Energy calibration via correlation

Abstract

The main task of an energy calibration is to find a relation between pulse-height values and the corresponding energies. Doing this for each pulse-height channel individually requires an elaborated input spectrum with an excellent counting statistics and a sophisticated data analysis. This work presents an easy to handle energy calibration process which can operate reliably on calibration measurements with low counting statistics. The method uses a parameter based model for the energy calibration and concludes on the optimal parameters of the model by finding the best correlation between the measured pulse-height spectrum and multiple synthetic pulse-height spectra which are constructed with different sets of calibration parameters. A CdTe-based semiconductor detector and the line emissions of an 241 Am source were used to test the performance of the correlation method in terms of systematic calibration errors for different counting statistics. Up to energies of 60 keV systematic errors were measured to be less than 0.1 keV. Energy calibration via correlation can be applied to any kind of calibration spectra and shows a robust behavior at low counting statistics. It enables a fast and accurate calibration that can be used to monitor the spectroscopic properties of a detector system in near realtime

Compton imaging reconstruction methods: a comparative performance study of direct back-projection, SOE, a new Bayesian algorithm and a new Compton inversion method applied to real data with Caliste

“…As shown in Figure 5, the line shape at 662 keV is composed of three event populations: the narrow peak structure is populated with events of type a (45%) summed up with two other bumpy populations from events of type b and c. The energy of the main line emission of the source is 662 keV. Because of the slightly non-linear detector response [17] and charge loss due to split events, we use a selection window, between 647 keV and 670 keV, which is considerably larger than the detector resolution for single events. The selection is made in the main peak of the spectrum so that we keep only the best events in energy to reduce the influence of the energy uncertainty on the computation of the scattering angle .…”

Energy calibration via correlation using an adaptive mesh refinement

“…A method that uses an Energy Calibration via Correlation approach was presented [1] to address the problems of low counting statistics in the calibration data set. The idea of ECC is not to use a peak fitting approach, which examines only specific line positions, but to use the complete spectral response of the calibration measurement.…”

“…Even though the presented examples show a linear calibration, the concept of ECC is not limited to any number of parameters. An example of a non-linear ECC using three parameters can be found in [1].…”

“…Another benefit of ECC is that it is not restricted to line peaks but can use the full spectral response like Comptonization structures. See reference [1] for more details on ECC and a quantitative comparison between ECC and a Gaussian peak fitting approach.…”

Tutorial on X-ray photon counting detector characterization

“…Another method uses a parameter based model for the energy calibration and concludes on the optimal parameters of the model by finding the best correlation between the measured pulse-height spectrum and multiple synthetic pulse-height spectra which are constructed with different sets of calibration parameters [75]. The capability of resolving the K-edges of certain high Z materials shows the potential to develop a convenient alternative for energy response calibration with a polychromatic X-ray source [35].…”