Advances in Scintillation Materials for Gamma and Neutron Detection

rmd.dynasil.comInspired by Light
Advances in Scintillation Materials
Kanai Shah, President, RMD, Inc.
1

• Dual Mode Scintillators
- Cs-Elpasolites
- Tl-Elpasolites
- LixNa1-xI (LNI) Scintillators
• Gamma-Only Scintillators
• Plastic, Organics and Composite Scintillators
- Organic Crystals
- Dual Mode Plastics
- Composites
• Ceramic Scintillators
• Summary
Presentation Outline
2

Cs-Li-Elpasolites
Cs2Li(RE)X6: Ce
RE – Rare Earth Ions (e.g. Y3+, La3+)
X – Halide Ions (Cl-, Br-, I-)
3

All crystals are 1”x1” right cylinders
Cs- Elpasolites: Good Proportionality & Energy Resolution
10 100 1000
0.9
1.0
1.1
1.2
Na
CsNa
CoAmCs
Relativelightyield
Energy, keV
Co
NaI:Tl
LaBr3
:Ce
CLYC:Ce
CLLBC:Ce
CLYC – Cs2LiYCl6
CLLBC – Cs2LiLa(Br,Cl)6
4

Cs2LiYCl6:Ce (CLYC): Thermal Neutron Detection
0 1000 2000 3000
0
1
2
3
4
5
6
7
neutron
Pulse
Height
Discrimination
662 keV
137
Cs
Am/Be 3400 keV
CLYC
intensity,counts/sec
gamma equivalent energy, keV
gamma
Pulse Height Discrimination (PHD)
6Li + 1n  α + T 4.8 MeV
“Standard” CLYC is enriched > 95% 6Li
2.35x higher n cross-section than He-3
4-5% FWHM energy resolution at 662 keV
Pulse Shape Discrimination (PSD)
Neutron
Gamma
FOM~4
0 200 400 600
0.0
0.2
0.4
0.6
0.8
1.0
1.2
gamma
neutron
window 2window 1
neutron
gamma
windows
counts,arb.units
time, ns
5

35Cl + 1n  1p + 35S + energy
Fast Neutron Detection with Cl-35: Triple Mode Detector
200 400 600 800 1000
0
100
200
300
400
500
600
Channel
C
o
u
n
t
s
893 keV
1202 keV
1508 keV
1913 keV
0 500 1000 1500 2000
0
200
400
600
Energy (keV)
C
h
a
n
n
e
l
• Linear function of 1n energy
• Clear full energy peaks
• Possible spectroscopy
0.2
0.4
0.6
0.8 DC B
241
Am/Be
CLYC:Ce 3 inch cylinder
PSDRatio
Gamma rays
Neutrons
A
20000 40000
FOM = 4.2
Counts
0 10 20 30 40
10
1
10
3
10
5 Total
Gamma
Neutron
Counts
Full Integral
6Li/35Cl(nf,a) – Region
D
35Cl(nf,p) – Region C
6Li(nth,a) – Region B
Discovered by BTI
6

CLYC Scale-up & Implementation in Instruments
3”
RIIDEye
RadEye GN+ SPRD GN
7

Lithium Enriched Elpasolite Scintillator
CLLBC = Cs2LiLa(BrCl)6:Ce
Follow-on Elpasolite: Cs2LiLa(Br,Cl)6:Ce (CLLBC)
• CLLBC has 2x higher light output and better energy
resolution than CLYC.
• Competitive with LaBr3 and CeBr3
• CLLBC has higher density and better γ-ray efficiency than
CLYC.
• Similar to CLYC, CLLBC is dual-mode (neutrons and γ-
rays) with good pulse height and pulse shape
discrimination
• CLLBC has better PSD than CLLB and it also provides fast
neutron spectroscopy with 35Cl (not possible with CLLB)
8

CLLBC Results – Results with 1” Crystals
0 200 400 600 800
0
3
6
9
1 -inch cylinder 506
R=2.9%
137
Cs spectrumCLLBC
Intensity(counts/s)
MCA channel
200 400 600 800 1000 1200 1400 1600 1800
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
E~2.9%
1562
PMT: R6233SBA_1; HV -650 V; LG preamp; gain 30x0.75; ST = varying, Tcol = 600 s
E~3.0%
1440
Intensity,counts/sec
MCA channel
0.5us
1us
2us
4us
8us
E~ 3.1%
1258
E~3.0%
1401
CLLBc:Ce
#316-1
E~ 3.1%
1205
137
Cs spectra
FOM = 3.4
10 100 1000
0.8
0.9
1.0
1.1
1.2
NaCsNa
CoAmCs
Co
CLLBC
1-inch cylinder
relativelightyield
energy, keV
9

Successful Scale-Up of CLLBC
0 200 400 600 800
0.5
1.0
1.5
2.0
Ø1inch
Ø1.5inch
Ø2inch
R ~ 3.0%
137
Cs spectra
CLLBC:Ce
Intensity(arb.units)
Energy (keV)
10

Neutron Detection with 1.5”x1.5” CLLBC: PHD & PSD
0 500 1000 1500 2000 2500 3000 3500
0.5
1.0
1.5
2.0
R ~ 3.0%
0.662 MeV
241
Am/Be
137
Cs
CLLBC:Ce
Intensity(arb.units)
Energy (keV)
R ~ 2.3%
3.1 MeV
FOM 3.4
11

1.5” CLLBC with SiPMs
0 200 400 600 800
0
1
2
3
137
Cs spectrumCLLBC Ø1.5inch
Detector packaged with SiPMs
Intensity(counts/s)
Energy (keV)
R ~ 3.5%
FOM 2.3
12

Handheld Radioactivity Monitor with Energy Spectroscopy
17x17x25 mm
CLLBC
Packaged
with SiPM
0 200 400 600 800
0
1
2
3
27.5V
Quad SensL / 27.5 V / ADMCA //100 x 1.0 /ST 4us/300s
137
Cs spectrum
CLLBC #337-1A ; packaged
LSP / 03-09-17
Intensity(counts/s)
Energy (keV)
R ~ 3.8%
Bluetooth
Cell Phone App for
Isotope ID, etc.
13

Tl-Elpasolites
14

Tuning: Cs2Li(RE)X6 Tl2Li(RE)X6
Considerable increase in gamma-ray stopping power
Tuning of CLYC to TLYC
Material Zeff
Density
(g/cc)
662 keV
photo-
fraction
662 keV
Atten. Length
(cm)
NaI:Tl 50 3.67 0.1 3.6
LaBr3 47 5.1 0.08 2.6
Cs2LiYCl6 45 3.3 0.08 3.9
Tl2LiYCl6 69 4.5 0.26 2.4
Cs2LiLaBr6 47 4.2 0.09 3.2
Tl2LiLaBr6 65 4.7 0.22 2.3
15

TLYC (Tl2LiYCl6:Ce) Crystals
 1” TLYC:5% Ce
16

TLYC Performance: 1”x1” Crystals
100 1000
0.8
0.9
1.0
1.1
1.2
NaCsNaCo
Am
Cs
TLYC:Ce
NaI:Tl
LaBr3
:Ce
Relativelightyield
Energy, keV
17

Comparison of NaI:Tl, CLYC, TLYC
18
Scintillator CLYC CLLBC TLYC
Density 3.31 4 4.58
Zeff 45 47 69
Photo-Fraction at 662 keV .08 .09 .25
Light Yield (ү-ray) (ph/MeV) 18,000 42,000 ~30,000
Emission Wavelength (nm) 370 410 440
Decay Times (ns) 60-5500 115-1500 57-1171
Energy Resolution (at 662keV) 4-5% 3% 3-4%
GEE for thermal n° (MeV) 3.2 3.1 2
n° Efficiency (at 1.5 cm) 80% 85% 82%
Ү-n PSD FOM >4 3.5 ~2
Fast Neutron Spectroscopy Yes Yes Yes

LixNa1-xI:Eu (LNI) Scintillators
19

High Resolution Neutron Detectors using 6Li1-xNaxI:Eu
LEFT: SEM of a 300 um thick film.
RIGHT: Good PSD is observed
4 × 4” of 6Li0.45Na0.45I:Eu0.05 film
300um thick, 40% neutron efficiency
0.75 mm1 mm
~2 lp/mm
Neutron radiography
with a 100 µm thick 4”
square 6LNI:Eu film.
LNI Properties:
GEE – 4 MeVee
LY(n) – 80K ph/n
LY() – 20K ph/MeV
Capable of PHD & PSD
Anger imaging at ORNL
33 x 33 mm2
20

High Energy Resolution
Gamma-Only Scintillators
21

• Energy resolution of 3-4% @ 662 keV
• Light yield of ~60k ph/MeV
• Excellent proportionality
• No intrinsic radioactivity
• Very fast (~20 ns decay)
• Good efficiency
CeBr3
• Developed, Patented by RMD
- Licensed to Hellma 3”x3” crystals
now available Co-doping improving
ER to 3%
22

Modulating Proportionality of CeBr3 via Co-doping
100 1000
0.8
0.9
1.0
1.1
1.2
1.3
NaCsNa
Co
Am
Cs
CeBr3
NaI:Tl
LaBr3
:Cerelativelightyield
Energy, keV
0 200 400 600 800
0.0
0.4
0.8
1.2
E ~ 3.0%
Counts/sec
CeBr3
:Ca
2+
662 keV
~6mmx6mmx2mm
Energy, keV
0 200 400 600 800
0.0
0.4
0.8
1.2
Undoped CeBr3
E ~ 4.1%
~6mmx6mmx2mm
Counts/secRMD, SNL, RSL, NST Collaboration
23

• Developed by collaboration of:
- LLNL, ORNL, Fisk, RMD
- 1”, 1.5” and 2” crystals prototypes produced
SrI2:Eu2+
• Energy resolution of 3% @ 662 keV
• Light yield of ~80k ph/MeV
• Excellent proportionality
• No intrinsic radioactivity
• Good efficiency
2” SrI2
7-elementorbital imaging spectrometer
0 200 400 600 800
0.0
0.4
0.8
1.2
1.6
2.0
662 keV
E ~ 2.97%
137
Cs Spectrum
intensity,counts/sec
energy, keV
24

Tl2LaCl5:Ce
100 1000
0.8
0.9
1.0
1.1
1.2
NaI:Tl
LaBr3
:Ce
Tl2
LaCl5
:3% Ce (TLC-001-1)
RelativeLY(arb.units)
Energy (keV)
200 400 600 800 1000
40
80
120
160
Tl2LaCl5:3%Ce
Counts
MCA channel
183 ps
PMT: H6533x2; hv -2200V; TAC=20 ns x1, ADC=2048 ch, Tcol = 2000 s
Calibration: 20 ns/2048 ch = 9.766 ps/ch
25

Properties of Gamma Scintillators
Material Zeff
Density
(g/cc)
Light Yield
(ph/MeV)
Decay Times
(ns)
NaI:Tl 50 3.67 38,000 230
LaBr3:Ce 47 5.1 60,000 20
CeBr3 47 5.1 60,000 20
SrI2:Eu 50 4.6 80,000 >1000
Tl2LaCl5:Ce 70 5.3 76,000 36
26

Organic Crystal, Plastic & Composite
Scintillators
Relevant Prior/On-Going Research:
PSD Plastics – investigated at LLNL, 2012
Metal loaded Plastics – investigated at LLNL, 2012
27

Plastic Scintillators with PSD
• Polystyrene doped with PPO
• Application dependent form factor
• Low cost & easy to scale up
• Good light output (10,000 ph/MeV)
• Excellent PSD (FOM 2.0 at 1 MeVee)
• Good timing resolution
(Ø5”x 8”) (Ø5”x 10”)
28

Tin-loaded Plastic Scintillator
3” x 3” Plastic
Scintillator loaded
with Organometallic
Tin
Light yield ~ 12,000 ph/MeV, Energy
resolution ~ 10%
0 100 200 300
180
200
220
240
260
280
n:
T ~ 25C
moderated -
252
Cf neutron
gamma
full integral
window2/window1
Tin-loaded plastic
200
220
240
260
0 1000 2000 3000 4000 5000
FOM ~ 1.5 @ 1 MeVee
Counts
PSDratio
Fast neutrons
Gamma
252
Cf source
29

CLYC pillar ~
12.5mm x 12.5 mm
x 31 mm
Plastic ~ 2” x 2” –
20% loading factor
Multi-signature Composite Detector
0
100
200
300
400
0 500 1000 1500 2000 2500 3000
CLYC FOM ~ 3.1
counts
ratio
Plastic FOM @ 800 keV ~ 1.6
30

Ceramic Scintillators
31

Ceramic (Gd,Lu)3(Ga,Al)5O12:Ce (GLuGAG)
Scintillators for High Energy Radiography & Medical Imaging
32

Ceramic GLuGAG – High Energy Radiography
Material ρ, g/cm3 Luminosity,
ph/MeV
Emission,
nm
Decay, ns
GLuGAG ~7 ~45,000 550 <100
CsI:Tl 4.5 ~50,000 540 >1000
CdWO4 7.9 ~15,000 480 14,000
Scale-up process
 Ceramic block and pixels manufactured
 Pixel evaluation (underway)
45mm×45mm×6m
m
GLuGAG selected as a composition with good
combination of properties (density, luminosity & speed).
GLuGAG scale-up on-going
33

GLuGAG Ceramics : Medical Imaging
Development of GLuGAG
composition
for PET
• Scale up to larger sizes
• Gd/Lu ratio studies
• Codoping for faster decay
• Shaped ceramics
2.6x2.6x20 mm
12x12 Ceramic Array
2.6x2.6x20 mm pixelsRings & Domes
GLuGAG-SiPM
Array
34

Summary
• Discovery of LaCl3:Ce, LaBr3:Ce led to a new era in halide scintillator research
- CeBr3, SrI2:Eu, Tl2LaCl5:Ce, others
- Elpasolites (CLYC, CLLBC, Tl-elpasolites)
• Li-containing elpasolites provide combined gamma-neutron detection, with chlorides adding fast neutron
spectroscopic capabilities
• Several new scintillators provide gamma-resolution of ≤3% (FWHM)
• Modulation of proportionality a new trend in scintillator optimization
• Organic crystals, plastics and organic-inorganic composites with gamma-neutron PSD attractive for
multimode, low cost, large systems
• Ceramic scintillators promising for high energy radiography and PET
• Commercialization of some of the promising candidates underway.
35

Acknowledgments
Work presented here was drawn by current and past projects sponsored by DNDO, DOE, and DTRA.
Their funding is greatly appreciated.
This work has been supported by the US Department of Homeland Security, Domestic
Nuclear Detection Office, under competitively awarded contract(s) HSHQDC-15-C-
B0041 and HSHQDC-16-C-00041. This support does not constitute an express or
implied endorsement on the part of the Government.
This work has been supported by the US Defense Threat Reduction Agency, under
competitively awarded contract(s) HDTRA1-12-C-0005, HDTRA1-14-C-0005 and
HDTRA1-14-C-0020, HDTRA1-14-D-0002
. This support does not constitute an express or implied endorsement on the part of the
Government. DISTRIBUTION A: Approved for public release: distribution unlimited
This work was supported by the Department of Energy grant number DE-SC0015793.
36

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