Development of a Front End Board for a Plastic Scintillation Detector

주경광,MiJin Lee,김재률,임인택,SooBong Kim 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.2

A new plastic scintillation detector was constructed to improve the measurement of the neutrino energy spectrum in the energy region around 1 GeV. The detector has plastic scintillator strips and fibers. Each strip is read out by using a wavelength shifting fiber attached to a 64-channel multi-anode photomultiplier (MAPMT). The readout system consists of front-end electronics attached to a MAPMT and a back-end versa module eurocard (VME) module. A combination of application specific integrated circuit (ASICs) is used for the front-end readout electronics. VA32HDR11 (VA) is a 32-ch preamplifier chip with a shaper and a multiplexer. TA32CG (TA) provides timing information after taking OR of 32 channels. Two packages of VA/TA are mounted on a custom-designed front-end board (FEB) in order to read out signals from 64 anodes. A total of 300 FEBs were designed and manufactured in Korea, after which quality control was performed. For the purpose of quality control, visual inspections, bias voltage checks, tests in the pulse mode, and tests with charge injection were carried out. All of the test results were transferred to a database on the Web. All FEBs were installed at the experiment site and are functioning well. This paper describes the details of the FEB development.

Past and Present Status in the Development of Liquid Scintillators for Neutrino Experiments

주경광 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.8

This paper describes the past and present status in the development of liquid scintillators (LSs)for several neutrino experiments. Various LSs are commonly used for detecting neutrinos comingfrom atmospheric, solar, accelerator beam and reactor experiments. For a successful neutrinoexperiment, the LS should be chemically stable over the duration of the experiment. Furthermore,certain optical and physical properties, as well as safety concerns, should be satisfied. Investigatingthe various characteristics of the LSs used in neutrino experiments is important. In this paper LSsused for several neutrino experiments are briefly summarized and reviewed.

Development of a Spark Chamber by Using a Thyratron

주경광,Young Jang Lee,김수봉,Hwa Ryun Lee,Young Kyu Choi,Yeong Il Choi 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.6

A spark chamber is a device used in particle physics for detecting electrically charged particles. It consists of a set of parallel conducting aluminum plates. We constructed top and bottom chambers of a spark chamber. The size of the gap is 10 mm, and 34 gaps have been used in one chamber. The overall dimension of one chamber is 870 × 430 × 580 mm3. The coincidence of three scintillators is used to provide a trigger signal. When charged particles pass through a scintillator, the coincidence module in the NIM crate functions as an AND gate and generates a pulse. A mixture of inert gases, He and Ne, is used to fill the chamber. A CX1157 thyratron is used as the high voltage switching device. It plays the important role of providing a high-voltage signal to the aluminium plates at the moment when a signal is received from a trigger system. A cosmic muon trajectory can be seen clearly from the chamber. This chamber has been successfully displayed to the public. This is one of the biggest chambers in the world. A spark chamber is a device used in particle physics for detecting electrically charged particles. It consists of a set of parallel conducting aluminum plates. We constructed top and bottom chambers of a spark chamber. The size of the gap is 10 mm, and 34 gaps have been used in one chamber. The overall dimension of one chamber is 870 × 430 × 580 mm3. The coincidence of three scintillators is used to provide a trigger signal. When charged particles pass through a scintillator, the coincidence module in the NIM crate functions as an AND gate and generates a pulse. A mixture of inert gases, He and Ne, is used to fill the chamber. A CX1157 thyratron is used as the high voltage switching device. It plays the important role of providing a high-voltage signal to the aluminium plates at the moment when a signal is received from a trigger system. A cosmic muon trajectory can be seen clearly from the chamber. This chamber has been successfully displayed to the public. This is one of the biggest chambers in the world.

원전 중성미자 실험을 위한 액체섬광검출용액의 개발 연구

소선행,주경광 한국물리학회 2014 새물리 Vol.64 No.8

For detecting neutrinos from a nuclear power plant, we use the inverse beta decay reaction which produces a positron and a neutron after a neutrino collision. For a neutrino experiment to be successful, several characteristics of the liquid scintillator (long attenuation length, good absorbency, chemically stability, steady concentration) are important. Because the physical and the optical properties of the scintillator should remain unchanged over several years, we measured the absorbency of the liquid scintillator by using an UV spectrometer and the Gd concentration of the sample by using EDTA titration regularly. 역베타 붕괴반응을 이용하여 원전에서 방출되는 중성미자를 검출할 수 있다. 역베타 붕괴란 중성미자가 표적에 충돌한 후 양전하와 중성자를 생성하는 반응이다. 성공적인 실험을 위해서는 검출기 내부에 채워진 액체섬광검출 용액의 특성을 파악하고 있어야 한다. 중요한 액체섬광 검출용액의 특성으로는 감쇠 거리가 길고, 흡광도가 낮아야 하며, 화학적으로 안정하여 농도가 변하지 않아야 한다. 이를 위해 본 실험에서는 가시광선 분광광도계를 이용해 흡광도를 측정하고 EDTA 적정법을 이용해 가돌리늄 농도를 측정하였다. 또한 실험이 수년에 걸쳐 진행되기 때문에 장기적으로도 물리광학적인 특성이 유지되어야 한다. 이를 위해 흡광도와 가돌리늄 농도를 2주마다 주기적으로 측정하면서 변화를 모니터링 하였다.

기계학습을 이용한 원자로 중성미자 선별 연구

신창동,주경광,문동호,박명렬,고정환 한국물리학회 2019 새물리 Vol.69 No.8

차세대 대형 중성미자 검출 실험에서 배경사건과 원하는 신호를 효율적으로 선별하는 것은 매우 중요하다. 이를 위해서 현재 유용하게 사용되고 있는 분석 기술의 하나인 기계학습을 사용하여 중성미자 신호 선별에 적용하였을 때의 결과를 살펴보고자 한다. 이를 위해 비교적 특징이 잘 알려지고, 상대적으로통계량이 높은 원자로 중성미자의 역베타 붕괴 반응 이후 신호와 배경사건들을 몬테카를로 시뮬레이션을통하여 재현하고, 기계학습을 통한 신호선별 효율을 확인하였다. 최종적으로는 향후 차세대 중성미자실험에서 중요한 도구로 사용될 수 있을 것으로 기대한다. For the next-generation massive neutrino experiments, selecting a signal in the background events is very important. To do this, we investigated the results of applying a machine learning technique to the selection of neutrino signals. The neutrino signal after inverse beta decay and the background events in a gadolinium-loaded liquid scintillation detector were reproduced by using Monte Carlo simulations. The inverse beta decay process is well-known and has relatively high statistical quantities for this simulation. In this study, an efficiency of signal selection through machine learning was obtained, and in this paper several results are briefly described. Finally, the machine learning technique is expected to become an important tool for use in the next-generation neutrino experiment.

RENO 실험에서 몬테카를로를 이용한 역베타붕괴 후 양전자의 에너지 분포 연구

신창동,주경광 한국물리학회 2013 새물리 Vol.63 No.9

RENO (Reactor Experiment for Neutrino Oscillation) aims to measure the neutrino mixing angle 13 by using the Younggwang nuclear power plant. Through inverse beta decay ( ¯ e + p ! e+ + n, IBD), followed by neutron capture, reactor anti-neutrinos are detected. Although precise knowledge at the energy spectrum of positron (e+) is important for measuring 13, the measured energy spectrum of the positron will be affected by interactions with matter in the detector. In this report, the influence of interactions with matter was estimated by using a detector simulation, and 8% of events difference was confirmed for neutrino oscillation. RENO (Reactor Experiment for Neutrino Oscillation) 실험은 원자로의핵분열 과정에서 생성되는 반전자 중성미자가 검출기내의 양성자와충돌하는 역베타붕괴 (Inverse Beta Decay, e+p ! e++n,IBD) 과정을 거쳐 생성되는 양전자와 중성자의 신호를 검출해중성미자 진동변환상수 (θ13)를 측정한다. 역베타붕괴에서생성되는 양전자의 에너지 분포는 진동변환상수를 결정하는데 있어서중요하며 검출기에서 물질과의 상호작용으로 인하여 변한다. 이러한물질과의 상호작용의 영향을 검출기 시뮬레이션을 이용하여 확인하고,RENO 실험에서의 양전자 에너지 분포를 예측 하였다. 또한 중성미자진동변환에 의한 약 8\%의 이벤트 차이를 확인하였다.

GLoBES를 이용한 장거리 중성미자 진동변환 연구

김바로,주경광 한국물리학회 2011 새물리 Vol.61 No.9

GLoBES is a computer-based simulator for the neutrino oscillation caused by setting a neutrino source, baseline and detector. We simulate one of the neutrino oscillation parameters, Θ_13,for a long baseline neutrino experiment. The oscillation probability of a neutrino as a function of distance is estimated under the conditior that a ν_μ neutrino is made at JPARC in Japan and travels over ~1200 km to Korea. GLoBES는 중성미자 발생원과 검출기를 임의로 설정하여 가상적으로중성미자 실험을 구현할 수 있는 컴퓨터 시뮬레이터이다. 이를 이용하여진동변환상수 중의 하나인 Θ_13를 장거리 중성미자의 경우에대해 알아보았는데, 일본의 JPARC에서 만든 ν_μ 중성미자 빔이~1200 km 떨어진 한국으로 투사될 때 거리에 따른 중성미자의진동변환 확률을 구하였다.

Measurement of the Optical and the Physical Properties of a Liquid Scintillator Containing Water at Different Times and under Different Environmental Conditions

김승찬,주경광,김바로,신창동,소선행,여인성 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.7

In this paper, we describe the optical and the physical properties of a liquid scintillator (LS)containing water with long-term stability. Gadolinium (Gd) is loaded into the liquid scintillatorto increase the intensity of the neutron capture signal. If a successful neutrino experiment is tobe performed, the Gd-loaded liquid scintillator (GdLS) must be stable over the entire duration ofthe experiment. If water is contained inside the GdLS, the optical and the physical parametersof the GdLS may change. We, therefore, briefly describe several characteristics of GdLS sampleswith various water contents under different environmental conditions. Measurements of the watercontent, Gd concentration, transmittance, and light yield (LY) were performed over 600 days.

Development of a Gadolinium-loaded Liquid Scintillator for the Hanaro Short Baseline Prototype Detector

여인성,주경광,소선향,송숙형,김홍주,소정호,박강순,마경주,전은주,Jin Yu Kim,김영덕,Jason Lee,이정연,선광민 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.3

We propose a new experiment on the site of the Korea Atomic Energy Research Institute (KAERI)located at Daejeon, Korea. The Hanaro short baseline (SBL) nuclear reactor with a thermal poweroutput 30 MW is used to investigate a reactor neutrino anomaly. A Hanaro SBL prototype detectorhaving a 60-l volume has been constructed 6 m away from the reactor core. A gadolinium (Gd)-loaded liquid scintillator (LS) is used as an active material to trigger events. The selection of theLS is guided by physical and technical requirements, as well as safety considerations. A linearalkyl benzene (LAB) is used as a base solvent of the Hanaro SBL prototype detector. Three g/lof PPO and 30 mg/l of bis-MSB are dissolved to formulate the LAB-based LS. Then, a 0.5%gadolinium (Gd) complex with carboxylic acid is loaded into the LAB-based LS by using the liquidliquidextraction method. In this paper, we will summarize all the characteristics of the Gd-loadedLAB-based LS for the Hanaro prototype detector.

메탈 용해 액체 섬광 검출용액의 농도 측정 비교 연구

소선행,주경광 한국물리학회 2013 새물리 Vol.63 No.9

For detecting neutrinos from a nuclear power plant, we use the inverse-beta-decay reaction which a positron and a neutron after a neutrino collision with a target. We melt Gd in a liquid scintillator in order to extend the neutron-capture cross section area. For a neutrino experiment to be successful, know the exact Gd concentration and maintain that concentration are important. To do that, we measure the Gd concentration by EDTA (Ethylene Diamine Tetra Acetic acid) and PGAA (Prompt gamma neutron activation analysis) methods and use standard samples for calibration. We confirmed that the measured Ga concentration well compares with the converted concentration value from experimental data. 원전에서 방출되는 중성미자를 검출하기 위해 중성미자가 표적에 충돌한후 양전하와 중성자를 생성하는 역베타 반응을 이용할 수 있다. 중성자포획 산란 단면적을 크게 하기 위해 액체섬광검출용액에 가돌리늄을용해한다. 성공적인 실험을 위해서는 가돌리늄의 침전이나 부유현상이일어나지 않고 농도가 일정해야 하고 가돌리늄의 농도를 정확히 아는것은 중요하다. 이를 위해 본 실험에서는 EDTA 적정법과 PGAA 방법을이용하여 농도를 측정하였고 표준용액을 이용해서 그 농도 값을보정하였다. 이렇게 보정된 가돌리늄의 농도 값을 실험 데이터에 의해환산된 농도 값과 비교했을 때 잘 일치하는 것을 확인할 수 있었다.