title: Estimation of Fano factor in inorganic scintillators.
abstract: The Fano factor of an integer-valued random variable is defined as the ratio of its variance to its mean. Correlation between the outputs of two photomultiplier tubes on opposite faces of a scintillation crystal was used to estimate the Fano factor of photoelectrons and scintillation photons. Correlations between the integrals of the detector outputs were used to estimate the photoelectron and photon Fano factor for YAP:Ce, SrI2:Eu and CsI:Na scintillator crystals. At 662 keV, SrI2:Eu was found to be sub-Poisson, while CsI:Na and YAP:Ce were found to be super-Poisson. An experiment setup inspired from the Hanbury Brown and Twiss experiment was used to measure the correlations as a function of time between the outputs of two photomultiplier tubes looking at the same scintillation event. A model of the scintillation and the detection processes was used to generate simulated detector outputs as a function of time for different values of Fano factor. The simulated outputs from the model for different Fano factors was compared to the experimentally measured detector outputs to estimate the Fano factor of the scintillation photons for YAP:Ce, LaBr3:Ce scintillator crystals. At 662 keV, LaBr3:Ce was found to be sub-Poisson, while YAP:Ce was found to be close to Poisson.
authors.affiliation: Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724, USA.
authors.forename: Vaibhav
authors.initials: V
authors.lastname: Bora
authors.affiliation: Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724, USA.
authors.forename: Harrison H
authors.initials: HH
authors.lastname: Barrett
authors.affiliation: Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724, USA.
authors.forename: David
authors.initials: D
authors.lastname: Fastje
authors.affiliation: Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Clarkson
authors.affiliation: Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724, USA.
authors.forename: Lars
authors.initials: L
authors.lastname: Furenlid
authors.affiliation: Qatar Foundation, QEERI, P.O. Box 5825, Doha, Qatar.
authors.forename: Abdelkader
authors.initials: A
authors.lastname: Bousselham
authors.affiliation: Radiation Monitoring Devices, Inc., Watertown, MA 02472, USA.
authors.forename: Kanai S
authors.initials: KS
authors.lastname: Shah
authors.affiliation: Radiation Monitoring Devices, Inc., Watertown, MA 02472, USA.
authors.forename: Jarek
authors.initials: J
authors.lastname: Glodo
keywords: Fano factor; Inorganic Scintillators