Some Remarks on the Energy Resolution of STJ

2012

J Low Temp Phys

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The scope of this work is to account for the phonon exchange in the process of multitunneling in superconducting tunnel junction (STJ) detector. The theory of branching cascade processes was applied to the process of multitunneling in STJ. The duality nature of quasiparticles and the coupling of the quasiparticle and phonon subsystems were taken into account. The extreme cases of the general formula were analyzed. It was shown that the general formula encloses all specific cases published in literature.

Section: Introductionmentioning

confidence: 99%

Influence of the Quasiparticle and Phonon Subsystem Coupling on the Multitunneling in STJ Detectors

2012

J Low Temp Phys

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“…In [1], the general formula for the energy resolution of STJ detector with trapping layers was derived. The mean value of output signal of STJ detector in units of electron charge Q and its relative variance η 2 Q are…”

Section: Introductionmentioning

confidence: 99%

Heating of Superconducting Tunnel Junction Detector by X-Ray Flux

Tulinov

2012

J Low Temp Phys

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Superconducting tunnel junction (STJ) detectors are in common use for high-resolution soft X-ray spectroscopy at high count rates. Each quasiparticle in superconductor should be treated as quantum superposition of electron-like and holelike excitations. This duality nature of quasiparticle leads to multitunneling in STJ. Because of the multitunneling process, one quasiparticle can transfers into heat the energy that equals to the difference in quasiparticle energy between two electrodes more than once. As a result, the energy transferred into heat in STJ detector is several times grater the energy of X-ray quantum. In this work, the theory of branching cascade processes is applied to the process of energy transfer caused by quasiparticle multitunneling. The mean and the variance of STJ temperature shift from the substrate temperature caused by heating of STJ by X-rays flux were derived.

“…(6) the relative variance of the signal of amplified scintillation detector for the accumulation time T is in the number of electron-hole pairs, in the number of scintillation photons emitted by a divalent ion RE 2+ during the accumulation time T , in the signal amplification relative variance of light collection probabilities caused by variation of X-ray quantum interaction point in detector volume and the relative variance of light collection probabilities caused by diffusion of electron-hole pairs through the scintillator material.The formula (10) is the general formula for the energy resolution of the amplified detector.…”

mentioning

confidence: 99%

Whether the light yield amplification by laser could significantly improve the energy resolution of a scintillation detector?

2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)

2013

In 2012, Wehe D.K. and coauthors proposed a method of light yield amplification in scintillation detectors. A trivalent activator ion RE 3+ captures an electron produced by a particle in scintillator and becomes a divalent rare earth ion RE 2+ . The scintillator is illuminated by laser photons that excite RE 2+ ions, which quickly de-excite and generate light photons. By cyclically excitation RE 2+ ions, one can obtain many light photons during any chosen accumulation time. Authors suggested that this method could remove scintillation yield as a limiting factor of the energy resolution of scintillation detectors. This conclusion was based on rather simplified theoretical examination of the pulse formation process in an amplified scintillator. In this work, the theory of branching cascade processes was applied to description of the pulse formation process. The general formula for the energy resolution of an amplified scintillator was derived. From this formula, it follows that the scintillation yield is not a limiting factor of the energy resolution of amplified scintillation detectors. It was shown that the relative reduction in the energy resolution of an amplified scintillation detector with reference to an ordinary scintillation detector is less than a few percent.