Transcript 20 Years of Professor`s Moszyński Research Team in Świerk

Energy resolution, Non-proportionality
1998-2013
1998 – a proportional response of YAP:Ce scintillator is reflected in the lowest
intrinsic resolution – Maciek Kapusta et al.
2002 – 2004 – scattering of secondary electrons (δ-rays) is dominating component
of intrinsic resolution
1999 – 2013 – influence of slow components of light pulses on non-proportionality
and intrinsic resolution (halide crystals)
2002 – 2008 – undoped NaI and CsI scintillators, influence of accidental impurities
on intrinsic resolution and non-proportionality
2007 – 2008 – correlation of „afterglow” and intrinsic resolution
2008 – deterioration of energy resolution by slow components of the light pulses
2010-2011 – Energy resolution and non-proportionality of Compton electrons
2012 – Świerk vs. Berkeley and Livermore: electron scattering or Landau fluctuations
2013 – The first test of nonproportionality of a Xe gas scintillator
Results: about 50 papers, 6 invited talks, 4 review papers
Nonproportionality of Compton electrons
LYSO – 2 x 2 x 2 cm3
Nonproportionality of Compton electrons
close geometry: ~ 1- 6 cm
and full energy peaks. Curves are
large solid angle: ≤ 90º
normalized to 662 keV full energy peak
weak sources: ~ 10 - 30 μCi of Cs-137.
What is the origin of the contribution of the
secondary electrons to the intrinsic resolution
of the scintillators?
• According to Steve Payne and Bill Moses (Livermore
and Berkeley), the Landau fluctuations are responsible
for the intrinsic resolution of scintillators.
see S. Payne et al., „Nonproportionality of Scintillator Detectors:
Theory and Experiment. II.”, IEEE TNS vol. 58, no. 6, pp. 3392, 2011
• According to Swierk group the dominating process
is related to the scattering of electrons (-rays).
Bill Moses at SCINT Conference 2011 in Giesen, Germany
Electrons in matter:
Electrons often undergo large angle
deflections loosing large part of energy
and producing -rays
Correlation between NP and
intrinsic resolution (at 662 keV)
LSO, LYSO: 6.8 – 8%
GSO, LGSO: 4.5 – 5.5%
LaBr3, LaCl3: 1.8 – 2.6%
TNS 54 (2007) 3 – A. Nassalski et al.
Intrinsic resolution vs nonproportionality
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Intrinsic Res. (%)
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Swierk data
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Degree of nPR
Following I. Khodyuk and P. Dorenbos, IEEE TNS
calculated between 10 keV and 662 keV
K-dip spectroscopy
Intrinsic resolution at 662 keV
LSO, LYSO: 6.8 – 8%
GSO, LGSO: 4.5 – 5.5%
LuAG:Pr: 2.6%
Nonproportionality curves at low
energies with similar slopes
TNS 57 (2010) 1175 – I.V. Khodyuk et al.

weak correlation with intrinsic
resolution
Fast and thermal neutron detection in
liquid scintillators
n/ discrimination with B-10 loaded
liquid scintillators
BC523A2 – n/ discrimination
A 2D plot of ZC time vs. pulse
height measured with EJ309B5
under irradiation of Pu-Be and
241Am.
L. Swiderski, et al., IEEE TNS – 3 papers, NIM A – 1 paper, osiągnięcie IPJ w 2010
Neutron/gamma discrimination in plastics
See Asia Iwanowska, IEEE NSS-MIC 2013
Large samples of plastic scintillators
neutron/gamma discrimination
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EJ 299-33
EJ 299-33 G
EJ 299-34
EJ 299-34 G
EJ301
Figure of Merit
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energy cut (keVee)
See Asia Iwanowska, IEEE NSS+MIC 2013
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Zastosowania
Medycyna
Projekt BIOCARE
Akcja COST
NOWOŚCI
Wspólny detektor dla tomografii PET/CT
Super timing w TOF PET
SiPM w spektrometrii gamma
z scyntylatorami
Ochrona kraju i monitoring
przejść granicznych
Kontrakty IAEA
Euritrack, MODES, TAWARA
AiD,
Przemysł
Ekspertyzy dla:
- ICx (d. Target)
- Photonis
- Projekt „Cement”
Common PET/CT detector
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Number of counts
4x10
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3x10
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2x10
LSO
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1x10
LSO pixels (2x2x15mm3) coupled to
Hamamatsu S8550 APD array
Number of counts
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I [nA]
Am-241
59.6 keV
Antoni Nassalski
„Common PET/CT detector”
PhD thesis