Beam background study for the Belle II Silicon Vertex Detector

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

Beam background study for the Belle II Silicon Vertex Detector

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

Beam background study for the Belle II Silicon Vertex Detector

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10303 - Particles and field physics

Projekt

<a href="/cs/project/LTT17020" target="_blank" >LTT17020: Studium fyziky za standardním modelem v mezinárodním experimentu Belle II v Japonsku</a><br>

Návaznosti

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

Rok uplatnění

2020

Kód důvěrnosti údajů

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

Název periodika

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

ISSN

0168-9002

e-ISSN

—

Svazek periodika

982

Číslo periodika v rámci svazku

2020

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

4

Strana od-do

164580

Kód UT WoS článku

000581805300032

EID výsledku v databázi Scopus

2-s2.0-85090031920