Astro-H XRT systemH.Awaki (Ehime University)

+ Astro-H XRT team

(Nagoya Univ., NASA/GSFC, ISAS/JAXA, Ehime Univ., Chubu Univ., Osaka City Univ., Nara women’s Univ., Kobe Univ., Chuo Univ., JASRI/SPring-8, JST )

Contents1. Astro-H satellite2. XRT components & design

3. HXT (foil production, calibration facility)

4. SXT (improvements from Suzaku to Astro-H)

Astro-H

Scientific objectives(1) Evolution of clusters of galaxies(2) Growth of super-massive black holes(3) Behavior of material in extreme gravitational field(4) Particle acceleration in the universe(5) Dark matter and dark energy

Scientific objectives(1) Evolution of clusters of galaxies(2) Growth of super-massive black holes(3) Behavior of material in extreme gravitational field(4) Particle acceleration in the universe(5) Dark matter and dark energy

The new Japanese X-ray mission following SuzakuAstro-H is currently planned to launch in fiscal 2013.

Length: 14 mWeight: 2.5 tLaunch vehicle: JAXA HII-AOrbit : 550 km circular i = 31 °

Instruments

FL=5.6 m

Double-sided Si Strip (4 layer) detector + CdTe double strip(1 layer) detector

(Micro calorimeter) (X-ray CCD camera)

Extended Optical bench

Fixed Optical bench

radiator

SUN

Si/CdTe Compton camera

Soft X-ray telescopeHard X-ray telescope (HXT)

FL=12 m

Soft X-ray imagerSoft X-ray spectrometer

Soft Gamma-ray detector

Hard X-ray Imager (HXI)

With these instruments, Astro-H will cover the bandpass between 0.3 keV to 600 keV.

Main features of Astro-H• Large collecting area above 10 keV 200cm2 @ 40 keV

• High-resolution spectroscopy with E/ΔE>1000 300cm2 @ 6 keV

• Wide band observation from 0.3 to 600 keV.

Angular resolution

Collecting areain the hard X-ray band

Suzaku

XMM-Newton

Chandra

Astro-H

Energy resolution

Collecting areain the soft X-ray band

Energy band

Effective area

0.1 1 10 100 1000 Energy [keV]

E

ffec

tive

area

[cm

2]

10

10

0

1

000

HXT+HXI

SGD (Compton mode)

SXT+SXS

SXT+SXI

Hard X-ray region: Continuum Sensitivity for point source

Energy ( keV)

5 10 20 50 100 200 500

Power law spectrum of a 1 mCrab source with Γ=1.7

F

lux

(ph

oto

ns

s-1 k

eV

-1 c

m-2) 10-4

10-5

10-6

10-7

10-8

ΔE/E=0.5T=100 ks

Thank to the hard X-ray imaging system of Astro-H, the sensitivity for point sources is much improved above 10 keV. 　 ⇒　　 The detection limit of Astro-H is about two orders of magnitude fainter than that of Suzaku PIN.

We will be able to obtain a spectrum of 0.01 mCrab source with NH=1024 cm-2,

HXI simulation for absorbed AGNs (Terashima)

3% of NXB

T=100ks

1 10 100

Energy ( keV)

ASTRO-H HXIASTRO-H SGD

Suzaku-HXD (GSO)Suzaku-HXD (PIN)

Main features of Astro-H• Large collecting area above 10 keV• High-resolution spectroscopy with E/ΔE>1000• Wide band observation from 0.3 to 600 keV.

Angular resolution

Collecting areain the hard X-ray band

Suzaku

XMM-Newton

Chandra

Astro-H

Energy resolution

Collecting areain the soft X-ray band

Energy band

Effective area

0.1 1 10 100 1000 Energy [keV]

E

ffec

tive

area

[cm

2]

10

10

0

1

000

HXT+HXI

SGD (Compton mode)

SXT+SXS

SXT+SXI

High resolution Spectroscopy in the soft X-ray region

FWHM~4 eV

5860 5880 5900 5920 Energy (eV)

Mn Kα

Takahashi et al. 2008, SPIE

1 10 Energy (keV)

Astro-H/SXS

A large effective area with a high energy resolution is realized by the NASA/GSFC thin foil optics (SXT-S). The thin foil optics has benefits of light weight and high throughput.

Main features of Astro-H• Large collecting area above 10 keV 200cm2@40 keV

• High-resolution spectroscopy with E/ΔE>1000 300cm2@6keV

• Wide band observation from 0.3 to 600 keV.

Effective area

0.1 1 10 100 1000 Energy [keV]

E

ffec

tive

area

[cm

2]

10

10

0

1

000

HXT+HXI

SGD (Compton mode)

SXT+SXS

SXT+SXI We can obtain these features with X-ray telescope.

Telescope is crucial for Astro-H

XRT system.

2. XRT componentTS is placed over the entire aperture of each mirror in order to isolate the XRT from space thermally.

PC is set on the top on the mirror in order to reduce the stray light.

Mirrors employ tightly-nested, conically approximated thin-foil Wolter-I optics.

Focal plane images formed by stray lightThese panels show simulated images of a point source locating at (-20’, 0) in cases of without and with pre-collimator . (Serlemitsos et al. 2007)

Without PC With PC

PET0.2 um Polyimide

XRT design parameters

~210

t0.15, 0.23, 0.31 mm h100mmx2

~1680

- S

Light weight and high throuput

Weight ~56 kg ~ 80 kgAngular resolution 1 arcmin 1.7 arcmin

Hard X-ray Telescope (HXT)

Al Substrate 0.2 mm

Epoxy 0.02mm

Pt/C Multilayer

Supper mirror

Depth-graded multilayer (ML) technology (supper mirror)

Reflector of HXT with depth-graded ML is produced through a replication methodThe ML uses the Bragg reflection and enhance reflectivity beyond the critical energy by the X-ray interference.

30 keV

measurementmodel

Critical angle of Pt at 30 keV(0.161 deg)

Reflectivity of Super mirror coating on float glass. The periodic structure is 46-126 Å level and micro-roughness~3Å.

Sputtering Chambers

Sputtering Chamber

Foil Production @ Nagoya Univ.(1)　Forming　foil

(4)　Curing(5)　

Separation

(3)　Spray　epoxy

(2)　ML　coating

(6)　Finished　reflector

Quality check

Surface profile of the reflectorAxial figure profile of a recently fabricated test reflector

2m

Replication mandrel (glass tube)Replicated reflector

Figure error of this test reflector is ±1 micron (P-V).

Based on a reflectivity measurement, surface roughness is about 3-4A, which is comparable to that of glass tube. smooth surface is trasferred to the foil.

E=30 keVσ~3A

Reflectivity measurement

Synchrotron radiation facility SPring-8

We use this facility for • Reflectivity measurement of an

X-ray reflector• Image quality measurement of

an XRT

SPring-8 BL20B2

Super Photon ring 8GeV

Synchrotron radiation ranging from the soft X-ray (E=300eV) to hard X-ray (E=300keV) region is available with high intensity.

These data are valuable for making the response function of HXT.

Reflectivity measurement @ SPring-8 BL20B2Experimental Hutch 2 & 3

E/E~104

beam size = 0.5x0.5mm

30 keV

measurementmodel

measurementmodel

60 keV

Image measurement @ SPring-8 BL20B2

E/E~104

12 m

HXT

Stages

Beam divergence < 1”, when beam size = 0.3x0.3mm

Direct beam after 4-axis slit

An X-ray image will be obtained by a pencil beam scan.

XRT for a balloon bone experiment

Telescopeholder

Stages

Telescope holder

SUMIT XRT: 1.54 arcmin (HPD) (87pairs)

Soft X-ray telescope for SXS~improvements from Suzaku to Astro-H ~

• (1) Substrate Shaping– To use thicker Al substrate for

the larger radii.– To use significantly larger

number of forming mandrels for better substrate shaping

• (2) Precise positioning– To make precise alignment bars– Reflector will be fixed onto the

bar by glue

• (3) Stronger housing– More mass is allocated to the

mirror housing

Suzaku Astro-H

Diameter 40 cm 45 cm

Focal length 4.5 / 4.75 m 5.6 m

Foil thickness 152 m 152, 229, 305 m

# of shells 168/175 ~210

Forming Mandrels

40 150

Precise Alignment bars

~40 m walk

~3 m accuracy

Reflector positioning

Free within a groove

Fix by glue

Strong housing(Housing mass)

25% of total mass

40% of total mass

Reflector fixing (testing with the Suzaku spare)

Since groove width of alignment bar is wider than the reflector thickness by 25 µm and the reflectors are free to move. Test gluing using “the Suzaku spare hardware”

1.26 arcmin (HPD) with 60 pairs.⇒The reflector will be fixed onto the bar by glue for ASTRO-H in order to improve angular resolution.

0 2 4 6 8 10 Diameter (arcmin)

Enc

ircle

d E

nerg

y F

unct

ion

0

0.

5

1

60 pairs Test1.26 arcmin Suzaku (1.7arcmin HPD)

ASCA (3.7arcmin HPD)

Okajima et al. 2009

Production schedule

We will start mass-production of foils for HXT in April 2010. launch

Mass production of HXT foils

Summary• Astro-H mission The new Japanese X-ray mission is currently planed to launch in 2013.　 　 the unique features are (1) Large collecting area above 10 keV (2) High-resolution spectroscopy with E/ΔE>1000 (3) Wide band observation from 0.3 to 600 keV. .

• XRT system　 　 　 X-ray telescope system consists of two HXT (5-80 keV) and two SXT (0.3-10

keV). 　 　 Mirrors employ tightly-nested, conically approximated thin-foil Wolter-I optics. 　 　 HXTs employ Pt/C depth-graded multilayers, while SXTs employ a single layer of

gold.

• Current statusWe are performing test productions, and are tuning production facility.Based on basic studies, detailed studies of the flight design are in progress, and

production facilities for the Astro-H XRT system are close to finish.