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an insight inside the


Academic year: 2022

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ISIS neutron and muon source:

an insight inside the materials.

Diego Alba Venero


Observatorio de El roque de los Muchachos, November 2019



• Dr. Sabrina Gaertner (space ice)

• Dr. Adrian Hillier (muons and Isis



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

From primitive technology



“Vieja friendo huevos.” Diego Velázquez


Oil allows temperature control

Confined heat

source Material with low specific heat

Waterproof and


Sharp, hard and strong Flexible,

strong and light

Dull and robust


Semiconductors LED



Composites Magnets

High melting point materials High performing glasses

Magnetron + Faraday cage

Antibacterial surface


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




Understanding the science

• Where the atoms are?

• What the atoms do?



• Where the atoms are? Diffraction (elastic scattering)

• What the atoms do? Spectroscopy

(inelastic 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!


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


Why neutrons?


Why neutrons?

A. Kaestner et al., PSI

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


Why neutrons?

• Charge ~0 e (<2x10 -22 e)

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

(spin = ½)


235 U fission (ILL, LLB, FMR II)



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)


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


Muons interact with local magnetic


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




1960 1970 1990



Earth Science

Studying ferropericlase helps understanding of earthquakes


catalyst for conversion of carbon dioxide to cyclic carbonates

Cultural Heritage

understanding molecular processes of preservation of polychrome

carved wood


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


Case of study: neutrons for Astrochemistry

What do Å - nm scale structures tell us about

planet formation?

Sabrina Gaertner



Jürgen Blum Bastian Gundlach

Judy Ratte Helen Fraser

Daniel Bowron Tom Headen Tristan Youngs


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




Fragmentation Mass Transfer


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


Only micrometer- sized ices or aggregates stick.


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


Neutron Diffraction


Specific Surface Area Slope:

Diffuse Interface



(Stacking Disordered)

Gärtner et al ApJ 2017



100 K 150 K 200 K 250 K 300 K

Sticking Threshold

150 K 200 K 250 K 300 K 100 K


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





Crystalline Ice Phase

Thicker diffuse interface


stickier particles!

Gundlach & Blum

ApJ 2015 Gärtner et al

ApJ 2017

Gärtner et al ApJ 2017


Thank you very much

for your attention!


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