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ISIS neutron and muon source:

an insight inside the materials.

Diego Alba Venero

diego.alba-venero@stfc.ac.uk

Observatorio de El roque de los Muchachos, November 2019

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Acknowledgments

• Dr. Sabrina Gaertner (space ice)

• Dr. Adrian Hillier (muons and Isis

facts)

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Flammable material Non-flammable, flat(-ish) material

From primitive technology

https://www.youtube.com/watch?v=uHN60owoFoE

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“Vieja friendo huevos.” Diego Velázquez

https://commons.wikimedia.org/w/index.php?curid=19980800

Oil allows temperature control

Confined heat

source Material with low specific heat

Waterproof and

concave

Sharp, hard and strong Flexible,

strong and light

Dull and robust

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Semiconductors LED

Piezoelectrics

Micelles

Composites Magnets

High melting point materials High performing glasses

Magnetron + Faraday cage

Antibacterial surface

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Physics Nobel prices on materials

• 2016 Topological materials

• 2014 Blue LED

• 2010 Graphene

• 2009 Optical fibres and CCD

• 2007 Giant Magneto Resistance

• 2003 Superfluidity and superconductivity

• 2001 Bose Einstein Condensate

• 2000 Semiconductor heterstructures and

integrated circuit

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?

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Understanding the science

• Where the atoms are?

• What the atoms do?

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Scattering!

• Where the atoms are? Diffraction (elastic scattering)

• What the atoms do? Spectroscopy

(inelastic scattering)

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Scattering

• Balls

• Alpha particles (Rutherford)

• Electromagnetic radiation (X-rays, UV,IR…)

• Electrons (TEM, e - diffraction)

• Neutrons (ISIS, ILL, NIST, etc.)

• Muons (ISIS, PSI, etc.)

• Everything!

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By Kurzon - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index .php?curid=32215297

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Why neutrons?

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Why neutrons?

A. Kaestner et al., PSI

https://www.youtube.com/watch?v=VESM U7JfVHU&feature=youtu.be

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Why neutrons?

• Charge ~0 e (<2x10 -22 e)

• Magnetic moment: µ N = 9.66x10 -27 JT -1

(spin = ½)

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235 U fission (ILL, LLB, FMR II)

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ISIS

Spallation neutron source

800 MeV proton beam Neutrons produced for 25 instruments 7 muon experimental areas

2000 users/yr

~800 experiments/yr

~500 publications/yr Free for UK users

Spallation (SNS, ISIS, ESS)

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Monitor the positron distribution to infer the muons’ polarisation after implantation. Learn about the muons’ local environment or the muon

behaviour itself.

π+ → μ+ + νμ 4 MeV muons are

100% spin polarised

Implantation, (stopped in ~1mm

water)

Muons interact with local magnetic

environment

Decay, lifetime 2.2μs μ+ → e+ + νe + νμ

we detect decay positrons High energy protons

(800 MeV at ISIS)

collide with carbon nuclei producing pions

The positrons are preferentially emitted in muon

spin direction

Muons

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2000

1960 1970 1990

1980

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Earth Science

Studying ferropericlase helps understanding of earthquakes

Chemistry

catalyst for conversion of carbon dioxide to cyclic carbonates

Cultural Heritage

understanding molecular processes of preservation of polychrome

carved wood

Engineering

3-D high speed tomography

Environmental Science

Electric-field-induced phase transformations in lead-free piezoelectric ceramics

Life Sciences

Structure and history of viruses

Physics and

Materials Science

Magnetic contrast imaging for FeRh films

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Case of study: neutrons for Astrochemistry

What do Å - nm scale structures tell us about

planet formation?

Sabrina Gaertner

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Acknowledgements

Jürgen Blum Bastian Gundlach

Judy Ratte Helen Fraser

Daniel Bowron Tom Headen Tristan Youngs

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Ice in Planetessimal Formation

Experime nts

Observati ons

Modelli ng

Snow Lines in Disks

Carrasco-Gonzalez et al ApJ Lett 2016

van der Marel et al

Science 2013

Protoplanetary Disks

ESA/Rosetta/MPS NASA-JHUAPL-SwRI Comets: low-density, fluffy grains Icy regolith (Pluto) Qi et al

Science 2013 Cieza et al Nature 2016

NASA/JPL-Caltech/R. Hurt (SSC)000 Protoplanetary

Disk Collisions Aggregation Planetessimal Formation

Sticking

Bouncing

Erosion

Fragmentation Mass Transfer

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Does Ice in Collisions Stick?

Ice is stickier than dust.

Warm ice is stickier than cold ice.

Gundlach & Blum ApJ 2015

Gärtner et al ApJ 2017

Nothing sticks at Proto-Planetary Disk

temperatures.

Only micrometer- sized ices or aggregates stick.

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What is the structure of the collided ices?

30 mbar 100 – 250 K

… quickly &

smoothly …

… transfer sample to beam

Be ready at beamline … Transfer ice into sample cell

Spray water into LN2 NIMROD ISIS TS2

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Neutron Diffraction

Intensity:

Specific Surface Area Slope:

Diffuse Interface

Peaks:

Crystalline

(Stacking Disordered)

Gärtner et al ApJ 2017

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Results

100 K 150 K 200 K 250 K 300 K

Sticking Threshold

150 K 200 K 250 K 300 K 100 K

Specific

Surface Area Diffuse Interface

150 K 200 K 250 K 300 K 100 K

Ic+ Ih+ Ix Ih+ Ix Ih

150 K 200 K 250 K 300 K

100 K

Specific Surface Area Diffuse

Interface Sticking Threshold Ic + Ih+ Ix

Ih Ih+ Ix Collision

Experiments

Neutrons:

Surface

Neutrons:

Crystalline Ice Phase

Thicker diffuse interface

=

stickier particles!

Gundlach & Blum

ApJ 2015 Gärtner et al

ApJ 2017

Gärtner et al ApJ 2017

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Thank you very much

for your attention!

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