Investigation and compensation of the nonlinear response in photomultiplier tubes for quantitative single-shot measurements

Abstract

General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal A concept for time-sensitive optical detectors is described that shows how to confirm whether the detection device is operating in the linear response regime. By evaluating the recorded time decay of a thermographic phosphor, even weak saturation effects far from obvious situations can be identified and further related to either optical or electrical saturation. The concept has been validated by running a PMT detector close to saturation and exposing it to the optical signal decay of two different thermographic phosphors, La 2 O 2 S:Eu and CdWO 4 . It was confirmed that short but intense light exposures at the beginning of an individual time decay influence the detector response for the rest of the decaying signal including temporal areas, where the anode current has dropped well below the manufacturer specified current limit. Such situations are common when applying, e.g., phosphor thermometry where it is necessary to retrieve the full decay curve from a single-shot event, i.e., standard techniques based on single-photon counting are omitted. Finally, means of compensation are introduced in order to facilitate the retrieval of useful information from the measurement data when operation in the non-linear response regime is inevitable.

A First Application of Thermographic Phosphors in a Marine Two-Stroke Diesel Engine for Surface Temperature Measurement

“…Severe signal distortions can occur to the measured signal if the detector is operating in its nonlinear region. The importance of detector linearity in phosphor thermometry was characterized and reported by Knappe et al [25,26]. The studies showed that photodetectors can severely distort the shape of the exponentially decaying signals.…”

Development of an automatic routine for calibration of thermographic phosphors

“…A well-constructed calibration curve is important for an accurate thermographic phosphor temperature determination. The process of obtaining a phosphor calibration curve can be tedious and accompanied with effects such as detector nonlinearity [13,14]. Despite the importance of the calibration, no major development has occurred or been reported for the method by which the temperature calibration is achieved.…”

Phosphor thermometry on a rotating flame holder for combustion applications

“…Being semi-invasive as it requires to add a thin coating of phosphor particles, this techniqueoften named laser-induced phosphorescence (LIP)-uses rare-earth-doped ceramic phosphors whose spectroscopic properties are highly sensitive to temperature (Allison and Gillies 1997;Khalid and Kontis 2008;Chambers and Clarke 2009). In practice, this technique can be either implemented in the temporal domain, by measuring the phosphorescence glowing after excitation (Knappe et al 2012), or in the spectral domain, by estimating a ratio of intensities (Feist et al 2002). Fuhrmann et al (2013) performed a systematic study of these two approaches and showed the advantages of the lifetime method, which is used in this study.…”