Thematic Strands

Advanced Materials

RADIATION FOR SCIENCE AND SOCIETY

KeywordsNuclear

Radioactive NanoscopicTechniques

New Materials

New Properties

Research & Training

C2TN members : João Guilherme Correia1, Ulrich Wahl1, Katharina Lorenz2

C2TN students: Eric David-Bosne 1, Ângelo Costa1, Ricardo Teixeira1, Daniela Pereira2

Other SENIOR & PhD: Gonçalo Oliveira3, João Pedro Araújo3, Armandina Lopes3, Manuel Ribeiro da Silva4, Vitor Amaral4, Heinz Haas4, Jens Roder4, João Nuno Gonçalves4, P. Tavares6, L.M.C. Pereira7

OTHER PhD students: Abel Fenta4,7, Carlos Amorim4, Marcelo Barbosa3, Pedro Rodrigues3, Tiago Lima7, Janni Moens7

Other students: Nuno Fortunato4, Ricardo Moreira, Tiago Leal Eugénia Queirós5

Email of corresponding author: jgmcnet@ctn.tecnico.ulisboa.pt

RADIOACTIVE LOCAL PROBE TECHNIQUES AT ISOLDE2018 achievements at the C2TN-ISOLDE experimental infrastructure

C2TN/IST acknowledges the financial support under the project UID/Multi/04349/2013

http://c2tn.tecnico.ulisboa.pt

Biophysics/Medical11%

Nuclear structure from ground state

properties22%

Nuclear structure from beta decay

14%Solid State Physics14%

TISD 3%

Coordinators reserve3%

Coulomb Excitation14%

Nuclear reactions19%

Beam pie (preliminary) 2018

Emission channeling(EC-SLI)

Lattice location of dopant atoms in functional electronic materials

e"#e"#

e"#

position- sensit ive

detector

emission patterns characterize

latt ice sites of the emitt ing atoms

β-

Position sensitive detector

Emission channeling caracterizeslattice sites of the emitting atoms

Both detector provide accurate measurements of the channeling effects, but the timepix detector can stay at about half the distance from the sample than the pad.

Timepix detector:• 300μm thick Si sensor• 512x512 pixels of 55μm• Distance to sample 315mm• 4000 counts per second

Pad detector:• 500μm thick Si sensor• 22x22 pixels of 1.3mm• Distance to sample 585mm• 5000 counts per second

Recently developed PyFDD software highlights- Fit of 2D channeling patterns from EC and RBS/C measurements- Fit patterns with pixels with low counts, ideal for RBS/C blocking or e-EC with high density pixel detectors.- Correction for large detector pixels and low resolution effects- Better method for statistical error calculation

Perturbed Angular Correlations (PAC)Hyperfine Interactions , local electronic density and polarization studies

APPLICATION CONTEXT: precise determination of the quadrupole moment of the 5/2 245 keVstate on 111Cd (standard reference in atomic nuclear spectroscopy)

The problem: Measure quadrupole interaction in free molecules to determine Q for 111*Cd (and 199*Hg)

The concept: Freely rotating linear molecules have the rotation axis J perpendicular to the molecule, thus the EFG along J is (minus) half the molecular one

The task: Produce highly dilute samples so that collisions do not change the orientation of J during the measuring time, typically 100ns.

The status: Concept has been confirmed for Hg halides last year. Now high precision data for CdI2 (less precise for CdCl2 and CdBr2)

The next step: Quantum chemistry calculations (in progress)

-2 -1 0 1 2

-2

-1

0

1

2

angle [°]

0.84

1.03

1.21

1.39

1.57

1.75-2 -1 0 1 2

-2

-1

0

1

2

angle [°]

0.94

0.99

1.03

1.07

1.12

1.16

27Mg (Mg RILIS)in n-type GaN

[0001] axis, T = 300 K

11Be (Be RILIS)in p-type GaN

[0001] axis, T = 300 K

Mg and Be are p-type dopants in GaN, a wide-gap semiconductor. Continuation of our previous work [1][1] U. Wahl et al., Phys. Rev. Lett. 118, 095501 (2017)

APPLICATION CONTEXT: Optoelectronics

-2 -1 0 1 2

-2

-1

0

1

2

angle [°]

0.90

1.03

1.15

1.27

1.39

1.51-2 -1 0 1 2

-2

-1

0

1

2

angle [°]

0.94

1.02

1.10

1.17

1.25

1.32

56Mn (Mn RILIS)in Ge0.87Mn0.13Te

<110> axis, T = 100 K

61Co (Mn RILIS)in diamond

<110> axis, T = 300 K

Mn is a magnetic dopant inGe1-xMnxTe, a model multiferroic Rashba semiconductor.

Co in diamond is a potential single-photon emitter.

APPLICATION CONTEXT:Spintronics

APPLICATION CONTEXT:Quantum information

-2 -1 0 1 2

-2

-1

0

1

2

angle [°]

0.94

1.02

1.10

1.17

1.25

1.32

229Ac (Ac RILIS)in CaF2

<110> axis, T = 300 K

229Th has an extremely low-energy isomer state of 7.8 eV. Bridging nuclear and atomic physics CaF2 provides an ideal transparent host with a large bandgap aiming influencing nuclear parameters with variations of the crystal field. 229Ac provides a preliminary study of the lattice site and defects recovery of an heavy impurity implanted into CaF2.

APPLICATION CONTEXT: atomic – nuclear clocks

APPLICATION CONTEXT: Detector and analysis R&D,TIMEPIX vs PAD; Case study 27Mg:p-GaN,

111mCd/Cd PAC (preliminary) studies in Ca3Mn2O7

naturally layered perovskite, Hybrid Improper Ferroelectric

OrthorhombicA21am–polar

OrthorhombicAcaa – non polar

A21am: Vzz atypical positive thermal dependency

Phase CoexistencePAC new data

DFT calculations using high-res. synchrotron diffraction data do not explain negative Vzz

thermal dependency(PRL 114, 035701, 2015 )

APPLICATION CONTEXT: Information storage in multiferroic materials

Acaa

A21am

AcaaA21am

!?

First 111Cd PAC measurements of free molecules (IS640), here CdI2

New C2TN collection chamberfor ICE samples

(PAC experimentsrequiring chemistry)

.

10%

2%

CERN-FIS-NUC-0004-2015 : https://cernbox.cern.ch/index.php/s/pxj7Vnco7y8gYrG

Collaborations3 LIP | Lab. Experimental Particle Physics , Lisboa4 CICECO | University of Aveiro , Aveiro5 IFIMUP | University of Porto , Porto6 UTAD | University of Trás-os-Montes e AltoDouro7 IKS- KULeuven | University of Leuven, Leuven, Belgian

Research group1 NET | Nuclear Engineering and Techniques Group2 INESC-MN, IPFN | LATR, CTN-IST

FundingFCT CERN-FIS-PAR-0005-2017, UID/Multi/04349/2013,FWO Vlaanderen and KU Leuven GOA/09/006, GOA/14/007 & BOF-STRT/14/002EC Horizon 2020 program (g.n. 654002 ENSAR2)