סמינר זה יחשב כסמינר שמיעה לתלמידי תואר שני

15:00 vited to attend a lecture on Thursday, July 20^th, 2023

Room 011, Kitot Building

Reconstruction of electric field in an M-S-M device, based on Transient current technique measurements

By:

Odelya Amzallag

M.Sc. student under the supervision of Prof. Arie Ruzin

Abstract

The profile of the electric field in the active volume of a detector affects its performance. In many practical devices this information is missing or not well established (e.g., the ohmic contacts may be not ideal, or the material can sustain radiation-induced damage and change its electrical properties). Thus, the ability to deduce the electric field distribution inside a detector, from experimental results is essential.  Such ability allows for exploration of the nature of the crystal, traps and their properties, the nature of the contacts, the effect of traditional treatments etc. This is the main goal of the TCT characterization. In TCT characterization the system injects short laser pulses into the semiconductor detector, to produce free charge carriers in a known location. The applied external voltage separates the holes and the electrons and drifts them in opposite directions. The resulting current pulses at the contacts of the device are amplified, measured, and recorded.  The moving carriers induce displacement currents in the contacts. Reconstruction of the electric field from the current pulses is not straightforward and requires certain simplifications. To address this issue, we present a few approximations that were designed to improve accuracy of the calculations. These approximations were developed based on TCAD high accuracy simulations. The method was then implemented on experimental current pulses, as part of different experiments.

You are invited to attend a lecture on Tuesday, July 18^th, 2023 15:00

Room 512, "Tochna" Building, Faculty of Engineering

DEEP-SUBWAVELENGTH DIRECTION-OF-ARRIVAL DETECTION WITH

ENHANCED PERFORMANCE USING TIME MODULATION

By:

Tamir Zchut Oskar

MSc student under the supervision of  Dr. Yarden Mazor

Abstract                   

In recent years, the interaction between electromagnetic waves and time-modulated systems has gained interest and research attention. Incorporating temporal variation allows for additional control over the system response, followed by the possibility to go beyond the known abilities of passive systems. Contemporary uses of such systems include aviation and military radars. In this work, we study the physical mechanisms that allow sensitivity enhancement of a time-modulated 2D dimer, for deep-subwavelength Direction of Arrival (DoA) sensing. Our 2D dimer is constructed from two infinite wires with periodic loading,
and the temporal modulation is achieved by incorporating a time-modulated capacitor as part of the periodic loading impedance. We formulate the scattering problem from the 2D dimer using an analytical model for the scattering from a single loaded wire. Then, we define a performance metric to facilitate a quantitative discussion of the sensitivity. We explore physical phenomena which cause the sensitivity enhancement and identify three separate operation regimes, each dominated by a specific physical mechanism: frequency conversion, which translates the incident wave to a resonance frequency; High-frequency sensitivity ripples; and parametric amplification. We study the high harmonies generated in the dimer wires and the information that can be retrieved from them. The energy that is received and scattered from the system is calculated, giving us a better understanding of the physical interactions in the system, and allowing us to study the frequency conversion efficiency. We demonstrate the difference in working in different fundamental frequencies and the energy balance as a function of the DoA. We show that time modulation allows for a new degree of freedom which can be used to optimize the sensor for a wide range of
frequencies, allowing wide-band operation.