Simulation of the response of a diamond-based radiation detector to ultra-short and intense high-energy electron pulses

2025-05-03 0 0 2.22MB 9 页 10玖币

侵权投诉

Simulation of the response of a diamond-based radiation detector to ultra-short

and intense high-energy electron pulses

Y. Jina, P. Cristaudoa, A. Gabriellia,b

aINFN, Sezione di Trieste, I-34127 Trieste, Italy

bDipartimento di Fisica, Universit`a di Trieste, I-34127 Trieste, Italy

Abstract

Single-crystal synthetic diamond sensors have been widely used in radiation dosimetry and beam diagnostics. The

foreseen harsh radiation environment in electron-positron colliders at the luminosity frontier requires a thorough

investigation of diamond’s response to large radiation burst, in particular, to intense high-energy electron pulses. In

this article, a two-step numerical simulation approach (Sentaurus +LTspice) is proposed to explore this topic. Time

response of the diamond detector is simulated via TCAD-Sentaurus while the transmission eﬀect of the electronic

circuit is taken into account using LTspice. Good agreement is observed between results of the numerical simulation

and preliminary experimental data from detector’s exposure to high-energy sub-picosecond electron pulses, on both

the amplitude and the shape of the induced signals. This simulation combination is a novel approach to designing and

optimising diamond detectors for radiation and beam loss monitoring in particle physics experiments.

Keywords: sCVD diamond, radiation monitor, TCAD-Sentaurus, LTspice, high-energy electrons

1. Introduction

Single-crystal diamond sensors synthesized by chem-

ical vapor deposition (sCVD) have been widely used in

radiation dosimetry and beam diagnostics [1, 2, 3, 4, 5].

We have developed and installed a diamond-based radi-

ation monitor and beam abort system [6] in the Belle II

experiment [7] at the SuperKEKB asymmetric-energy

electron-positron collider [8]. With the push towards

higher instantaneous luminosity of the collider, beam

backgrounds become more severe, and high radiation

bursts induced by beam losses can cause localized dam-

age on essential Belle II sub-detectors and SuperKEKB

components. Thus, the harsh radiation environment at

the luminosity frontier urges a thorough investigation of

diamond’s response to large and fast radiation transients

such as those induced by intense high-energy electron

pulses.

In its simplest conﬁguration, a typical diamond de-

tector is obtained by the deposition of two metallic elec-

trodes on opposite faces of a ﬂat crystal. When a volt-

age bias is applied by an external circuit, the electrons

and holes, liberated by ionization, drift towards the elec-

trodes, inducing a current signal in the external circuit.

Thanks to their high charge carrier mobility, diamond

detectors can generate very fast signals. However, in the

case of large ionization energy deposited in diamond,

the large concentration of excess charge carriers in the

diamond bulk gives rise to plasma eﬀects that aﬀect the

rising time and amplitude of the signal. In addition,

further signal reﬂection and distortion occur due to the

external circuit. The determination of the signal is an

interplay between charge carrier transport in diamond

bulk and signal transmission in the circuit. As a result,

unlike the steady continuous radiation that has been well

calibrated for our diamond system [9], the dose rate esti-

mated on radiation bursts that have spikes-like time de-

pendence will encounter non-linear eﬀects and lead to

an underestimated dose value.

Successful attempts have been made using Technol-

ogy Computer-Aided Design (TCAD) software [10] to

investigate some properties of diamond devices, e.g.,

the charge collection eﬃciency under diﬀerent bias volt-

ages [11], transient current caused by single α-particle

hit [12]. In light of these successful applications, we

carry out the simulation of the detector embedded in

a simpliﬁed external circuit via “mixed-mode” TCAD-

Sentaurus with its SPICE implementation. Subse-

quently, to take into account the circuit eﬀects with a de-

tailed model overcoming the limitations of the “mixed-

mode” TCAD, the results of the ﬁrst step are input to

LTspice simulator [13]. This new factorized numeri-

Preprint submitted to Nuclear Instruments and Methods A October 27, 2022

arXiv:2210.14690v1 [physics.ins-det] 26 Oct 2022

cal simulation approach is proposed to explore the time

response of a diamond device to ultra-short and intense

high-energy electron pulses. Such a two-step simulation

(Sentaurus +LTspice) can interpret the measured data

and extrapolate the performance of diamond device in

similar radiation environments.

An experimental program is ongoing at the electron-

linac of the FERMI free-electron laser in Trieste [14], to

study the response of the diamond detectors to the irra-

diation by intense, sub-picosecond bunches of electrons

accelerated to about 1 GeV. We compare our simula-

tions with preliminary data from Ref. [15].

The experimental setup is briefed in Section 2. The

two-step simulation approach is elucidated in Section 3.

The two steps with regard to the response of the dia-

mond detector and the eﬀect of the electronic circuit are

demonstrated in Section 4 and Section 5, respectively.

A validation of the approach has been devised in Sec-

tion 6. Final results of the numerical simulation overlaid

with the experimental data are shown in Section 7.

2. Experimental setup

We brieﬂy describe here the diamond detectors de-

veloped for the Belle II experiment and the beam test

facility set up to characterize their behaviour under ex-

treme irradiation conditions.

2.1. Diamond detectors

The diamond sensors consist of (4.5×4.5×0.5) mm3

high-purity sCVD diamond crystals provided by Ele-

ment Six Ltd [16] and two (4.0×4.0) mm2electrodes

on opposite faces. The electrodes are made of Ti/Pt/Au

layers with (100+120+250) nm thickness, processed

by CIVIDEC [17]. More details can be found else-

where [6]. During the measurements, one electrode of

the diamond sensor is connected to a custom-made HV

power supply [18], the other is connected to a LeCroy

HDO9000 oscilloscope [19].

2.2. Beam facility

Collimated electron bunches of about 1 ps duration

with energy up to 1.5 GeV are available at the linac of

the FERMI free-electron laser in Trieste [14]. Bunch

charge can be tuned from tens to 1000 pC and trans-

verse size down to about 0.1 mm. The ﬁrst data tak-

ing is carried out using 0.9 GeV electron bunches of

35 pC charge (<1% of bunch charge at SuperKEKB)

and 120 µm transverse size.

3. Simulation workﬂow

TCAD-Sentaurus is regarded as the industry standard

for the numerical simulation of the electrical character-

istics of silicon-based and compound semiconductor de-

vices [10]. The predictive power of its numerical calcu-

lation on the response of semiconductor devices to ex-

ternal electrical, thermal, and optical sources has been

veriﬁed via numerous applications in the semiconductor

industry. Using TCAD-Sentaurus, a series of sequential

processes of the diamond detector are simulated, includ-

ing a radiation beam interacting with the diamond crys-

tal, the creation of electron-hole pairs, the drift of charge

carriers, and the evolution of the induced voltage drop

on electrodes. In addition, the space-time evolution of

the concentration of charge carriers inside the diamond

crystal is also obtained. These processes are regarded

as the ﬁrst step of the simulation workﬂow and are de-

scribed in Section 4.

Though a SPICE-like utility is embedded in the

TCAD-Sentaurus package, its functionalities and mod-

els are not adequate to fully take into account the ef-

fect of transmission cables, which plays a leading role

in dealing with fast pulses. To overcome these limita-

tions, LTspice, the most widely used SPICE software in

the industry [13] is employed to take over as the second

step. In our model described in Section 5, the diamond

detector is implemented by a combination of a voltage

source in series with a resistor and in parallel with a ca-

pacitor. The simulated result of the evolution of voltage

drop on electrodes from the ﬁrst step serves as an input

to the LTspice simulation for the voltage source. The

resistance in the diamond detector model is obtained

from the time evolution of voltage and current in TCAD.

Coaxial cables, power supply, and oscilloscope all are

properly modeled to take into account the transmission

eﬀects on the electrical signal such as reﬂection, atten-

uation, and distortion.

4. Response of the diamond detector

The First step of the simulation is described here,

including our choices for the physical parameters and

models in TCAD and the generation of excess charge

carrier by the ionizing electron beam.

4.1. Diamond physical parameters

The default values of parameters for the physi-

cal properties of diamond in the database of TCAD-

Sentaurus are set according to Ref. [20]. In addition,

we update several sets of parameters. The mobility

and saturation velocity of charge carriers are updated

文档加载中……请稍候！
如果长时间未打开，您也可以点击刷新试试。

下载文档到电脑，查找使用更方便

10 玖币 0人已下载

立即下载

摘要：

Simulationoftheresponseofadiamond-basedradiationdetectortoultra-shortandintensehigh-energyelectronpulsesY.Jina,P.Cristaudoa,A.Gabriellia,baINFN,SezionediTrieste,I-34127Trieste,ItalybDipartimentodiFisica,UniversitadiTrieste,I-34127Trieste,ItalyAbstractSingle-crystalsyntheticdiamondsensorshavebeenwid...

展开>> 收起<<

Simulation of the response of a diamond-based radiation detector to ultra-short and intense high-energy electron pulses.pdf

共9页,预览2页

还剩页未读，继续阅读

声明：本站为文档C2C交易模式，即用户上传的文档直接被用户下载，本站只是中间服务平台，本站所有文档下载所得的收益归上传人(含作者)所有。玖贝云文库仅提供信息存储空间，仅对用户上传内容的表现方式做保护处理，对上载内容本身不做任何修改或编辑。若文档所含内容侵犯了您的版权或隐私，请立即通知玖贝云文库，我们立即给予删除！

Simulation of the response of a diamond-based radiation detector to ultra-short and intense high-energy electron pulses

相关推荐

开通VIP享超值会员特权

作者详情

相关内容

热门标签

举报选择: