)

103 104 1050

200

400

600

800

1000

0.00

0.04

0.08

0.12

0.16

0.20

r

Frequency (Hz)

0.65 m 0.88 m 1.06 m

tan

-600 -400 -200 0 200 400 600-60

-40

-20

0

20

40

60

P (C

/cm

2)

E (kV/cm)

0.65 m 0.88 m 1.06 m

SAO


Pyrolysis and crystallization performed in box furnace

Film is 1.09 μm thick

No evidence of pyrochlore phase

Film on 4 x 4 Inch Substrate: X-ray Analysis

15 20 25 30 35 40 45 50 55 602.5

3.0

3.5

4.0

4.5

PZ

T (

11

2/2

11

)

PZ

T (

20

1/2

10

)

PZ

T (

00

2)

Pt

(20

0)PZ

T (

20

0)

Pt

(11

1)

PZ

T (

11

1)

PZ

T (

10

1)

PZ

T (

00

1/1

00

)

log(

coun

ts)

(a.u

.)

2 (o)

SAO


Film on 4 x 4 Inch Substrate: Electrical Data

Measured on 1 x 1 mm electrodes – 1 x 1 cm electrodes all shorted

10 kHz: εr~ 770, tan δ~ 0.04

-750 -500 -250 0 250 500 750-60

-40

-20

0

20

40

60

P (C

/cm

2 )

E (kV/cm)

1 mm2 Electrode

Ec=64 kV/cm

Pr=24 C/cm2

102 103 1040

200

400

600

800

1000

0.00

0.02

0.04

0.06

0.08

0.10

r

Frequency (Hz)

1 mm2 Electrode

tan

SAO


Piezoelectric Properties: e31,f

e31,f=D3/(x1+x2)

Measurement error ~ +/- 10%

Typical values for randomly oriented thin films are -6 to -7 C/m2

0.6 0.7 0.8 0.9 1.0 1.10

2

4

6

8

-e31

,f (C

/m2 )

Thickness (m)

SAO


Sputter Deposition of PZT at PSU

Three gun sputter system installed and operational

– Developing sputtering parameters and appropriate stoichiometry Initial test produced appropriate film prior to crystallization - awaiting

results of this step.

SAO


Summary and Acknowledgements

Summary

– Initial finite element modeling of adjustable optics mounting constraints demonstrates “less is less” – less constrained system has what appears to be less desirable influence functions in terms of lateral extent and dynamic range of adjustment

– ~ 1 um thick piezo films have been deposited on thermally formed glass

• Good piezoelectric properties• Improved deposition approach defined (sol-gel spin coat sputtering)

– Finite element modeling demonstrates that 1 um thick PZT yields sufficiently large deformations at 100 ppm strain for 100 um thick Ni/Co mirrors and, at ~ 500 ppm strain, for 400 um thick glass mirrors.

Acknowledgements

– This work supported by a NASA APRA and the Gordon and Betty Moore Foundation

SAO


Adjustable Grazing Incidence Optics

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