EUV and Soft X-ray Optics, Thin Films and Outer Space.

Or what you can to do to help your local universe.

David D. Allred, allred@byu.edu

Preparing & studying soft x-ray and EUV optical elements

Over the years we have participated in a number of space and planetary physics projects. These have allowed out students to have some amazing experiences. Projects include:

1. The Goldhelox project in the late 80’s and early 90’s, 2. Preparing the boron coating for the x-ray window

on the chemical analysis snout of the Sojourner Rover. This was part of the 1997 Pathfinder Mission.

3. The Image Mission: (It sees some of the Van Allen radiation belts.)

Launched March 25, 2000

http://solar.physics.montana.edu/YPOP/FilmFestival/index.html

Sun in x ray and visible light

Pathfinder Mission.• Preparing the x-ray window on the chemical

analysis snout of the Sojourner Rover.

IMAGE Mission http://image.gsfc.nasa.gov/

More projects4. Preparing a reflective surface for the neutral particle

detector for the European Space agencies Mars Express. To be launched this year.

5. Uranium and thorium oxide coatings for soft x-rays (150-400 eV) astronomy mirrors.

6. Support for the Mars Society Desert Research Station near Hanksville. (A group of students and teachers in Utah are organizing to help.)

I will focus on three of the projects (2,4 and 6) in some detail.

May mention: 1. the tie in to the billion $+ future of EUV optics in

microelectronic device fabrication. 2. several opportunities for undergraduate students to do

important research in our area

Sun’s Magnetic Field

Earth’s Magnetic Field

Charged Particle in Magnetic Field

EM Spectrum

Divisions of EM Spectrum

EUV Pictures

EUV Movie of May 24, 2000 bright aurora and plasmasphere tail

EUV Movie of July 10, 2000

Tail and Shoulder: March 20,2001

EUV Movie of June 24, 2000

Mars Projects

4. Preparing a reflective surface for the neutral particle detector for the European Space agencies Mars Express. To be launched this year.

5. 6. Support for the Mars Society Desert

Research Station near Hanksville. (A group of students and teachers in Utah are organizing to help.)

Start Surface for Neutral Particle Detector of Mars

Express Mission

A near grazing incidence, antireflective coating for 121.6 nm- Spencer Olson*, David Allred, Matt Squires, Douglas Markos, Cynthia Mills and R.

Steven Turley- Brigham Young University, *now at University of Michigan

Planet Mars

• Third brightest object in the sky

Fundamental Considerations:

• Did Water Once Exist on Mars?

Does Water Now Exist on Mars?

Can Water Ever Exist on Mars?

Water is the most fundamental ingredients to life.Therefore, if we, as humans, want to decide whetherlife, our own or otherwise, can exist for longer periods of time on Mars, we must determine whetherthis basic necessity of life can be found on Mars.

Evidence:

RiverbedsRiverbeds

River canyonsRiver canyons

Existing evidence of water on Marscomes in the form of visible riverbedsand river canyons.

The question is then, if we can see that there is ahistory of water on the surface of Mars, where hasall of this water gone?

Several speculations state that the water existsfrozen beneath the permafrost of the planets surface.Another speculation is that water on Mars evaporatedinto its atmosphere where it was then literally blownaway by the solar wind.

Solar Wind

• Neutral and Charged Particles Emitted From the Sun.

Interacts With Atmospheres of Planets in Space.

Solar wind is comprised of

This stream of particles, or the solar wind, then

Examples of this can be seen when a comet’s tail is blownaway from the direction of the sun.

Mars Express - 2003

In 2003, the European Space Association (ESA) plans to launch a spacecraft to Marsthat will aid in determining the possibilities water.

Energetic Neutral Particle Analyzer

One of several instruments on the ESA spacecraft, the Energetic Neutral Particle Analyzer contains a time-of-flight neutral particle detector (NPD). The purpose of this instrument is to study the effect of the solar wind on the atmosphere of Mars. To do this, the NPD will measure the momentum with which neutral particles in the solar wind might bombard atmospheric particles, thus showing how much the solar wind might erode the atmosphere of Mars.

Neutral Particle Detector (NPD)

When a particle enters into the NPD it reflects off of a surface, labeled the Start Surface. Upon impact on the Start Surface, an electron (depicted as e-) is emitted from the surface and attracted by an electric field to a detector labeled the Start Detector, whereon a timer is started. The neutral particle continues on after reflection until it hits a detector labeled Stop Detector, whereon the timer is stopped. The speed of the particle is then calculated using sixth grade physics speed = distance / time.

BYU’s Participation

Energetic light, entering the orifice of the instrument, may also reflect on the Start Surface and create false stop signal in the Stop Detector. In space, there is an abundant supply of vacuum ultraviolet photons (especially 121.6 nm=10.2 ev), which is energetic enough to cause this effect. The XUV Research Group of BYU was asked to provide a solution to this problem. The remaining portion of this presentation will focus on BYU’s efforts in designing, this surface.

Absorption of Light withUltrathin Multilayers

A common method for controlling light is the use of a thin film. A thin film is just what we expect it to be; it is a very thin layer of some material. The principle for making an optic with thin films lies in the fact that there can be many interfaces where light can be reflected. For the Start Surface, the superposition of these many reflections must result in a minimum amount of light leaving the surface. An example of a thin film causing similar interference, with which we are all familiar, is that of oil on a puddle, on a rainy day.