Nonproportionality of Scintillator Detectors: Theory and Experiment

On the basis of nonproportionality data obtained for several scintillators, we have developed a model to describe the carrier dynamics to fit the light yield versus electron energy. The theory of Onsager was adapted to explain how the carriers form excitons or sequentially arrive at the activators to promote the ion to an excited state, and the theory of Birks was employed to allow for exciton-exciton annihilation. We then developed a second model to deduce the degradation in resolution that results from nonproportionality by evoking Landau fluctuations, which are essentially variations in the deposited energy density that occur as the high energy electron travels along its trajectory. In general there is agreement with the data, in terms of fitting the nonproportionality curves and reproducing the literature values of nonproportionality's contribution to the scintillator resolution.

[1]  M. Moszynski,et al.  Avalanche photodiodes in scintillation detection , 2003 .

[2]  Woon-Seng Choong,et al.  Performance of a Facility for Measuring Scintillator Non-Proportionality , 2008, IEEE Transactions on Nuclear Science.

[3]  Energy and length scales in scintillator nonproportionality , 2007 .

[4]  M. Moszynski,et al.  Intrinsic energy resolution of NaI(Tl) , 2002 .

[5]  N. H. Lazar,et al.  Intrinsic Scintillator Resolution , 1956, IRE Transactions on Nuclear Science.

[6]  C. Melcher.  Perspectives on the future development of new scintillators , 2005 .

[7]  T. Niedermayr,et al.  Light collection optimization in scintillator-based gamma-ray spectrometers , 2008 .

[8]  J. D. Valentine,et al.  The measured electron response nonproportionalities of CaF/sub 2/, BGO, and LSO , 1997 .

[9]  M. Klintenberg,et al.  The Quest for the Ideal Inorganic Scintillator , 2002 .

[10]  Anthony J. Peurrung,et al.  Energy nonlinearity in radiation detection materials: Causes and consequences , 2007 .

[11]  J. Valentine,et al.  Light yield nonproportionality of CsI(Tl), CsI(Na), and YAP , 1997, 1997 IEEE Nuclear Science Symposium Conference Record.

[12]  G. Hull,et al.  Design of a Facility for Measuring Scintillator Non-Proportionality , 2008, IEEE Transactions on Nuclear Science.

[13]  Arnold Burger,et al.  Strontium and barium iodide high light yield scintillators , 2008 .

[14]  H. B. Dietrich,et al.  Kinetics of the diffusion of self-trapped holes in alkali halide scintillators , 1972 .

[15]  R. B. Murray,et al.  Scintillation Response of Activated Inorganic Crystals to Various Charged Particles , 1961 .

[16]  P. Iredale.  The effect of the non-proportional response of NaI(Tl) crystals to electrons upon the resolution for γ-rays , 1961 .

[17]  D. Wolski,et al.  Energy resolution of scintillation detectors readout with large area avalanche photodiodes and photomultipliers , 1998 .

[18]  G. Knoll.  Radiation detection and measurement , 1979 .

[19]  P. Dorenbos,et al.  Non-Proportionality and Energy Resolution of a LaCl :10% Ce Scintillation Crystal , 2003 .

[20]  Jai Singh,et al.  The role of different linear and non-linear channels of relaxation in scintillator non-proportionality , 2009 .

[21]  A. Burshtein,et al.  Viscosity dependence of geminate recombination efficiency after bimolecular charge separation , 2002 .

[22]  A. Vasil’ev,et al.  From Luminescence Non-Linearity to Scintillation Non-Proportionality , 2008, IEEE Transactions on Nuclear Science.

[23]  J. D. Valentine,et al.  The light yield nonproportionality component of scintillator energy resolution , 1997, IEEE Nuclear Science Symposium Conference Record.

[24]  P. Dorenbos,et al.  Energy resolution of some new inorganic-scintillator gamma-ray detectors , 2001 .

[25]  D. Wolski,et al.  Comparative study of avalanche photodiodes with different structures in scintillation detection , 2000, 2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149).

[26]  J. B. Birks,et al.  The Theory and Practice of Scintillation Counting , 1965 .

[27]  P. Dorenbos,et al.  Non-proportionality in the scintillation response and the energy resolution obtainable with scintill , 1995 .

[28]  C. Powell,et al.  New universal expression for the electron stopping power for energies between 200 eV and 30 keV , 2006 .

[29]  J. E. Moyal.  XXX. Theory of ionization fluctuations , 1955 .

[30]  G. Bizarri,et al.  Measurements of NaI(Tl) Electron Response: Comparison of Different Samples , 2009, IEEE Transactions on Nuclear Science.

[31]  Andrzej J. Wojtowicz,et al.  Fundamental limits of scintillator performance , 1993 .

[32]  P. Dorenbos,et al.  Development and characterization of highly efficient new cerium doped rare earth halide scintillator materials , 2006 .

[33]  NaI(Tl) electron energy resolution , 2002 .