P.Finocchiaro 1Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

HELNED: Helium-3-free low-cost neutron detectors

6Li

n

4He

7Li

3H

Paolo Finocchiaro

Luigi Cosentino, Carmelo Marchetta, Alfio Pappalardo, Sergio Scirè, Carlotta Scirè, Gianfranco Vecchio

INFN Laboratori Nazionali del Sud, Catania, Italy

P.Finocchiaro 2Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

where did we start from?

radioactive waste in almost every country in the world

P.Finocchiaro 3Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

Detector Mesh for Nuclear RepositoriesDMNR

wirelessnetwork

Data

wirednetwork

localdata

storage

remotedata

storage

Web

we implemented a low-cost granular radwaste monitoring system (gamma rays)

see tomorrow’s talk of Alfio Pappalardo

P.Finocchiaro 4Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

why neutrons?

upgrade: thermal neutron monitoring

spent fuel monitoringin place and/or during transportation

(P.Peerani, M.Galletta, Nuclear Engineering and Design 237 (2007) 94-99)

Plutonium, I love you...

detection of possible diversion of fuel elements from

Castor containers

out-of-core monitoring in NPP

P.Finocchiaro 5Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

our idea: granular, real time, automatic

current monitoring method: video camera

ensuring continuity of knowledge

P.Finocchiaro 6Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

(0.025)≈ 5330 b

available energy0.76 MeVno gamma rays

3He

n

p

3H

How?

materials for thermal neutron conversion: 3He

perfect gas detector but... worldwide lack of 3He

P.Finocchiaro 7Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

6Li

10B

157Gd

113Cd

(0.025)≈ 940 b

(0.025)≈ 3840 b

(0.025)≈ 240 kb

(0.025)≈ 20 kb

available E4.78 MeV

available E2.79 MeV(and gamma rays)

large available Ebut in form of gamma rays:difficult neutron identification

materials for thermal neutron conversion: which one?

P.Finocchiaro 8Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

thermalneutrons

Cross section ≈ 940 b

detection of 3H and/or 4He

6Li – natural abundance: 7%

a 6LiF convertercaptures a neutron...

...and produces 4He ed 3H which can be detected

4He

7Li

3H

6Li

n

2.05 MeV 2.73 MeV

physical process

how?

P.Finocchiaro 9Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

9cm2 Si detector + 6LiF(1.5µm)

3cm x 3cm

Si

6LiF

neutrons

difference between spectra not needed to reject gammas

n/gamma ≈ 10-5

3He-free Lithium-based NEutron Detectorswith removable converter

gammabackground

AmBe neutron source 5E4 n/sthermal flux ≈ 4 n/s/cm2

P.Finocchiaro 10Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

Si detector + 6LiF: comparison with simulation

semi-quantitative GEANT4 simulation:

• neutrons: thermal• gamma: 60 keV• gamma: 662 keV• gamma: 1.2 MeV• gamma: 4 MeV

• # alpha and tritium normalized to data• # gamma manually scaled

quite encouraging data-simulation agreement (surprising?)

P.Finocchiaro 11Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

100%neutrons

gammabackground Alpha Tritium

≈ neutrons PET castle

Si + 6LiF

neutronsource

expected ≈ 4 cps measured 3.3

AmBe neutron source 1.6E6 n/sthermal flux ≈ 150 n/s/cm2

P.Finocchiaro 12Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

ΔE calculated: 195 keVΔE measured: 200 keV

thickness: 1.8µm vs 1.5µm20% more efficient

added 2 gamma sourcesto test rejection (740 MBq)

Si detector + 6LiF

optimal 6LiF thickness 1.8µm

P.Finocchiaro 13Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

2 converters:double efficiency

Si detector + 6LiF

6LiF on plastics

6LiF on glass

double sided silicon 3cm x 3cm x 300µm

P.Finocchiaro 14Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

no source: background2 converters: double efficiency (2%)no converter: only gamma contribution

but... in log scale...

unexpected neutrons?

part of the 6LiF migrated from the

plastic substrate to the silicon face!

log

lin

Si detector + 6LiF

P.Finocchiaro 15Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

log

lin

heavy material close to the detector:higher energy gamma (scattering)

heavy material removed:the gamma background is suppressed

same as before in log scale

Si detector + 6LiF

advice:no heavy material inside

the PET moderator

P.Finocchiaro 16Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

collaboration with nTOF @ CERN

Si detector + 6LiF

Si

Si Si

Si

6Li foil

4He

3H

SiMon2: neutron beam monitor for flux normalization

P.Finocchiaro 17Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

BeaMon: neutron beam characterization

16-strip Si6Li foil

forward-backward asymmetry XY distribution

Si detector + 6LiF

collaboration with nTOF @ CERN

P.Finocchiaro 18Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

better efficiency (up to 50%?)

6Li deposits over large area (A4)

scintillators...

features

• mechanically simple and robust

• reasonably cheap

• commercial solid state detectors

• strips for position measurements

• simple use (no spectrum analysis or subtraction for gamma rejection)

patent? YES

next steps

P.Finocchiaro 19Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

tritium neutrons

alpha + gamma

alpha + gamma

tritium neutrons

Posi

tion

Light

neutrons

• good intrinsic efficiency

• position sensitive (Δx ≈ 1-2 mm)

• low cost

• many possible geometries and schemesRM2013A000254

filed on 2013-04-29

...with scintillator detectors

P.Finocchiaro 20Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

localdata

storage

remotedata

storage

Web

real-time castor storage monitoring

P.Finocchiaro 21Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

easily integrated into the existing hardware and software architecture of DMNR:electronicsdata acquisitionsystem controldata logging database handlingGraphical User Interface

wireless transmission

collaboration with JRC & Euratom...

real-time castor storage monitoring

P.Finocchiaro 22Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

• Nuclear physics research

• Homeland security (nuclear material smuggling)

• Dosimetry

• Radwaste monitoring

• Spent fuel handling and storage monitoring

• Search for nuclear material accidentally lost among scrap metal

• Material structure (with neutron beams)

• other...

possible applications

P.Finocchiaro 23Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

Time-of-Flight Neutron Diffraction (ToF- ND)e.g.: University of Milan, inorganic stereochemistry

Neutron Resonance Capture Analysise.g.: Ancient Charm EU projectsecrets of Bronze Age sword unveiled

Bragg Edge Transmission e.g.: S.Petriw, J.Dawidowski, J.Santisteban, Porosity effects on the neutron total cross section of graphite Journal of Nuclear Materials 396 (2010)181-188

Neutron Radiographye.g.: Institute of Atomic and Subatomic Physics - TU Wien

neutron X-ray

applications with neutron beams

material analysis: composition and structure

P.Finocchiaro 24Third European Energy Conference E2C 2013 Budapest 27-30 October 2013 3He-free low-cost neutron detectors

compact neutron monitors?

thank you

picture: ETNA volcano eruption, Catania 2013