Design and simulation of a novel concentric silicon drift detector with equal width divider resistor chain and floating cathodes

Xuanang Huang,Zheng Li,Manwen Liu,Chaosheng Wu

doi:10.1063/5.0023970

Xuanang Huang, Zheng Li + Show 2 more

Open Access

https://doi.org/10.1063/5.0023970

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Abstract

Enabling the traditional concentric silicon drift detector (CSDD) does not need an external voltage divider in the application; hence, a novel CSDD structure is proposed in this paper, in which resistor chains of equal width are deposited equally between the cathode rings and come in contact with the cathode rings. The new CSDD can achieve voltage division automatically and only needs to bias the voltage on the cathodes of the innermost ring and the outermost ring. In addition, floating cathodes were designed between the cathodes to obtain a nearly straight line drift channel and to reduce the low electric field area near the surface. The electrical properties of three types of floating cathodes (called floating cathodes of a single-ring, floating cathodes of a double-ring, and floating cathodes of a four-ring) were simulated and compared using the technology computer aided design tool. Under the field effect between the floating cathodes and the bulk, the electric field near the surface increased substantially. Moreover, the electric field near the surface of the CSDD with the floating cathodes of a double-ring changes the most uniformly so that the drift path is the straightest.

Highlights

Enabling the traditional concentric silicon drift detector (CSDD) does not need an external voltage divider in the application; a novel CSDD structure is proposed in this paper, in which resistor chains of equal width are deposited between the cathode rings and come in contact with the cathode rings
The traditional concentric silicon drift detector (CSDD), which was proposed by Gatti and Rehak in 1984,3 is widely used in x-ray detection due to its high sensitivity and high energy resolution
In order to make the bulk between the cathode rings to be more depleted and to obtain a uniform potential distribution, floating cathodes were designed between the cathode rings, and three types of floating cathodes were simulated and compared by the Technology Computer Aided Design (TCAD) tool

Summary

INTRODUCTION

The traditional concentric silicon drift detector (CSDD), which was proposed by Gatti and Rehak in 1984,3 is widely used in x-ray detection due to its high sensitivity and high energy resolution. After decades of development, the CSDD generally consists of concentric peripheral cathode rings and a small area collecting anode in the center. Due to the strictly symmetrical geometric structure, the CSDD has a very uniform potential distribution; when x-rays or high energy particles are incident into the silicon bulk, the bulk will be ionized, and the excited carriers (electrons) will drift to the channel in the fastest way and get collected by the anode along a nearly straight channel.. The traditional concentric silicon drift detector (CSDD), which was proposed by Gatti and Rehak in 1984,3 is widely used in x-ray detection due to its high sensitivity and high energy resolution.. Due to the strictly symmetrical geometric structure, the CSDD has a very uniform potential distribution; when x-rays or high energy particles are incident into the silicon bulk, the bulk will be ionized, and the excited carriers (electrons) will drift to the channel in the fastest way and get collected by the anode along a nearly straight channel.. The resistance of the external rheostat group varies from several thousand ohms to several megohms, and each cathode ring needs to be matched with a suitable resistance to ensure that the potential distribution in the detector meets the requirements. In order to make the bulk between the cathode rings to be more depleted and to obtain a uniform potential distribution, floating cathodes were designed between the cathode rings, and three types of floating cathodes (called floating cathodes of a single-ring, floating cathodes of a double-ring, and floating cathodes of four-ring) were simulated and compared by the Technology Computer Aided Design (TCAD) tool

STRUCTURE

SIMULATION

Floating cathodes of a single-ring

Floating cathodes of a double-ring and a four-ring

CONCLUSION