Nov 18 – 20, 2019
CERN
Europe/Zurich timezone

On the frequency dependence of the admittance of radiation damaged pad diodes

Nov 18, 2019, 2:50 PM
20m
30/7-018 - Kjell Johnsen Auditorium (CERN)

30/7-018 - Kjell Johnsen Auditorium

CERN

30/7-018
190
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Speaker

Joern Schwandt (Hamburg University (DE))

Description

The admittance of n+p pad diodes (200 μm thickness, 5×5 mm$^2$ area) irradiated by 24 GeV/c protons to 1 MeV neutron equivalent fluences Φ$_{eq}$ = 3, 6, 8 and 13×10$^{15}$ cm$^{-2}$ has been measured for reverse voltages Vrev between 1 and 1000 V and for frequencies f between 100 Hz and 2 MHz at temperatures T = –30 °C and –20 °C. A simple model, which assumes that radiation damage causes a position-dependent resistivity ρ only, provides an excellent description of the data. For the position dependence a phenomenological parametri¬sation with 3 parameters for every Φ$_{eq}$, V$_{rev}$ and T is used. In part of the pad diode a “low ρ” region is obtained, with a ρ value compatible with the intrinsic resistivity ρ$_{intr}$(T). In the remainder of the pad diode a value ρ ≫ρ$_{intr}$ is found. The “low ρ” region is interpreted as the non-depleted region, and the “high ρ” region as the depleted region. It is con¬cluded that the f dependence of the admittance of irradiated silicon detectors can be described without assumptions about the response time of radiation-induced traps and that dependence of the admittance on f allows determining the depletion depth in irradiated silicon pad diodes

Authors

Eckhart Fretwurst (Hamburg University (DE)) Erika Garutti (Hamburg University (DE)) Robert Klanner (Hamburg University (DE)) Joern Schwandt (Hamburg University (DE)) Georg Steinbrueck (Hamburg University (DE))

Presentation materials