# Presentation: 170586

## Beyond Einstein Technology

- Louis Barbier
- GSFC
- July 23, 2007

## Overview

- BE Missions
- Constellation-X, LISA, BHFP, Inflation Probe, Dark Energy Probe, Black Hole Imager, BBO
- Constellation-X: Mirror technology, micro-calorimeters
- LISA: in-space I/F, laser stabilization, micro-newton thrusters
- BHFP: CZT (room temp. semiconductor)
- Inflation Probe: microwave polarization detection
- BHI: future technologies

- Louis Barbier, BETA Workshop

- July 23, 2007

## Constellation-X

- Black hole of 10,000 solar masses

- Constellation-X will measure the velocity and condition of matter accreting onto black holes.

- Louis Barbier, BETA Workshop

- July 23, 2007

## Constellation-X Technology

- Grazing Incidence X-Ray Optics

-  Micro-calorimeters for x-ray detection
- Transition Edge Sensors (TES)

- Louis Barbier, BETA Workshop

- July 23, 2007

## Constellation-X Mirrors

- Glass slumped over mandrel

- Foil removed from glass

- Foil mirrors with 500 microns gold coating

- Louis Barbier, BETA Workshop

- July 23, 2007

## Astro-E mirrors

- Louis Barbier, BETA Workshop

- July 23, 2007

## Mirror Reflector Progress

- Dominant Error Term

- Louis Barbier, BETA Workshop

- July 23, 2007

## Micro-calorimeters

- micro-calorimeter: 8x8, 250 micron pixels

- 32 pixels

- Louis Barbier, BETA Workshop

- July 23, 2007

## Micro-calorimeter Progress:  E@6 keV

- ionization detectors

- Micro-calorimeter Progress:  ****E@6 keV

- FWHM 4.8 eV ± 0.1 eV

- Louis Barbier, BETA Workshop

- July 23, 2007

## Transition Edge Sensors (TES)

- Superconductor biased near its transition
- Temperature ... small changes in temperature
- Result in large changes in resistance.

- Louis Barbier, BETA Workshop

- July 23, 2007

## LISA - Laser Interferometer Space Antenna

- Measuring gravitational waves in space.

- Louis Barbier, BETA Workshop

- July 23, 2007

## Orbits

-  Orbits are chosen so that the spacecraft passively hold formation.
-  Spacecraft have constant solar illumination and benign environment.

- Louis Barbier, BETA Workshop

- July 23, 2007

## LISA Technologies

- 3 S/C Michelson Interferometer
- Stability requirement
- Proof mass and isolation
- Laser stabilization techniques
- Micro-newton thrusters

- Louis Barbier, BETA Workshop

- July 23, 2007

## Michelson Interferometry

- No interferometers have yet flown in space.

- Louis Barbier, BETA Workshop

- July 23, 2007

## LISA Measurement Concept

**Gravitational wave is observed as phase change of light traversing changing path between spacecraft**

**Measurement requires very high frequency stability**

- Louis Barbier, BETA Workshop

- July 23, 2007

## Sciencecraft

***Drag-free control protects the proof masses from the ambient environment and reduces the disturbances on the proof masses from the spacecraft.***

*** ******Three interacting spacecraft make up the “science instrument”***
*** ******Multiple combinations of one-way measurements.***

- Louis Barbier, BETA Workshop

- July 23, 2007

## LISA Interferometry

**Proof mass in spacecraft follows geodesic in space**
**Must be measured to 10****-12**** m over 1000 sec**

- 30 cm

- Louis Barbier, BETA Workshop

- July 23, 2007

## Laser

- LISA requirement
- 1 Watt power
- 2 year lifetime
- Stable ( low drift < 30 Hz/Hz1/2)
- Space qualified

- NPRO

- Nd:YAG

- Louis Barbier, BETA Workshop

- July 23, 2007

## Frequency Noise Reduction

- Noise requirement: 10-6 Hz
- Requires an attenuation factor of 1012
- 2 steps: stabilization to external reference, then signal processing (TDI)

- Louis Barbier, BETA Workshop

- July 23, 2007

## Phasemeter

- Must be able to measure a phase variation of 10-6 cycles
- Signal rides on a 10-20 MHz Doppler shift from relative spacecraft motion

- Louis Barbier, BETA Workshop

- July 23, 2007

## Laser Stabilization

- Iodine or acetylene cells on testbed

- Louis Barbier, BETA Workshop

- July 23, 2007

## Laser stabilization

- Louis Barbier, BETA Workshop

- July 23, 2007

## Optical Bench

- At each optical bench, the incoming laser is beat against a local laser, and the phase is recorded
- The lasers associated with each optical bench are beat against each other
- The distance between optical benches is measured separately from the distance between optical bench and proof mass.

- The optical bench has an ultra-stable glass substrate.
- Optical components are bonded to the substrate by hydroxy-catalysis bonding.
- Small angle between incoming and outgoing beams varies throughout the year.

- Louis Barbier, BETA Workshop

- July 23, 2007

## Proof Mass for LISA

- Platinum - Gold Alloy

- “Heart of Gold”

- Louis Barbier, BETA Workshop

- July 23, 2007

## Drag-Free Control of Spacecraft

**Use capacitive sensing, microthrusters to center spacecraft about test mass**
**Need precision of 10****-9**** m**
**Limits gravitational, electrical noise on mass to**** < 10****-15**** Nt over 1000 sec**

**Factor 10****4**** beyond state of the art (GP-B)**
**To be tested on LISA Test Package (LTP)**

- Louis Barbier, BETA Workshop

- July 23, 2007

## Micronewton Thrusters

**Range of 100 ********Nt, noise < 0.1 ********Nt**
**Ion thruster and colloid thruster under study**
**Lifetime requirement (8 years) is difficult**

**Provides thrust by acceleration and ejection of ions**

**After ~ 1 year, contamination and needle damage have been seen**

- Louis Barbier, BETA Workshop

- July 23, 2007

## Ion Thruster schematic

- Capillary action drives liquid Cs (or In or Rb) to nozzle where electrostatic fields accelerate ions

- Louis Barbier, BETA Workshop

- July 23, 2007

## Black Hole Finder	Probe

- “BAT” Technique - Identify black holes by looking for gamma-ray bursts

- Room temperature semiconductor detector

- Louis Barbier, BETA Workshop

- July 23, 2007

## Black Hole Finder Probe Technique

- CZT

- Mask of random lead tiles

- Louis Barbier, BETA Workshop

- July 23, 2007

## Inflation Probe

- Detecting early Universe inflation via CMB polarization
- Quantum fluctuations 10-35 s after Big Bang impart distinct signature to CMB polarization
- Micro-wave polarization detection - differences of 30 - 100 nK

- Louis Barbier, BETA Workshop

- July 23, 2007

## Inflation Probe  balloon prototype

- 60 cm primary mirror

- Louis Barbier, BETA Workshop

- July 23, 2007

## Inflation Probe balloon prototype

- 300 microns

- 1.5K

- 100 mK

- Louis Barbier, BETA Workshop

- July 23, 2007

## Feedhorn array assembly

- Louis Barbier, BETA Workshop

- July 23, 2007

## Black Hole Imager	

- Micro-arc-second imaging
- Multi-spacecraft x-ray interferometry
- Fresnel lenses for x-rays and gamma-rays (up to 1 MeV)!

- Louis Barbier, BETA Workshop

- July 23, 2007

## BHI – Technology Areas

- Louis Barbier, BETA Workshop

- July 23, 2007

**Notes:**
Mention formation flying and Jesse’s talk !

## Hubble resolution ... and beyond!

- Barred Spiral NGC 1672

- 0.03 arc-sec ... 30 milli-arc-sec

- BHI - ~ micro-arc-sec !

- HDTV: 1920x1080 ~ 2 million pixels
- Analog TV: 480 lines x 720 pixels/line ~ 350,000 pixels

- Louis Barbier, BETA Workshop

- July 23, 2007

## Improved Imaging Capability

- Louis Barbier, BETA Workshop

- July 23, 2007

## BHI Mission Concept

- Micro-arc-second imager!
- 1000 times better than Hubble.....
- Long baseline ***x-ray interferometery***

- Louis Barbier, BETA Workshop

- July 23, 2007

## Fresnel Lenses for x-rays

- Concept - direct focusing, avoid grazing incidence
- Design - fabricate in silicon (or aluminum)
- Image - high resolution, small FOV

- Louis Barbier, BETA Workshop

- July 23, 2007

## PFL Fabrication: Gray Scale Lithography SO(Silicon On Insulator)

- Morgan, Waits, Krizmanic, Ghodssi (2004)
-  Jour. Micro-Electro-mechanical-Systems (JMEMS), **13,** 113

- PFL Fabrication: Gray Scale Lithography SO(Silicon On Insulator)

- B. Morgan, University of Maryland

- Scale: Microns

- Scale: Microns

- Louis Barbier, BETA Workshop

- July 23, 2007

## Silicon Wafers of PFLs

- 70 m
- 500 m

- 2 m

- 41 m
- ~25 m

- 100 mm

- Fabricated by Brian Morgan, University of Maryland

- Louis Barbier, BETA Workshop

- July 23, 2007

## Large Area Potential: Coded Silicon PFL Array

- Large Area Potential: Coded Silicon PFL Array

-  Individual PFL(few cm size)  are placed in a coded array
-  Array size arbitrarily large
-  ≈ one km focal length
-  Point-spread-function for system, including post-processing is like that of a single lens
-  Effective sensitivity increases as N1/2

- Louis Barbier, BETA Workshop

- July 23, 2007

## PFL Alignment Tolerances

- Inherently tolerant of lens & detector                  tilt angles ~ 1 deg
- Tolerant of slight shifts in focal length
- Axial positioning to fraction of focal plane size
- Axial position knowledge to focal plane pixel size
- Spacecraft alignment via laser beacons

- Louis Barbier, BETA Workshop

- July 23, 2007

## Conclusions

-    Technological developments in many areas of science over the past two decades have enabled us to develop amazing new missions to test Einstein’s theories in regimes unattainable before.

- Louis Barbier, BETA Workshop

- July 23, 2007