Energy Resolution of Cryogenic Imaging Detectors

2012

There are a number of processes in superconducting tunnel junction (STJ) detectors that lead to peak broadening. In many papers, semi-empirical approach is used to take into account the contribution of one or another factor to the signal variance of an STJ detector. The correct formula for the signal variance cannot be semiempirical at the researcher's option. It must result strictly from exact mathematical description of the particle registration by detector. In this work, using the theory of branching cascade processes the general expression for the energy resolution of STJ detector for optical photons and soft X-rays was derived. It was shown that the general formula encloses all specific contributions of the peak broadening published in literature and has additional contributions to the energy resolution caused by fluctuations of photon energy and of absorber temperature.

Section: General Formula For the Variance Of The Output Signal Of Stjmentioning

confidence: 99%

Some Remarks on the Energy Resolution of STJ

2012

“…The influence of different factors on quasiparticle multitunneling for the first time was treated in detail in [4]. In [4] the GFs of the charge multiplication factor caused by quasiparticle multitunneling were derived by summation of infinite series.…”

Section: Charge Multiplication Factor Caused By Quasiparticle Multitumentioning

confidence: 99%

“…In [4] the GFs of the charge multiplication factor caused by quasiparticle multitunneling were derived by summation of infinite series. In this work, I solved this problem in more elegant way by using a set of coupled equations for generating functions.…”

Section: Charge Multiplication Factor Caused By Quasiparticle Multitumentioning

confidence: 99%

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

2012

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.

“…As the branch-mixing rate is very high, populations of these states are always equal [6]. The correct formulae for charge transfer caused by quasiparticle multitunneling, which properly accounts for the duality nature of a quasiparticle, were deduced in work [7] and were applied to the analysis of asymmetric junctions [8]. In the semiconductor representation of a superconductor a quasiparticle can tunnel as an electron and as a hole (Fig.…”

Section: Competition Between Electron and Hole Channelsmentioning

confidence: 99%

Intrinsic Resolution of STJ Detectors due to Competition Between Electron and Hole Channels in Quasiparticle Multitunneling

Andrianov

2012

The effect of competition between electron and hole channels of tunneling on the intrinsic resolution of STJ-detectors is considered. The formulae for the mean value, the variance and the relative variance of the detector signal for general case 1 = 2 are given. For a symmetric junction the tunneling rates, the mean value of the transferred charge and the noise G-factor were calculated as a function of the junction bias voltage. The results demonstrate the importance of these effects at low bias voltages.