Two-dimensional SR Interferometer for PLS-II

Kim, Changbum; Hwang, Ilmoon; Choi, Hyojin; Park, Sung-Ju; Huang, J. Y.; Han, Yeongjin; Park, Yong Woon; Ko, In Soo; Ryu, Jin Yeong; Hwang, Ji-Gwang

doi:10.3938/jkps.58.725

Cited by 9 publications

(5 citation statements)

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“…The external γ background from the radioactive isotopes in the surrounding rocks is shielded by the 20 cmthick lead castle and the 3 cm-thick copper box. By using the full shielding structure with N 2 gas flowing into the inside of the copper shield to avoid backgrounds from 222 Rn in the air at Y2L (measured to be 1.20±0.49 pCi/L [23]), we reduced the environmental background by a factor of 10,000 based on the measurements of a high-purity Ge (HPGe) detector, thus ensuring that those contributions are negligibly small. Despite all the efforts to block backgrounds due to external sources, some backgrounds from radioactive contaminations in detector components inside the shielding are still expected, including from the PMTs, grease, copper case, bolts, cables, acrylic supports, liquid scintillator, copper box, and steel that supports the lead block housing.…”

Section: External Background Sourcesmentioning

confidence: 99%

Background model for the NaI(Tl) crystals in COSINE-100

Adhikari

Souza

et al. 2018

Eur. Phys. J. C

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The COSINE-100 dark matter search experiment is an array of NaI(Tl) crystal detectors located in the Yangyang Underground Laboratory (Y2L). To understand measured backgrounds in the NaI(Tl) crystals we have performed Monte Carlo simulations using the Geant4 toolkit and developed background models for each crystal that consider contributions from both internal and external sources, including cosmogenic nuclides. The background models are based on comparisons of measurement data with Monte Carlo simulations that are guided by a campaign of material assays and are used to evaluate backgrounds and identify their sources. The average background level for the six crystals (70 kg total mass) that are studied is 3.5 counts/day/keV/kg in the (2-6) keV energy interval. The dominant contributors in this energy region are found to be 210 Pb and 3 H.

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Section: External Background Sourcesmentioning

confidence: 99%

Background model for the NaI(Tl) crystals in COSINE-100

Adhikari

Souza

et al. 2018

Eur. Phys. J. C

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“…To block such an environmental background we installed several shielding layers, as described in section 2.1, and measured the background reduction with an ultra-low background 100% HPGe detector at Y2L. By using the full shielding structure and N 2 gas flowing into the inside of the copper shield to avoid backgrounds from 222 Rn in the air at Y2L, we could reduce the environmental background by a factor of 10,000 (measured to be 1.20 ± 0.49 pCi/L [23]), thus ensuring that those contributions would be negligible. However, there exist some background from radioactive sources in detector components inside the shielding.…”

Section: Effects Of External Background Sourcesmentioning

confidence: 99%

“…• 22 Na (solid cyan line) 22 Na can be produced through the (n, 2n) reaction on 23 Na by energetic cosmic neutrons at sea level. It decays via positron emission (90%) and electron capture (10%), followed by 1270-keV γ-ray emission with a mean lifetime of 3.8 yr.…”

Section: Backgrounds From Cosmogenic Isotopesmentioning

confidence: 99%

Understanding NaI(Tl) crystal background for dark matter searches

Adhikari

et al. 2017

Eur. Phys. J. C

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We have developed ultra-low-background NaI(Tl) crystals to reproduce the DAMA results with the ultimate goal of achieving purity levels that are comparable to or better than those of the DAMA/LIBRA crystals. Even though the achieved background level does not approach that of DAMA/LIBRA, it is crucial to have a quantitative understanding of the backgrounds. We have studied background simulations toward a deeper understanding of the backgrounds and developed background models for a 9.16-kg NaI(Tl) crystal used in the test arrangement. In this paper we describe the contributions of background sources quantitatively by performing Geant4 Monte Carlo simulations that are fitted to the measured data to quantify the unknown fractions of the background compositions. In the fitted results, the overall simulated background spectrum well describes the measured data with a 9.16-kg NaI(Tl) crystal and shows that the background sources are dominated by surface 210 Pb and internal 40 K in the 2-6-keV energy interval, which produce 2.4 counts/day/keV/kg (dru) and 0.5 dru, respectively.

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“…This longitudinally coupled bunch instability was also observed in the horizontal beam size measurement using the two-dimensional synchrotron radiation (SR) interferometer system. 8 When the longitudinally coupled bunch instability occurs, the contrast in the interferometer image is smeared as shown in Fig. 4.…”

Section: Instability In the Pls-iimentioning

confidence: 94%

A transverse bunch by bunch feedback system for Pohang Light Source upgrade

Lee

Kim

Huang

et al. 2014

Review of Scientific Instruments

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The Pohang Light Source upgrade (PLS-II) project has successfully upgraded the Pohang Light Source (PLS). The main goals of the PLS-II project are to increase the beam energy to 3 GeV, increase the number of insertion devices by a factor of two (20 IDs), increase the beam current to 400 mA, and at the same time reduce the beam emittance to below 10 nm by using the existing PLS tunnel and injection system. Among 20 insertion devices, 10 narrow gap in-vacuum undulators are in operation now and two more in-vacuum undulators are to be installed later. Since these narrow gap in-vacuum undulators are most likely to produce coupled bunch instability by the resistive wall impedance and limit the stored beam current, a bunch by bunch feedback system is implemented to suppress coupled bunch instability in the PLS-II. This paper describes the scheme and performance of the PLS-II bunch by bunch feedback system.

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Two-dimensional SR Interferometer for PLS-II

Cited by 9 publications

References 0 publications

Background model for the NaI(Tl) crystals in COSINE-100

Background model for the NaI(Tl) crystals in COSINE-100

Understanding NaI(Tl) crystal background for dark matter searches

A transverse bunch by bunch feedback system for Pohang Light Source upgrade

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