Development of time projection chamber for precise neutron lifetime measurement using pulsed cold neutron beams
Y. Arimoto, N. Higashi, Y. Igarashi, Y. Iwashita, T. Ino, R. Katayama, R. Kitahara, M. Kitaguchi, H. Matsumura, K. Mishima, H. Oide, H. Otono, R. Sakakibara, T.… 展开作者
Y. Arimoto, N. Higashi, Y. Igarashi, Y. Iwashita, T. Ino, R. Katayama, R. Kitahara, M. Kitaguchi, H. Matsumura, K. Mishima, H. Oide, H. Otono, R. Sakakibara, T. Shima, H. M. Shimizu, T. Sugino, N. Sumi, H. Sumino, K. Taketani, G. Tanaka, M. Tanaka, K. Tauchi, A. Toyoda, T. Yamada, S. Yamashita, H. Yokoyama, T. Yoshioka
备注：
33 pages, 10 figures
发表信息：
Nuclear Instrument sand Methods in Physics Research A, 799 (2015) 187
A new time projection chamber (TPC) was developed for neutron lifetime measurement using a pulsed cold neutron spallation source at the Japan Proton Accelerator Research Complex (J-PARC). Managing considerable background events from natural sources and the beam radioactivity is a challenging aspect of this measurement. To overcome this problem, the developed TPC has unprecedented features such as the use of polyether-ether-ketone plates in the support structure and internal surfaces covered with $^6$Li-enriched tiles to absorb outlier neutrons. In this paper, the design and performance of the new TPC are reported in detail.
As a future charge management light source, UV light-emitting diodes (UV LEDs) offer far superior performance in a range of metrics compared to the mercury lamps used in the past. As part of a qualification program a number of short wavelength UV LEDs have been subjected to a series of lifetime tests for potential use on the Laser Interferometer Space Antenna (LISA) mission. These tests were performed at realistic output levels for both fast and continuous discharging in either a DC or pulsed mode of operation and included a DC fast discharge test spanning 50 days, a temperature dependent puls…
This paper describes the development of a pulsed light source using the discharge from an electrode in a medium of various noble gases. This source can be used to aid in the characterization and testing of new vacuum-ultraviolet (VUV) sensitive light detection devices. The source includes a novel spark driver circuit, a spark chamber into which different noble gases can be introduced, and an optical attenuation cell capable of being filled with different gases to allow for the attenuation of the pulsed light down to single photon levels. We describe the construction, calibration, and character…
The subject of space charge in ionisation detectors is reviewed, with particular attention to the case of liquid argon time projection chambers. Analytical and numerical description of the effects on the reconstructed coordinates along the drift and the transverse directions are presented. The cases of limited electron lifetime, of dual-phase detectors with ion feedback, and of detectors with small and comparable ratio between drift length and width are considered. Two design solutions that mitigates the effects are discussed.
We present measurements of light and charge signals in a dual-phase time projection chamber at electric fields varying from 10 V/cm up to 500 V/cm and at zero field using 511 keV gamma rays from a $^{22}$Na source. We determine the drift velocity, electron lifetime, diffusion constant, and light and charge yields at 511 keV as a function of the electric field. In addition, we fit the scintillation pulse shape to an effective exponential model, showing a decay time of 43.5 ns at low field that decreases to 25 ns at high fields.
A high-pressure hydrogen time projection chamber for the MuCap experiment
Paul Scherrer研究所的MuCap实验对质子捕获核μ子的基本电弱过程的速率进行了高精度测量，$μ^- + p \rightarrow n + ν_μ$。实验方法基于使用时间投影室（TPC），该时间投射室在10巴的压力下在纯氢气中操作，并用作主动μ子停止靶。TPC在三维空间中探测单个μ子到达的轨迹，而传出衰变（Michel）电子的轨迹则由两个周围的线室和塑料闪烁描迹器测量。μ子和电子探测器一起使得能够精确测量$μp$原子的寿命，由此推导出核μ子捕获率。TPC也被用来监测氢气的纯度，通过检测元素杂质捕获μ子后的核反冲。本文详细介绍了TPC的设计和性能。
The neutron lifetime, $τ$ = 880.2 $\pm$ 1.0 sec , is an important parameter for particle physics and cosmology. There is, however, an 8.4 sec (4.0$\,σ$) deviation between the measured value of the neutron lifetime using two methods : one method counts neutrons that survive after some time, while the other counts protons resulting from neutron beta decay. A new method is being implemented at J-PARC / MLF / BL05 using a pulsed cold neutron beam. A Time Projection Chamber (TPC) records both the electrons from neutron beta decay and protons from the neutron-$^3$He capture reactions in order to est…
"Neutron Optics and Physics (NOP/ BL05)" at MLF in J-PARC is a beamline for studies of fundamental physics. The beamline is divided into three branches so that different experiments can be performed in parallel. These beam branches are being used to develop a variety of new projects. We are developing an experimental project to measure the neutron lifetime with total uncertainty of 1 s (0.1%). The neutron lifetime is an important parameter in elementary particle and astrophysics. Thus far, the neutron lifetime has been measured by several groups; however, different values are obtained from dif…
Absolute intensity measurement of pulsed muon beams using in-beam activation
CMMS, TRIUMF（TRIUMF）；Department of Physics, Graduate School of Science, The University of Tokyo（东京大学理学研究科物理学系）；Nishina Center, RIKEN（理化学研究所仁科加速器科学研究中心）；ISIS Neutron and Muon Facility, STFC Rutherford Appleton Laboratory（STFC卢瑟福阿普尔顿实验室ISIS中子与μ子设施）；High Energy Accelerator Research Organization (KEK)（高能加速器研究机构(KEK)）；Department of Advanced Energy Science and Engineering, Kyushu University（九州大学先进能源工学部）；Research Center for Nuclear Physics, The University of Osaka（大阪大学核物理研究中心）
Gated wires are widely used in Time Projection Chamber (TPC) to avoid ion back-flow (IBF) in the drift volume. The anode wires can provide stable gain at high voltage with a long lifetime. However, switching on and off the gated grid (GG) leads to a dead time and also limit the readout efficiency of the TPC. Gas Electron Multiplier (GEM) foil provides a possibility of continuous readout for TPC, which can suppress IBF efficiently while keeping stable gain. A prototype chamber including two layers of GEM foils and anode wires has been built to combine both advantages from GEM and anode wire. Us…
An investigation of the α-decay of $^{147}$Sm was performed using an ultra low-background Twin Frisch-Grid Ionisation Chamber (TF-GIC). Four natural samarium samples were produced using pulsed laser deposition in ultra high vacuum. The abundance of the $^{147}$Sm isotope was mea- sured using inductively coupled plasma mass spectrometry. A combined half-life value for 147Sm of $1.079(26)\times{}10^{11}$ years was measured. A search for the α-decay into the first excited state of $^{143}$Nd has been performed using $γ$-spectroscopy, resulting in a lower half-life limit of $T_{1/2} > 3.1 \times{}…
The Long Baseline Neutrino Facility (LBNF) will produce the worlds most intense neutrino beam. Three series connected magnetic horns will require 5 kV, 300 kA, 800 $μ$s pulses at a rate of 1.4 Hz to focus the beam. Connecting a single power supply to these focusing horns will require a low impedance connection measuring over 60 m in length. To meet the challenging requirements of connecting the horns to the power supply, this connection is engineered as a nine-conductor, high-current pulsed stripline. It must pass through a harsh radiation environment, be passively cooled, and have an operatio…
We describe the construction and calibration of a multi-channel liquid time projection chamber filled with Tetramethylsilane (TMS). Its charge readout system consists of 8 wires each in the $X$ and $Y$ directions. The chamber is also equipped with a Cherenkov light readout system consisting of a 5-inch photomultiplier tube (PMT) coupled to the liquid volume through a viewport. The energy scale of the detector is calibrated using positron-electron pairs produced by 4.4 MeV gamma rays emitted from an AmBe source, using an external trigger on the positron annihilation gammas. The external trigger…
A calibration procedure is proposed for the ITER Radial Neutron Camera. No in-vessel calibration using external neutron sources is required: instead, it is proposed to rely on embedded sources, reference ITER pulses and cross-calibration with ITER fission chambers and activation system coupled to Monte Carlo simulations of radiation transport for the validation of the RNC calibration and for its tracking during ITER lifetime.
Development of a novel high-sensivitiy LAr purity monitor based on an $α$-source
研制了一种新型的液氩纯度监测器，其灵敏度可达ppb级（O $_2$当量）。这种高纯度例如在LAr漂移室中是需要的。其原理是测量LAr中准自由电子的寿命，因为这是漂移室操作的重要参数。自由电子是通过用$α$ -粒子电离LAr产生的，该粒子由同位素$^{210}Pb$源的$^{210}Po$链子体发射。通过测量漂移路径开始和结束时电子云的电荷以及漂移时间，可以获得电子的寿命。$α$ -粒子具有约50 μ $m in LAr and the ionization density is very high, typically between $ 750 <$1500 \rm MeV/cm $, leading to a high recombination rate. To suppress the recombination of the argon ions with the electrons, the $ α $-source was put in a strong electric field of $ 40 <$150 $ kV/cm的非常短的范围。这是通过将源沉积在直径约为0.5 mm的球形高压阴极的表面上来实现的。阳极也被制成与阴极直径大致相同的球体，因此，靠近两个电极之间的轴，电漂移场近似为偶极场。
A high-intensity pulsed muon beam is becoming available at the at the Japan Proton Accelerator Research Complex (J-PARC). Many experiments to study fundamental physics using this high-intensity muon beam are proposed. An experiment to measure the muon magnetic moment anomaly ($g-2$) and the muon electric dipole moment (EDM) is one of these experiments and it requires a tracking detector for positrons from muon decay. Fine segmentation is required in a detector to tolerate the high rate of positrons. The time resolution is required to be much better than the muon anomalous spin precession perio…
Experimental observation of an extremely high electron lifetime with the ICARUS-T600 LAr-TPC
ICARUS T600探测器是经过多年研发活动实现的最大液态氩时间投影室（LAr-TPC），已在INFN Gran Sasso地下实验室安装并成功运行3年。最重要的问题之一是需要在液态氩中具有极低的残余电负性杂质含量，以便以非常小的衰减沿漂移路径传输由电离粒子产生的自由电子。氩再循环和纯化系统所采用的解决方案在氩纯度和超过15 ms的自由电子寿命方面实现了令人印象深刻的结果，相当于约万亿分之20的当量O2污染，这是涉及LAr-TPC的任何未来项目和更高探测器质量尺度的开发的里程碑。
Liquid argon time projection chamber technology is an attractive choice for large neutrino detectors, as it provides a high-resolution active target and it is expected to be scalable to very large masses. Consequently, it has been chosen as the technology for the first module of the DUNE far detector. However, the fiducial mass required for "far detectors" of the next generation of neutrino oscillation experiments far exceeds what has been demonstrated so far. Scaling to this larger mass, as well as the requirement for underground construction places a number of additional constraints on the d…
Scanning Microwave Impedance Microscopy (MIM) measurement of photoconductivity with 50 nm resolution is demonstrated using a modulated optical source. The use of a modulated source allows for measurement of photoconductivity in a single scan without a reference region on the sample, as well as removing most topographical artifacts and enhancing signal to noise as compared with unmodulated measurement. A broadband light source with tunable monochrometer is then used to measure energy resolved photoconductivity with the same methodology. Finally, a pulsed optical source is used to measure local …
