Beam background study for the Belle II Silicon Vertex Detector

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F20%3A10423583" target="_blank" >RIV/00216208:11320/20:10423583 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=ck658g19uD" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=ck658g19uD</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.nima.2020.164580" target="_blank" >10.1016/j.nima.2020.164580</a>

Result language

angličtina

Original language name

Beam background study for the Belle II Silicon Vertex Detector

Original language description

The Belle II experiment aims to accumulate 50 ab(-1) of e(+)e(-) collision data at the SuperKEKB asymmetric energy collider (Tsukuba, Japan). The first physics data using all Belle II detectors were taken in spring 2019. In the vast physics program of the Belle II experiment, the vertex detector plays a crucial role for the determination of the B-meson decay vertices. It consists of two inner layers of pixelated silicon detectors and four outer layers of double-sided silicon strip detectors (SVD). To achieve a design luminosity of 8 x 10(35) cm(-2)s(-1), 40 times higher than the recorded luminosity of its predecessor, the SuperKEKB collider squeezes the beams to a vertical size of 50 nm (&quot;nano-beam scheme&quot;) and doubles the beam currents. Therefore, the detectors are required to tolerate intense beam induced background due to the very high luminosity. During the 2019 spring run we measured the occupancy rate in the SVD to estimate the level of the beam induced background. With the low initial luminosity, the observed beam induced background mostly originated from Touschek processes and beam-gas scattering within individual beams. Since these different background contributions depend differently on accelerator conditions, such as the beam current, beam size and pressure, they can be disentangled. We estimate the background rate of each contribution and compare them with simulated ones. The results enable us to predict the background levels at increased beam currents and luminosity in the coming years. They also hint at background mitigation measures for running at higher luminosity. In this proceeding we present the results of our study of the beam induced background in the SVD and the prospects for future operation.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10303 - Particles and field physics

Project

<a href="/en/project/LTT17020" target="_blank" >LTT17020: Study of Beyond Standard Model Physics with the International Experiment Belle II in Japan</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2020

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Nuclear Instruments &amp; Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment

ISSN

0168-9002

e-ISSN

—

Volume of the periodical

982

Issue of the periodical within the volume

2020

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

4

Pages from-to

164580

UT code for WoS article

000581805300032

EID of the result in the Scopus database

2-s2.0-85090031920