WorldWideScience

Sample records for anechoic chambers

  1. Directed Energy Anechoic Chamber

    Data.gov (United States)

    Federal Laboratory Consortium — The Directed Energy Anechoic Chamber comprises a power anechoic chamber and one transverse electromagnetic cell for characterizing radiofrequency (RF) responses of...

  2. Design of a Fully Anechoic Chamber

    OpenAIRE

    Rusz, Roman

    2015-01-01

    This thesis deals with fully anechoic chamber design. The main aim of this thesis is to design fully anechoic chamber according to acoustics laws and customers (Honeywell’s) requirements. The fully anechoic chamber will be used for measuring sound and vibration quantities. This work is divided into two main parts. The first part deals with the general anechoic chamber theory and all its related design aspects. The second part, practical part, focus on specific design according to requirements...

  3. NRAO RF Anechoic Chamber & Antenna Range

    Data.gov (United States)

    Federal Laboratory Consortium — A shielded anechoic chamber measuring 15 by 15 by 37 feet is located in the Jansky Laboratory at Green Bank. This chamber has been outfitted as a far-field antenna...

  4. RADAR Anechoic Chamber/RCS Measurements Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The RF Anechoic Chamber is 56 feet long by 12 feet high by 13.5 feet wide, with an adjoining electronic computer control room. A double door entrance at one end of...

  5. Almond test body. [for microwave anechoic chambers

    Science.gov (United States)

    Dominek, Allen K. (Inventor); Wood, Richard M. (Inventor); Gilreath, Melvin C. (Inventor)

    1989-01-01

    The invention is an almond shaped test body for use in measuring the performance characteristics of microwave anechoic chambers and for use as a support for components undergoing radar cross-section measurements. The novel aspect of this invention is its shape, which produces a large dynamic scattered field over large angular regions making the almond valuable for verifying the performance of microwave anechoic chambers. As a component mount, the almond exhibits a low return that does not perturb the measurement of the component and it simulates the backscatter characteristics of the component as if over an infinite ground plane.

  6. RF Anechoic Chambers, Tri-Service Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — In collaboration with the Navy, there are 12 RF Anechoic and static free exposure chambers located at TSRL. These chambers cover the majority of the RF spectrum and...

  7. Precision Radio Frequency Anechoic Chamber Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Performs measurements and calibration of antennas for satellites and aircraft or groundbased systems. The chamber is primarily used for optimizing antenna...

  8. Experimental Anechoic Chamber Measurements of a Target Near an Interface

    OpenAIRE

    Marquart, Nicolas Pascal

    2006-01-01

    Abstract-The backscattered field of an illuminated sphere with diameter Ø = 30.5 cm above a perfect conducting plate is measured in an anechoic chamber at different heights for a varying incidence angle φ in the range 5° to 75°. A high frequency field λ « Ø is transmitted, so that two significant transitions from lit to shadow regions are given over the entire incidence angle range for the considered ray field. The polarimetric behavior of the measured scattering matrix [S] is investigated by...

  9. On Probe Weighting for MIMO OTA testing in Anechoic Chamber Setups

    DEFF Research Database (Denmark)

    Fan, Wei; Kyösti, Pekka; Nuutinen, Jukka-Pekka; Nielsen, Jesper Ødum; Pedersen, Gert F.

    The multi-probe anechoic chamber method is promising for OTA testing. The reason can be attributed to its potential for enabling evaluating MIMO terminals in realistic environments. The focus of the paper is on investigating how to create desired spatial channel models with the multi-probe anechoic...... chamber setups. Simulation results have shown that with the discussed methods, the number of probes and probe power weights determine to which level the spatial characteristics of the target channel models can be accurately approximated. With the optimized weights, better agreement is achieved for all...

  10. Transfer functions of a linear array prototype measured in the ISVR Anechoic Chamber

    OpenAIRE

    Olivieri, Ferdinando

    2016-01-01

    The matrix of transfer functions of a linear array prototype was measured in the ISVR anechoic chamber under free-field conditions. The setup is as follows. The loudspeaker array, mounted on a turntable, and an omni-directional microphone were installed in the anechoic chamber and placed at a reciprocal distance 3 m. The elements of the transfer function matrix were estimated using the so-called H1 estimator from the recordings of the responses between each loudspeaker of the array and the ...

  11. Emulating Ray-Tracing Channels in Multi-probe Anechoic Chamber Setups for Virtual Drive Testing

    DEFF Research Database (Denmark)

    Fan, Wei; Llorente, Ines Carton; Kyösti, Pekka;

    2016-01-01

    This paper discusses virtual drive testing (VDT) for multiple-input multiple-output (MIMO) capable terminals in multi-probe anechoic chamber (MPAC) setups. We propose to perform VDT, via reproducing ray tracing (RT) simulated channels with the field synthesis technique. Simulation results...

  12. A two dimensional finite difference time domain analysis of the quiet zone fields of an anechoic chamber

    Science.gov (United States)

    Ryan, Deirdre A.; Luebbers, Raymond J.; Nguyen, Truong X.; Kunz, Karl S.; Steich, David J.

    1992-01-01

    Prediction of anechoic chamber performance is a difficult problem. Electromagnetic anechoic chambers exist for a wide range of frequencies but are typically very large when measured in wavelengths. Three dimensional finite difference time domain (FDTD) modeling of anechoic chambers is possible with current computers but at frequencies lower than most chamber design frequencies. However, two dimensional FDTD (2D-FTD) modeling enables much greater detail at higher frequencies and offers significant insight into compact anechoic chamber design and performance. A major subsystem of an anechoic chamber for which computational electromagnetic analyses exist is the reflector. First, an analysis of the quiet zone fields of a low frequency anechoic chamber produced by a uniform source and a reflector in two dimensions using the FDTD method is presented. The 2D-FDTD results are compared with results from a three dimensional corrected physical optics calculation and show good agreement. Next, a directional source is substituted for the uniform radiator. Finally, a two dimensional anechoic chamber geometry, including absorbing materials, is considered, and the 2D-FDTD results for these geometries appear reasonable.

  13. Multi-dimensional scattering properties diagnosis system of scale aircraft model in an anechoic chamber

    Institute of Scientific and Technical Information of China (English)

    Chufeng Hu; Zhou Zhou; Nanjing Li; Kun Zhang

    2014-01-01

    Aiming at the concept of “diagnosis”, a simple and ef-fective broadband radar cross section (RCS) measurement system is constructed, and some multi-dimensional scattering properties diagnosis techniques are presented based on the system. Firstly, a stepped-frequency signal is employed to achieve high range resolution, combining with a variety of signal processing tech-niques. Secondly, cross-range resolution is gained with a rotating table, and the high-resolution two-dimensional (2-D) imaging of the scale model is obtained by the microwave imaging theory. Fi-nal y, two receiving antennas with a smal distance in altitude are used, and the three-dimensional (3-D) height distribution of scattering points on the scale model is extracted from the phase of images. Some typical bodies and a scale aircraft model are diagnosed in an anechoic chamber. The experimental results show that, after scaling with a metal sphere, the accurate one-dimensional (1-D) RCS pattern of the model is obtained, and it has a large dynamic range. When the bandwidth of the transmit-ting signal is 4 GHz, the resolution of the 2-D image can reach to 0.037 5 m. The 3-D height distribution of scattering points is given by interferometric measurement. This paper provides a feasible way to obtain high-precision scattering properties parameters of the scale aircraft model in a conventional rectangular anechoic chamber.

  14. A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber

    International Nuclear Information System (INIS)

    Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system

  15. A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber

    Science.gov (United States)

    Chiang, W. Y.; Wu, M. H.; Wu, K. L.; Lin, M. H.; Teng, H. H.; Tsai, Y. F.; Ko, C. C.; Yang, E. C.; Jiang, J. A.; Barnett, L. R.; Chu, K. R.

    2014-08-01

    Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system.

  16. A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber.

    Science.gov (United States)

    Chiang, W Y; Wu, M H; Wu, K L; Lin, M H; Teng, H H; Tsai, Y F; Ko, C C; Yang, E C; Jiang, J A; Barnett, L R; Chu, K R

    2014-08-01

    Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system. PMID:25173291

  17. A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, W. Y.; Wu, M. H.; Wu, K. L.; Lin, M. H.; Teng, H. H.; Barnett, L. R.; Chu, K. R., E-mail: krchu@yahoo.com.tw [Department of Physics, National Taiwan University, Taipei, Taiwan (China); Tsai, Y. F.; Ko, C. C.; Yang, E. C. [Department of Entomology, National Taiwan University, Taipei, Taiwan (China); Jiang, J. A. [Department of Bio-Industrial Mechatronics Engineering, National Taiwan University, Taipei, Taiwan (China)

    2014-08-15

    Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system.

  18. Supervised Self-Organizing Classification of Superresolution ISAR Images: An Anechoic Chamber Experiment

    Directory of Open Access Journals (Sweden)

    Radoi Emanuel

    2006-01-01

    Full Text Available The problem of the automatic classification of superresolution ISAR images is addressed in the paper. We describe an anechoic chamber experiment involving ten-scale-reduced aircraft models. The radar images of these targets are reconstructed using MUSIC-2D (multiple signal classification method coupled with two additional processing steps: phase unwrapping and symmetry enhancement. A feature vector is then proposed including Fourier descriptors and moment invariants, which are calculated from the target shape and the scattering center distribution extracted from each reconstructed image. The classification is finally performed by a new self-organizing neural network called SART (supervised ART, which is compared to two standard classifiers, MLP (multilayer perceptron and fuzzy KNN ( nearest neighbors. While the classification accuracy is similar, SART is shown to outperform the two other classifiers in terms of training speed and classification speed, especially for large databases. It is also easier to use since it does not require any input parameter related to its structure.

  19. A Test Model in a RF Anechoic Chamber for the Application of Wi-Fi Communication in Korean Operating NPPs

    International Nuclear Information System (INIS)

    The objective of this study is to make a test model and confirm its effectiveness in a radio frequency (RF) anechoic chamber before conducting a field test in Korean operating NPPs for use of Wi-Fi communication technology. This paper is focused on electromagnetic/radio-frequency interference (EMI/RFI) issue and discusses a methodology and its test result for overcoming that issue. Whenever wireless communication is performed between an access point (AP) and a smart phone, EMI/RFI problem always happens around those devices. It is necessary to decide how many wireless devices local workers will use and select what facilities and systems to protect from EMI/RFI, which are so-called EMI/RFI sensitive equipment. The number of wireless devices was decided as many as possible in the area where those devices could be used, and some sensitive equipment that shall not malfunction under electromagnetic environment were chosen. The test bed which considered above mentioned conditions was constructed and an experiment was carried out inside a radio-frequency anechoic chamber. Comparing with the allowable operating envelopes for electromagnetic level from RG-1.180, each maximum level of the test results acquired from a RF anechoic chamber is not over the limit even in case of considering the maximum local workers' usage. This result shows that it is highly likely that Wi-Fi communication can be used without any problem if sensitive equipment has observed the electromagnetic susceptibility limit of RG-1.180

  20. Radio Frequency Anechoic Chamber Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports the design, manufacture, and test of antenna systems. The facility is also used as an electromagnetic compatibility/radio frequency interference...

  1. Low-Power Anechoic Chamber

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Develops and evaluates the effectiveness of electronic attack (EA) techniques against antiship cruise missiles. All terminal countermeasures programmed in...

  2. Design and implementation aspects of a small anechoic room and sound-actuation system

    OpenAIRE

    García Rodríguez, Joel

    2011-01-01

    Looking for future projects, the possibility to have optimum conditions to perform microphone tests and any noise measurements of different small devices which will be constructed in the university, the need to construct a anechoic chamber was considered, so in this thesis a research about anechoic chambers was made. An acoustic anechoic chamber is a shielded room designed for performing sound measurements under conditions close to free space. Due to the difficulties that might entail t...

  3. 基于VISA和Mint的微波暗室自动测量系统实现%Implemenation of the Microwave Anechoic Chamber Automatic Measuring System Based on VISA and Mint

    Institute of Scientific and Technical Information of China (English)

    李瑞阳; 韦高; 韩旭; 符礼

    2013-01-01

    建立了一套基于VISA和Mint的微波暗室自动测量系统,通过计算机控制矢网和转台以实现高效率的天线与RCS的微波暗室自动测量.在Visual C++开发环境下,运用多线程技术将矢网和转台结合,同时采用VISA和SCPI命令实现矢网的自动控制,采用Mint ActiveX控件技术实现转台的自动控制,该方法易于实现矢网与转台的高效同步.实测表明,该系统操作方便,测量效率、测量精度与自动化程度较高,所采用的控制方法有着较好的通用性和可拓展性,具有广阔的应用前景.%In order to realize efficient automatic antenna and RCS measurement,a microwave anechoic chamber automatic measurement system has been established,using the computer to control the vector network analyzer and the test turntable.In visual C++development environment,the multithread technology is used to combine the vector network analyzer with the test turntable.The vector network analyzer is auto-controlled by VISA and SCPI command ; the test turntable is auto-controlled by Mint ActiveX control technology.The methods are easy to efficiently synchronize the two devices.The actual measurement shows that the system is easy to control,and has high measurement efficiency,high precision,and high automaticity.The controlling method has broad application prospects for it has good universality and is easy to expand.

  4. Electromagnetic Radiation (EMR) coupling to complex systems : aperture coupling into canonical cavities in reverberant and anechoic environments and model validation.

    Energy Technology Data Exchange (ETDEWEB)

    Charley, Dawna R.; Higgins, Matthew B.

    2007-12-01

    Mode-stirred chamber and anechoic chamber measurements were made on two sets of canonical test objects (cylindrical and rectangular) with varying numbers of thin slot apertures. The shielding effectiveness was compared to determine the level of correction needed to compensate the mode-stirred data to levels commensurate with anechoic data from the same test object.

  5. An approach of harmonic suppression circuit and reactive power compensation in anechoic chamber%一种电波暗室的谐波抑制电路及其无功补偿方法

    Institute of Scientific and Technical Information of China (English)

    袁瑞铭; 巨汉基; 高迪雅; 李斯琪; 丁恒春; 田海亭; 钟侃

    2015-01-01

    Two stages series active power filter are used to harmonic suppression circuit and reactive power compensa-tion in anechoic chamber.The dry-type iron core reactor is shunt between the filter and the load power supply termi-nal.Dry iron core reactor is mainly used for the inhibition of 10kHz and above high-frequency interference.It can ef-fectively suppress high order harmonic, limit switch flow and operate over-voltage, improve power factor and voltage waveform of the system without affecting the filter performance of the series passive power filter.It plays an important role in the safe operation of power capacitor and power equipment.Parallel dry iron core reactor not only solves the problem of voltage variation of different reactor loads at the entrance, but also improves the accuracy and reliability of the performance measurement in electromagnetic compatibility testing.%电波暗室的谐波抑制电路及无功补偿方法采用正向串联的两级串联型无源电力滤波器,滤波器和负载的电源端之间并联干式铁芯电抗器。干式铁芯电抗器主要用于抑制10 kHz及以上的高频干扰,在不影响串联型无源电力滤波器的滤波性能的基础上,抑制高次谐波,限制合闸涌流及操作过电压,改善系统的电压波形,提高功率因数,保障电力电容器及其他电力设备的安全运行,并联干式铁芯电抗器解决了各类负载入口处的电压变化的问题,提高了电磁兼容检测中计量性能的可靠性和准确性。

  6. 基于双层涂敷模型的暗室静区精确计算方法%Calculation method for quiet zone of anechoic chamber based on double layer coating model

    Institute of Scientific and Technical Information of China (English)

    徐若曦; 周鹏; 章锦文

    2015-01-01

    针对大型微波暗室静区性能仿真中,数值方法在高频段效率急剧降低,而传统高频算法计算准确度难以保证的问题,提出一种基于弹跳射线理论的双层涂敷模型仿真方法。该方法利用实测数据,分级地对模型进行计算与校正,双层涂敷模型有效简化了锥形吸波材料,弹跳射线法解决了曲面反射及远场精确求取问题。仿真结果表明:该方法与传统的几何光学法相比,高频段的计算精度显著提高,同时平均计算时间短,消耗内存少。理论分析和仿真结果验证了方法的正确性和有效性。%To solve the problem that the efficiency of numerical method drops sharply at high frequen‐cy and the accuracy of high frequency algorithm is difficult to ensure in the quiet zone performance simulation of large scale anechoic chamber .A simulation method of double layer coating model based on shooting and bouncing ray was proposed .The model using real measurements was calculated and corrected .Double layer coating model simplified the cone wave absorbing materials ,and the shooting and bouncing ray (SBR) method effectively solved the curve reflection and far field accurately obtai‐ning problem .The simulation results indicate that this method can improve precision compared with the traditional method and can reduce time and memory .Both of the theoretical analysis and the simu‐lation results verified the validity and feasibility of the proposed method .

  7. Static and wind tunnel near-field/far-field jet noise measurements from model scale single-flow base line and suppressor nozzles. Summary report. [conducted in the Boeing large anechoic test chamber and the NASA-Ames 40by 80-foot wind tunnel

    Science.gov (United States)

    Jaeck, C. L.

    1977-01-01

    A test program was conducted in the Boeing large anechoic test chamber and the NASA-Ames 40- by 80-foot wind tunnel to study the near- and far-field jet noise characteristics of six baseline and suppressor nozzles. Static and wind-on noise source locations were determined. A technique for extrapolating near field jet noise measurements into the far field was established. It was determined if flight effects measured in the near field are the same as those in the far field. The flight effects on the jet noise levels of the baseline and suppressor nozzles were determined. Test models included a 15.24-cm round convergent nozzle, an annular nozzle with and without ejector, a 20-lobe nozzle with and without ejector, and a 57-tube nozzle with lined ejector. The static free-field test in the anechoic chamber covered nozzle pressure ratios from 1.44 to 2.25 and jet velocities from 412 to 594 m/s at a total temperature of 844 K. The wind tunnel flight effects test repeated these nozzle test conditions with ambient velocities of 0 to 92 m/s.

  8. Method for material characterization in a non-anechoic environment

    Science.gov (United States)

    Pometcu, L.; Sharaiha, A.; Benzerga, R.; Tamas, R. D.; Pouliguen, P.

    2016-04-01

    This paper presents a characterization method for extracting the reflection coefficient of materials and the real part of their permittivity. The characterization is performed in a real environment, as opposed to the classical measurement methods that require an anechoic chamber. In order to reduce the effects of the multipath propagation, a free space bistatic measurement was performed at different distances material-antennas in far field. By using a Teflon sample and a commercial absorbing material sample, measurements have been performed in order to validate the characterization technique.

  9. Processing of Prosthetic Heart Valve Sounds from Anechoic Tank Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J V; Meyer, A W

    2001-03-20

    People with serious cardiac problems have had their life span extended with the development of the prosthetic heart valve. However, the valves operate continuously at approximately 39 million cycles per year and are therefore subject to structural failures either by faulty design or material fatigue. The development of a non-invasive technique using an acoustic contact microphone and sophisticated signal processing techniques has been proposed and demonstrated on limited data sets. In this paper we discuss an extension of the techniques to perform the heart valve tests in an anechoic like. Here the objective is to extract a ''pure'' sound or equivalently the acoustical vibration response of the prosthetic valves in a quiet environment. The goal is to demonstrate that there clearly exist differences between values which have a specific mechanical defect known as single leg separation (SLS) and non-defective valves known as intact (INT). We discuss the signal processing and results of anechoic acoustic measurements on 50 prosthetic valves in the tank. Finally, we show the results of the individual runs for each valve, point out any of the meaningful features that could be used to distinguish the SLS from INT and summarize the experiments.

  10. Analysis of absorption performances of anechoic layers with steel plate backing.

    Science.gov (United States)

    Meng, Hao; Wen, Jihong; Zhao, Honggang; Lv, Linmei; Wen, Xisen

    2012-07-01

    Rubber layers with air-filled cavities or local resonance scatters can be used as anechoic coatings. A lot of researches have focused on the absorption mechanism of the anechoic coatings. As the anechoic coatings are bonded to the hull of submarine, the vibration of the hull should not be neglected when the analysis of the absorption characters is carried out. Therefore, it is more reasonable to treat the anechoic coating and the backing as a whole when the acoustic performance is analyzed. Considering the effects of the steel plate backing, the sound absorption performances on different models of anechoic coatings are investigated in this paper. The Finite Element Method is used to illustrate the vibrational behaviors of the anechoic coatings under the steel backings by which the displacement contours is obtained for analysis. The theoretical results show that an absorption peak is induced by the resonance of the steel slab and rubber layer. At the frequency of this absorption peak, the steel plate and the coating vibrates longitudinally like a mass-spring system in which the steel slab serves for mass and the coating layer is the spring. To illuminate the effects of the steel slab backing on the acoustic absorption, the thicknesses of the steel slab and the anechoic layer are discussed. Finally, an experiment is performed and the results show a good agreement with the theoretical analysis. PMID:22779456

  11. Wideband MIMO Channel Capacity Analysis in Multi-probe Anechoic Chamber Setups

    DEFF Research Database (Denmark)

    Fan, Wei; Kyosti, Pekka; Nielsen, Jesper Ødum;

    2016-01-01

    been used to determine the test area size for a limited number of probes. However, it is desirable that the test area size is defined in terms of data rate deviation of the simulated channel in the laboratory from that of the target channel model. This paper reports MIMO capacity analysis results for...

  12. Aeroacoustic Study of a Model-Scale Landing Gear in a Semi-Anechoic Wind Tunnel

    OpenAIRE

    Remillieux, Marcel Christophe

    2007-01-01

    An aeroacoustic study was conducted on a 26%-scale Boeing 777 main landing gear in the Virginia Tech (VT) Anechoic Stability Wind Tunnel. The VT Anechoic Stability Wind Tunnel allowed noise measurements to be carried out using both a 63-elements microphone phased array and a linear array of 15 microphones. The noise sources were identified from the flyover view under various flow speeds and the phased array positioned in both the near and far-field. The directivity pattern of the landing ge...

  13. Application of Multi-Layered Polyurethane Foams for Flat-Walled Anechoic Linings

    DEFF Research Database (Denmark)

    Xu, J. F.; Buchholz, Jörg; Fricke, Fergus R.

    2006-01-01

    application of multi-layered polyurethane foams as the flat-walled anechoic lining. The investigation includes aspects such as the efficacy of a single layer of material, the minimum number of layers of linings to achieve the minimum overall thickness for low (100Hz), mid (250Hz) and high (500Hz) cut...

  14. Subjective evaluation of auralizations created from multi-channel anechoic recordings of a talker in motion

    Science.gov (United States)

    Vigeant, Michelle C.; Wang, Lily M.

    2005-04-01

    A high degree of speech intelligibility is very important in educational environments. When designing such spaces, like classrooms, auralizations can be used to subjectively assess the degree of speech intelligibility and clarity. Auralizations are most commonly made by convolving the impulse response (IR) of an omni-directional source with a single channel anechoic speech recording. This paper explores the idea of using multi-channel recordings to create the auralizations, using a female talker in motion. An omni-directional source is split into quadrants and the IR is calculated for each section. These IR's are convolved with the appropriate channel of the anechoic recording and then the four auralizations are mixed to create one final auralization. The auralizations were made using four-channel anechoic recordings of a person walking on a platform while talking. Subjective tests were conducted to determine the ease with which subjects could identify the direction of the movement of the source in rooms with varying amounts of absorption. This method can be used to create more realistic classroom auralizations, as teachers typically move around the room as they teach. [Work supported by the National Science Foundation.

  15. LLNL heart valve condition classification project anechoic testing results at the TRANSDEC evaluation facility

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J V

    1999-10-31

    This report first briefly outlines the procedures and support/activation fixture developed at LLNL to perform the heart valve tests in an anechoic-like tank at the US Navy Transducer Evaluation Facility (TransDec) located in San Diego, CA. Next they discuss the basic experiments performed and the corresponding experimental plan employed to gather meaningful data systematically. The signal processing required to extract the desired information is briefly developed along with some of the data. Finally, they show the results of the individual runs for each valve, point out any of the meaningful features and summaries.

  16. Microchannel Anechoic Corner for Microparticle Manipulation via Travelling Surface Acoustic Waves

    Science.gov (United States)

    Destgeer, Ghulam; Ha, Byung Hang; Park, Jinsoo; Jung, Jin Ho; Alazzam, Anas; Sung, Hyung Jin

    We present a particle manipulation device composed of a pair of slanted interdigitated transducers (SIDTs) and a polydimethyl-siloxane (PDMS) microfluidic channel. Tunable travelling surface acoustic waves (TSAWs) produced by the SIDTs at desired locations are used to separate polystyrene (PS) microspheres of different diameters. The acoustic radiation force (ARF) acting on PS microspheres is estimated to predict the variable deflection of two distinct diameter microspheres that results in bi-separation of particles (3.2 and 4.8 μm). Interaction of TSAWs with the fluid and propagation of leaky acoustic waves at Rayleigh angle produce an anechoic corner inside the microchannel. An adequate choice of TSAW-frequency with reference to the particles' diameters, corresponding ARF-estimation and incorporation of the microchannel anechoic corner results in a tri-separation of PS microspheres (3, 4.2, 5 μm). The tri-separation is achieved by TSAWs - 135 MHz to deflect 5 μm particles upstream of microchannel and 175 MHz to deflect 4.2 μm particles downstream.

  17. A Wide Band Strong Acoustic Absorption in a Locally Network Anechoic Coating

    International Nuclear Information System (INIS)

    Composite materials with interpenetrating network structures usually exhibit unexpected merit due to the cooperative interaction. Locally resonant phononic crystals (LRPC) exhibit excellent sound attenuation performance based on a periodical arrangement of sound wave scatters. Inspired by the interpenetrating network structure and the LRPC concept, we develop a locally network anechoic coating (LNAC) that can achieve a wide band of underwater strong acoustic absorption. The experimental results show that the LNAC possesses an excellent underwater acoustic absorbing capacity in a wide frequency range. Moreover, in order to investigate the impact of the interpenetrating network structure, we fabricate a faultage structure sample and the network is disconnected by hard polyurethane (PU). The experimental comparison between the LNAC and the faultage structure sample shows that the interpenetrating network structure of the LNAC plays an important role in achieving a wide band strong acoustic absorption

  18. spark chamber

    CERN Multimedia

    A few cosmic rays pass through your body every second of every day, no matter where you are. Look at the spark chamber to your right – every flash is the track made by a cosmic ray from outer space. The spark chamber is filled with a special gas mixture. Cosmic rays knock electrons out of the atoms in the gas. These electrons accelerate towards high voltage metal strips layered throughout the chamber, creating sparks like little bolts of lightning.

  19. spark chamber

    CERN Multimedia

    A few cosmic rays pass through your body every second of every day, no matter where you are. Look at the spark chamber to your right – every flash is the track made by a cosmic ray from outer space. The spark chamber is filled with a special gas mixture. Cosmic rays knock electrons out of the atoms in the gas. These electrons accelerate towards high voltage metal strips layered throughout the chamber, creating sparks like little bolts of lightning.

  20. Ussing Chamber

    NARCIS (Netherlands)

    Westerhout, J.; Wortelboer, H.; Verhoeckx, K.

    2015-01-01

    The Ussing chamber system is named after the Danish zoologist Hans Ussing, who invented the device in the 1950s to measure the short-circuit current as an indicator of net ion transport taking place across frog skin (Ussing and Zerahn, Acta Physiol Scand 23:110-127, 1951). Ussing chambers are increa

  1. Wire Chamber

    CERN Multimedia

    1986-01-01

    Two wire chambers made originally for the R807 Experiment at CERN's Intersecting Storage Rings. In 1986 they were used for the PS 201 experiment (Obelix Experiment) at LEAR, the Low Energy Antiproton Ring. The group of researchers from Turin, using the chambers at that time, changed the acquisition system using for the first time 8 bit (10 bit non linear) analog to digital conversion for incoming signals from the chambers. The acquisition system was controlled by 54 CPU and 80 digital signal processors. The power required for all the electronics was 40 kW. For the period, this system was one of the most powerful on-line apparatus in the world. The Obelix Experiment was closed in 1996. To find more about how a wire chamber works, see the description for object CERN-OBJ-DE-038.

  2. Vacuum chamber

    International Nuclear Information System (INIS)

    A detailed description is given of the vacuum chamber of the so-called experimental equipment DEMAS (double-arm-time-of-flight spectrometer) at the heavy ion accelerator U-400 at the JINR-Dubna. (author)

  3. wire chamber

    CERN Multimedia

    Was used in ISR (Intersecting Storage Ring) split field magnet experiment. Multi-wire detectors contain layers of positively and negatively charged wires enclosed in a chamber full of gas. A charged particle passing through the chamber knocks negatively charged electrons out of atoms in the gas, leaving behind positive ions. The electrons are pulled towards the positively charged wires. They collide with other atoms on the way, producing an avalanche of electrons and ions. The movement of these electrons and ions induces an electric pulse in the wires which is collected by fast electronics. The size of the pulse is proportional to the energy loss of the original particle.

  4. Robert Chambers

    NARCIS (Netherlands)

    K. Biekart (Kees); D.R. Gasper (Des)

    2013-01-01

    textabstractProfessor Robert Chambers is a Research Associate at the Institute of Development Studies (IDS), University of Sussex (Brighton, UK), where he has been based for the last 40 years, including as Professorial Research Fellow. He became involved in the field of development management in the

  5. Ionization chamber

    International Nuclear Information System (INIS)

    An ionization chamber X-ray detector is described. It comprises a flat cathode sheet parallel to an anode which has a perforated insulating layer on its surface. An open grid, a thin perforated metal sheet is disposed on the insulating layer - the perforations of the layer and sheet are aligned. There is a detector gas and means for maintaining the grid at an electric potential between that of the anode and cathode and for measuring the current flow from the anode to the cathode. The grid shields the anode from the electric field produced by the positive ions which flow towards the cathode and this permits an independent measurement of the electron current flowing to the anode; even when the X-ray pulse length is not much shorter than the ion drift time. The recovery time of the ionization chamber is thus decreased by several orders of magnitude over previous chambers. The grid will normally be fixed to the anode and by shielding the anode from the cathode electric field, tends to eliminate capacitive microphone currents which would otherwise flow in the anode circuit. (U.K.)

  6. Anechoic Performance Analysis of Porous Ceramics%某种多孔陶瓷的消声性能试验

    Institute of Scientific and Technical Information of China (English)

    杨碧君; 潘国培; 贺华; 丁炜; 周相荣

    2014-01-01

    调研了多孔陶瓷材料在声学领域的应用,阐述了其作为吸声材料、隔声材料及消声器使用时的声学原理。基于多孔陶瓷作为消声器使用的相关研究较少,为确定影响多孔陶瓷消声性能的主要因素,在两种试验工况下对不同规格的多孔陶瓷管进行排气试验。孔隙率是表征多孔陶瓷的基本参量,它与多项物理性能存在紧密联系,为排除它的影响,选择40%孔隙率的多孔陶瓷进行试验,结果表明壁厚越厚,消声效果越好,孔径为20μ的多孔陶瓷管消声效果最佳。随着温度的升高,多孔陶瓷管的消声频谱特性曲线向高频移动。%Application of porous ceramics to acoustics area is summarized. Acoustics theory of the porous ceramics is expatiated when they are used as sound absorption material, sound insulation material and in mufflers. However, the researches of application of porous ceramics to mufflers are very few. In order to determine the major factors affecting anechoic properties of the porous ceramics, exhaust experiments on different porous ceramics are carried out in two different conditions. Porosity is a basic parameter of the porous ceramics related to the physical performance. The porosity of the porous ceramic is chosen to be a 40%constant in the experiments to eliminate the porosity effect. The results show that the thicker the porous ceramic is, the better the anechoic property is. And anechoic property of the porous ceramic with 20 μaperture is the best. With the temperature rising, the anechoic spectrum curve of the porous ceramic moves towards the high frequency direction.

  7. Chamber transport

    Energy Technology Data Exchange (ETDEWEB)

    OLSON,CRAIG L.

    2000-05-17

    Heavy ion beam transport through the containment chamber plays a crucial role in all heavy ion fusion (HIF) scenarios. Here, several parameters are used to characterize the operating space for HIF beams; transport modes are assessed in relation to evolving target/accelerator requirements; results of recent relevant experiments and simulations of HIF transport are summarized; and relevant instabilities are reviewed. All transport options still exist, including (1) vacuum ballistic transport, (2) neutralized ballistic transport, and (3) channel-like transport. Presently, the European HIF program favors vacuum ballistic transport, while the US HIF program favors neutralized ballistic transport with channel-like transport as an alternate approach. Further transport research is needed to clearly guide selection of the most attractive, integrated HIF system.

  8. Separation of radiated sound field components from waves scattered by a source under non-anechoic conditions

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Jacobsen, Finn

    2010-01-01

    A method of estimating the sound field radiated by a source under non-anechoic conditions has been examined. The method uses near field acoustic holography based on a combination of pressure and particle velocity measurements in a plane near the source for separating outgoing and ingoing wave...... components. The outgoing part of the sound field is composed of both radiated and scattered waves. The method compensates for the scattered components of the outgoing field on the basis of the boundary condition of the problem, exploiting the fact that the sound field is reconstructed very close...... to the source. Thus the radiated free-field component is estimated simultaneously with solving the inverse problem of reconstructing the sound field near the source. The method is particularly suited to cases in which the overall contribution of reflected sound in the measurement plane is significant....

  9. Time-Domain Measurement of the Ear-to-Ear On-Body Path Gain at 2.45 GHz in a Radio Anechoic Environment

    DEFF Research Database (Denmark)

    Kvist, Søren Helstrup; Thaysen, Jesper; Jakobsen, Kaj Bjarne

    2012-01-01

    The ear-to-ear on-body path gain (jS21j) at 2:45 GHz is measured in the time domain. The measurements were conducted in a radio anechoic environment to study the effects of the on-body paths only. Two different monopole antenna configurations that are polarized normal and tangential to the surface...

  10. Transabdominal ultrasonography of the small bowel after oral administration of a non-absorbable anechoic solution: Comparison with barium enteroclysis

    International Nuclear Information System (INIS)

    AIM: The aim of this study was to determine if oral administration of a non-absorbable anechoic solution conveys any benefit during abdominal ultrasound (US), with special reference to its accuracy. MATERIALS AND METHODS: Fifty-three adult out-patients scheduled for small bowel barium enema (SBE) were included. The day before SBE all patients underwent abdominal US before and after oral administration of an isotonic non-absorbable electrolyte solution containing polyethylene glycol (PEG-ELS). Sensitivity and specificity were evaluated using SBE as a gold standard. RESULTS: After ingestion of PEG-ELS satisfactory distension of the intestinal lumen was obtained (11-25 mm) with sequential visualization of jejunoileal loops in 30.9 ± 17.3 min. In 15 out of 53 cases both US and SBE showed bowel changes characteristic of Crohn's disease. In three out of 53 cases both US and SBE showed neoplasms. In one out of 53 cases US was negative, SBE positive for local nodularity and ulcerations typical of Crohn's disease. In one out of 53 cases US was negative, SBE positive for macronodularity consistent with coeliac disease. In five out of 53 cases US was negative, while SBE was positive for mininodularity expressive of lymphoid hyperplasia. In 28 out of 53 cases both examinations were negative. CONCLUSION: PEG-ELS administration allows a thorough US investigation of the small bowel, with fair sensitivity (72%) and excellent specificity (100%). False negative findings are mainly due to lymphoid hyperplasia, a feature of uncertain significance in adults. Cittadini G. et al.(2001)

  11. Streamer chamber: pion decay

    CERN Multimedia

    1992-01-01

    The real particles produced in the decay of a positive pion can be seen in this image from a streamer chamber. Streamer chambers consist of a gas chamber through which a strong pulsed electric field is passed, creating sparks as a charged particle passes through it. A magnetic field is added to cause the decay products to follow curved paths so that their charge and momentum can be measured.

  12. Prototype multiwire proportional chamber

    CERN Multimedia

    1975-01-01

    Chambers of this type were initially developed within the Alpha project (finally not approved). They were designed such to minimize the radiation length with a view to a mass spectrometer of high resolution meant to replace the Omega detector. The chambers were clearly forerunners for the (drift) chambers later built for R606 with the novel technique of crimping the wires. See also photo 7510039X.

  13. Electromagnetic reverberation chambers

    CERN Document Server

    Besnier, Philippe

    2013-01-01

    Dedicated to a complete presentation on all aspects of reverberation chambers, this book provides the physical principles behind these test systems in a very progressive manner. The detailed panorama of parameters governing the operation of electromagnetic reverberation chambers details various applications such as radiated immunity, emissivity, and shielding efficiency experiments.In addition, the reader is provided with the elements of electromagnetic theory and statistics required to take full advantage of the basic operational rules of reverberation chambers, including calibration proc

  14. BEBC bubble chamber

    CERN Multimedia

    1972-01-01

    Looking up into the interior of BEBC bubble chamber from the expansion cylinder. At the top of the chamber two fish-eye lenses are installed and three other fish-eye ports are blanked off. In the centre is a heat exchanger.

  15. High resolution drift chambers

    International Nuclear Information System (INIS)

    High precision drift chambers capable of achieving less than or equal to 50 μm resolutions are discussed. In particular, we compare so called cool and hot gases, various charge collection geometries, several timing techniques and we also discuss some systematic problems. We also present what we would consider an ''ultimate'' design of the vertex chamber. 50 refs., 36 figs., 6 tabs

  16. OPAL Jet Chamber Prototype

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. OPAL's central tracking system consists of (in order of increasing radius) a silicon microvertex detector, a vertex detector, a jet chamber, and z-chambers. All the tracking detectors work by observing the ionization of atoms by charged particles passing by: when the atoms are ionized, electrons are knocked out of their atomic orbitals, and are then able to move freely in the detector. These ionization electrons are detected in the dirfferent parts of the tracking system. This piece is a prototype of the jet chambers

  17. Gridded ionization chamber

    International Nuclear Information System (INIS)

    An improved ionization chamber type x-ray detector comprises a heavy gas at high pressure disposed between an anode and a cathode. An open grid structure is disposed adjacent the anode and is maintained at a voltsge intermediate between the cathode and anode potentials. The electric field which is produced by positive ions drifting toward the cathode is thus shielded from the anode. Current measuring circuits connected to the anode are, therefore, responsive only to electron current flow within the chamber and the recovery time of the chamber is shortened. The grid structure also serves to shield the anode from electrical currents which might otherwise be induced by mechanical vibrations in the ionization chamber structure

  18. ALICE Time Projection Chamber

    CERN Multimedia

    Lippmann, C

    2013-01-01

    The Time Projection Chamber (TPC) is the main device in the ALICE 'central barrel' for the tracking and identification (PID) of charged particles. It has to cope with unprecedented densities of charges particles.

  19. Toxic Test Chambers

    Data.gov (United States)

    Federal Laboratory Consortium — Description/History: Hazardous material test facility Both facilities have 16,000 cubic foot chambers, equipped with 5000 CFM CBR filter systems with an air change...

  20. Calorimetry with flash chambers

    International Nuclear Information System (INIS)

    The flash chambers used in the Fermilab E594 neutrino experiment are described, and their use in a calorimeter discussed. Resolutions obtained with a calibration beam are presented, and comments made about the pattern recognition capabilities of the calorimeter

  1. Bubble chamber: antiproton annihilation

    CERN Multimedia

    1971-01-01

    These images show real particle tracks from the annihilation of an antiproton in the 80 cm Saclay liquid hydrogen bubble chamber. A negative kaon and a neutral kaon are produced in this process, as well as a positive pion. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that had been heated to boiling point.

  2. Gridded Ionization Chamber

    International Nuclear Information System (INIS)

    In the present paper the working principles of a gridded ionization chamber are given, and all the different factors that determine its resolution power are analyzed in detail. One of these devices, built in the Physics Division of the JEN and designed specially for use in measurements of alpha spectroscopy, is described. finally the main applications, in which the chamber can be used, are shown. (Author) 17 refs

  3. Target Chamber Manipulator

    Science.gov (United States)

    Tantillo, Anthony; Watson, Matthew

    2015-11-01

    A system has been developed to allow remote actuation of sensors in a high vacuum target chamber used with a particle accelerator. Typically, sensors of various types are placed into the target chamber at specific radial and angular positions relative to the beam line and target. The chamber is then evacuated and the experiments are performed for those sensor positions. Then, the chamber is opened, the sensors are repositioned to new angles or radii, and the process is repeated, with a separate pump-down cycle for each set of sensor positions. The new sensor positioning system allows scientists to pre-set the radii of up to a dozen sensors, and then remotely actuate their angular positions without breaking the vacuum of the target chamber. This reduces the time required to reposition sensors from 6 hours to 1 minute. The sensors are placed into one of two tracks that are separately actuated using vacuum-grade stepping motors. The positions of the sensors are verified using absolute optical rotary encoders, and the positions are accurate to 0.5 degrees. The positions of the sensors are electronically recorded and time-stamped after every change. User control is through a GUI using LabVIEW.

  4. The KLOE drift chamber

    Energy Technology Data Exchange (ETDEWEB)

    Adinolfi, M.; Aloisio, A.; Ambrosino, F.; Andryakov, A.; Antonelli, A.; Antonelli, M.; Anulli, F.; Bacci, C.; Bankamp, A.; Barbiellini, G.; Bellini, F.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocci, V.; Bossi, F.; Branchini, P.; Bulychjov, S.A.; Cabibbo, G.; Calcaterra, A.; Caloi, R.; Campana, P.; Capon, G.; Carboni, G.; Cardini, A.; Casarsa, M.; Cataldi, G.; Ceradini, F.; Cervelli, F.; Cevenini, F.; Chiefari, G.; Ciambrone, P.; Conetti, S.; Conticelli, S.; Lucia, E. De; Robertis, G. De; Sangro, R. De; Simone, P. De; Zorzi, G. De; Dell' Agnello, S.; Denig, A.; Domenico, A. Di; Donato, C. Di; Falco, S. Di; Doria, A.; Drago, E.; Elia, V.; Erriquez, O.; Farilla, A.; Felici, G.; Ferrari, A.; Ferrer, M.L.; Finocchiaro, G.; Forti, C.; Franceschi, A.; Franzini, P.; Gao, M.L.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Golovatyuk, V.; Gorini, E.; Grancagnolo, F.; Grandegger, W.; Graziani, E.; Guarnaccia, P.; Hagel, U.V.; Han, H.G.; Han, S.W.; Huang, X.; Incagli, M.; Ingrosso, L.; Jang, Y.Y.; Kim, W.; Kluge, W.; Kulikov, V.; Lacava, F.; Lanfranchi, G.; Lee-Franzini, J.; Lomtadze, F.; Luisi, C.; Mao, C.S.; Martemianov, M.; Matsyuk, M.; Mei, W.; Merola, L.; Messi, R.; Miscetti, S.; Moalem, A.; Moccia, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nedosekin, A.; Panareo, M.; Pacciani, L.; Pages, P.; Palutan, M.; Paoluzi, L.; Pasqualucci, E.; Passalacqua, L.; Passaseo, M.; Passeri, A.; Patera, V.; Petrolo, E.; Petrucci, G.; Picca, D.; Pirozzi, G.; Pistillo, C.; Pollack, M.; Pontecorvo, L.; Primavera, M.; Ruggieri, F.; Santangelo, P.; Santovetti, E.; Saracino, G.; Schamberger, R.D.; Schwick, C.; Sciascia, B.; Sciubba, A.; Scuri, F.; Sfiligoi, I.; Shan, J.; Silano, P.; Spadaro, T.; Spagnolo, S.; Spiriti, E.; Stanescu, C.; Tong, G.L.; Tortora, L.; Valente, E.; Valente, P. E-mail: paolo.valente@lnf.infn.it; Valeriani, B.; Venanzoni, G.; Veneziano, S.; Wu, Y.; Xie, Y.G.; Zhao, P.P.; Zhou, Y

    2001-04-01

    The tracking detector of the KLOE experiment is 4 m diameter, 3.3 m length drift chamber, designed to contain a large fraction of the decays of low-energy K{sub L} produced at the Frascati DAPHINE phi-factory. The chamber is made by a thin carbon fiber structure and operated with a helium-based gas mixture in order to minimise conversion of low-energy photons and multiple scattering inside the sensitive volume. The tracking information is provided by 58 layers of stereo wires defing 12,582 cells, 2x2 cm{sup 2} in size in the 12 innermost layers and 3x3 cm{sup 2} in the outer ones. Details of the chamber design, calibration procedure and tracking performances are presented.

  5. The KLOE drift chamber

    International Nuclear Information System (INIS)

    The tracking detector of the KLOE experiment is 4 m diameter, 3.3 m length drift chamber, designed to contain a large fraction of the decays of low-energy KL produced at the Frascati DAPHINE phi-factory. The chamber is made by a thin carbon fiber structure and operated with a helium-based gas mixture in order to minimise conversion of low-energy photons and multiple scattering inside the sensitive volume. The tracking information is provided by 58 layers of stereo wires defing 12,582 cells, 2x2 cm2 in size in the 12 innermost layers and 3x3 cm2 in the outer ones. Details of the chamber design, calibration procedure and tracking performances are presented

  6. Automated Electrostatics Environmental Chamber

    Science.gov (United States)

    Calle, Carlos; Lewis, Dean C.; Buchanan, Randy K.; Buchanan, Aubri

    2005-01-01

    The Mars Electrostatics Chamber (MEC) is an environmental chamber designed primarily to create atmospheric conditions like those at the surface of Mars to support experiments on electrostatic effects in the Martian environment. The chamber is equipped with a vacuum system, a cryogenic cooling system, an atmospheric-gas replenishing and analysis system, and a computerized control system that can be programmed by the user and that provides both automation and options for manual control. The control system can be set to maintain steady Mars-like conditions or to impose temperature and pressure variations of a Mars diurnal cycle at any given season and latitude. In addition, the MEC can be used in other areas of research because it can create steady or varying atmospheric conditions anywhere within the wide temperature, pressure, and composition ranges between the extremes of Mars-like and Earth-like conditions.

  7. Wire chamber conference

    International Nuclear Information System (INIS)

    This booklet contains program and the abstracts of the papers presented at the conference, most of them dealing with performance testing of various types of wire chambers. The publication of proceedings is planned as a special issue of 'Nuclear instruments and methods' later on. All abstracts are in English. An author index for the book of abstracts is given. (A.N.)

  8. Scanning bubble chamber pictures

    CERN Multimedia

    1974-01-01

    These were taken at the 2 m hydrogen bubble chamber. The photo shows an early Shiva system where the pre-measurements needed to qualify the event were done manually (cf photo 7408136X). The scanning tables were located in bld. 12. Gilberte Saulmier sits on foreground, Inge Arents at centre.

  9. LEP Vacuum Chamber

    CERN Multimedia

    1983-01-01

    This is a cut-out of a LEP vacuum chamber for dipole magnets showing the beam channel and the pumping channel with the getter (NEG) strip and its insulating supports. A water pipe connected to the cooling channel can also be seen at the back.The lead radiation shield lining is also shown. See also 8305563X.

  10. Drift chamber detectors

    International Nuclear Information System (INIS)

    A review of High Energy Physics detectors based on drift chambers is presented. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysied, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author)

  11. LEP vacuum chamber, prototype

    CERN Multimedia

    1983-01-01

    Final prototype for the LEP vacuum chamber, see 8305170 for more details. Here we see the strips of the NEG pump, providing "distributed pumping". The strips are made from a Zr-Ti-Fe alloy. By passing an electrical current, they were heated to 700 deg C.

  12. Three chamber negative ion source

    International Nuclear Information System (INIS)

    A negative ion vessel is divided into an excitation chamber, a negative ionization chamber and an extraction chamber by two magnetic filters. Input means introduces neutral molecules into a first chamber where a first electron discharge means vibrationally excites the molecules which migrate to a second chamber. In the second chamber a second electron discharge means ionizes the molecules, producing negative ions which are extracted into or by a third chamber. A first magnetic filter prevents high energy electrons from entering the negative ionization chamber from the excitation chamber. A second magnetic filter prevents high energy electrons from entering the extraction chamber from the negative ionizing chamber. An extraction grid at the end of the negative ion vessel attracts negative ions into the third chamber and accelerates them. Another grid, located adjacent to the extraction grid, carries a small positive voltage in order to inhibit positive ions from migrating into the extraction chamber and contour the plasma potential. Additional electrons can be suppressed from the output flux using ExB forces provided by magnetic field means and the extractor grid electric potential

  13. Scintillations in ionization chambers

    International Nuclear Information System (INIS)

    High purity Ar and mixtures of Ar with 1% CH4, 3% CH4, CO2 and N2, respectively, have been applied for fission fragment detection in a gridded ionization chamber. Gas scintillation has been observed simultaneously with a photomultiplier VALVO-XP 2041. Whereas all mixtures work equally well as an ionization gas, only Ar + 3% N2 shows a primary scintillation yield sufficient for fas timing. (orig.)

  14. Double chambered right ventricle

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chul Koo; Yu, Yun Jeong; Yeon, Kyung Mo; Han, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1983-12-15

    Fourteen cases of double chambered right ventricle were diagnosed angiographically and of these nine cases were confirmed after operation and autopsy at Seoul National University Hospital in recent four years since 1979. The clinical and radiological findings with the emphasis on the cinecardiographic findings were analysed. The summaries of the analysis are as follows: 1. Among 14 cases, 6 cases were male and 8 cases were female. Age distribution was from 4 years to 36 years. 2. In chest x-ray findings, pulmonary vascularity was increased in 8 cases, decreased in 4 cases, and normal in 2 cases. Cardiomegaly was observed in 8 cases and other showed normal heart size. 3. In cinecardiography, 11 cases had interventricular septal defect. Among these 11 cases, VSD located in proximal high pressure chamber was in 2 cases and located in distal low pressure chamber was in 9 cases. 4. The location of aberrant muscle bundle in sinus portion of right ventricle was in 8 cases. In the rest 6 cases, the aberrant muscle bundle was located below the infundibulum of right ventricle. 5. For accurate diagnosis and differential diagnosis with other congenital cardiac anomalies such as Tetralogy of Fallot or isolated pulmonic stenosis, biplane cineangiography and catheterization is an essential procedure.

  15. Vacuum Chambers for LEP sections

    CERN Multimedia

    1983-01-01

    The picture shows sections of the LEP vacuum chambers to be installed in the dipole magnets (left) and in the quadrupoles (right). The dipole chamber has three channels: the beam chamber, the pumping duct where the NEG (non-evaporabe getter) is installed and the water channel for cooling (on top in the picture). The pumping duct is connected to the beam chamber through holes in the separating wall. The thick lead lining to shield radiation can also be seen. These chambers were manufactured as extruded aluminium alloy profiles.

  16. Wire chambers revisited

    International Nuclear Information System (INIS)

    Multiwire proportional chambers (MWPCs) have long been used as position-sensitive charged particle detectors in nuclear and high-energy physics. MWPCs are large-area gas-filled ionisation chambers in which large arrays of fine wires are used to measure the position of ionisation produced in the gas by the passage of charged particles. The important properties of MWPCs are high-spatial-resolution, large-area, high-count-rate performance at low cost. For research applications, detectors several metres square have been built and small-area detectors have a charged particle resolution of 0.4 mm at a count rate of several million per second. Modification is required to MWPCs for nuclear medicine imaging. A gamma rays or X-rays cannot be detected directly, they must be converted into photo- or Compton scatter electrons. Photon-electron conversion requires the use of high atomic number materials in the body of the chamber. Pressurised xenon is the most useful form of ''gas only'' photon-electron convertor and has been used successfully in a gamma camera for the detection of gamma rays at energies below 100 keV. This camera has been developed specifically for high-count-rate first-pass cardiac imaging. This high-pressure xenon gas MWPC is the key to a highly competitive system which can outperform scintillator-based systems. The count rate performance is close to a million counts per second and the intrinsic spatial resolution is better than the best scintillator-based camera.The only clinical detector have been developed for positron emission tomography, where thin lead or lead-glass can provide an acceptable convertor for 511 keV photons. Two MWPC positron cameras have been evaluated clinically and one is now routine use in clinical oncology. The problems of detection efficiency have not been solved by these detectors although reliability and large-area PET imaging have been proven. (orig./HSI)

  17. Review of wire chamber aging

    International Nuclear Information System (INIS)

    This paper makes an overview of the wire chamber aging problems as a function of various chamber design parameters. It emphasizes the chemistry point of view and many examples are drawn from the plasma chemistry field as a guidance for a possible effort in the wire chamber field. The paper emphasizes the necessity of variable tuning, the importance of purity of the wire chamber environment, as well as it provides a practical list of presently known recommendations. In addition, several models of the wire chamber aging are qualitatively discussed. The paper is based on a summary talk given at the Wire Chamber Aging Workshop held at LBL, Berkeley on January 16-17, 1986. Presented also at Wire Chamber Conference, Vienna, February 25-28, 1986. 74 refs., 18 figs., 11 tabs

  18. Council Chamber exhibition

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    To complete the revamp of CERN’s Council Chamber, a new exhibition is being installed just in time for the June Council meetings.   Panels will showcase highlights of CERN’s history, using some of the content prepared for the exhibitions marking 50 years of the PS, which were displayed in the main building last November. The previous photo exhibition in the Council Chamber stopped at the 1970s. To avoid the new panels becoming quickly out of date, photos are grouped together around specific infrastructures, rather than following a classic time-line. “We have put the focus on the accelerators – the world-class facilities that CERN has been offering researchers over the years, from the well-known large colliders to the lesser-known smaller facilities,” says Emma Sanders, who worked on the content. The new exhibition will be featured in a future issue of the Bulletin with photos and an interview with Fabienne Marcastel, designer of the exhibit...

  19. Cardiac chamber scintiscanning

    International Nuclear Information System (INIS)

    The two methods of cardiac chamber scintiscanning, i.e. 'first pass' and 'ECG-triggered' examinations, are explained and compared. Two tables indicate the most significant radiation doses of the applied radio tracers, i.e. 99m-Tc-pertechnetate and 99m-Tc-HSA, to which a patient is exposed. These averaged values are calculated from various data given in specialised literature. On the basis of data given in literature, an effective half-life of approximately 5 hours in the intravascular space was calculated for the erythrocytes labelled with technetium 99m. On this basis, the radiation doses for the patients due to 99m-Tc-labelled erythrocytes are estimated. The advantages and disadvantages of the two methods applied for cardiac chamber scintiscanning are put into contrast and compared with the advantages and disadvantages of the quantitative X-ray cardiography of the left heart. The still existing problems connected with the assessment of ECG-triggered images are discussed in detail. The author performed investigations of his own, which concerned the above-mentioned problems. (orig./MG)

  20. Mush Column Magma Chambers

    Science.gov (United States)

    Marsh, B. D.

    2002-12-01

    Magma chambers are a necessary concept in understanding the chemical and physical evolution of magma. The concept may well be similar to a transfer function in circuit or time series analysis. It does what needs to be done to transform source magma into eruptible magma. In gravity and geodetic interpretations the causative body is (usually of necessity) geometrically simple and of limited vertical extent; it is clearly difficult to `see' through the uppermost manifestation of the concentrated magma. The presence of plutons in the upper crust has reinforced the view that magma chambers are large pots of magma, but as in the physical representation of a transfer function, actual magma chambers are clearly distinct from virtual magma chambers. Two key features to understanding magmatic systems are that they are vertically integrated over large distances (e.g., 30-100 km), and that all local magmatic processes are controlled by solidification fronts. Heat transfer considerations show that any viable volcanic system must be supported by a vertically extensive plumbing system. Field and geophysical studies point to a common theme of an interconnected stack of sill-like structures extending to great depth. This is a magmatic Mush Column. The large-scale (10s of km) structure resembles the vertical structure inferred at large volcanic centers like Hawaii (e.g., Ryan et al.), and the fine scale (10s to 100s of m) structure is exemplified by ophiolites and deeply eroded sill complexes like the Ferrar dolerites of the McMurdo Dry Valleys, Antarctica. The local length scales of the sill reservoirs and interconnecting conduits produce a rich spectrum of crystallization environments with distinct solidification time scales. Extensive horizontal and vertical mushy walls provide conditions conducive to specific processes of differentiation from solidification front instability to sidewall porous flow and wall rock slumping. The size, strength, and time series of eruptive behavior

  1. Experiments with a spark chamber

    International Nuclear Information System (INIS)

    The authors constructed an experimental spark chamber with a useable volume of 7 x 7 x 5 cm having six parallel 2-mm thick stainless steel plates. The distance between each plate is 8 mm. The chamber is filled with neon under a pressure of one atmosphere. On applying a pulse of about 10 keV on the plates immediately after the passage of a charged particle through the chamber, sparks form along the trajectory of the particle and may easily be photographed. The chamber was first used with cosmic ray μ mesons and then put into the π-meson beam of the SATURN synchrocyclotron. The efficiency of the chamber as a function of voltage and retardation of the applied electric pulse and the dead time are given. The first results obtained with a chamber of 10-litre volume are also presented. (author)

  2. Multi-chamber ionization detector

    International Nuclear Information System (INIS)

    For the detector a single beta ionization source and a double- or three-chamber set-up is used, the chambers being designed in the shape of a truncated cone and facing each other with their bases. The source can be positioned with respect to the common center or modal electrode, the adjustment of the ionization in each chamber this becoming easier. The center or modal electrode also can be adjusted with respect to the source. (DG)

  3. A spark-chamber spectrometer

    International Nuclear Information System (INIS)

    A programme of developing techniques for the construction and use of spark chambers in high-energy physics experiments has been undertaken. Several methods of construction have been tested and found satisfactory. One method is to cement aluminium plates to frames made from glass or Plexiglas strips. Another is to place the aluminium plates in grooves machined in Plexiglas, forming a ''shelf'' design. A chamber made of rows of wires was successfully operated with a He-alcohol mixture. These chambers can either be filled with gas and sealed, or gas can be passed through them continuously. Chambers have been constructed with plates of various thicknesses ranging from 0.032 in downwards. The operation of the chambers with various spacings between the plates was also investigated. The performance of these chambers, when filled with several different gases (Ne, He, A) and with gas-alcohol mixtures, has been investigated. Several methods of applying high-voltage pulses to the chambers have been attempted. The results of these investigations are presented. Spark chambers placed in a magnetic field can be used in principle to determine the momentum of charged particles and if lead converter-plates are incorporated with them, the resulting system should serve as a gamma-ray spectrometer of high resolution and high efficiency. A magnet with an 18-in useful diameter and a 13000-G field is being fitted with spark chambers, whose performance will be tested with cosmic rays and with an accelerator beam. Results from such tests are presented. (author)

  4. National Ignition Facility Target Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Wavrik, R W; Cox, J R; Fleming, P J

    2000-10-05

    On June 11, 1999 the Department of Energy dedicated the single largest piece of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) in Livermore, California. The ten (10) meter diameter aluminum target high vacuum chamber will serve as the working end of the largest laser in the world. The output of 192 laser beams will converge at the precise center of the chamber. The laser beams will enter the chamber in two by two arrays to illuminate 10 millimeter long gold cylinders called hohlraums enclosing 2 millimeter capsule containing deuterium, tritium and isotopes of hydrogen. The two isotopes will fuse, thereby creating temperatures and pressures resembling those found only inside stars and in detonated nuclear weapons, but on a minute scale. The NIF Project will serve as an essential facility to insure safety and reliability of our nation's nuclear arsenal as well as demonstrating inertial fusion's contribution to creating electrical power. The paper will discuss the requirements that had to be addressed during the design, fabrication and testing of the target chamber. A team from Sandia National Laboratories (SNL) and LLNL with input from industry performed the configuration and basic design of the target chamber. The method of fabrication and construction of the aluminum target chamber was devised by Pitt-Des Moines, Inc. (PDM). PDM also participated in the design of the chamber in areas such as the Target Chamber Realignment and Adjustment System, which would allow realignment of the sphere laser beams in the event of earth settlement or movement from a seismic event. During the fabrication of the target chamber the sphericity tolerances had to be addressed for the individual plates. Procedures were developed for forming, edge preparation and welding of individual plates. Construction plans were developed to allow the field construction of the target chamber to occur parallel to other NIF construction activities. This

  5. National Ignition Facility Target Chamber

    International Nuclear Information System (INIS)

    On June 11, 1999 the Department of Energy dedicated the single largest piece of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) in Livermore, California. The ten (10) meter diameter aluminum target high vacuum chamber will serve as the working end of the largest laser in the world. The output of 192 laser beams will converge at the precise center of the chamber. The laser beams will enter the chamber in two by two arrays to illuminate 10 millimeter long gold cylinders called hohlraums enclosing 2 millimeter capsule containing deuterium, tritium and isotopes of hydrogen. The two isotopes will fuse, thereby creating temperatures and pressures resembling those found only inside stars and in detonated nuclear weapons, but on a minute scale. The NIF Project will serve as an essential facility to insure safety and reliability of our nation's nuclear arsenal as well as demonstrating inertial fusion's contribution to creating electrical power. The paper will discuss the requirements that had to be addressed during the design, fabrication and testing of the target chamber. A team from Sandia National Laboratories (SNL) and LLNL with input from industry performed the configuration and basic design of the target chamber. The method of fabrication and construction of the aluminum target chamber was devised by Pitt-Des Moines, Inc. (PDM). PDM also participated in the design of the chamber in areas such as the Target Chamber Realignment and Adjustment System, which would allow realignment of the sphere laser beams in the event of earth settlement or movement from a seismic event. During the fabrication of the target chamber the sphericity tolerances had to be addressed for the individual plates. Procedures were developed for forming, edge preparation and welding of individual plates. Construction plans were developed to allow the field construction of the target chamber to occur parallel to other NIF construction activities. This was

  6. Ion chamber based neutron detectors

    Science.gov (United States)

    Derzon, Mark S; Galambos, Paul C; Renzi, Ronald F

    2014-12-16

    A neutron detector with monolithically integrated readout circuitry, including: a bonded semiconductor die; an ion chamber formed in the bonded semiconductor die; a first electrode and a second electrode formed in the ion chamber; a neutron absorbing material filling the ion chamber; and the readout circuitry which is electrically coupled to the first and second electrodes. The bonded semiconductor die includes an etched semiconductor substrate bonded to an active semiconductor substrate. The readout circuitry is formed in a portion of the active semiconductor substrate. The ion chamber has a substantially planar first surface on which the first electrode is formed and a substantially planar second surface, parallel to the first surface, on which the second electrode is formed. The distance between the first electrode and the second electrode may be equal to or less than the 50% attenuation length for neutrons in the neutron absorbing material filling the ion chamber.

  7. The multigap resistive plate chamber

    Energy Technology Data Exchange (ETDEWEB)

    Zeballos, E. Cerron [European Organization for Nuclear Research (CERN), Geneva (Switzerland); World Lab., Lausanne (Switzerland); Crotty, I. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Hatzifotiadou, D. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); World Lab., Lausanne (Switzerland); Valverde, J. Lamas [European Organization for Nuclear Research (CERN), Geneva (Switzerland); World Lab., Lausanne (Switzerland); Univ. Louis Pasteur, Strasbourg (France); Neupane, S. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); World Lab., Lausanne (Switzerland); Williams, M. C. S. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Zichichi, A. [Univ. of Bologna, Bologna (Italy)

    2015-02-03

    The paper describes the multigap resistive plate chamber (RPC). This is a variant of the wide gap RPC. However it has much improved time resolution, while keeping all the other advantages of the wide gap RPC design.

  8. Cyclically controlled welding purge chamber

    Science.gov (United States)

    Gallagher, Robert L. (Inventor)

    1996-01-01

    An arrangement for butt-welding cylindrical sections of large, thin-wall tanks includes a rotatable mandrel with side-by-side sets of radial position adjusters. Each set of adjusters bears on one of the tank sections adjacent the seam, to prevent the sections from sagging out-of-round. The mandrel rotates relative to the welder, so that a continuous seam is formed. A purge chamber is fixed in position behind the seam at the weld head, and is flushed with inert gas. The purge chamber includes a two-sided structure which is contiguous with the cylindrical sections and a circumferential vane to form an open-ended tube-like structure, through which the radial position adjusters pass as the mandrel and cylindrical workpiece sections rotate. The tube-like structure is formed into a chamber by a plurality of movable gates which are controlled to maintain a seal while allowing adjusters to progress through the purge chamber.

  9. The HERMES Back Drift Chambers

    OpenAIRE

    al, S. Bernreuther et

    1998-01-01

    The tracking system of the HERMES spectrometer behind the bending magnet consists of two pairs of large planar 6-plane drift chambers. The design and performance of these chambers is described. This description comprises details on the mechanical and electronical design, information about the gas mixture used and its properties, results on alignment, calibration, resolution, and efficiencies, and a discussion of the experience gained through the first three years of operation.

  10. BEBC Big European Bubble Chamber

    CERN Multimedia

    1974-01-01

    A view of the dismantling of the magnet of BEBC, the 3.7 m European Bubble Chamber : iron magnetic shielding ; lower and upper parts of the vacuum enclosure of the magnet; turbo-molecular vacuum pumps for the "fish-eye" windows; the two superconducting coils; a handling platform; the two cryostats suspended from the bar of the travelling crane which has a 170 ton carrying capacity. The chamber proper, not dismantled, is inside the shielding.

  11. Anterior chamber depth during hemodialysis

    Directory of Open Access Journals (Sweden)

    Gracitelli CPB

    2013-08-01

    Full Text Available Carolina Pelegrini Barbosa Gracitelli,1 Francisco Rosa Stefanini,1 Fernando Penha,1 Miguel Ângelo Góes,2 Sérgio Antonio Draibe,2 Maria Eugênia Canziani,2 Augusto Paranhos Junior1 1Ophthalmology Department, 2Division of Nephrology, Federal University of São Paulo – UNIFESP, São Paulo, Brazil Background: Exacerbation of chronic glaucoma or acute glaucoma is occasionally observed in patients undergoing hemodialysis (HD because of anterior chamber depth changes during this therapy. Purpose: To evaluate anterior chamber depth and axial length in patients during HD sessions. Methods: A total of 67 eyes of 35 patients were prospectively enrolled. Axial length and anterior chamber depth were measured using ultrasonic biometry, and these measures were evaluated at three different times during HD sessions. Body weight and blood pressure pre- and post-HD were also measured. Results: There was no difference in the axial length between the three measurements (P = 0.241. We observed a significantly decreased anterior chamber depth (P = 0.002 during HD sessions. Conclusion: Our results support the idea that there is a change in anterior chamber depth in HD sessions. Keywords: anterior chamber, hemodialysis, axial length, acute angle-closure glaucoma

  12. Air ionization wire plane chamber

    International Nuclear Information System (INIS)

    Radiation Measurement for protection level instrumentation requires large number of detectors. Since the number is large, the detector should be cost effective and yet should have good sensitivity. Gas detectors with presently available microelectronics and signal processing capabilities opened a new era in radiation monitoring. Present paper describes the use of air filled multi anode grid planes as detector for alpha detection. Due to multiple anode wire planes, the charge collection efficiency of the air ionization chamber is higher as compared to conventional ionization chamber. The signal from this Wire Plane Chamber (WPC) has a faster and narrower pulse shape as compared to conventional two-electrode chamber of similar dimensions. The reduction in capacitance also improves the signal to noise ratio so that air can be used as the ionization medium without any special cleaning procedure etc and it may be possible to use even engineering plastic as the structural material for the chamber. The paper gives the results obtained so far with this air ionization chamber. (author)

  13. Plasma chemistry in wire chambers

    International Nuclear Information System (INIS)

    The phenomenology of wire chamber aging is discussed and fundamentals of proportional counters are presented. Free-radical polymerization and plasma polymerization are discussed. The chemistry of wire aging is reviewed. Similarities between wire chamber plasma (>1 atm dc-discharge) and low-pressure rf-discharge plasmas, which have been more widely studied, are suggested. Construction and use of a system to allow study of the plasma reactions occurring in wire chambers is reported. A proportional tube irradiated by an 55Fe source is used as a model wire chamber. Condensable species in the proportional tube effluent are concentrated in a cryotrap and analyzed by gas chromatography/mass spectrometry. Several different wire chamber gases (methane, argon/methane, ethane, argon/ethane, propane, argon/isobutane) are tested and their reaction products qualitatively identified. For all gases tested except those containing methane, use of hygroscopic filters to remove trace water and oxygen contaminants from the gas resulted in an increase in the average molecular weight of the products, consistent with results from low-pressure rf-discharge plasmas. It is suggested that because water and oxygen inhibit polymer growth in the gas phase that they may also reduce polymer deposition in proportional tubes and therefore retard wire aging processes. Mechanistic implications of the plasma reactions of hydrocarbons with oxygen are suggested. Unresolved issues in this work and proposals for further study are discussed

  14. Emulsion Chamber Technology Experiment (ECT)

    Science.gov (United States)

    Gregory, John C.; Takahashi, Yoshiyuki

    1996-01-01

    The experimental objective of Emulsion Chamber Technology (ECT) was to develop space-borne emulsion chamber technology so that cosmic rays and nuclear interactions may subsequently be studied at extremely high energies with long exposures in space. A small emulsion chamber was built and flown on flight STS-62 of the Columbia in March 1994. Analysis of the several hundred layers of radiation-sensitive material has shown excellent post-flight condition and suitability for cosmic ray physics analysis at much longer exposures. Temperature control of the stack was 20 +/-1 C throughout the active control period and no significant deviations of temperature or pressure in the chamber were observed over the entire mission operations period. The unfortunate flight attitude of the orbiter (almost 90% Earth viewing) prevented any significant number of heavy particles (Z greater than or equal to 10) reaching the stack and the inverted flow of shower particles in the calorimeter has not allowed evaluation of absolute primary cosmic ray-detection efficiency nor of the practical time limits of useful exposure of these calorimeters in space to the level of detail originally planned. Nevertheless, analysis of the observed backgrounds and quality of the processed photographic and plastic materials after the flight show that productive exposures of emulsion chambers are feasible in low orbit for periods of up to one year or longer. The engineering approaches taken in the ECT program were proven effective and no major environmental obstacles to prolonged flight are evident.

  15. The CLAS drift chamber system

    CERN Document Server

    Mestayer, M D; Asavapibhop, B; Barbosa, F J; Bonneau, P; Christo, S B; Dodge, G E; Dooling, T; Duncan, W S; Dytman, S A; Feuerbach, R; Gilfoyle, G P; Gyurjyan, V; Hicks, K H; Hicks, R S; Hyde-Wright, C E; Jacobs, G; Klein, A; Klein, F J; Kossov, M; Kuhn, S E; Magahiz, R A; Major, R W; Martin, C; McGuckin, T; McNabb, J; Miskimen, R A; Müller, J A; Niczyporuk, B B; O'Meara, J E; Qin, L M; Raue, B A; Robb, J; Roudot, F; Schumacher, R A; Tedeschi, D J; Thompson, R A; Tilles, D; Tuzel, W; Vansyoc, K; Vineyard, M F; Weinstein, L B; Wilkin, G R; Yegneswaran, A; Yun, J

    2000-01-01

    Experimental Hall B at Jefferson Laboratory houses the CEBAF Large Acceptance Spectrometer, the magnetic field of which is produced by a superconducting toroid. The six coils of this toroid divide the detector azimuthally into six sectors, each of which contains three large multi-layer drift chambers for tracking charged particles produced from a fixed target on the toroidal axis. Within the 18 drift chambers are a total of 35,148 individually instrumented hexagonal drift cells. The novel geometry of these chambers provides for good tracking resolution and efficiency, along with large acceptance. The design and construction challenges posed by these large-scale detectors are described, and detailed results are presented from in-beam measurements.

  16. "Flat-Fish" Vacuum Chamber

    CERN Multimedia

    1978-01-01

    The picture shows a "Flat-Fish" vacuum chamber being prepared in the ISR workshop for testing prior to installation in the Split Field Magnet (SFM) at intersection I4. The two shells of each part were hydroformed from 0.15 mm thick inconel 718 sheet (with end parts in inconel 600 for easier manual welding to the arms) and welded toghether with two strips which were attached by means of thin stainless steel sheets to the Split Field Magnet poles in order to take the vertical component of the atmospheric pressure force. This was the thinnest vacuum chamber ever made for the ISR. Inconel material was chosen for its high elastic modulus and strenght at chamber bake-out temperature. In this picture the thin sheets transferring the vertical component of the atmosferic pressure force are attached to a support frame for testing. See also 7712182, 7712179.

  17. Particle detection with drift chambers

    CERN Document Server

    Blum, Walter; Rolandi, Luigi

    2008-01-01

    This volume presents a thorough introduction to the theory and operation of drift chambers, one of the most important modern methods of elementary particle detection. The topics, presented in a text-book style with many illustrations, include the basics of gas ionization, by particles and by lasers, drift of electrons and ions in gases and signal creation and discuss in depth the fundamental limits of accuracy and the issue of particle identification. The book also surveys all types of drift chambers and the various drift-chamber gases in use. The calculation of the device parameters and physical processes are presented in some detail, as is all necessary background material. Thus the treatment, well beyond addressing the specialist in the field, is well suited to graduate physics students and nuclear engineers seeking a both thorough and pedagogical introduction to the field. The second edition presents a completely revised, updated and expanded version of this classic text. In particular, significantly more...

  18. Tohoku one meter bubble chamber

    International Nuclear Information System (INIS)

    At the request of Tohoku University and the National Laboratory for High Energy Physics, IHI has developed a complete freon bubble chamber system successfully, which is used for photo analysis of elementary particles physics. This system will be delivered to Fermi National Accelerator Laboratory (FNAL) in Illinois (U.S.A.) and will be coupled with the superconducting accelerator (TEVATRON) for the study of elementary particles. The total system of the freon bubble chamber is composed of a stainless steel casting spherical bubble chamber with a diameter of about one meter, an expansion system for freon pressure control, hydraulic system for driving an expansion piston, a freon feed system, a temperature control system, an overall control system as well as camera and flashlight for photograph. (author)

  19. The CLAS drift chamber system

    Energy Technology Data Exchange (ETDEWEB)

    Mestayer, M.D.; Carman, D.S.; Asavaphibhop, B. [and others

    1999-04-01

    Experimental Hall B at Jefferson Laboratory houses the CEBAF Large Acceptance Spectrometer, the magnetic field of which is produced by a superconducting toroid. The six coils of this toroid divide the detector azimuthally into six sectors, each of which contains three large multi-layer drift chambers for tracking charged particles produced from a fixed target on a toroidal axis. Within the 18 drift chambers are a total of 35,148 individually instrumented hexagonal drift cells. The novel geometry of these chambers provides for good tracking resolution and efficiency, along with large acceptance. The design and construction challenges posed by these large-scale detectors are described, and detailed results are presented from in-beam measurements.

  20. Impedances of Laminated Vacuum Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Burov, A.; Lebedev, V.; /Fermilab

    2011-06-22

    First publications on impedance of laminated vacuum chambers are related to early 70s: those are of S. C. Snowdon [1] and of A. G. Ruggiero [2]; fifteen years later, a revision paper of R. Gluckstern appeared [3]. All the publications were presented as Fermilab preprints, and there is no surprise in that: the Fermilab Booster has its laminated magnets open to the beam. Being in a reasonable mutual agreement, these publications were all devoted to the longitudinal impedance of round vacuum chambers. The transverse impedance and the flat geometry case were addressed in more recent paper of K. Y. Ng [4]. The latest calculations of A. Macridin et al. [5] revealed some disagreement with Ref. [4]; this fact stimulated us to get our own results on that matter. Longitudinal and transverse impendances are derived for round and flat laminated vacuum chambers. Results of this paper agree with Ref. [5].

  1. General purpose nuclear irradiation chamber

    International Nuclear Information System (INIS)

    Nuclear technology has found a great need for use in medicine, industry, and research. Smoke detectors in our homes, medical treatments and new varieties of plants by irradiating its seeds are just a few examples of the benefits of nuclear technology. Portable neutron source such as Californium-252, available at Industrial Technology Division (BTI/ PAT), Malaysian Nuclear Agency, has a 2.645 year half-life. However, 252Cf is known to emit gamma radiation from the source. Thus, this chamber aims to provide a proper gamma shielding for samples to distinguish the use of mixed neutron with gamma-rays or pure neutron radiation. The chamber is compatible to be used with other portable neutron sources such as 241Am-Be as well as the reactor TRIGA PUSPATI for higher neutron dose. This chamber was designed through a collaborative effort of Kulliyyah Engineering, IIUM with the Industrial Technology Division (BTI) team, Malaysian Nuclear Agency. (Author)

  2. The CLAS drift chamber system

    International Nuclear Information System (INIS)

    Experimental Hall B at Jefferson Laboratory houses the CEBAF Large Acceptance Spectrometer, the magnetic field of which is produced by a superconducting toroid. The six coils of this toroid divide the detector azimuthally into six sectors, each of which contains three large multi-layer drift chambers for tracking charged particles produced from a fixed target on the toroidal axis. Within the 18 drift chambers are a total of 35,148 individually instrumented hexagonal drift cells. The novel geometry of these chambers provides for good tracking resolution and efficiency, along with large acceptance. The design and construction challenges posed by these large-scale detectors are described, and detailed results are presented from in-beam measurements

  3. The knife-edge chamber

    International Nuclear Information System (INIS)

    In this paper the design for a new technology for particle track detectors is described. Using standard IC fabrication techniques, a pattern of microscopic knife edges and field-shaping electrodes can be fabricated on a silicon substrate. The knife-edge chamber uniquely offers attractive performance for the track chambers required for SSC detectors, for which no present technology is yet satisfactory. Its features include: excellent radiation hardness (10 Mrad), excellent spatial resolution (∼20 μm), short drift time (20 ns), and large pulse height (1 mV)

  4. Test chamber for alpha spectrometry

    Science.gov (United States)

    Larsen, Robert P.

    1977-01-01

    Alpha emitters for low-level radiochemical analysis by measurement of alpha spectra are positioned precisely with respect to the location of a surface-barrier detector by means of a chamber having a removable threaded planchet holder. A pedestal on the planchet holder holds a specimen in fixed engagement close to the detector. Insertion of the planchet holder establishes an O-ring seal that permits the chamber to be pumped to a desired vacuum. The detector is protected against accidental contact and resulting damage.

  5. Drift and proportional tracking chambers

    International Nuclear Information System (INIS)

    Many techniques have been exploited in constructing tracking chambers, particle detectors which measure the trajectories and momenta of charged particles. The particular features of high-energy interactions - charged particle multiplicities, angular correlations and complex vertex topologies, to name a few - and the experimental environment of the accelerator - event rates, background rates, and so on - accent the importance of certain detector characteristics. In high energy e+e-, anti pp and pp interactions the final states are dominated by closely collimated jets of high multiplicity, requiring good track-pair resolution in the tracking chamber. High energy particles deflect very little in limited magnetic field volumes, necessitating good spatial resolution for accurate momentum measurements. The colliding beam technique generally requires a device easily adapted to full solid-angle coverage, and the high event rates expected in some of these machines put a premium on good time resolution. Finally, the production and subsequent decays of the tau, charmed and beautiful mesons will provide multiple vertex topologies. To reconstruct these vertices reliably will require considerable improvements in spatial resolution and track-pair resolution. This lecture considers the proportional counter and its descendant, the drift chamber, as tracking chambers. Its goal is to review the physics of this device in order to understand its performance limitations and promises

  6. DELPHI's Ring Imaging Cherenkov Chamber

    CERN Multimedia

    1989-01-01

    The hundreds of mirrors around this Ring Imaging Cherenkov Chamber reflect cones of light created by fast moving particles to a detector. The velocity of a particle can be measured by the size of the ring produced on the detector. DELPHI, which ran from 1989 to 2000 on the LEP accelerator, was primarily concerned with particle identification.

  7. The TESLA Time Projection Chamber

    OpenAIRE

    Ghodbane, Nabil

    2002-01-01

    A large Time Projection Chamber is proposed as part of the tracking system for a detector at the TESLA electron positron linear collider. Different ongoing R&D studies are reviewed, stressing progress made on a new type readout technique based on Micro-Pattern Gas Detectors.

  8. Bubble chamber: colour enhanced tracks

    CERN Multimedia

    1998-01-01

    This artistically-enhanced image of real particle tracks was produced in the Big European Bubble Chamber (BEBC). Liquid hydrogen is used to create bubbles along the paths of the particles as a piston expands the medium. A magnetic field is produced in the detector causing the particles to travel in spirals, allowing charge and momentum to be measured.

  9. Establishment of a radon test chamber

    International Nuclear Information System (INIS)

    A walk-in type radon test chamber of 23 m3 has been built for testing and calibration of radon measurement instruments. The environmental conditions of the test chamber can be varied within a wide range of values. The design objectives specification, monitoring instruments and testing results of this chamber are discussed. This test chamber is available for domestic radon researchers and its accuracy can be traced to the international standard. A routine intercomparison study will be held annually by using this chamber. Other tests like radon progeny and thoron standard may also be performed in this chamber. (1 fig.)

  10. A mathematical model of aerosol holding chambers

    DEFF Research Database (Denmark)

    Zak, M; Madsen, J; Berg, E;

    1999-01-01

    A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (VT), chamber volume (Vch), apparatus dead space (VD), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol......-mentioned factors, initial loss of aerosol by impact on the chamber wall is most important for the efficiency of a spacer. With a VT of 195 mL, the AeroChamber and Babyhaler were emptied in two breaths, the NebuChamber in four breaths, and the Nebuhaler in six breaths. Insufficiencies of the expiratory valves were...

  11. Chamber dynamic research with pulsed power

    Energy Technology Data Exchange (ETDEWEB)

    PETERSON,ROBERT R.; OLSON,CRAIG L.; RENK,TIMOTHY J.; ROCHAU,GARY E.; SWEENEY,MARY ANN

    2000-05-15

    In Inertial Fusion Energy (IFE), Target Chamber Dynamics (TCD) is an integral part of the target chamber design and performance. TCD includes target output deposition of target x-rays, ions and neutrons in target chamber gases and structures, vaporization and melting of target chamber materials, radiation-hydrodynamics in target chamber vapors and gases, and chamber conditions at the time of target and beam injections. Pulsed power provides a unique environment for IFE-TCD validation experiments in two important ways: they do not require the very clean conditions which lasers need and they currently provide large x-ray and ion energies.

  12. A new plant chamber facility PLUS coupled to the atmospheric simulation chamber SAPHIR

    OpenAIRE

    Hohaus, T.; Kuhn, U.; S. Andres; Kaminski, M.; Rohrer, F.; Tillmann, R.; A. Wahner; R. Wegener; Yu, Z.; Kiendler-Scharr, A.

    2015-01-01

    A new PLant chamber Unit for Simulation (PLUS) for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) has been build and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees are mixed with synthetic air and are transferred to the SAPHIR chamber ...

  13. Development of multiwire proportional chambers

    CERN Multimedia

    Charpak, G

    1969-01-01

    It has happened quite often in the history of science that theoreticians, confronted with some major difficulty, have successfully gone back thirty years to look at ideas that had then been thrown overboard. But it is rare that experimentalists go back thirty years to look again at equipment which had become out-dated. This is what Charpak and his colleagues did to emerge with the 'multiwire proportional chamber' which has several new features making it a very useful addition to the armoury of particle detectors. In the 1930s, ion-chambers, Geiger- Muller counters and proportional counters, were vital pieces of equipment in nuclear physics research. Other types of detectors have since largely replaced them but now the proportional counter, in new array, is making a comeback.

  14. LEP vacuum chamber, early prototype

    CERN Multimedia

    1978-01-01

    The structure of LEP, with long bending magnets and little access to the vacuum chamber between them, required distributed pumping. This is an early prototype for the LEP vacuum chamber, made from extruded aluminium. The main opening is for the beam. The small channel to the right is for cooling water, to carry away the heat deposited by the synchroton radiation from the beam. The 4 slots in the channel to the left house the strip-shaped ion-getter pumps (see 7810255). The ion-getter pumps depended on the magnetic field of the bending magnets, too low at injection energy for the pumps to function well. Also, a different design was required outside the bending magnets. This design was therefore abandoned, in favour of a thermal getter pump (see 8301153 and 8305170).

  15. Actuator System with Dual Chambers

    DEFF Research Database (Denmark)

    2015-01-01

    (8), the lid having a shaft opening (17) for a shaft (6) coupled to the magnetic rotor (5), wherein the magnetic rotor (5), when inserted in the translator cylinder (2), is arranged to translate a linear movement of the translator cylinder (2) into a rotational movement of the magnetic rotor by using...... magnetic flux (82) interacting between the magnetic stator and the magnetic rotor, said rotational movements is being transferred through a shaft (6), the lid (8) with a shaft opening (17) arranged for receiving the shaft (6), wherein the shaft is arranged to make both the linear and the rotational...... movement in the shaft opening (17), the lid (8) being arranged for confining the second end (15) of the translator cylinder (2), the translator cylinder confined by the lid (8) forms,when divided by the magnetic rotor (5), a first chamber (TC) with a first volume and a second chamber(BC) with a second...

  16. MPS II drift chamber system

    International Nuclear Information System (INIS)

    The MPS II detectors are narrow drift space chambers designed for high position resolution in a magnetic field and in a very high particle flux environment. Central to this implementation was the development of 3 multi-channel custom IC's and one multi-channel hybrid. The system is deadtimeless and requires no corrections on an anode-to-anode basis. Operational experience and relevance to ISABELLE detectors is discussed

  17. SMOG CHAMBER VALIDATION USING LAGRANGIAN ATMOSPHERIC DATA

    Science.gov (United States)

    A method was developed for validating outdoor smog chamber experiments as a means of determining the relationships between oxidant concentrations and its precursors - hydrocarbons and nitrogen oxides. When chamber experiments were performed in a manner that simulated relevant met...

  18. The KEK 1 m hydrogen bubble chamber

    International Nuclear Information System (INIS)

    A medium size hydrogen bubble chamber has been constructed at the National Laboratory for High Energy Physics, KEK. The bubble chamber has been designed to be operated with a maximum rate of three times per half a second in every two second repetition time of the accelerator, by utilizing a hydraulic expansion system. The bubble chamber has a one meter diameter and a visible volume of about 280 l. A three-view stereo camera system is used for taking photographic pictures of the chamber. A 2 MW bubble chamber magnet is constructed. The main part of the bubble chamber vessel is supported by the magnet yoke. The magnet gives a maximum field of 18.4 kG at the centre of the fiducial volume of the chamber. The overall system of the KEK 1 m hydrogen bubble chamber facility is described in some detail. Some operational characteristics of the facility are also reported. (auth.)

  19. A mathematical model of aerosol holding chambers

    DEFF Research Database (Denmark)

    Zak, M; Madsen, J; Berg, E;

    1999-01-01

    A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (VT), chamber volume (Vch), apparatus dead space (VD), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol...... in the chamber with time. Four different spacers were connected via filters to a mechanical lung model, and aerosol delivery during "breathing" was determined from drug recovery from the filters. The formula correctly predicted the delivery of budesonide aerosol from the AeroChamber (Trudell Medical, London......-mentioned factors, initial loss of aerosol by impact on the chamber wall is most important for the efficiency of a spacer. With a VT of 195 mL, the AeroChamber and Babyhaler were emptied in two breaths, the NebuChamber in four breaths, and the Nebuhaler in six breaths. Insufficiencies of the expiratory valves were...

  20. Growing and analyzing biofilms in flow chambers

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim; Sternberg, Claus

    2011-01-01

    This unit describes the setup of flow chamber systems for the study of microbial biofilms, and methods for the analysis of structural biofilm formation. Use of flow chambers allows direct microscopic investigation of biofilm formation. The biofilms in flow chambers develop under hydrodynamic......, and disassembly and cleaning of the system. In addition, embedding and fluorescent in situ hybridization of flow chamber-grown biofilms are addressed....

  1. Ionization chamber kit for in core dosimetry

    International Nuclear Information System (INIS)

    Sensitivity of a set of ionization walled precise chambers, including chambers with a wall made of a material with different atomic number Z (from 6 to 92), is investigated. It is noted that the considered chambers differ by high radiation stability at slight leakage current on isolators. Using the chambers for determining effective energy of gamma-radiation of the stopped IRT-2000 reactor has shown a good agreement of measuring results with the calculation

  2. LEP vacuum chamber cross-section

    CERN Multimedia

    1987-01-01

    This diagram shows the layout of the vacuum chambers used at LEP, which was in operation at CERN between 1989 and 2000. Vacuum chambers are necessary in accelerators to prevent unwanted interactions that can destabilise the beam. The pump on the right sucks air out of the chamber allowing the beam to progress with minimal interactions.

  3. Wire chamber degradation at the Argonne ZGS

    International Nuclear Information System (INIS)

    Experience with multiwire proportional chambers at high rates at the Argonne Zero Gradient Synchrotron is described. A buildup of silicon on the sense wires was observed where the beam passed through the chamber. Analysis of the chamber gas indicated that the density of silicon was probably less than 10 ppM

  4. A cryogenic chamber for scattering measurements

    OpenAIRE

    Lopes, M. I.; Chepel, V.; Kuchenkov, A.; Gonçalves, O. D.; Schechter, H.

    1999-01-01

    We have constructed a cryogenic chamber to measure scattering cross sections of photons in liquids of low-boiling point. The chamber was tested with liquid xenon using a 137Cs radioactive source emitting 662 keV photons. The spectra obtained are presented and analyzed, attesting the good performance of the chamber for the desired purposes.

  5. Sensitivity of gaseous xenon ionisation chambers (1961)

    International Nuclear Information System (INIS)

    It seems advantageous to fill an ionization chamber with xenon gas when this chamber is used for measuring a low intensity and high energy electron or positron beam, or monitoring a gamma beam. In the study of 5 to 50 MeV electrons, xenon allows for the ionization chamber yield, an improvement of a factor 4,5. (author)

  6. Cosmic test of honeycomb drift chambers

    International Nuclear Information System (INIS)

    The status of the test of pokalon-C honeycomb drift chambers by cosmic rays is presented. We discuss the cosmic track reconstruction, autocalibration of drift chambers and identification of cross-talk hits. Preliminary results of the test performed for drift chambers with 5 mm cells are given

  7. Subminiature fission chamber with gas tight penetration

    International Nuclear Information System (INIS)

    Fission chambers suffer from gas leaks at electric feed-trough. This micro chamber suppresses that defect thanks to an alumina plug and welded seal of the chamber sleeve. This device is easy to produce at industrial scale with reduced dimensions (1,5 mm diameter, 25 mm length). It can work with 30 m long feeding cables. (D.L.). 3 figs

  8. A Sensitive Cloud Chamber without Radioactive Sources

    Science.gov (United States)

    Zeze, Syoji; Itoh, Akio; Oyama, Ayu; Takahashi, Haruka

    2012-01-01

    We present a sensitive diffusion cloud chamber which does not require any radioactive sources. A major difference from commonly used chambers is the use of a heat sink as its bottom plate. The result of a performance test of the chamber is given. (Contains 8 figures.)

  9. Simple Cloud Chambers Using Gel Ice Packs

    Science.gov (United States)

    Kamata, Masahiro; Kubota, Miki

    2012-01-01

    Although cloud chambers are highly regarded as teaching aids for radiation education, school teachers have difficulty in using cloud chambers because they have to prepare dry ice or liquid nitrogen before the experiment. We developed a very simple and inexpensive cloud chamber that uses the contents of gel ice packs which can substitute for dry…

  10. Vacuum chamber at intersection I-6

    CERN Multimedia

    1971-01-01

    The vacuum chamber at intersection region I-6, one of these where experiments in colliding-beam physics will be taking place. The "wheels" prevent the thin wall (1.5 mm) of the chamber from collapsing. The chamber is equipped with heating tapes and its wrapped in thermal insulation. Residual gas pressure at this and other similar regions is around 10_11.

  11. Cylindrical ionization chamber on compressed krypton

    International Nuclear Information System (INIS)

    A cylindrical ionization chamber with a grid is described. The chamber is used in experiments to search for double positron decay and conversion of atom electron into positron in Kr78. The working substance of the chamber is krypton. The spectrometric characteristics of the chamber filled with krypton and xenon are presented. Energy resolution is 2.1% for 1.84 MeV energy (the gamma quantum source is 88Y) when using the chamber filled with Kr+0.2%H2 mixture at pressure of 25 atm

  12. Ionization chambers for LET determination

    DEFF Research Database (Denmark)

    Kaiser, Franz-Joachim; Bassler, Niels; Tölli, Heikki;

    2010-01-01

    Modern radiotherapy facilities for cancer treatment such as the Heavy Ion Therapy Centre (HIT) in Heidelberg (Germany) enable sub millimetre precision in dose deposition. For the measurement of such dose distributions and  characterization of the particle beams, detectors with high spatial...... of columnar recombination was designed to model the detector efficiency of an ionization chamber. Here, we have shown that despite the approximations and simplification made, the theory is correct for the LETs typically found in clinical radiotherapy employing particles from protons to carbon ions...

  13. TRU waste characterization chamber gloveboxes

    International Nuclear Information System (INIS)

    Argonne National Laboratory-West (ANL-W) is participating in the Department of Energy's (DOE) National Transuranic Waste Program in support of the Waste Isolation Pilot Plant (WIPP). The Laboratory's support currently consists of intrusive characterization of a selected population of drums containing transuranic waste. This characterization is performed in a complex of alpha containment gloveboxes termed the Waste Characterization Gloveboxes. Made up of the Waste Characterization Chamber, Sample Preparation Glovebox, and the Equipment Repair Glovebox, they were designed as a small production characterization facility for support of the Idaho National Engineering and Environmental Laboratory (INEEL). This paper presents salient features of these gloveboxes

  14. Nova target chamber decontamination study

    International Nuclear Information System (INIS)

    An engineering study was performed to determine the most effective method for decontamination of the Nova target chamber. Manual and remote decontamination methods currently being used were surveyed. In addition, a concept that may not require in-situ decontamination was investigated. Based on the presently available information concerning material and system compatibility and particle penetration, it is recommended that a system of removable aluminum shields be considered. It is also recommended that a series of tests be performed to more precisely determine the vacuum compatibility and penetrability of other materials discussed in this report

  15. Experimental work on drift chambers

    International Nuclear Information System (INIS)

    An experimental work made on drift chambers is described in two chapters. In the firt chapter we present the description of the experimental installation used, as well as some details on the data adquisition systems and the characteristics on three ways used for calibration proposes (cosmic muons, β radiation and test beam using SPS at CERN facilities). The second chapter describes the defferent prototypes studied. The experimental set up and the analysis are given. Some results are discussed. The magnetic field effect is also studied. (Author)

  16. Pupillary block glaucoma following implantation of a posterior chamber pseudophakos in the anterior chamber.

    Directory of Open Access Journals (Sweden)

    Mandal Anil

    2002-01-01

    Full Text Available Pupillary block glaucoma is a common complication of cataract surgery, especially following anterior chamber intraocular lens implantation. We report a case of pupillary block glaucoma with a posterior chamber IOL that was implanted in the anterior chamber following a complicated extracapsular cataract extraction. The case was successfully managed by explantation of the posterior chamber lens, anterior vitrectomy, peripheral iridectomy and secondary anterior chamber intraocular lens implantation. The intraocular pressure was controlled with a single topical antiglaucoma medication.

  17. Physicist makes muon chamber sing

    CERN Document Server

    2007-01-01

    This Monitored Drift Tube detector, consisting of argon-CO2-filled aluminium tubes with a wire down the centre of each, will track muons in ATLAS; Tiecke used a single tube from one of these detectors to create the pipes in his organ. Particle physicists can make good musicians; but did you know particle detectors can make good music? That's what NIKHEF physicist Henk Tiecke learned when he used pipes cut from the ATLAS Monitored Drift Tube detector (MDT) to build his own working Dutch-style barrel organ in the autumn of 2005. 'I like to work with my hands,' said Tiecke, who worked as a senior physicist at NIKHEF, Amsterdam, on ZEUS until his retirement last summer. Tiecke had already constructed his barrel organ when he visited some colleagues in the ATLAS muon chambers production area at Nikhef in 2005. He noticed that the aluminium tubes they were using to build the chambers were about three centimetres in diameter-just the right size for a pipe in a barrel organ. 'The sound is not as nice as from wooden...

  18. Picture chamber for radiographic system

    International Nuclear Information System (INIS)

    The picture chamber for a radiographic system is characterised by a base, a first electrode carried in the base, an X-ray irradiation window provided with an outer plate and an inner plate and a conducting surface which serves as a second electrode, which has a plate gripping it at each adjacent edge and which has at the sides a space which is occupied by a filling material, maintained at a steady pressure, by means of the mounting against the base and wherein the inner plate lies against the first electrode and which is provided with a split, and with means for the separation of the split in the area of the inner plate so that a fluid may be retained in the split. (G.C.)

  19. Legacies of the bubble chamber

    International Nuclear Information System (INIS)

    Legacies are what we pass on to those who follow us, the foundations on which the next advances in our science are being made; the things by which we shall be remembered, recorded in learned journals, written in the text books -food for the historians of science. This is not a summary, and it will draw no conclusions. It is a personal view which will look a little wider than the main physics results to include a mention of one or two of the technologies and methods handed on to both particle physics and other branches of sciences, a brief reference to bubble chamber pictures as aids in teaching, and a comment on the challenge now increasingly applied in the UK - and perhaps elsewhere -as a criterion for funding research: will it contribute to ''wealth creation''? (orig.)

  20. Repatriation of Gamma Chambers Exported by India

    International Nuclear Information System (INIS)

    The Board of Radiation and Isotope Technology (BRIT) is engaged in the production and supply of laboratory gamma chambers. The gamma chambers are self-shielded devices in which a number of 60Co source pencils placed in a cylindrical cage. The gamma chambers are type approved as a device and a transportation package separately by the Atomic Energy Regulatory Board. BRIT has exported number of such gamma chambers. For some of the gamma chambers, the type approval validity period is over and can no longer be transported. Hence, the radiation sources need to be transferred to a type approved package before transportation. BRIT has decommissioned five such gamma chambers so far and sources have been repatriated back to India. (author)

  1. Neutron-chamber detectors and applications

    International Nuclear Information System (INIS)

    Detector applications in Nuclear Safeguards and Waste Management have included measuring neutrons from fission and (alpha,n) reactions with well-moderated neutron proportional counters, often embedded in a slab of polyethylene. Other less-moderated geometries are useful for detecting both bare and moderated fission-source neutrons with good efficiency. The neutron chamber is an undermoderated detector design comprising a large, hollow, polyethylene-walled chamber containing one or more proportional counters. Neutron-chamber detectors are relatively inexpensive; can have large apertures, usually through a thin chamber wall; and offer very good detection efficiency per dollar. Neutron-chamber detectors have also been used for monitoring vehicles and for assaying large crates of transuranic waste. Our Monte Carlo calculations for a new application (monitoring low-density waste for concealed plutonium) illustrate the advantages of the hollow-chamber design for detecting moderated fission sources. 9 refs., 6 figs., 2 tabs

  2. Bubble chamber: Omega production and decay

    CERN Multimedia

    1973-01-01

    This image is taken from one of CERN's bubble chambers and shows the decay of a positive kaon in flight. The decay products of this kaon can be seen spiraling in the magnetic field of the chamber. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that has been heated to boiling point.

  3. Vacuum Chamber for the Booster Bending Magnets

    CERN Multimedia

    1974-01-01

    To minimize eddy currents, induced by the rising magnetic field, the chamber was made from thin stainless steel of high specific electric resistance. For mechanical stength, it was corrugated in a hydro-forming process. The chamber is curved, to follow the beam's orbital path. Under vacuum, the chamber tends to staighten, the ceramic spacer along half of its length keeps it in place (see also 7402458).

  4. IFE Chamber Technology - Status and Future Challenges

    International Nuclear Information System (INIS)

    Significant progress has been made on addressing critical issues for inertial fusion energy (IFE) chambers for heavy-ion, laser and Z-pinch drivers. A variety of chamber concepts are being investigated including drywall (currently favored for laser IFE), wetted-wall (applicable to both laser and ion drivers), and thick-liquid-wall (favored by heavy ion and z-pinch drivers). Recent progress and remaining challenges in developing IFE chambers are reviewed

  5. Construction and performance of large flash chambers

    International Nuclear Information System (INIS)

    The construction and performance of 12' x 12' flash chambers used in a 340 ton neutrino detector under construction at Fermilab is described. The flash chambers supply digital information with a spatial resolution of 0.2'', and are used to finely sample the shower development of the reaction products of neutrino interactions. The flash chambers are easy and inexpensive to build and are electronically read out

  6. Drift chamber tracking with neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Lindsey, C.S.; Denby, B.; Haggerty, H.

    1992-10-01

    We discuss drift chamber tracking with a commercial log VLSI neural network chip. Voltages proportional to the drift times in a 4-layer drift chamber were presented to the Intel ETANN chip. The network was trained to provide the intercept and slope of straight tracks traversing the chamber. The outputs were recorded and later compared off line to conventional track fits. Two types of network architectures were studied. Applications of neural network tracking to high energy physics detector triggers is discussed.

  7. Vapor wall deposition in Teflon chambers

    OpenAIRE

    Zhang, X; R. H. Schwantes; R. C. McVay; H Lignell; M. M. Coggon; Flagan, R C; Seinfeld, J.H.

    2014-01-01

    Teflon chambers are ubiquitous in studies of atmospheric chemistry. Secondary organic aerosol (SOA) formation can be substantially underestimated owing to deposition of SOA-forming compounds to chamber walls. We present here an experimental protocol to constrain the nature of wall deposition of organic vapors in Teflon chambers. We measured the wall deposition rates of 25 oxidized organic compounds generated from the photooxidation of isoprene, toluene, α-pinene, and dodecan...

  8. Drift chamber tracking with neural networks

    International Nuclear Information System (INIS)

    We discuss drift chamber tracking with a commercial log VLSI neural network chip. Voltages proportional to the drift times in a 4-layer drift chamber were presented to the Intel ETANN chip. The network was trained to provide the intercept and slope of straight tracks traversing the chamber. The outputs were recorded and later compared off line to conventional track fits. Two types of network architectures were studied. Applications of neural network tracking to high energy physics detector triggers is discussed

  9. Bicone vacuum chamber for ISR intersection

    CERN Multimedia

    1975-01-01

    This is one of the bicone chambers made of titanium for experiment R 702. The central corrugated part had a very thin titanium wall (0.28 mm). The first of these chambers collapsed in its central part when baked at 300 C (August 1975). After an intensive effort to develop better quality and reproducible welds for this special material, the ISR workshop was able to build two new chambers of this type. One of them was installed at I 7 for R 702 in 1976 and worked perfectly. It was at that time the most "transparent" intersection vacuum chamber. See also 7609219, 7609221.

  10. The Mark II Vertex Drift Chamber

    International Nuclear Information System (INIS)

    We have completed constructing and begun operating the Mark II Drift Chamber Vertex Detector. The chamber, based on a modified jet cell design, achieves 30 μm spatial resolution and 2 gas mixtures. Special emphasis has been placed on controlling systematic errors including the use of novel construction techniques which permit accurate wire placement. Chamber performance has been studied with cosmic ray tracks collected with the chamber located both inside and outside the Mark II. Results on spatial resolution, average pulse shape, and some properties of CO2 mixtures are presented. 10 refs., 12 figs., 1 tab

  11. Cylindrical ionization chamber with compressed krypton

    International Nuclear Information System (INIS)

    A cylindrical ionization chamber with a grid is used to search for double positron decay and atomic electron conversion to a positron in 78Kr. Krypton is the working gas material of the chamber. The spectrometric characteristics of the chamber filled with krypton and xenon are presented. The energy resolution is 2.1% for an energy of 1.84 MeV (the source of γ-quanta is 88Y) when the chamber is filled with a mixture of Kr+0.2% H2 under a pressure of 25 atm

  12. Engineering verification of the biomass production chamber

    Science.gov (United States)

    Prince, R. P.; Knott, W. M., III; Sager, J. C.; Jones, J. D.

    1992-01-01

    The requirements for life support systems, both biological and physical-chemical, for long-term human attended space missions are under serious study throughout NASA. The KSC 'breadboard' project has focused on biomass production using higher plants for atmospheric regeneration and food production in a special biomass production chamber. This chamber is designed to provide information on food crop growth rate, contaminants in the chamber that alter plant growth requirements for atmospheric regeneration, carbon dioxide consumption, oxygen production, and water utilization. The shape and size, mass, and energy requirements in relation to the overall integrity of the biomass production chamber are under constant study.

  13. D0 central tracking chamber performance studies

    International Nuclear Information System (INIS)

    The performance of the completed DO central tracking chamber was studied using cosmic rays at the State University of New York at Stony Brook. Also studied was a prototype tracking chamber identical in design to the completed DO tracking chamber. The prototype chamber was exposed to a collimated beam of 150 GeV pions at the Fermilab NWA test facility. Results indicate an RΦ tracking resolution compatible with the limitations imposed by physical considerations, excellent 2 track resolution, and a high track reconstruction efficiency along with a good rejection power against γ → e + e- events

  14. D0 central tracking chamber performance studies

    Energy Technology Data Exchange (ETDEWEB)

    Pizzuto, D.

    1991-12-01

    The performance of the completed DO central tracking chamber was studied using cosmic rays at the State University of New York at Stony Brook. Also studied was a prototype tracking chamber identical in design to the completed DO tracking chamber. The prototype chamber was exposed to a collimated beam of 150 GeV pions at the Fermilab NWA test facility. Results indicate an R{Phi} tracking resolution compatible with the limitations imposed by physical considerations, excellent 2 track resolution, and a high track reconstruction efficiency along with a good rejection power against {gamma} {yields} e {sup +} e{sup {minus}} events.

  15. Dosimetry by paired chambers (TEP-TEG and C-CO2 chamber)

    International Nuclear Information System (INIS)

    Paired chambers are defined as the combination of a neutron and γ sensitive detector and a γ sensitive one, such as the combination of a tissue equivalent ionization chamber (TEP-TEG chamber) and a carbon ionization chamber (C-CO2 chamber). The paired chambers have a feature to be capable of measuring the dose in an irradiation field directly by absorbed dose unit. The authors performed dosimetry by using the paired chambers to investigate the possibility of medical and biological researches by means of the fast neutron beam obtained in the reactor ''Yayoi''. First, the specifications for the paired chambers used, and next, the dose evaluation method are described. The result of dose calibration for the paired chambers shows that the carbon chamber has the reproducibility within 3% deviation and the TEP chamber system has that of 2%. As the examples of measurement, the dosimetry for a living body radiation field by fast neutron beam and that for epithermal neutron irradiation system are reported. The comparison of these dosimetrical results with the other paired chambers seems to show that the satisfactory dosimeter has been produced. The parameters employed for dose conversion are considered to be applicable to the measurement of the epithermal neutron irradiation system. (Wakatsuki, Y.)

  16. Chamber Music's Lesson in Performing Confidence.

    Science.gov (United States)

    Stubbs, Darrel W.

    1983-01-01

    Chamber music has the advantage of offering the student maximum exposure as an individual performer. The absence of a conductor means that the student assumes the role of interpreter, thereby gaining musical maturity. For these reasons, curriculum hours should be more evenly divided between chamber music and larger ensembles. (CS)

  17. The Drift Chambers Of The Nomad Experiment

    CERN Document Server

    Anfreville, M G; Authier, M; Baldisseri, Alberto; Banner, M; Besson, N; Bouchez, J; Castera, A; Cloué, O; Dumarchez, J; Dumps, Ludwig; Gangler, E; Gosset, J; Hagner, C; Jollec, C; Lachaud, C; Letessier-Selvon, A A; Lévy, J M; Linssen, Lucie; Meyer, J P; Ouriet, J P; Passerieux, J P; Pédrol, T; Placci, Alfredo; Poinsignon, J; Popov, B; Rathouit, P; Schahmaneche, K; Stolarczyk, T; Urós, V; Vannucci, François; Vo, M K; Zaccone, Henri

    2002-01-01

    We present a detailed description of the drift chambers used as an active target and a tracking device in the NOMAD experiment at CERN. The main characteristics of these chambers are a large area, a self supporting structure made of light composite materials and a low cost. A spatial resolution of 150 microns has been achieved with a single hit efficiency of 97%.

  18. Supersonic Jet Interactions in a Plenum Chamber

    Directory of Open Access Journals (Sweden)

    K. M. Venugopal

    2004-07-01

    Full Text Available Understanding thè supersonic jet interactions in a plenum chamber is essential for thè design of hot launch systems. Static tests were conducted in a small-scale rocket motor ioaded with a typical nitramine propellaiit to produce a nozzle exit Mach number of 3. This supersonic jet is made to interact with plenum chambers having both open and closed sides. The distance between thè nozzle exit and thè back piate of plenum chamber are varied from 2. 5 to 7. 0 times thè nozzle exit diameter. The pressure rise in thè plenum chamber was measured using pressure transducers mounted at different locatìons. The pressure-time data were analysed to obtain an insight into thè flow field in thè plenum chamber. The maximum pressure exerted on thè back piate of plenum chamber is about 25-35 per cent. of thè maximum stagnation pressure developed in thè rocket motor. Ten static tests were carried out to obtain thè effect of axial distance between thè nozzle exit and thè plenum chamber back piate, and stagnation pressure in thè rocket motoron thè flow field in thè open-sided and closed-sided plenum chambers configurations.

  19. Space Power Facility Reverberation Chamber Calibration Report

    Science.gov (United States)

    Lewis, Catherine C.; Dolesh, Robert J.; Garrett, Michael J.

    2014-01-01

    This document describes the process and results of calibrating the Space Environmental Test EMI Test facility at NASA Plum Brook Space Power Facility according to the specifications of IEC61000-4-21 for susceptibility testing from 100 MHz to 40 GHz. The chamber passed the field uniformity test, in both the empty and loaded conditions, making it the world's largest Reverberation Chamber.

  20. Wet drift chambers for precise luminosity

    International Nuclear Information System (INIS)

    A set of high-precision compact drift chambers has been a vital component of the OPAL luminosity monitor since the start of data-taking at LEP. They were augmented in 1992 by the addition of Small Angle Reference Chambers with a very similar design to the original chamber. The performance of the chambers is reviewed, highlighting both the importance of using polyalkylene glycol (Breox) to maintain a uniform and parallel electric field and the construction techniques used to sustain the required field strength. We describe some of the operating problems, with their solutions, and show how the chambers have been used in achieving a systematic error of 0.41% on the luminosity measurement. ((orig.))

  1. Ionization-chamber smoke detector system

    Science.gov (United States)

    Roe, Robert F.

    1976-10-19

    This invention relates to an improved smoke-detection system of the ionization-chamber type. In the preferred embodiment, the system utilizes a conventional detector head comprising a measuring ionization chamber, a reference ionization chamber, and a normally non-conductive gas triode for discharging when a threshold concentration of airborne particulates is present in the measuring chamber. The improved system is designed to reduce false alarms caused by fluctuations in ambient temperature. Means are provided for periodically firing the gas discharge triode and each time recording the triggering voltage required. A computer compares each triggering voltage with its predecessor. The computer is programmed to energize an alarm if the difference between the two compared voltages is a relatively large value indicative of particulates in the measuring chamber and to disregard smaller differences typically resulting from changes in ambient temperature.

  2. Compact ion chamber based neutron detector

    Science.gov (United States)

    Derzon, Mark S.; Galambos, Paul C.; Renzi, Ronald F.

    2015-10-27

    A directional neutron detector has an ion chamber formed in a dielectric material; a signal electrode and a ground electrode formed in the ion chamber; a neutron absorbing material filling the ion chamber; readout circuitry which is electrically coupled to the signal and ground electrodes; and a signal processor electrically coupled to the readout circuitry. The ion chamber has a pair of substantially planar electrode surfaces. The chamber pressure of the neutron absorbing material is selected such that the reaction particle ion trail length for neutrons absorbed by the neutron absorbing material is equal to or less than the distance between the electrode surfaces. The signal processor is adapted to determine a path angle for each absorbed neutron based on the rise time of the corresponding pulse in a time-varying detector signal.

  3. The emulsion chamber technology experiment

    Science.gov (United States)

    Gregory, John C.

    1992-01-01

    Photographic emulsion has the unique property of recording tracks of ionizing particles with a spatial precision of 1 micron, while also being capable of deployment over detector areas of square meters or 10's of square meters. Detectors are passive, their cost to fly in Space is a fraction of that of instruments of similar collecting. A major problem in their continued use has been the labor intensiveness of data retrieval by traditional microscope methods. Two factors changing the acceptability of emulsion technology in space are the astronomical costs of flying large electronic instruments such as ionization calorimeters in Space, and the power and low cost of computers, a small revolution in the laboratory microscope data-taking. Our group at UAH made measurements of the high energy composition and spectra of cosmic rays. The Marshall group has also specialized in space radiation dosimetry. Ionization calorimeters, using alternating layers of lead and photographic emulsion, to measure particle energies up to 10(exp 15) eV were developed. Ten balloon flights were performed with them. No such calorimeters have ever flown in orbit. In the ECT program, a small emulsion chamber was developed and will be flown on the Shuttle mission OAST-2 to resolve the principal technological questions concerning space exposures. These include assessments of: (1) pre-flight and orbital exposure to background radiation, including both self-shielding and secondary particle generation; the practical limit to exposure time in space can then be determined; (2) dynamics of stack to optimize design for launch and weightlessness; and (3) thermal and vacuum constraints on emulsion performance. All these effects are cumulative and affect our ability to perform scientific measurements but cannot be adequately predicted by available methods.

  4. Multiwire proportional chamber with a dielectric film. Numerical study

    International Nuclear Information System (INIS)

    Electrostatical properties of multiwire proportional chambers with a dielectric film of low conductivity are considered. Distribution of the electric field in the chamber was obtained using numerical methods. This allowed investigating the influence of various parameters (chamber geometry, voltage at the electrodes) on the chamber working characteristics. Dependence of the chamber amplitude characteristics on the counting rate was also obtained

  5. Monitored Drift Chambers in the ATLAS Detector

    CERN Multimedia

    Herten, G

    Monitored Drift Chambers (MDT) are used in the ATLAS Detector to measure the momentum of high energy muons. They consist of drift tubes, which are filled with an Ar-CO2 gas mixture at 3 bar gas pressure. About 1200 drift chambers are required for ATLAS. They are up to 6 m long. Nevertheless the position of every wire needs to be known with a precision of 20 µm within a chamber. In addition, optical alignment sensors are required to measure the relative position of adjacent chambers with a precision of 30µm. This gigantic task seems impossible at first instance. Indeed it took many years of R&D to invent the right tools and methods before the first chamber could be built according to specifications. Today, at the time when 50% of the chambers have been produced, we are confident that the goal for ATLAS can be reached. The mechanical precision of the chambers could be verified with the x-ray tomograph at CERN. This ingenious device, developed for the MDT system, is able to measure the wire position insid...

  6. Comparison among different CT ionization chambers

    International Nuclear Information System (INIS)

    The dosimetry in computed tomography (CT) is carried out by the use of a pencil type ionization-chamber, because it has a uniform response at all angles relative to the incident beam of radiation, which is essential for CT equipment since the X-ray tube executes a circular movement around the table during irradiation. The commercial ionization chamber used to perform quality control procedures of this kind of equipment has a length of the sensitive volume of 10 cm. In the Calibration Laboratory of Instruments (LCI) of the IPEN there were already developed some prototypes with small differences in construction, when compared to commercially available ionization chambers. They have been used in previous studies and showed results within internationally acceptable limits. The ionization chambers tested in this study present the sensitive volume lengths of 1 cm, 3 cm and 10 cm. The objective of this study was to present results on the stability test of the three homemade ionization chambers and a commercial chamber, as well to obtain the calibration coefficients for each of them in CT standard X radiation beams. The obtained results for both characterization tests are within the recommended limits, except for the homemade ionization chambers with sensitive volume lengths of 3 cm and 1 cm in the case of the stability test. (author)

  7. Making MUSIC: A multiple sampling ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Shumard, B. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States)]. E-mail: shumard@phy.anl.gov; Henderson, D.J. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States); Rehm, K.E. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States); Tang, X.D. [Argonne National Laboratory, Building 203 H-113, Argonne, IL 60439 (United States)

    2007-08-15

    A multiple sampling ionization chamber (MUSIC) was developed for use in conjunction with the Atlas scattering chamber (ATSCAT). This chamber was developed to study the ({alpha}, p) reaction in stable and radioactive beams. The gas filled ionization chamber is used as a target and detector for both particles in the outgoing channel (p + beam particles for elastic scattering or p + residual nucleus for ({alpha}, p) reactions). The MUSIC detector is followed by a Si array to provide a trigger for anode events. The anode events are gated by a gating grid so that only ({alpha}, p) reactions where the proton reaches the Si detector result in an anode event. The MUSIC detector is a segmented ionization chamber. The active length of the chamber is 11.95 in. and is divided into 16 equal anode segments (3.5 in. x 0.70 in. with 0.3 in. spacing between pads). The dead area of the chamber was reduced by the addition of a Delrin snout that extends 0.875 in. into the chamber from the front face, to which a mylar window is affixed. 0.5 in. above the anode is a Frisch grid that is held at ground potential. 0.5 in. above the Frisch grid is a gating grid. The gating grid functions as a drift electron barrier, effectively halting the gathering of signals. Setting two sets of alternating wires at differing potentials creates a lateral electric field which traps the drift electrons, stopping the collection of anode signals. The chamber also has a reinforced mylar exit window separating the Si array from the target gas. This allows protons from the ({alpha}, p) reaction to be detected. The detection of these protons opens the gating grid to allow the drift electrons released from the ionizing gas during the ({alpha}, p) reaction to reach the anode segment below the reaction.

  8. Making MUSIC: A multiple sampling ionization chamber

    Science.gov (United States)

    Shumard, B.; Henderson, D. J.; Rehm, K. E.; Tang, X. D.

    2007-08-01

    A multiple sampling ionization chamber (MUSIC) was developed for use in conjunction with the Atlas scattering chamber (ATSCAT). This chamber was developed to study the (α, p) reaction in stable and radioactive beams. The gas filled ionization chamber is used as a target and detector for both particles in the outgoing channel (p + beam particles for elastic scattering or p + residual nucleus for (α, p) reactions). The MUSIC detector is followed by a Si array to provide a trigger for anode events. The anode events are gated by a gating grid so that only (α, p) reactions where the proton reaches the Si detector result in an anode event. The MUSIC detector is a segmented ionization chamber. The active length of the chamber is 11.95 in. and is divided into 16 equal anode segments (3.5 in. × 0.70 in. with 0.3 in. spacing between pads). The dead area of the chamber was reduced by the addition of a Delrin snout that extends 0.875 in. into the chamber from the front face, to which a mylar window is affixed. 0.5 in. above the anode is a Frisch grid that is held at ground potential. 0.5 in. above the Frisch grid is a gating grid. The gating grid functions as a drift electron barrier, effectively halting the gathering of signals. Setting two sets of alternating wires at differing potentials creates a lateral electric field which traps the drift electrons, stopping the collection of anode signals. The chamber also has a reinforced mylar exit window separating the Si array from the target gas. This allows protons from the (α, p) reaction to be detected. The detection of these protons opens the gating grid to allow the drift electrons released from the ionizing gas during the (α, p) reaction to reach the anode segment below the reaction.

  9. Liquid-argon cylindrical pulsed ionization chamber

    International Nuclear Information System (INIS)

    A liquid-argon cylindrical ionization chamber with a working volume of 200 cm2 is described. The chamber anode is made of stainless steel in the form of a hollow cylinder 30 mm in diameter and 140 mm in length. A beryllium bronze wire in diameter of 0.1 mm and at a spacing of 1 mm is used for winding the chamber screen grid. The chamber cathode is a brass thin-walled cylinder having an internal diameter of 56 mm and a height of 156 mm. The cathode-grid gap is 10 mm, the cathode-case gap is 2 mm. A 0.5 l cooling bath filled with liquid nitrogen is used to refrigirate the chamber. The chamber is evacuated to about 10-5 mm Hg. The total concentration of electronegative impurities in argon does not exceed 6x10-9. Dependences of the chamber counting and amplitude responses, on the cathode voltage under irradiation with γ-quanta at energies of 0.898 MeV and 1.836 MeV are given. The value of the energy resolution was evaluated by differentiating the high-energy edge of the Compton spectrum. The total width at a peak half-height constitutes 5% for an electron energy of 1.612 MeV. To achieve better resolution of the chamber it is necessary to reduce preamplifier noises by three times, to increase the working gap of the chamber and decrease the grid-anode gap

  10. Making MUSIC: A multiple sampling ionization chamber

    International Nuclear Information System (INIS)

    A multiple sampling ionization chamber (MUSIC) was developed for use in conjunction with the Atlas scattering chamber (ATSCAT). This chamber was developed to study the (α, p) reaction in stable and radioactive beams. The gas filled ionization chamber is used as a target and detector for both particles in the outgoing channel (p + beam particles for elastic scattering or p + residual nucleus for (α, p) reactions). The MUSIC detector is followed by a Si array to provide a trigger for anode events. The anode events are gated by a gating grid so that only (α, p) reactions where the proton reaches the Si detector result in an anode event. The MUSIC detector is a segmented ionization chamber. The active length of the chamber is 11.95 in. and is divided into 16 equal anode segments (3.5 in. x 0.70 in. with 0.3 in. spacing between pads). The dead area of the chamber was reduced by the addition of a Delrin snout that extends 0.875 in. into the chamber from the front face, to which a mylar window is affixed. 0.5 in. above the anode is a Frisch grid that is held at ground potential. 0.5 in. above the Frisch grid is a gating grid. The gating grid functions as a drift electron barrier, effectively halting the gathering of signals. Setting two sets of alternating wires at differing potentials creates a lateral electric field which traps the drift electrons, stopping the collection of anode signals. The chamber also has a reinforced mylar exit window separating the Si array from the target gas. This allows protons from the (α, p) reaction to be detected. The detection of these protons opens the gating grid to allow the drift electrons released from the ionizing gas during the (α, p) reaction to reach the anode segment below the reaction

  11. Bubble chamber: Omega production and decay

    CERN Multimedia

    1973-01-01

    This image is of real particle tracks taken from the CERN 2 m liquid hydrogen bubble chamber and shows the production and decay of a negative omega particle. A negative kaon enters the chamber which decays into many particles, including a negative omega that travels a short distance before decaying into more particles. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real tracks left by particles to be seen and photographed by expanding liquid that had been heated to boiling point.

  12. Growing and Analyzing Biofilms in Flow Chambers

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim; Sternberg, Claus

    2011-01-01

    This unit describes the setup of flow chamber systems for the study of microbial biofilms, and methods for the analysis of structural biofilm formation. Use of flow chambers allows direct microscopic investigation of biofilm formation. The biofilms in flow chambers develop under hydrodynamic......, and disassembly and cleaning of the system. In addition, embedding and fluorescent in situ hybridization of flow chamber–grown biofilms are addressed. Curr. Protoc. Microbiol. 21:1B.2.1-1B.2.17. © 2011 by John Wiley & Sons, Inc....

  13. Development of an α grid ionization chamber

    International Nuclear Information System (INIS)

    The article introduces the parallel grid ionization chamber used to measure the α radioactivity, which has a independent vacuum system. The system is composed of main body of the chamber, gas-filled and electronics system. Energy resolution is 25 keV for 239Pu, background is 4 counts for one hour from 4 MeV to 6 MeV energy range, detect efficiency approach to 50%. The chamber can measure the energy of nuclide, analyze the structure, moreover authenticate both the nuclide and the relative and absolute content. (authors)

  14. APS Storage Ring vacuum chamber fabrication

    International Nuclear Information System (INIS)

    The 1104-m circumference Advanced Photon Source Storage Ring Vacuum System is composed of 240 individual sections, which are fabricated from a combination of aluminum extrusions and machined components. The vacuum chambers will have 3800 weld joints, each subject to strict vacuum requirements, as well as a variety of related design criteria. The vacuum criteria and chamber design are reviewed, including a discussion of the weld joint geometries. The critical fabrication process parameters for meeting the design requirements are discussed. The experiences of the prototype chamber fabrication program are presented. Finally, the required facilities preparation for construction activity is briefly described. 6 refs., 6 figs., 1 tab

  15. LEP vacuum chamber, cross-section

    CERN Multimedia

    1983-01-01

    Cross-section of the final prototype for the LEP vacuum chamber. The elliptic main-opening is for the beam. The small channel to the left is for the cooling water, to carry away the heat deposited by the synchrotron radiation. The square channel to the right houses the Non-Evaporable Getter (NEG) pump. The chamber is made from extruded aluminium. Its outside is clad with lead, to stop the synchrotron radiation emitted by the beam. For good adherence between Pb and Al, the Al chamber was coated with a thin layer of Ni. Ni being slightly magnetic, some resulting problems had to be overcome. See also 8301153.

  16. Cloud chamber photographs of the cosmic radiation

    CERN Document Server

    Rochester, George Dixon

    1952-01-01

    Cloud Chamber Photographs of the Cosmic Radiation focuses on cloud chamber and photographic emulsion wherein the tracks of individual subatomic particles of high energy are studied. The publication first offers information on the technical features of operation and electrons and cascade showers. Discussions focus on the relationship in time and space of counter-controlled tracks; techniques of internal control of the cloud chamber; cascade processes with artificially-produced electrons and photons; and nuclear interaction associated with an extensive shower. The manuscript then elaborates on

  17. One meter holographic bubble chamber for TEVATRON neutrino experiments

    International Nuclear Information System (INIS)

    A one meter holographic bubble chamber was constructed for Fermilab TEVATRON neutrino experiments. Bubble chamber and optics are briefly outlined. Developments in holography for this bubble chamber and two types of reconstruction projectors are reported. (orig.)

  18. Developing cloud chambers with high school students

    CERN Document Server

    Ishizuka, Ryo; Sato, Shoma; Zeze, Syoji

    2013-01-01

    The result and outcome of the cloud chamber project, which aims to develop a cloud chamber useful for science education is reported in detail. A project includes both three high school students and a teacher as a part of Super Science High School (SSH) program in our school. We develop a dry ice free cloud chamber using salt and ice (or snow). Technical detail of the chamber is presented. We also argue how the project affects student's cognition, motivation, academic skills and behavior. The research project had been done in very similar way to those of professional researchers, i.e., planning research, applying fund, writing a paper and giving a talk in conferences. From interviews with students, we learn that such style of scientific activity is very effective in promoting student's motivation for learning science.

  19. Proportional chamber application to ionization measurements

    International Nuclear Information System (INIS)

    The possibility is investigated to use a proportional chamber measuring ionization particle losses in developing a detector capable of tracking the simultaneous passage of several particles against the background of a large number of single particles. The chamber used, with a 100x100 mm2 working plane, has three high-voltage electrodes and two signal planes spaced at 6 mm. The operating gas is argon + methylal (C3H8O2) at atmospheric pressure. The calculations made with consideration for the resolution obtained in the chamber, i.e., approximately 20% (5.9 keV) indicate that by using four chamber clearances it is possible to obtain the tracking efficiency of three particles over 99%

  20. Room temperature liquid ionization chambers using tetramethylsilane

    International Nuclear Information System (INIS)

    Ionization pulse signals due to 207Bi conversion electrons were observed in ionization chambers filled with tetramethylsilane which was purified by a simple method. Pulse height spectra and its variation with the electric field were measured. (orig.)

  1. MAN-IN-SIMULANT TEST (MIST) CHAMBER

    Data.gov (United States)

    Federal Laboratory Consortium — The MIST chamber uses methyl salicylate (oil of wintergreen) vapor as a simulant for HD agent to conduct system level evaluations of chemical protective ensembles....

  2. Developing Cloud Chambers with High School Students

    Science.gov (United States)

    Ishizuka, Ryo; Tan, Nobuaki; Sato, Shoma; Zeze, Syoji

    The result and outcome of the cloud chamber project, which aims to develop a cloud chamber useful for science education is reported in detail. A project includes both three high school students and a teacher as a part of Super Science High School (SSH) program in our school. We develop a dry-ice-free cloud chamber using salt and ice (or snow). Technical details of the chamber are described. We also argue how the project have affected student's cognition, motivation, academic skills and behavior. The research project has taken steps of professional researchers, i.e., in planning research, applying fund, writing a paper and giving a talk in conferences. From interviews with students, we have learnt that such style of scientific activity is very effective in promoting student's motivation for learning science.

  3. High Performance Methane Thrust Chamber (HPMTC) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop a High-Performance Methane Thrust Chamber (HPMRE) to meet the demands of advanced chemical propulsion systems for deep-space mission...

  4. Georges Charpak and his multiwire chamber

    CERN Multimedia

    1970-01-01

    In 1968, Georges Charpak developed the 'multiwire proportional chamber', a gas-filled box with a large number of parallel detector wires, each connected to individual amplifiers. Linked to a computer, it could achieve a counting rate a thousand times better than existing techniques - without a camera in sight. From left to right, Georges Charpak, Fabio Sauli and Jean-Claude Santiard working on a multiwire chamber in 1970.

  5. The world's largest time projection chamber

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    Peter Glassel, the technical coordinator for the ALICE time projection chamber, is seen sitting inside the detector; the largest in the world at nearly 100 cubic metres. Thousands of wires are connected to read out electronic data produced as particles are created in lead-lead collisions at the centre of the detector. These particles will cause the medium within the time projection chamber to ionise along their tracks allowing the particle paths to be recreated.

  6. Electrostatic problems in multiwire proportional chambers

    CERN Document Server

    Erskine, George A

    1972-01-01

    Starting from the known complex potential of an infinite grid of thin wires lying between parallel grounded electrodes, the following problems are discussed: 1) the electrostatic coupling between wires, 2) the effect of varying the diameter of a single wire, 3) the effect of displacing a single wire. Figures are given which show the magnitude of these effects for a symmetric chamber of arbitrary dimensions. The computer generation of field plots for proportional chambers is briefly discussed. (5 refs).

  7. The CDF vertex time projection chamber system

    International Nuclear Information System (INIS)

    The vertex time projection chamber (VTPC) system is one of the major components of the charged particle tracking system for the Collider Detector at Fermilab (CDF). The chambers cover about seven units of pseudorapidity (η) and must be capable of handling substantially more than the 30-35 charged particle tracks produced by typical anti pp collisions at center-of-mass energies of 1.8 TeV. The chambers are optimized to provide the good pattern recognition in the r-z view required to locate the event vertex, measure the overall event topology, and to complement the r-φ tracking in the large axial wire drift chamber that surrounds them. The chambers provide r-z information using TDC data from sense wire signals. Information on the φ of tracks is obtained from cathode pad signals on a subset of chambers read out by a FADC system. A similar system measures dE/dx of tracks in the forward cones surrounding the exiting beams. Because of the large number of photons that pass through the detector during each collision, novel techniques are required to reduce the amount of material in the chamber. These techniques include a custom surface mount integrated circuit preamplifier, epoxy-graphite and Kapton covered foam structural members, and miniature coaxial signal cables. The mechanical construction of the chamber, radiation length vs angle, and details of the electronics are described. The event reconstruction, corrections, and preliminary performance results for 1.8 TeV anti pp collisions are also discussed. (orig.)

  8. Impact excited strain gage for multiwire chambers

    International Nuclear Information System (INIS)

    A method for measuring multiwire chamber tension by impact excitation of mechanical oscillations and measuring their periods is described. A flowsheet of an automated electron gaugeis presented; the gauge provides high efficiency and possibility for measurements under conditions of difficult availability of the multiwire chamber system. The range of tension measurements is 0.5-70 g for gilded tugsten wires of 20 μm in diameter and 60 cm length

  9. Virtual Calibration Chamber CPT on Ticino sand

    OpenAIRE

    Butlanska, Joanna; Arroyo Alvarez de Toledo, Marcos; Gens Solé, Antonio

    2010-01-01

    The following paper surnmarizes results of CPT's performed in virtual calibration chamber (VCC) built with a 3D model based on the distinct element method (DEM). A discrete material tailored to mimic Ticino sand is tested at different densities, stress and stress history. The limit cone tip resistance from the numerical experiments shows quantitative agreement with different empirical curves summarizing previous tests on Ticino sand in physical calibration chambers (ENEL and ISMES).

  10. Numerical simulation of magma chamber dynamics.

    Science.gov (United States)

    Longo, Antonella; Papale, Paolo; Montagna, Chiara Paola; Vassalli, Melissa; Giudice, Salvatore; Cassioli, Andrea

    2010-05-01

    Magma chambers are characterized by periodic arrivals of deep magma batches that give origin to complex patterns of magma convection and mixing, and modify the distribution of physical quantities inside the chamber. We simulate the transient, 2D, multi-component homogeneous dynamics in geometrically complex dyke+chamber systems, by means of GALES, a finite element parallel C++ code solving mass, momentum and energy equations for multi-component homogeneous gas-liquid (± crystals) mixtures in compressible-to-incompressible flow conditions. Code validation analysis includes several cases from the classical engineering literature, corresponding to a variety of subsonic to supersonic gas-liquid flow regimes (see http://www.pi.ingv.it/~longo/gales/gales.html). The model allows specification of the composition of the different magmas in the domain, in terms of ten major oxides plus the two volatile species H2O and CO2. Gas-liquid thermodynamics are modeled by using the compositional dependent, non-ideal model in Papale et al. (Chem.. Geol., 2006). Magma properties are defined in terms of local pressure, temperature, and composition including volatiles. Several applications are performed within domains characterized by the presence of one or more magma chambers and one or more dykes, with different geometries and characteristic size from hundreds of m to several km. In most simulations an initial compositional interface is placed at the top of a feeding dyke, or at larger depth, with the deeper magma having a lower density as a consequence of larger volatile content. The numerical results show complex patterns of magma refilling in the chamber, with alternating phases of magma ingression and magma sinking from the chamber into the feeding dyke. Intense mixing takes place in feeding dykes, so that the new magma entering the chamber is always a mixture of the deep and the initially resident magma. Buoyant plume rise occurs through the formation of complex convective

  11. A very large multigap resistive plate chamber

    CERN Document Server

    Cerron-Zeballos, E; Hatzifotiadou, D; Kim, D W; Lamas-Valverde, J; Lee, S C; Platner, E D; Roberts, J; Williams, M C S; Zichichi, A

    1999-01-01

    We have built and tested a very large multigap resistive plate chamber (MRPC). We discuss the suitability of the multigap RPC for the construction of large area modules. We give details of the construction technique and results from a scan across the surface of the chamber. We also report on the implementation of `half-strip resolution', where we improve the spatial resolution by a factor 2 without increasing the number of read-out channels. (9 refs).

  12. Characteristic parameters of drift chambers calculation

    International Nuclear Information System (INIS)

    We present here the methods we used to analyse the characteristic parameters of drift chambers. The algorithms to calculate the electric potential in any point for any drift chamber geometry are presented. We include the description of the programs used to calculate the electric field, the drift paths, the drift velocity and the drift time. The results and the errors are discussed. (Author) 7 refs

  13. The OPAL jet chamber full scale prototype

    International Nuclear Information System (INIS)

    The concept of a jet chamber for the central detector of OPAL has been tested with a full scale prototype. The design of this prototype, its mechanical and electrical structure and its support system for high voltage, gas, laser calibration and readout are described. Operating experience has been gathered since summer 1984. The chamber performance in terms of spatial resolution and particle identification capability is given. (orig.)

  14. High intensity electromagnetic field gerenation using a transportable reverberation chamber

    OpenAIRE

    Leferink, F.B.J.

    2008-01-01

    A reverberation chamber can create very high field strength with moderate input power. Existing chambers are making use of a paddle wheel to change the resonant modes in the chamber. A transportable reverberation chamber with vibrating walls will be presented. Inside this Vibrating Intrinsic Reverberation Chamber (VIRC) a diffuse, statistically uniform electromagnetic field is created, without the use of a mechanical, rotating, mode stirrer. This chamber results in a better homogeneity and in...

  15. Close cathode chamber: Low material budget MWPC

    International Nuclear Information System (INIS)

    Performance of asymmetric-type MWPC-s are presented. In this structure, referred to as Close Cathode Chamber in an earlier study, the material budget is significantly reduced on one hand by the elimination of external support frame, on the other hand by thin detector walls. In this paper it is demonstrated that the outline is compatible with large size detectors (1 m wire length), maintaining mechanical and operation stability, with total weight of 3 kg (including support structure) for a half square meter surface. The detection efficiency and response time is shown to be sufficient for L0 triggering in the ALICE VHMPID layout. Reduced sensitivity to cathode deformations (due to internal overpressure as mechanical strain) is directly demonstrated. On small sized chambers, improvement of position resolution with analog readout is evaluated, reaching 0.09 mm RMS with 2 mm wide cathode segments. Simulation results on signal time evolutions are presented. With the above studies, comparison of classical MWPC-s and the Close Cathode Chamber design is performed in all major aspects. -- Highlights: ► Asymmetric multi-wire proportional chamber, called the Close Cathode Chamber, is studied. ► Large size construction feasibility up to 1 m wire length is demonstrated in test beam and cosmic rays. ► Reduction of dependence of gas gain on chamber internal pressure is directly demonstrated. ► Position resolution and signal formation is shown to be compatible with classical MWPC.

  16. The GODDESS ionization chamber: developing robust windows

    Science.gov (United States)

    Blanchard, Rose; Baugher, Travis; Cizewski, Jolie; Pain, Steven; Ratkiewicz, Andrew; Goddess Collaboration

    2015-10-01

    Reaction studies of nuclei far from stability require high-efficiency arrays of detectors and the ability to identify beam-like particles, especially when the beam is a cocktail beam. The Gammasphere ORRUBA Dual Detectors for Experimental Structure Studies (GODDESS) is made up of the Oak Ridge-Rutgers University Barrel Array (ORRUBA) of silicon detectors for charged particles inside of the gamma-ray detector array Gammasphere. A high-rate ionization chamber is being developed to identify beam-like particles. Consisting of twenty-one alternating anode and cathode grids, the ionization chamber sits downstream of the target chamber and is used to measure the energy loss of recoiling ions. A critical component of the system is a thin and robust mylar window which serves to separate the gas-filled ionization chamber from the vacuum of the target chamber with minimal energy loss. After construction, windows were tested to assure that they would not break below the required pressure, causing harm to the wire grids. This presentation will summarize the status of the ionization chamber and the results of the first tests with beams. This work is supported in part by the U.S. Department of Energy and National Science Foundation.

  17. Quality control of ATLAS muon chambers

    CERN Document Server

    Fabich, Adrian

    ATLAS is a general-purpose experiment for the future Large Hadron Collider (LHC) at CERN. Its Muon Spectrometer will require ∼ 5500m2 of precision tracking chambers to measure the muon tracks along a spectrometer arm of 5m to 15m length, embedded in a magnetic field of ∼ 0.5T. The precision tracking devices in the Muon System will be high pressure drift tubes (MDTs). Approximately 370,000 MDTs will be assembled into ∼ 1200 drift chambers. The performance of the MDT chambers is very much dependent on the mechanical quality of the chambers. The uniformity and stability of the performance can only be assured providing very high quality control during production. Gas tightness, high-voltage behaviour and dark currents are global parameters which are common to gas detectors. For all chambers, they will be tested immediately after the chamber assembly at every production site. Functional tests, for example radioactive source scans and cosmic-ray runs, will be performed in order to establish detailed performan...

  18. A large scale knife-edge chamber

    International Nuclear Information System (INIS)

    To date, three different tracking detectors, Straw Tube Chamber, Silicon Strip Detector and Scintillation Fiber Detector, as well as their combinations, have been proposed for the SSC experiments. However all of them have their own problems as tracking detectors for use in very high luminosity experiment at the SSC. Scintillation fiber detector is excellent in its speed, spatial resolution and low occupancy. However the fatal problem is the readout devices. Questions on its radiation hardness have not yet been totally solved. As a solution to this challenge, a knife-edge chamber was proposed. The knife-edge chamber is essentially a multi-wire proportional chamber. This chamber has, however, a drawback which is shared with the silicon strip detector, i.e., the size of a single chamber is limited by that of the silicon wafer. Recently at KEK, a program has been started to overcome this problem. The KEK method is to make v-shape grooves on a metal plate, such as a nickel-plated steel, and to use the metal plate as a negative to make sharp-edged electrodes. After this process, there are two possibilities, which are under consideration at the moment. The first possibility is to use the electroforming technique. The second possibility is to use the plastic molding technique by using the machined metal plate as a negative. The KEK machine shop has recently built a high precision shaper machine to produce gratings for synchrotron radiation research. (N.K.)

  19. Chamber for Growing and Observing Fungi

    Science.gov (United States)

    Pierson, Duane L.; Molina, Thomas C.

    2005-01-01

    A chamber has been designed to enable growth and observation of microcolonies of fungi in isolation from the external environment. Unlike prior fungus-growing apparatuses, this chamber makes it possible to examine a fungus culture without disrupting it. Partly resembling a small picture frame, the chamber includes a metal plate having a rectangular through-thethickness opening with recesses for a top and a bottom cover glass, an inlet for air, and an inlet for water. The bottom cover glass is put in place and held there by clips, then a block of nutrient medium and a moisture pad are placed in the opening. The block is inoculated, then the top cover glass is put in place and held there by clips. Once growth is evident, the chamber can be sealed with tape. Little (if any) water evaporates past the edges of the cover glasses, and, hence there is little (if any) need to add water. A microscope can be used to observe the culture through either cover glass. Because the culture is sealed in the chamber, it is safe to examine the culture without risking contamination. The chamber can be sterilized and reused.

  20. Bulkhead chamber ignition for internal combustion engines. Schottkammerzuendung fuer Verbrennungsmotore

    Energy Technology Data Exchange (ETDEWEB)

    Fox, G.

    1990-12-06

    Bulkhead chamber ignition makes for reliable ignition of different fuels (e.g. petrol or diesel) in internal combustion engines (multifuel engine) that can be operated with an extremely lean fuel-air mixture. This is realized by an open chamber (referred to as bulkhead chamber in the following) inside the combustion chamber which diverts a fraction of the compressed fuel-air mixture from the combustion chamber. After this the pressure in the bulkhead chamber is increased until the mixture ignites spontaneously. The combustion pressure drives back the piston and opens the bulkhead chamber. Then the compressed fuel-air mixture in the combustion chamber is ignited by the released combustion gas.

  1. In vitro penetration of bleaching agents into the pulp chamber

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Valera, M C; Mancini, M N G;

    2004-01-01

    To investigate pulp chamber penetration of bleaching agents in teeth following restorative procedures.......To investigate pulp chamber penetration of bleaching agents in teeth following restorative procedures....

  2. Change of Pressing Chamber Conicalness at Briquetting Process in Briquetting Machine Pressing Chamber

    OpenAIRE

    Peter Križan; Miloš Matúš; Jaan Kers; Djordje Vukelić

    2012-01-01

    In this paper, we will present the impact of the conical shape of a pressing chamber, an important structural parameter. Besides the known impact of the technological parameters of pressing chambers, it is also very important to pay attention to their structural parameters. In the introduction, we present a theoretical analysis of pressing chamber conicalness. An experiment aimed at detecting this impact was performed at our institute, and it showed that increasing the conicalness of a pressi...

  3. Innovations in gas filled ionisation chambers

    International Nuclear Information System (INIS)

    The gas filled parallel plate ion chamber and coaxial cylindrical ion chambers are widely used for detection of nuclear radiations for more than hundred years. Thin Metal electrodes or metal coated planes are used as cathode and anodes in both parallel plate and cylindrical ionization chambers since its invention. For neutral particle detection, either the ionising medium or a coated electrode surface is used as a converter material for producing secondary charged particles which are detected in these ionisation chambers. Boron, and 235U are coated as thin layer on the cathode surface with optimum thickness to give maximum neutron detection sensitivity. The neutron sensitivity mostly depends upon the coated surface area and to enhance the neutron sensitivity diameter and the length/ diameter of the coated electrodes have to be increased which also results in an increase in the volume of the counter. For many applications, it is necessary to reduce the size of the counter by a factor of 2 to 5 but having the same efficiency. Recently this has been achieved by designing a non planar electrode surface/ s which has surface area larger by a factor or up to five keeping the external dimensions the same. By using this new technique, it is possible to increase the coated area up to 5 times, without changing the overall dimensions of the counter both for proportional counters and ion chambers. The three methods have been developed to enhance the neutron sensitivity the use of: additional coated wires, coated baffles, coated fins: in sensitive volume of gas detectors. The introduction of these three-dimensional boron coated structures into the sensitive volume without enlarging the outer detector dimensions increases the Boron/Uranium content in the sensitive region without any significant change in the nature of the pulses from these counters. In the newly developed Wire Plane Chambers both in the DC mode and pulse mode, wire planes have been used as anode and cathodes with

  4. Organization of inspection of bubble chamber photographs

    International Nuclear Information System (INIS)

    A program for inspection of bubble chamber photographs is described. The program was developed for a DEC-10 computer and is designed for PUOS-2M and PUOS-4 semiautomatic inspection and measuring projectors. Formalization of the inspection procedure allows it to be used for various physics experiments. As an example the authors consider the problem of the physical inspection in an experiment on scattering of kaons plus with momenta of 70 GeV/c by protons performed in a BEBC chamber. Primary vertices were analyzed in the following cases: low quality of reconstruction of parameters in the geometric program; lack of agreement of the number of reconstructed tracks with that indicated by inspection; and unmeasured events and events with candidate tracks for identification of proton tracks by degree of ionization. The performance of the program in these cases is evaluated. The program has been used to process 50,000 events recorded with a BEBC chamber as well as experiments recorded with the SCAT chamber and the European Hybrid Spectrometer using the RCBC, LEBC and HOLEBC chambers

  5. Investigation of Swirling Flows in Mixing Chambers

    Directory of Open Access Journals (Sweden)

    Jyh Jian Chen

    2011-01-01

    Full Text Available This investigation analyzed the three-dimensional momentum and mass transfer characteristics arising from multiple inlets and a single outlet in micromixing chamber. The chamber consists of a right square prism, an octagonal prism, or a cylinder. Numerical results which were presented in terms of velocity vector plots and concentration distributions indicated that the swirling flows inside the chamber dominate the mixing index. Particle trajectories were utilized to demonstrate the rotational and extensional local flows which produce steady stirring, and the configuration of colored particles at the outlet section expressed at different Re represented the mixing performance qualitatively. The combination of the Taylor dispersion and the vorticity was first introduced and made the mixing successful. The effects of various geometric parameters and Reynolds numbers on the mixing characteristics were investigated. An optimal design of the cylindrical chamber with 4 inlets can be found. At larger Reynolds number, Re>15, more inertia caused the powerful swirling flows in the chamber, and more damping effect on diffusion was diminished, which then increased the mixing performance.

  6. Proportional chambers for the Σ installation

    International Nuclear Information System (INIS)

    Two types of proportional chambers used in experiments with SIGMA set are considered. The main parameters of detecting electronics, high-voltage, low-voltage and gas supplies are presented. The first type chambers consist of the round or square frames of sheet foiled glass-cloth-base laminate, on which surface electrode lands and joints between them are applied by photographic printing. The second type chamber electrodes are also made of the sheet foiled glass-cloth-base laminate as strips arranged at the ends of two rectangular metallic profiles. The chamber sensitive regions vary from 64x64 mm to 768x2500 mm. The chambers are used for more than 15 years in different experiments, such as determination of elastic scattering, study of J/ψ and ψ' particle production, search for charm particles in hadron interactions, measuring the change of π--meson polarizability, study of μ+μ-π- system production. The experience of past years manifested their high efficiency and reliability

  7. Chamber, Target and Final Focus Integrated Design

    International Nuclear Information System (INIS)

    Liquid wall protection, which challenges chamber clearing, has such advantages it's Heavy Ion Fusion's (HIF) main line chamber design. Thin liquid protection from x rays is necessary to avoid erosion of structural surfaces and thick liquid makes structures behind 0.5 m of Flibe (7 mean free paths for 14 MeV neutrons), last the life of the plant. Liquid wall protection holds the promise of greatly increased economic competitiveness. Driver designers require ∼200 beams to illuminate recent target designs from two sides. The illumination must be compatible with liquid wall protection. The ''best'' values for driver energy, gain, yield and pulse rate comes out of well-known trade-off studies. The chamber design is based on several key assumptions, which are to be proven before HIF can be shown to be feasible. The chamber R and D needed to reduce the unknowns and risks depend on resolving a few technical issues such as jet surface smoothness and rapid chamber clearing

  8. Chamber, Target and Final Focus Integrated Design

    International Nuclear Information System (INIS)

    Liquid wall protection, which challenges chamber clearing, has such advantages it's Heavy Ion Fusion's (HIF) main line chamber design. Thin liquid protection from x rays is necessary to avoid erosion of structural surfaces and thick liquid makes structures behind 0.5 m of Flibe (7 mean free paths for 14 MeV neutrons), last the life of the plant. Liquid wall protection holds the promise of greatly increased economic competitiveness. Driver designers require ∼200 beams to illuminate recent target designs from two sides. The illumination must be compatible with liquid wall protection. The ''best'' values for driver energy, gain, yield and pulse rate comes out of well-known trade-off studies. An integrated chamber design, yet to be made, depends on several key assumptions, which are to be proven before HIF can be shown to be feasible. The chamber R and D needed to reduce the unknowns and risks depend on resolving a few technical issues such as jet surface smoothness and rapid chamber clearing

  9. Study and analysis of drift chamber parameters

    International Nuclear Information System (INIS)

    The present work deals mainly with drift chambers. In the first chapter a summary of drift chamber properties is presented. The information has been collected from the extensive bibliography available in this field. A very simple calculation procedure of drift chamber parameters has been developed and is presented in detail in the second chapter. Some prototypes have been made following two geometries (multidrift chamber and Z-chambers). Several installations have been used for test and calibration of these prototypes. A complete description of these installations is given in the third chapter. Cosmic rays, beta particles from a Ru106 radiactive source and a test beam in the WA (West Area) of SPS at CERN have been used for experimental purposes. The analysis and the results are described for the different setups. The experimental measurements have been used to produce a complete cell parametrization (position as function of drift time) and to obtain spatial resolution values (in the range of 200-250 um). Experimental results are in good agreement with numerical calculations. (Author)

  10. 21 CFR 884.5225 - Abdominal decompression chamber.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Abdominal decompression chamber. 884.5225 Section... Devices § 884.5225 Abdominal decompression chamber. (a) Identification. An abdominal decompression chamber... decompression chamber that was in commercial distribution before May 28, 1976, or that has, on or...

  11. Change of Pressing Chamber Conicalness at Briquetting Process in Briquetting Machine Pressing Chamber

    Directory of Open Access Journals (Sweden)

    Peter Križan

    2012-01-01

    Full Text Available In this paper, we will present the impact of the conical shape of a pressing chamber, an important structural parameter. Besides the known impact of the technological parameters of pressing chambers, it is also very important to pay attention to their structural parameters. In the introduction, we present a theoretical analysis of pressing chamber conicalness. An experiment aimed at detecting this impact was performed at our institute, and it showed that increasing the conicalness of a pressing chamber improves the quality of the final briquettes. The conicalness of the pressing chamber has a significanteffect on the final briquette quality and on the construction of briquetting machines. The experimental findings presented here show the importance of this parameter in the briquetting process.

  12. Design of the CLIC Quadrupole Vacuum Chambers

    CERN Document Server

    Garion, C

    2010-01-01

    The Compact Linear Collider, under study, requires vacuum chambers with a very small aperture, of the order of 8 mm in diameter, and with a length up to around 2 m for the main beam quadrupoles. To keep the very tight geometrical tolerances on the quadrupoles, no bake out is allowed. The main issue is to reach UHV conditions (typically 10-9 mbar static pressure) in a system where the vacuum performance is driven by water outgassing. For this application, a thinwalled stainless steel vacuum chamber with two ante chambers equipped with NEG strips, is proposed. The mechanical design, especially the stability analysis, is shown. The key technologies of the prototype fabrication are given. Vacuum tests are carried out on the prototypes. The test set-up as well as the pumping system conditions are presented.

  13. ON THE ANALYSIS OF BUBBLE CHAMBER TRACKS

    International Nuclear Information System (INIS)

    Since its invention by Glaser in 1953, the bubble chamber has become a most valuable tool in high-energy physics. It combines a number of advantages of various older methods of particle detection: it offers high spatial resolution, rapid accumulation of data, some time resolution, and some choice of the nucleus whose interaction one wants to study (bubble chambers have been made to operate with a large number of different liquids, including H2, D2, He, Xe, and several hydrocarbons). In order to exploit the advantages of spatial resolution and rapid data accumulation, high-speed high-precision analysis procedures must be developed. In this article they discuss some of the problems posed by such analysis. The discussion is based largely on experience gained in performing hydrogen bubble chamber experiments with the University of California's Bevatron (6-Bev proton synchrotron)

  14. Rapid-Cycling Bubble-Chamber, details

    CERN Multimedia

    1980-01-01

    Parts of the hydraulic expansion system of the Rapid-Cycling Bubble-Chamber (RCBC). RCBC was the largest of 3 rapid-cycling bubble-chambers (the others were LEBC and HOLEBC), used as target- and vertex-detectors within the European Hybrid Spectrometer (EHS) in the SPS North Area (EHN1). RCBC contained 250 l of liquid hydrogen and was located inside a 3 T superconducting magnet. It was designed for 30 expansions/s (100 times faster than BEBC), the system shown here allowed 50 expansions/s. RCBC operated from 1981 to 1983 for experiments NA21, NA22 and NA23 at a rate of 15 expansions/s, clocking up a total of over 4 million. In the rear, at left, is bearded Lucien Veillet; Augustin Didona is at the right. See also 8001009. The installation of the piston assembly in the RCBC chamber body is shown in the Annual Report 1980, p.65.

  15. Drift chamber tracking with neural networks

    International Nuclear Information System (INIS)

    With the very high event rates projected for experiments at the SSC and LHC, it is important to investigate new approaches to on line pattern recognition. The use of neural networks for pattern recognition. The use of neural networks for pattern recognition in high energy physics detectors has been an area of very active research. The authors discuss drift chamber tracking with a commercial analog VLSI neural network chip. Voltages proportional to the drift times in a 4-layer drift chamber were presented to the Intel ETANN chip. The network was trained to provide the intercept and slope of straight tracks traversing the chamber. The outputs were recorded and later compared off line to conventional track fits. Two types of network architectures were studied. Applications of neural network tracking to high energy physics detector triggers is discussed

  16. Posing the first LEAR vacuum chamber

    CERN Multimedia

    1982-01-01

    The photo shows one of the four bending magnets of LEAR. They were of C-type with the opening ('mouth') to the outside of the ring (yoke to the inside). Last preparations are made before the vacuum chamber is slid through the mouth into the magnet. Stochastic cooling pickups/kickers were installed inside the chamber. One can distinguish a large number of feed-throughs on the chamber (leading to the pickup/kicker gaps). The free space in the middle of the block was left to offer room for an internal target in the magnet. This possibility was never exploited. Instead it is used here, to accommodate a pumping port for the high vacuum system. Michel Chanel (left) and Pierre Lefevre admire the mechanics at work.

  17. Oil shale generators with circular retorting chamber

    International Nuclear Information System (INIS)

    The method of semi-coking oil shale in the circular retorting chamber makes it possible to ensure a more uniform distribution of the heat carriers gas across the shale bed, than in the vertically placed retorting chambers with cross-current heat carrier flow, and in the generators using the counter-current method of heat exchange. This also ensures the most favourable conditions for effective heat transfer in the retorting chamber from the gas flow to the shale bed due to the following factors: absence of the lateral outer walls in the retorting chamber; the concentrical arrangement of the retorting chamber and the passage of the gaseous heat carrier through the shale bed from the periphery of the retort to its center; the bulk of the oil shale charged passes through the hot part of the retorting chamber (i.e. on the side of inlet of the gaseous heat carrier into the shale bed). As a result, processing the oil shale in the generators with circular retorting chambers leads to a decrease in the temperature of oil vapours at the gas outlet on an average from 220 to 150o C and the reduction of the specific air consumption for the process - from 360 to 250 m3/t. According to the calculated data, it ensures an increase in oil yield from 78 to 84% of the Fischer assay oil. The application of the circular retorting chamber in the generators, creates conditions for increased unit throughput rates of the retorts 1.5-2.0 times with a simultaneous increase in the oil yield. For processing oil shales rich in organic material, which readily bitumenize, retorts for a throughput of 1500 tonnes per day have been developed and are already under construction at the P O 'Slantsekhim'. Project designs for the leaner shales can be developed for throughput rates in excess of 5000-6000 tonnes per day. The retorts will have a comparatively small diameter and a simpler design than the 1000 t/day generators being now in operation. (author). 14 refs., 2 tabs., fig

  18. A view inside the Gargamelle bubble chamber

    CERN Multimedia

    1970-01-01

    Gargamelle was the name given to a big bubble chamber built at the Saclay Laboratory in France during the late 1960s. It was designed principally for the detection at CERN of the elusive particles called neutrinos. A bubble chamber contains a liquid under pressure, which reveals the tracks of electrically charged particles as trails of tiny bubbles when the pressure is reduced. Neutrinos have no charge, and so leave no tracks, but the aim with Gargamelle was "see neutrinos" by making visible any charged particles set in motion by the interaction of neutrinos in the liquid

  19. Quasi-Porous Plug With Vortex Chamber

    Science.gov (United States)

    Walsh, J. V.

    1985-01-01

    Pressure-letdown valve combines quasi-porous-plug and vortex-chamber in one controllable unit. Valve useful in fossil-energy plants for reducing pressures in such erosive two-phase process streams as steam/water, coal slurries, or combustion gases with entrained particles. Quasi-Porous Plug consists of plenums separated by perforated plates. Number or size of perforations increases with each succeeding stage to compensate for expansion. In Vortex Chamber, control flow varies to control swirl and therefore difference between inlet and outlet pressures.

  20. Brookhaven National Laboratory's multiparticle spectrometer drift chamber system

    International Nuclear Information System (INIS)

    A system of drift chambers is being built to replace the present spark chambers in the Brookhaven National Laboratory's Multiparticle Spectrometer. This system will handle a beam of approx. 3 million particles per second and have a resolution of 200 μm. A summary of the status of the chambers and the custom integrated circuits is presented. The data acquisition system is described. Prototype chambers have been built and tested with results that are consistent with the expected chamber properties

  1. The cloud chamber and its metamorphoses

    International Nuclear Information System (INIS)

    The stunning invention of the Wilson chamber in 1911 stayed almost ignored by the physicist community for more than a decade although it permitted the visualization of the track of an alpha particle as soon as 1911. The detection principle is based on the expansion of a saturated vapor that allows the visualization of a ionizing particle motion through the formation of droplets around the ions created all along the particle path. The original device was too slow (only one expansion per minute) to be used for the detection of rare events unless to operate it for months or years. A decisive step was made in the beginning of the twenties by the Japanese physicist Takeo Shimizu, working at the Cavendish Laboratory. He managed to automate the Wilson chamber and to equip it with 2 mirrors and a camera. This new generation allowed 5 expansion per second and the knowledge of the particle track orientation in space thanks to a simultaneous photography following 2 perpendicular directions. A rate of 4 shots a minute was achieved. The Wilson chamber was constantly improved during its 30 years long career and was only supplanted by the bubble chamber in the fifties. (A.C.)

  2. Progress in timing Resistive Plate Chambers

    OpenAIRE

    Blanco, A.; Carolino, N.; Correia, C. M. B. A.; Ferreira-Marques, R.; P. Fonte(LIP-Laboratório de Instrumentação e Física Experimental de Partículas, Portugal); Gobbi, A.; González-Díaz, D.; Lopes, M.I.; Lopes, L.; Macedo, M. P.; Mangiarotti, A.; V. Peskov; Policarpo, A.

    2004-01-01

    Timing RPCs are Resistive Plate Chambers made with glass and metal electrodes separated by precision spacers. Typical gas gaps are a few hundred micrometers wide. Such counters were introduced in 1999 and have since reached timing accuracies below 50 ps [sigma] with efficiencies above 99% for MIPs. Applications in high-energy physics have already taken place with several more under study.

  3. Anterior Chamber Live Loa loa: Case Report.

    Science.gov (United States)

    Kagmeni, G; Cheuteu, R; Bilong, Y; Wiedemann, P

    2016-01-01

    We reported a case of unusual intraocular Loa loa in a 27-year-old patient who presented with painful red eye. Biomicroscopy revealed a living and active adult worm in the anterior chamber of the right eye. After surgical extraction under local anesthesia, parasitological identification confirmed L. loa filariasis. PMID:27441005

  4. Detecting dark matter with scintillating bubble chambers

    Science.gov (United States)

    Zhang, Jianjie; Dahl, C. Eric; Jin, Miaotianzi; Baxter, Daniel

    2016-03-01

    Threshold based direct WIMP dark matter detectors such as the superheated bubble chambers developed by the PICO experiment have demonstrated excellent electron-recoil and alpha discrimination, excellent scalability, ease of change of target fluid, and low cost. However, the nuclear-recoil like backgrounds have been a limiting factor in their dark matter sensitivity. We present a new type of detector, the scintillating bubble chamber, which reads out the scintillation pulse of the scattering events as well as the pressure, temperature, acoustic traces, and bubble images as a conventional bubble chamber does. The event energy provides additional handle to discriminate against the nuclear-recoil like backgrounds. Liquid xenon is chosen as the target fluid in our prototyping detector for its high scintillation yield and suitable vapor pressure which simplifies detector complexity. The detector can be used as an R&D tool to study the backgrounds present in the current PICO bubble chambers or as a prototype for standalone dark matter detectors in the future. Supported by DOE Grant DE-SC0012161.

  5. Anterior Chamber Live Loa loa: Case Report

    Science.gov (United States)

    Kagmeni, G.; Cheuteu, R.; Bilong, Y.; Wiedemann, P.

    2016-01-01

    We reported a case of unusual intraocular Loa loa in a 27-year-old patient who presented with painful red eye. Biomicroscopy revealed a living and active adult worm in the anterior chamber of the right eye. After surgical extraction under local anesthesia, parasitological identification confirmed L. loa filariasis. PMID:27441005

  6. Opposite expansion system of fast bubble chambers

    International Nuclear Information System (INIS)

    Pneumatic opposite expansion system, operating on frequency up to 100 Hz and minimal cycle duration up to 3 ms, is created for accomplishingh expansion working cycle of a precision liquid-hydrogen fast bubble chamber. Fast-action hydraulic servo slide valves with electric control are used as command and control elements

  7. Vacuum chamber for intersection I-4

    CERN Multimedia

    1972-01-01

    Vacuum chamber for intersection I-4 of the ISR being assembled inside a wooden mock-up of the gap of the split-field magnet. The central round-cylinder section is provisional and is to be replaced by an elliptic-cylinder section to give more space vertically for installation of detectors. Supports for the central section are of carbon fibre composite.

  8. Pressurized ionization chamber detectors for industrial use

    International Nuclear Information System (INIS)

    The measurement of the thickness of the sheets made of different materials, e.g. metal, plastic, paper, cellulose, rubber, etc., is one of many industrial applications of nuclear techniques. The ionizing radiation detectors of ionization chamber type are based on measuring the variations in either exposure rate (for gamma radiation) or absorbed dose rate (for beta radiation) occurring in materials of different thickness, placed between the radiation source and the detector. The variations in exposure rate and absorbed dose rate can be traced by using radiation detectors of the ionization chamber type, which convert the exposure rate, X point, or the absorbed dose rate, D point, into a proportional electric current. The more stable the ionization current of the chambers (keeping a constant exposure rate or absorbed dose rate), the slighter the variations that can be detected in either exposure rate or absorbed dose rate, hence in the absorbing material placed between the radiation source and the detector. Based on these facts, several variants of such detectors, including the ionization chamber CIS-P5M-100Kr, CIS-P2M-1000Kr and CIS-P8M-70Kr, have been made. (author)

  9. A double grid position sensitive avalanche chamber

    International Nuclear Information System (INIS)

    A double grid position sensitive avalanche chamber (DGAC) has been developed. Its sensitive area is 250 x 200 mm2. The properties of the DGAC were tested in flowing isobutylene gas at a pressure of 360 Pa. The position resolution of 4 mm in both x and y coordinates and the time resolution of 290 ps are obtained for 252Cf fission fragment source

  10. The arrival of the CLOUD chamber

    CERN Multimedia

    CERN AVC

    2009-01-01

    The team from the CLOUD experiment - the world’s first experiment using a high-energy particle accelerator to study the climate - were on cloud nine after the arrival of their new three-metre diameter cloud chamber. This marks the end of three years’ R&D; and design, and the start of preparations for data taking later this year.

  11. The FTU (Frascati Tokamak Upgrade) vacuum chamber

    International Nuclear Information System (INIS)

    The FTU vacuum vassel has been designed to withstand high electromagnetic and thermal loads and to reach high vacuum conditions which are essential to obtain clean, impurity free plasma. After a survey of the vacuum chamber requirements and of the design development, the paper reports the main manufactoring process such as welding, stress relieving, machining, nondestructive testing, outgassing and preassembly

  12. Chamber transport for heavy ion fusion

    International Nuclear Information System (INIS)

    A brief review is given of research on chamber transport for HIF (heavy ion fusion) dating from the first HIF Workshop in 1976 to the present. Chamber transport modes are categorized into ballistic transport modes and channel-like modes. Four major HIF reactor studies are summarized (HIBALL-II, HYLIFE-II, Prometheus-H, OSIRIS), with emphasis on the chamber transport environment. In general, many beams are used to provide the required symmetry and to permit focusing to the required small spots. Target parameters are then discussed, with a summary of the individual heavy ion beam parameters required for HIF. The beam parameters are then classified as to their line charge density and perveance, with special emphasis on the perveance limits for radial space charge spreading, for the space charge limiting current, and for the magnetic (Alfven) limiting current. The major experiments on ballistic transport (SFFE, Sabre beamlets, GAMBLE II, NTX, NDCX) are summarized, with specific reference to the axial electron trapping limit for charge neutralization. The major experiments on channel-like transport (GAMBLE II channel, GAMBLE II self-pinch, LBNL channels, GSI channels) are discussed. The status of current research on HIF chamber transport is summarized, and the value of future NDCX-II transport experiments for the future of HIF is noted

  13. Acoustical-Levitation Chamber for Metallurgy

    Science.gov (United States)

    Barmatz, M. B.; Trinh, E.; Wang, T. G.; Elleman, D. D.; Jacobi, N.

    1983-01-01

    Sample moved to different positions for heating and quenching. Acoustical levitation chamber selectively excited in fundamental and second-harmonic longitudinal modes to hold sample at one of three stable postions: A, B, or C. Levitated object quickly moved from one of these positions to another by changing modes. Object rapidly quenched at A or C after heating in furnace region at B.

  14. Wave Phenomena in an Acoustic Resonant Chamber

    Science.gov (United States)

    Smith, Mary E.; And Others

    1974-01-01

    Discusses the design and operation of a high Q acoustical resonant chamber which can be used to demonstrate wave phenomena such as three-dimensional normal modes, Q values, densities of states, changes in the speed of sound, Fourier decomposition, damped harmonic oscillations, sound-absorbing properties, and perturbation and scattering problems.…

  15. Prototype Vacuum Chamber for ISR Intersection Region

    CERN Multimedia

    1974-01-01

    The vacuum chambers at the ISR interaction region had to be as transparent as possible to the secondary particles emerging from the collision points. Made from stainless steel or titanium, only a fraction of a millimeter thick, they were most delicate to handle.

  16. Prototype vacuum chamber for ISR intersection region

    CERN Multimedia

    1974-01-01

    The vacuum chambers at the ISR interaction regions had to be as transparent as possible to the secondary particles emerging from the collision points. Made from stainless steel or titanium, only a fraction of a millimeter thick, they were most delicate to handle.

  17. IKAR, a ionization chamber for WA9

    CERN Multimedia

    1976-01-01

    This ionization chamber arrived at CERN from Leningrad for a high precision study of hadron elastic scattering by a CERN-Clermont-Ferrand-Leningrad-Lyon-Uppsala Collaboration in the H3 beam (WA9). G.A. Korolev (third from right) looks at the drawings.

  18. Drift Chambers detectors; Detectores de deriva

    Energy Technology Data Exchange (ETDEWEB)

    Duran, I.; Martinez laso, L.

    1989-07-01

    We present here a review of High Energy Physics detectors based on drift chambers. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysed, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author) 115 refs.

  19. Pressure vessel rupture within a chamber: the pressure history on the chamber wall

    International Nuclear Information System (INIS)

    Generally there is a large number of pressure vessels containing high pressure gas on power stations and chemical plant. In many instances, particularly on power plant, these vessels are within the main building. If a pressure vessel were to fail, the surrounding structures would be exposed to blast loads and the forces resulting from jets of fluid issuing from the breached vessel. In the case where the vessel is in a relatively closed chamber there would also be a general overpressurisation of the chamber. At the design stage it is therefore essential to demonstrate that the plant could be safely shut down in the event of a pressure vessel failure, that is, it must be shown that the chamber will not collapse thus putting the building at risk or hazarding equipment essential for a safe shut down. Such an assessment requires the loads applied to the chamber walls, roof, etc. to be known. (author)

  20. Anterior chamber fixation of a posterior chamber intraocular lens: A novel technique

    Directory of Open Access Journals (Sweden)

    A Sahap Kükner

    2014-01-01

    Full Text Available We aimed to evaluate the implantation of a posterior chamber intraocular lens (IOL in the anterior chamber (AC with the haptics passing through two iridectomies to the posterior chamber. A total of 33 eyes of 33 patients with inadequate posterior capsular support due to either previous aphakia or posterior capsular rupture during cataract extraction were included in the study. A double iridectomy was performed on all patients using a vitrectomy probe on the midperiphery of the iris. IOLs were implanted in the AC, and the haptics were passed through the iridectomies to the posterior chamber. The mean follow-up time was 25.3 months. AC hemorrhage occurred in five patients during the iridectomy procedure. Corneal edema was detected in eight of 14 patients with primary IOL insertions. Haptic dislocation was detected in only one patient. This technique may be a good alternative to scleral-fixated IOL implantation in eyes with aphakia.

  1. Achievable field strength in reverberation chambers

    Directory of Open Access Journals (Sweden)

    N. Eulig

    2003-01-01

    Full Text Available Feldvariable Kammern (FVK, engl.: modestirred- chamber werden unter anderem für EMV-Störfestigkeitsprüfungen verwendet. Ein häufig genanntes Argument, das die Einführung dieser Kammern als normgerechte Prüfumgebung vorantreiben soll, ist eine hohe Feldstärke, die im Vergleich zu anderen Testumgebungen mit relativ moderaten HF-Leistungen erreicht werden kann. Besonders für sicherheitskritische Geräte, wie Komponenten aus der Avionik- oder KFZ-Industrie, sind heutzutage Testfeldstärken von mehreren 100 V/m notwendig. Derart hohe Feldstärken können in Umgebungen, die ein ebenes Wellenfeld erzeugen oder nachbilden, nur mit großen HFLeistungen generiert werden. Durch die Resonanzeigenschaften einer FVK können demgegenüber mit sehr viel weniger Leistung und damit Verstärkeraufwand vergleichbare Werte der Feldstärke erzeugt werden. Allerdings sinkt mit zunehmendem Volumen die erreichbare Feldstärke bei gleicher Speiseleistung. Idealerweise sollen Feldvariable Kammern bei möglichst niedrigen Frequenzen für EMVTests nutzbar sein, was jedoch ein großes Kammervolumen erfordert. Das Problem, bei niedrigen Frequenzen hohe Feldstärken erzeugen zu können, relativiert deshalb den Vorteil von FVKn gegenüber bekannten Testumgebungen bei niedrigen Testfrequenzen. Der Posterbeitrag erläutert, welche Feldstärken in verschieden großen Feldvariablen Kammern beim Einspeisen einer bestimmten hochfrequenten Leistung erreicht werden können. Anhand dieser Ergebnisse wird aufgezeigt, oberhalb welcher Grenzfrequenz eine Anwendung von FVKn nur sinnvoll erscheint. Mode-stirred chambers (MSCs can be used for radiated immunity tests in EMC testing. Advantageous compared to conventional test methods is the high field strength which can here be generated with less RF-Power. This point is often the main argument for pushing the standardization of MSCs as an other EMC testing environment. Especially for safety-critical electronic equipment like avionic or

  2. A new plant chamber facility PLUS coupled to the atmospheric simulation chamber SAPHIR

    Directory of Open Access Journals (Sweden)

    T. Hohaus

    2015-11-01

    Full Text Available A new PLant chamber Unit for Simulation (PLUS for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber has been build and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees are mixed with synthetic air and are transferred to the SAPHIR chamber where the atmospheric chemistry and the impact of biogenic volatile organic compounds (BVOC can be studied in detail. In PLUS all important enviromental parameters (e.g. temperature, PAR, soil RH etc. are well-controlled. The gas exchange volume of 9.32 m3 which encloses the stem and the leafes of the plants is constructed such that gases are exposed to FEP Teflon film and other Teflon surfaces only to minimize any potential losses of BVOCs in the chamber. Solar radiation is simulated using 15 LED panels which have an emission strength up to 800 μmol m−2 s−1. Results of the initial characterization experiments are presented in detail. Background concentrations, mixing inside the gas exchange volume, and transfer rate of volatile organic compounds (VOC through PLUS under different humidity conditions are explored. Typical plant characteristics such as light and temperature dependent BVOC emissions are studied using six Quercus Ilex trees and compared to previous studies. Results of an initial ozonolysis experiment of BVOC emissions from Quercus Ilex at typical atmospheric concentrations inside SAPHIR are presented to demonstrate a typical experimental set up and the utility of the newly added plant chamber.

  3. A new plant chamber facility PLUS coupled to the atmospheric simulation chamber SAPHIR

    Science.gov (United States)

    Hohaus, T.; Kuhn, U.; Andres, S.; Kaminski, M.; Rohrer, F.; Tillmann, R.; Wahner, A.; Wegener, R.; Yu, Z.; Kiendler-Scharr, A.

    2015-11-01

    A new PLant chamber Unit for Simulation (PLUS) for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) has been build and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees are mixed with synthetic air and are transferred to the SAPHIR chamber where the atmospheric chemistry and the impact of biogenic volatile organic compounds (BVOC) can be studied in detail. In PLUS all important enviromental parameters (e.g. temperature, PAR, soil RH etc.) are well-controlled. The gas exchange volume of 9.32 m3 which encloses the stem and the leafes of the plants is constructed such that gases are exposed to FEP Teflon film and other Teflon surfaces only to minimize any potential losses of BVOCs in the chamber. Solar radiation is simulated using 15 LED panels which have an emission strength up to 800 μmol m-2 s-1. Results of the initial characterization experiments are presented in detail. Background concentrations, mixing inside the gas exchange volume, and transfer rate of volatile organic compounds (VOC) through PLUS under different humidity conditions are explored. Typical plant characteristics such as light and temperature dependent BVOC emissions are studied using six Quercus Ilex trees and compared to previous studies. Results of an initial ozonolysis experiment of BVOC emissions from Quercus Ilex at typical atmospheric concentrations inside SAPHIR are presented to demonstrate a typical experimental set up and the utility of the newly added plant chamber.

  4. A new plant chamber facility, PLUS, coupled to the atmosphere simulation chamber SAPHIR

    Science.gov (United States)

    Hohaus, T.; Kuhn, U.; Andres, S.; Kaminski, M.; Rohrer, F.; Tillmann, R.; Wahner, A.; Wegener, R.; Yu, Z.; Kiendler-Scharr, A.

    2016-03-01

    A new PLant chamber Unit for Simulation (PLUS) for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) has been built and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow-through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees is mixed with synthetic air and transferred to the SAPHIR chamber, where the atmospheric chemistry and the impact of biogenic volatile organic compounds (BVOCs) can be studied in detail. In PLUS all important environmental parameters (e.g., temperature, photosynthetically active radiation (PAR), soil relative humidity (RH)) are well controlled. The gas exchange volume of 9.32 m3 which encloses the stem and the leaves of the plants is constructed such that gases are exposed to only fluorinated ethylene propylene (FEP) Teflon film and other Teflon surfaces to minimize any potential losses of BVOCs in the chamber. Solar radiation is simulated using 15 light-emitting diode (LED) panels, which have an emission strength up to 800 µmol m-2 s-1. Results of the initial characterization experiments are presented in detail. Background concentrations, mixing inside the gas exchange volume, and transfer rate of volatile organic compounds (VOCs) through PLUS under different humidity conditions are explored. Typical plant characteristics such as light- and temperature- dependent BVOC emissions are studied using six Quercus ilex trees and compared to previous studies. Results of an initial ozonolysis experiment of BVOC emissions from Quercus ilex at typical atmospheric concentrations inside SAPHIR are presented to demonstrate a typical experimental setup and the utility of the newly added plant chamber.

  5. High efficiency ionization chamber for fission experiments

    International Nuclear Information System (INIS)

    Complete text of publication follows. The width of fission fragment mass distribution indicates the number of di rent fragments which are produced during the fission process from a given excited state. Smaller width means more limited variety of fission fragments which can indicate clusterization effect in hyperdeformed states before fission and also means less amount of nuclear waste. A new gridded ionization chamber was constructed at Atomki to examine the mass distribution of the fission fragments from neutron induced fission of some U and Th isotopes. The design is based on a twin ionization chamber developed by C. Budtz-Jorgensen et al. Our aim was to increase the efficiency of the measurements by applying multiple detector units. This compound detector permits simultaneous measurement of the total kinetic energy and fission fragment emission angle with respect to the detector symmetry axis. The chamber consists of five twin parallel plate ionization chambers with Frisch grids. Assuming that at low counting rates only one target emits fission fragments in one event, the an- odes and the grids were interconnected form- ing two groups (A1-G1, A2-G2). In order to identify which target emitted the fission fragments the signals from each cathodes are also processed. The energy of the fission fragments is determined from the anode pulse heights, while the sum of the grid and anode signals is used to deduce the fragment emission angle θ with respect to the symmetry axis of the chamber: Qsum = -n0e[1 - (X/D)cosθ). The angle dependent energy losses in the tar get can be determined using this angular information. In order to minimize the distance between the targets and the neutron source, smaller distance between the plates and a smaller diameter had to be chosen as in Ref. This arrangement required higher gas pressure, which is necessary to stop the fission fragments before reaching the electrodes. A gas mixture of 90% Ar + 10% CH4 at 2 atm pressure was used. With a

  6. Chamber Structure of Double Hurwitz numbers

    CERN Document Server

    Cavalieri, Renzo; Markwig, Hannah

    2010-01-01

    Double Hurwitz numbers count covers of the projective line by genus g curves with assigned ramification profiles over 0 and infinity, and simple ramification over a fixed branch divisor. Goulden, Jackson and Vakil have shown double Hurwitz numbers are piecewise polynomial in the orders of ramification, and Shadrin, Shapiro and Vainshtein have determined the chamber structure and wall crossing formulas for g=0. This paper gives a unified approach to these results and strengthens them in several ways -- the most important being the extension of the results of Shapiro, Shadrin and Vainshtein to arbitrary genus. The main tool is the authors' previous work expressing double Hurwitz number as a sum over certain labeled graphs. We identify the labels of the graphs with lattice points in the chambers of certain hyperplane arrangements, which are well known to give rise to piecewise polynomial functions. Our understanding of the wall crossing for these functions builds on the work of Varchenko, and could have broader ...

  7. HYLIFE-II reactor chamber mechanical design

    International Nuclear Information System (INIS)

    Mechanical design features of the reactor chamber for the HYLIFE-II inertial confinement fusion power plant are presented. A combination of oscillating and steady, molten salt streams are used for shielding and blast protection. The system is designed for an 8 Hz repetition rate. Beam path clearing, between shots, is accomplished with the oscillating flow. The mechanism for generating the oscillating streams is described. A design configuration of the vessel wall allows adequate cooling and provides extra shielding to reduce thermal stresses to tolerable levels. The bottom portion of the reactor chamber is designed to minimize splash back of the high velocity (20 m/s) salt streams and also recover up to half of the dynamic head

  8. Tailored vacuum chambers for ac magnets

    International Nuclear Information System (INIS)

    The proposed LAMPF-II accelerator has a 60-Hz booster synchrotron and a 3-Hz main ring. To provide a vacuum enclosure inside the magnets with low eddy-current losses and minimal field distortion, yet capable of carrying rf image currents and providing beam stabilization, we propose an innovative combination pipe. Structurally, the enclosure is high-purity alumina ceramic, which is strong, radiation resistant, and has good vacuum properties. Applied to the chamber are thin, spaced, silver conductors using adapted thick-film technology. The conductor design can be tailored to the stabilization requirements, for example, longitudinal conductors for image currents, circumferential for transverse stabilization. The inside of the chamber has a thin, resistive coating to avoid charge build-up. The overall 60-Hz power loss is less than 100 W/m

  9. Liquid scintillator time projection chamber concept

    International Nuclear Information System (INIS)

    Results are presented from a small-scale experiment to investigate the use of room temperature organic liquid scintillators as the active medium for a time projection chamber (TPC). The optical properties of liquid scintillators have long been known, but their ability to transport charge has remained, until now, largely untested. The idea of using room temperature liquids as an active medium for an ionisation chamber was first presented in [1]. Since then the range of liquid scintillators available has been greatly developed. We present successful transport of ionization charges in a selection of both, pure organic liquid solvents and liquid scintillator cocktails over 20 mm using a variety of electric drift field strengths. The target of this research is to offer a cost effective alternative to liquid noble gas detectors in neutrino physics

  10. The physics of Resistive Plate Chambers

    CERN Document Server

    Riegler, Werner

    2004-01-01

    Over the last 3 years we investigated theoretical aspects of Resistive Plate Chambers (RPC) in order to clarify some of the outstanding questions on space charge effects, high efficiency of small gap RPCs, charge spectra, signal shape and time resolution. In a series of reports we analyzed RPC performance including all detector aspects covering primary ionization, avalanche multiplication, space charge effects, signal induction in presence of resistive materials, crosstalk along detectors with long strips and front-end electronics. Using detector gas parameters entirely based on theoretical predictions and physical models for avalanche development and space charge effects we are able to reproduce measurements for 2 and 0.3 mm RPCs to very high accuracy without any additional assumptions. This fact gives a profound insight into the workings of RPCs and also underlines the striking difference in operation regime when compared to wire chambers. A summary of this work as well as recent results on three-dimensiona...

  11. The KLOE drift chamber VCI 2001

    Energy Technology Data Exchange (ETDEWEB)

    Adinolfi, M.; Aloisio, A.; Ambrosino, F.; Andryakov, A.; Antonelli, A.; Antonelli, M.; Anulli, F.; Bacci, C.; Bankamp, A.; Barbiellini, G.; Bellini, F.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocci, V.; Bossi, F.; Branchini, P.; Bulychjov, S.A.; Cabibbo, G.; Calcaterra, A.; Caloi, R.; Campana, P.; Capon, G.; Carboni, G.; Cardini, A.; Casarsa, M.; Cataldi, G.; Ceradini, F.; Cervell, F.; Cevenini, F.; Chiefari, G.; Ciambrone, P.; Conetti, S.; Conticelli, S.; De Lucia, E. E-mail: erika.delucia@roma1.infn.it; De Robertis, G.; De Sangro, R.; De Simone, P.; De Zorzi, G.; Dell' Agnello, S.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Falco, S.; Doria, A.; Drago, E.; Elia, V.; Erriquez, O.; Farilla, A.; Felici, G.; Ferrari, A.; Ferrer, M.L.; Finocchiaro, G.; Forti, C.; Franceschi, A.; Franzini, P.; Gao, M.L.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Golovatyuk, V.; Gorini, E.; Grancagnolo, F.; Grandegger, W.; Graziani, E.; Guarnaccia, P.; Hagel, U. von.; Han, H.G.; Han, S.W.; Huang, X.; Incagli, M.; Ingrosso, L.; Jang, Y.Y.; Kim, W.; Kluge, W.; Kulikov, V.; Lacava, F.; Lanfranchi, G.; Lee-Franzini, J.; Lomtadze, F.; Luisi, C.; Mao, C.S.; Martemianov, M.; Matsyuk, M.; Mei, W.; Merola, L.; Messi, R.; Miscetti, S.; Moalem, A.; Moccia, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nedosekin, A.; Panareo, M.; Pacciani, L.; Pages, P.; Palutan, M.; Paoluzi, L.; Pasqualucci, E.; Passalacqua, L.; Passaseo, M.; Passeri, A.; Patera, V.; Petrolo, E.; Petrucci, G.; Picca, D.; Pirozzi, G.; Pistillo, C.; Pollack, M.; Pontecorvo, L.; Primavera, M.; Ruggieri, F.; Santangelo, P.; Santovetti, E.; Saracino, G.; Schamberger, R.D.; Schwick, C.; Sciascia, B.; Sciubba, A.; Scuri, F.; Sfiligoi, I.; Shan, J.; Silano, P.; Spadaro, T.; Spagnolo, S.; Spiriti, E.; Stanescu, C.; Tong, G.L.; Tortora, L.; Valente, E.; Valente, P.; Valeriani, B.; Venanzoni, G.; Veneziano, S.; Wu, Y.; Xie, Y.G.; Zhao, P.P.; Zhou, Y

    2002-02-01

    The main goal of the KLOE experiment at the Frascati DAPHINE phi-factory is the study CP violation in kaon decays. The tracking device of the experiment is a drift chamber whose dimensions, 4 m of diameter and 3.3 m length, provide a large acceptance volume for the decay products of low momentum K{sub L} ({lambda}{sub L}=3.4 m). A complete stereo geometry with 12.582 cells arranged in 58 layers guarantees a high and uniform efficiency in the reconstruction of the charged K{sub L} decays. Very light materials have been chosen both for the drift medium, a helium-based gas mixture, and for the mechanical structure, made of carbon fiber, to minimize multiple scattering and conversion of low-energy photons. The design requirements, the adopted solutions together with the calibration procedure and the tracking performances of the drift chamber are discussed.

  12. The KLOE drift chamber VCI 2001

    International Nuclear Information System (INIS)

    The main goal of the KLOE experiment at the Frascati DAPHINE phi-factory is the study CP violation in kaon decays. The tracking device of the experiment is a drift chamber whose dimensions, 4 m of diameter and 3.3 m length, provide a large acceptance volume for the decay products of low momentum KL (λL=3.4 m). A complete stereo geometry with 12.582 cells arranged in 58 layers guarantees a high and uniform efficiency in the reconstruction of the charged KL decays. Very light materials have been chosen both for the drift medium, a helium-based gas mixture, and for the mechanical structure, made of carbon fiber, to minimize multiple scattering and conversion of low-energy photons. The design requirements, the adopted solutions together with the calibration procedure and the tracking performances of the drift chamber are discussed

  13. Reproducibility of the chamber scarification test

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner

    1996-01-01

    The chamber scarification test is a predictive human skin irritation test developed to rank the irritation potential of products and ingredients meant for repeated use on normal and diseased skin. 12 products or ingredients can be tested simultaneously on the forearm skin of each volunteer....... The test combines with the procedure scratching of the skin at each test site and subsequent closed patch tests with the products, repeated daily for 3 days. The test is performed on groups of human volunteers: a skin irritant substance or products is included in each test as a positive control......, and a compound with low irritant potential as a negative control, to obtain relative characterization of the irritant potential of the unknown products. The outcome of tests with a positive and negative control product used repeatedly in 13 chamber scarification tests over a 7-year period is reported, and shows...

  14. The fast Ice Nucleus chamber FINCH

    Science.gov (United States)

    Bundke, U.; Nillius, B.; Jaenicke, R.; Wetter, T.; Klein, H.; Bingemer, H.

    2008-11-01

    We present first results of our new developed Ice Nucleus (IN) counter FINCH from the sixth Cloud and Aerosol Characterization Experiment (CLACE 6) campaign at Jungfraujoch station, 3571 m asl. Measurements were made at the total and the ICE CVI inlet. Laboratory measurements of ice onset temperatures by FINCH are compared to those of the static diffusion chamber FRIDGE (FRankfurt Ice Deposition Freezing Experiment). Within the errors of both new instruments the results compare well to published data.

  15. The 'Diogene' detector, 4π drift chamber

    International Nuclear Information System (INIS)

    'Diogene' is a detector with a solid angle near the steradian 4π, mainly comprising a drift chamber and capable of detecting in coincidence several tens of charged particles. Built by several laboratories (Dph-N/Saclay, CRN/Strasbourg and LPC/Clermont-Ferrand) it should be ready round about June 1980 to use the heavy ion beams of Saturne II for studying the multiple production of pions and protons in central collisions of relativistic heavy ions

  16. Alpha particle spectroscopy by gridded ionization chamber

    International Nuclear Information System (INIS)

    A gridded ionization chamber has been constructed with the aim of determining its ultimate energy resolution in alpha spectroscopy, utilizing a cooled FET pre-amplifier of the type normally employed with semiconductor detectors. With suitable mechanical collimation of the alpha particles, their fine structure has been measured with an energy resolution of -11.5 keV (fwhm), achieved using an Ar + 0.75% C2H2 mixture as the filling gas. (orig.)

  17. Foreign Body Embedded in Anterior Chamber Angle

    OpenAIRE

    Shmuel Graffi; Beatrice Tiosano; Ran Ben Cnaan; Jonathan Bahir; Modi Naftali

    2012-01-01

    Introduction. We present a case of a metallic foreign body embedded in the anterior chamber angle. After standing in close proximity to a construction worker breaking a tile, a 26-year-old woman using soft contact lens for the correction of mild myopia presented to emergency department for evaluation of a foreign body sensation of her right eye. Methods and Results. Diagnosis was confirmed by gonioscopic examination and a noncontrast CT scan of head and orbits. The foreign body was removed by...

  18. Design of an ionization diffusion chamber detector

    International Nuclear Information System (INIS)

    Prototype of an Ionization Diffusion Chamber detector has been made. It is a silindrical glass, 20 cm in diameter, 13,5 cm in height, air gas filled, operated at room pressure and room temperature at the top of this instrument while for the box temperature dry ice (CO2 solid) temperature is used. This detector is ready for seeing alpha and beta particle tracks. (author)

  19. Update on Scroll Compressor Chamber Geometry

    OpenAIRE

    Bell, Ian; Groll, Eckhard; Braun, James; King, Galen

    2010-01-01

    The geometry of the scroll compressor determines the efficiency of the scroll compressor and controls all elements of its operation. It is therefore critical to be able to accurately model the volumes of the compressor over the course of a revolution. This paper proposes a novel quasi-analytic formulation of the suction, compression and discharge chambers based on a change of variables from involute angle to polar integration angle. This solution has been compared against a reference polyg...

  20. Development and progress in resistive plate chamber

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong-Fang; WU Jian

    2004-01-01

    Resistive Plate Chamber (RPC) is a robust and low cost gas detector, which is extensively used in high-energy physics, cosmic and astroparticle physics experiments. Over the past twenty years, as a particle detector,RPC has made remarkable progress. The main achievements, features and results of experiemantal tests including R&D and production of the RPCs by several Chinese groups in recent years are reported in this article.

  1. Angular resolution of stacked resistive plate chambers

    CERN Document Server

    Samuel, Deepak; Murgod, Lakshmi P

    2016-01-01

    We present here detailed derivations of mathematical expressions for the angular resolution of a set of stacked resistive plate chambers (RPCs). The expressions are validated against experimental results using data collected from the prototype detectors (without magnet) of the upcoming India-based Neutrino Observatory (INO). In principle, these expressions can be used for any other detector with an architecture similar to that of RPCs.

  2. Neutron measurements performed with miniature fission chambers

    International Nuclear Information System (INIS)

    This research aims at proposing solutions regarding instruments to perform neutron flow measurements in nuclear power reactors and to perform measurements of the reaction rates of highly radioactive transuranic fissile elements in experimental reactors. This research is also part of a program aimed at the adjustment of the Cadarache cross section set. The report defines the instrumentation, recalls the operation of fission chambers, discusses the implemented instrumentation, and discusses the obtained measurements

  3. Vacuum Chamber for the Booster Bending Magnets

    CERN Multimedia

    1974-01-01

    To minimise eddy currents, induced by the rising magnetic field, the chamber was made from thin stainless steel of high specific electric resistance. For mechanical strength, it was corrugated in a hydro-forming process. The cross-section was designed for maximum strength and maximum aperture. To accept particles with simultaneous large amplitudes in both planes, the cross-section approaches a rectangular shape (see also 7402463).

  4. The Bern Infinitesimal Bubble Chamber (BIBC)

    CERN Multimedia

    1977-01-01

    The chamber body was machined from a block of aluminium. The visible volume was cylindrical with 65 mm diameter and 35 mm depth. It was filled with propane or freon. It was meant as vertex detector in the search of short-lived particles. It was also used with in-line holography resulting in 8 µm bubble size and 9 cm depth of the field. See E. Ramseyer, B. Hahn and E. Hugentobler, Nucl. Instrum. Methods 201 (1982) 335.

  5. Calorimeter tests with liquid ionization chambers

    International Nuclear Information System (INIS)

    Configurations of sampling calorimeters with iron, lead and uranium as absorbers have been investigated using liquid ionization chambers as active elements. As liquid tetramethylsilane has been used. Results of beam tests with electrons, pions and muons in the energy range of 2 to 6 GeV are presented and compared with Monte Carlo simulations. In particular the questions regarding which configuration can compensate and the separation of sampling from intrinsic fluctuations have been studied. (orig.)

  6. Performance of a proton irradiation chamber

    International Nuclear Information System (INIS)

    A Proton Irradiation Chamber aiming to perform radiation tests of electronic components was developed. The precision on the measurement of the ion currents was pushed beyond the resolution of the picoammeter by means of a series of collimators on the beam showing a linear correlation among the currents measured on them and the smaller, not measurable, current on the target. As an example of the obtained results the tests done on a Si microdosimeter and a power p-MOS are reported.

  7. Bubble Chambers for Experiments in Nuclear Astrophysics

    OpenAIRE

    DiGiovine, B.; Henderson, D.; Holt, R. J.; Rehm, K. E.; Raut, R.; Robinson, A.; Sonnenschein, A.; Rusev, G.; A.P. Tonchev; Ugalde, C.

    2015-01-01

    A bubble chamber has been developed to be used as an active target system for low energy nuclear astrophysics experiments. Adopting ideas from dark matter detection with superheated liquids, a detector system compatible with gamma-ray beams has been developed. This detector alleviates some of the limitations encountered in standard measurements of the minute cross sections of interest to stellar environments. While the astrophysically relevant nuclear reaction processes at hydrostatic burning...

  8. Bubble chamber: D meson production and decay

    CERN Multimedia

    1978-01-01

    This event shows real particle tracks from the Big European Bubble Chamber (BEBC), which was used to observe neutrino and hadron beams between 1973 and 1984 from the PS and SPS accelerators. In this event a neutrino interacts with a proton producing an excited D meson. A labeled diagram is seen on the right as the particles spiral in the magnetic field of the detector.

  9. Comment on 'Proton beam monitor chamber calibration'.

    Science.gov (United States)

    Palmans, Hugo; Vatnitsky, Stanislav M

    2016-09-01

    We comment on a recent article (Gomà et al 2014 Phys. Med. Biol. 59 4961-71) which compares different routes of reference dosimetry for the energy dependent beam monitor calibration in scanned proton beams. In this article, a 3% discrepancy is reported between a Faraday cup and a plane-parallel ionization chamber in the experimental determination of the number of protons per monitor unit. It is further claimed that similar discrepancies between calorimetry and ionization chamber based dosimetry indicate that [Formula: see text]-values tabulated for proton beams in IAEA TRS-398 might be overestimated. In this commentary we show, however, that this supporting argument misrepresents the evidence in the literature and that the results presented, together with published data, rather confirm that there exist unresolved problems with Faraday cup dosimetry. We also show that the comparison in terms of the number of protons gives a biased view on the uncertainty estimates for both detectors while the quantity of interest is absorbed dose to water or dose-area-product to water, even if a beam monitor is calibrated in terms of the number of protons. Gomà et al (2014 Phys. Med. Biol. 59 4961-71) also report on the discrepancy between cylindrical and plane-parallel ionization chambers and confirm experimentally that in the presence of a depth dose gradient, theoretical values of the effective point of measurement, or alternatively a gradient correction factor, account for the discrepancy. We believe this does not point to an error or shortcoming of IAEA TRS-398, which prescribes taking the centre of cylindrical ionization chambers as reference point, since it recommends reference dosimetry to be performed in the absence of a depth dose gradient. But these observations reveal that important aspects of beam monitor calibration in scanned proton beams are not addressed in IAEA TRS-398 given that those types of beams were not widely implemented at the time of its publication

  10. Liquid rocket combustion chamber acoustic characterization

    OpenAIRE

    Cândido Magno de Souza; Luiz Carlos Sandoval Góes; Dimas Donizeti da Silveira; Rogério Pirk; Carlos d’Andrade Souto

    2010-01-01

    Over the last 40 years, many solid and liquid rocket motors have experienced combustion instabilities. Among other causes, there is the interaction of acoustic modes with the combustion and/or fluid dynamic processes inside the combustion chamber. Studies have been showing that, even if less than 1% of the available energy is diverted to an acoustic mode, combustion instability can be generated. On one hand, this instability can lead to ballistic pressure changes, couple with other propulsion...

  11. High pressure hydrogen time projection chamber

    International Nuclear Information System (INIS)

    We describe a high pressure hydrogen gas time projection chamber which consists of two cylindrical drift regions each 45 cm in diameter and 75 cm long. Typically, at 15 atm of H2 with 2 kV/cm drift field and 7 kV on the 35μ sense wires, the drift velocity is about 0.5 cm/μsec and the spatial resolution +-200μ

  12. Timing Resistive Plate Chambers with Ceramic Electrodes

    OpenAIRE

    Laso Garcia, Alejandro

    2015-01-01

    The focus of this thesis is the development of Resistive Plate Chambers (RPCs) with ceramic electrodes. The use of ceramic composites, Si3N4/SiC, opens the way for the application of RPCs in harsh radiation environments. Future Experiments like the Compressed Baryonic Matter (CBM) at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt will need new RPCs with high rate capabilities and high radiation tolerance. Ceramic composites are specially suited for this purpose due to th...

  13. Wire chambers with their magnetostrictive readout

    CERN Multimedia

    1974-01-01

    This set of wire chamber planes shaped as a cylinder sector was installed inside the magnet of a polarized spin target modified to allow as well momentum analysis of the produced particles. The experiment (S126) was set up by the CERN-Trieste Collaboration in the PS beam m9 to measure spin effects in the associated production of of a positive kaon and a positive Sigma by interaction of a positive pion with polarized protons.

  14. SONTRAC: A solar neutron track chamber detector

    Science.gov (United States)

    Jenkins, T. L.; Frye, G. M., Jr.; Owens, A.

    1985-01-01

    The recent detection on the solar maximum mission (SMM) satellite of high energy neutrons emitted during large solar flares has provided renewed incentive to design a neutron detector which has the sensitivity, energy resolution, and time resolution to measure the neutron time and energy spectra with sufficient precision to improve our understanding of the basic flare processes. Over the past two decades a variety of neutron detectors has been flown to measure the atmospheric neutron intensity above 10 MeV and to search for solar neutrons. The SONTRAC (Solar Neutron Track Chamber) detector, a new type of neutron detector which utilizes n-p scattering and has a sensitivity 1-3 orders of magnitude greater than previous instruments in the 20-200 MeV range is described. The energy resolution is 1% for neutron kinetic energy, T sub n 50 MeV. When used with a coded aperture mask at 50 m (as would be possible on the space station) an angular resolution of approx. 4 arc sec could be achieved, thereby locating the sites of high energy nuclear interactions with an angular precision comparable to the existing x-ray experiments on SMM. The scintillation chamber is investigated as a track chamber for high energy physics, either by using arrays of scintillating optical fibers or by optical imaging of particle trajectories in a block of scintillator.

  15. Suppressing drift chamber diffusion without magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Martoff, C.J. E-mail: cmartoff@nimbus.temple.edu; Snowden-Ifft, D.P.; Ohnuki, T.; Spooner, N.; Lehner, M

    2000-02-01

    The spatial resolution in drift chamber detectors for ionizing radiation is limited by diffusion of the primary electrons. A strong magnetic field along the drift direction is often applied (Fancher et al., Nucl. Instr. and Meth. A 161 (1979) 383) because it suppresses the transverse diffusion, improving the resolution but at considerable increase in cost and complexity. Here we show that transverse track diffusion can be strongly suppressed without any magnetic field. This is achieved by using a gas additive which reversibly captures primary ionization electrons, forming negative ions. The ions drift with thermal energies even at very high drift fields and low pressures (E/P=28.5 V/cm torr), and the diffusion decreases with increasing drift field. Upon arrival at the avalanche region of the chamber the negative ions are efficiently stripped and ordinary avalanche gain is obtained. Using this technique, r.m.s. transverse diffusion less than 200 {mu}m has been achieved over a 15 cm drift path at 40 torr with zero magnetic field. The method can provide high spatial resolution in detectors with long drift distances and zero magnetic field. Negative ion drift chambers would be particularly useful at low pressures and in situations such as space-based or underground experiments where detector size scaleability is important and cost, space, or power constraints preclude the use of a magnetic field.

  16. Chamber Design For Slow Nucleation Protein Crystal Growth

    Science.gov (United States)

    Pusey, Marc Lee

    1995-01-01

    Multiple-chamber dialysis apparatus grows protein crystals on Earth or in microgravity with minimum of intervention by technician. Use of multiple chambers provides gradation of nucleation and growth rates.

  17. Introduction to the Workshop "30 years of bubble chamber physics"

    OpenAIRE

    Giorgio GiacomelliUniversity of Bologna and INFN, Bologna, Italy

    2014-01-01

    After some recollections of the early bubble chamber times, a brief overview of the golden age of the field is made, including its legacy and the use of bubble chamber events for the popularization of science.

  18. Cone penetration tests in a virtual calibration chamber

    OpenAIRE

    Arroyo Alvarez de Toledo, Marcos; Butlanska, Joanna; Gens Solé, Antonio; Calvetti, Francesco; Jamiolkowski, Michael

    2011-01-01

    A virtual calibration chamber was built using a threedimensional model based on the discrete-element method. The chamber was then filled with a scaled granular equivalent of Ticino sand, the material properties of which were selected by curve-fitting triaxial tests. Cone penetration tests were then performed under different initial densities and isotropic stresses. Penetration resistance in the virtual calibration chamber was affected by the same cone/chamber size effect that affects ph...

  19. The Impedance of the Ceramic Chamber in J-PARC

    CERN Document Server

    Shobuda, Yoshihiro; Ohmi, Kazuhito; Toyama, Takeshi

    2005-01-01

    The ceramic chamber is adopted at the RCS (rapid cycling synchrotron) in J-PARC. The copper stripes are on the outer surface of the chamber in order to shield the electro-magnetic field produced by the beam. The inner surface of the chamber is coated by TiN to suppress the secondary electron emission. In this paper, we calculate the strength of electro-magnetic field produced by the beam and evaluate the impedance of this ceramic chamber.

  20. Ionization chamber for high dose measurements

    International Nuclear Information System (INIS)

    Industrial gamma irradiators facilities are designed for processing large amounts of products, which are exposed to large doses of gamma radiation. The irradiation, in industrial scale, is usually carried out in a dynamic form, where the products go through a 60Co gamma source with activity of TBq to P Bq (k Ci to MCi). The dose is estimated as being directly proportional to the time that the products spend to go through the source. However, in some situations, mainly for research purposes or for validation of customer process following the ISO 11137 requirements, it is required to irradiate small samples in a static position with fractional deliver doses. The samples are put inside the irradiation room at a fixed distance from the source and the dose is usually determined using dosimeters. The dose is only known after the irradiation, by reading the dosimeter. Nevertheless, in the industrial irradiators, usually different kinds of products with different densities go through between the source and the static position samples. So, the dose rate varies in function of the product density. A suitable methodology would be to monitor the samples dose in real time, measuring the dose on line with a radiation detector, which would improve the dose accuracy and avoid the overdose. A cylindrical ionization chamber of 0.9 cm3 has been developed for high-doses real-time monitoring, during the sample irradiation at a static position in a 60Co gamma industrial plant. Nitrogen and argon gas at pressure of 10 exp 5 Pa (1 bar) was utilized to fill the ionization chamber, for which an appropriate configuration was determined to be used as a detector for high-dose measurements. To transmit the signal generated in the ionization chamber to the associated electronic and processing unit, a 20 m mineral insulated cable was welded to the ionization chamber. The signal to noise ratio produced by the detector was about 100. The dosimeter system was tested at a category I gamma irradiator

  1. Herds of methane chambers grazing bubbles

    Science.gov (United States)

    Grinham, Alistair; Dunbabin, Matthew

    2014-05-01

    Water to air methane emissions from freshwater reservoirs can be dominated by sediment bubbling (ebullitive) events. Previous work to quantify methane bubbling from a number of Australian sub-tropical reservoirs has shown that this can contribute as much as 95% of total emissions. These bubbling events are controlled by a variety of different factors including water depth, surface and internal waves, wind seiching, atmospheric pressure changes and water levels changes. Key to quantifying the magnitude of this emission pathway is estimating both the bubbling rate as well as the areal extent of bubbling. Both bubbling rate and areal extent are seldom constant and require persistent monitoring over extended time periods before true estimates can be generated. In this paper we present a novel system for persistent monitoring of both bubbling rate and areal extent using multiple robotic surface chambers and adaptive sampling (grazing) algorithms to automate the quantification process. Individual chambers are self-propelled and guided and communicate between each other without the need for supervised control. They can maintain station at a sampling site for a desired incubation period and continuously monitor, record and report fluxes during the incubation. To exploit the methane sensor detection capabilities, the chamber can be automatically lowered to decrease the head-space and increase concentration. The grazing algorithms assign a hierarchical order to chambers within a preselected zone. Chambers then converge on the individual recording the highest 15 minute bubbling rate. Individuals maintain a specified distance apart from each other during each sampling period before all individuals are then required to move to different locations based on a sampling algorithm (systematic or adaptive) exploiting prior measurements. This system has been field tested on a large-scale subtropical reservoir, Little Nerang Dam, and over monthly timescales. Using this technique

  2. Test of an undulated vacuum chamber for the ISR

    CERN Multimedia

    1975-01-01

    This picture shows mechanical tests of an undulated vacuum chamber for downstream arms of ISR intersections. This chamber, made of 0.3 mm thick inconel, had inner dimensions of 150 mm by 50 mm. The deflection under vacuum is measured by dial gauges. On the left one sees the large vessel where vacuum chambers were tested at pressures above atmospheric pressure.

  3. 21 CFR 878.5650 - Topical oxygen chamber for extremities.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Topical oxygen chamber for extremities. 878.5650... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Therapeutic Devices § 878.5650 Topical oxygen chamber for extremities. (a) Identification. A topical oxygen chamber for extremities is a device...

  4. A time expansion chamber as a vertex detector

    International Nuclear Information System (INIS)

    A high-resolution drift chamber based on the time expansion principle has been built as a vertex detector for the Mark J experiment at DESY. The chamber design and the associated control and readout system are described. Results on chamber performance obtained from test beam measurements and first results from running at PETRA are reported. (orig.)

  5. Characterization of a homemade ionization chamber for radiotherapy beams.

    Science.gov (United States)

    Neves, Lucio P; Perini, Ana P; dos Santos, Gelson P; Xavier, Marcos; Khoury, Helen J; Caldas, Linda V E

    2012-07-01

    A homemade cylindrical ionization chamber was studied for routine use in therapy beams of (60)Co and X-rays. Several characterization tests were performed: leakage current, saturation, ion collection efficiency, polarity effect, stability, stabilization time, chamber orientation and energy dependence. All results obtained were within international recommendations. Therefore the homemade ionization chamber presents usefulness for routine dosimetric procedures in radiotherapy beams. PMID:22153889

  6. 30 CFR 57.11054 - Communication with refuge chambers.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Communication with refuge chambers. 57.11054... and Escapeways Escapeways-Underground Only § 57.11054 Communication with refuge chambers. Telephone or other voice communication shall be provided between the surface and refuge chambers and such...

  7. Bi-cone vacuum chamber in the ISR

    CERN Multimedia

    1976-01-01

    The "bi-cone" vacuum chamber in ISR intersection I-7, for experiment R702. Made from 0.28 mm thick titanium, it was at its time the most transparent chamber ever built. Ian Wilson is standing next to the chamber. See also 7609219.

  8. Central Drift Chamber for rare kaon decay spectrometer

    International Nuclear Information System (INIS)

    Design of the Central Drift Chamber for BNL experiment 787 and measurement of a rare kaon decay are discussed. A jet chamber type cell with 6 sense wires and no interspersed field wires has been designed to achieve good spatial resolution and efficiency in a 1 T magnetic field. Results of the testing of a prototype chamber are presented

  9. 46 CFR 197.332 - PVHO-Decompression chambers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false PVHO-Decompression chambers. 197.332 Section 197.332... STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.332 PVHO—Decompression chambers. Each decompression chamber must— (a) Meet the requirements of § 197.328; (b) Have internal...

  10. Engineering analyses of large precision cathode strip chambers for GEM

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, J.A.; Belser, F.C.; Pratuch, S.M.; Wuest, C.R. [Lawrence Livermore National Lab., CA (United States); Mitselmakher, G. [Superconducting Super Collider Lab., Dallas, TX (United States); Gordeev, A. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Johnson, C.V. [Lawrence Livermore National Lab., CA (United States)]|[Superconducting Super Collider Lab., Dallas, TX (United States); Polychronakos, V.A. [Brookhaven National Lab., Upton, NY (United States); Golutvin, I.A. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    1993-10-21

    Structural analyses of large precision cathode strip chambers performed up to the date of this publication are documented. Mechanical property data for typical chamber materials are included. This information, originally intended to be an appendix to the {open_quotes}CSC Structural Design Bible,{close_quotes} is presented as a guide for future designers of large chambers.

  11. Installation and Commissioning of the new GLM Implantation Chamber

    CERN Document Server

    Pohl, Christoph

    2016-01-01

    Summer student report about the work with the new implantation chamber for the GLM branch of ISOLDE. In the context of this project an API for the vacuum system of the new chamber was developed and implemented in web application that will be used to control the new implantation chamber at some point.

  12. A novel non invasive measurement of hemodynamic parameters: Comparison of single-chamber ventricular and dual-chamber pacemaker

    OpenAIRE

    Ingrid M. Pardede; Yoga Yuniadi

    2008-01-01

    We carried out a cross sectional study to analyze hemodynamic parameters of single-chamber ventricular pacemaker compared with dual-chamber pacemaker by using thoracic electrical bioimpedance monitoring method (Physio Flow™) - a novel simple non-invasive measurement. A total of 48 consecutive outpatients comprised of 27 single chamber pacemaker and 21 dual chamber were analyzed. We measured cardiac parameters: heart rate, stroke volume index, cardiac output index, estimated ejection fraction,...

  13. A novel non invasive measurement of hemodynamic parameters: Comparison of single-chamber ventricular and dual-chamber pacemaker

    Directory of Open Access Journals (Sweden)

    Ingrid M. Pardede

    2008-03-01

    Full Text Available We carried out a cross sectional study to analyze hemodynamic parameters of single-chamber ventricular pacemaker compared with dual-chamber pacemaker by using thoracic electrical bioimpedance monitoring method (Physio Flow™ - a novel simple non-invasive measurement. A total of 48 consecutive outpatients comprised of 27 single chamber pacemaker and 21 dual chamber were analyzed. We measured cardiac parameters: heart rate, stroke volume index, cardiac output index, estimated ejection fraction, end diastolic volume, early diastolic function ratio, thoracic fluid index, and systemic parameters: left cardiac work index and systemic vascular resistance index. Baseline characteristic and pacemaker indication were similar in both groups. Cardiac parameters assessment revealed no significant difference between single-chamber pacemaker and dual-chamber pacemaker in heart rate, stroke volume index, cardiac index, estimated ejection fraction, end-diastolic volume, thoracic fluid index. There was significantly higher early diastolic function ratio in single-chamber pacemaker compared to dual-chamber pacemaker: 92% (10.2-187.7% vs. 100.6% (48.7-403.2%; p=0.006. Systemic parameters assessment revealed significantly higher left cardiac work index in single-chamber group than dual-chamber group 4.9 kg.m/m² (2.8-7.6 kg.m/m² vs. 4.3 kg.m/m² (2.9-7.2 kg.m/m²; p=0.004. There was no significant difference on systemic vascular resistance in single-chamber compared to dual-chamber pacemaker. Single-chamber ventricular pacemaker provides similar stroke volume, cardiac output and left cardiac work, compared to dual-chamber pacemaker. A non-invasive hemodynamic measurement using thoracic electrical bioimpedance is feasible for permanent pacemaker outpatients. (Med J Indones 2008; 17: 25-32Keywords: Permanent pacemaker, single chamber, dual chamber, thoracic electrical bioimpedance, hemodynamic parameter

  14. SHAPE OF PRESSING CHAMBER FOR WOOD BIOMASS COMPACTING

    Directory of Open Access Journals (Sweden)

    Peter Krizan

    2015-11-01

    Full Text Available The main goal of this contribution is to present results of analyse of mathematical models of wood biomass compacting. Doesn't exist a lot of models which describes real state in pressing chamber and amount of factors impact at compacting process and thereby on briquette quality. According to our suggestion have also constructional parameters of pressing chamber (pressing spout and pressing ram expressive impact on result briquette quality. We did theoretical analyses which showed us that impact on briquette quality have also change of pressing chamber length, change of friction coefficient, change of pressing chamber conicalness and also change of pressing chamber diameter.

  15. Advanced photon source experience with vacuum chambers for insertion devices

    International Nuclear Information System (INIS)

    During the last five years, a new approach to the design and fabrication of extruded aluminum vacuum chambers for insertion devices was developed at the Advanced Photon Source (APS). With this approach, three different versions of the vacuum chamber, with vertical apertures of 12 mm, 8 mm, and 5 mm, were manufactured and tested. Twenty chambers were installed into the APS vacuum system. All have operated with beam, and 16 have been coupled with insertion devices. Two different vacuum chambers with vertical apertures of 16 mm and 11 mm were developed for the BESSY-II storage ring and 3 of 16 mm chambers were manufactured

  16. Measuring the sensitivity of a boron-lined ion chamber

    International Nuclear Information System (INIS)

    Boron-lined ion chambers are used to monitor external neutron flux from fissionable materials assembled at the Los Alamos Critical Assembly Experiment Facility. The sensitivity of these chambers must be measured periodically in order to detect changes in filling gas and to evaluate other factors that may affect chamber performance. We delineate a procedure to measure ion chamber response using a particular neutron source (239PuBe) in a particular moderating geometry of polyethylene. We also discuss use of the amplifier, high-voltage power supply, recorders, and scram circuits that comprise the complete ion chamber monitoring system

  17. Liquid rocket combustion chamber acoustic characterization

    Directory of Open Access Journals (Sweden)

    Cândido Magno de Souza

    2010-09-01

    Full Text Available Over the last 40 years, many solid and liquid rocket motors have experienced combustion instabilities. Among other causes, there is the interaction of acoustic modes with the combustion and/or fluid dynamic processes inside the combustion chamber. Studies have been showing that, even if less than 1% of the available energy is diverted to an acoustic mode, combustion instability can be generated. On one hand, this instability can lead to ballistic pressure changes, couple with other propulsion systems such as guidance or thrust vector control, and in the worst case, cause motor structural failure. In this case, measures, applying acoustic techniques, must be taken to correct/minimize these influences on the combustion. The combustion chamber acoustic behavior in operating conditions can be estimated by considering its behavior in room conditions. In this way, acoustic tests can be easily performed, thus identifying the cavity modes. This paper describes the procedures to characterize the acoustic behavior in the inner cavity of four different configurations of a combustion chamber. Simple analytical models are used to calculate the acoustic resonance frequencies and these results are compared with acoustic natural frequencies measured at room conditions. Some comments about the measurement procedures are done, as well as the next steps for the continuity of this research. The analytical and experimental procedures results showed good agreement. However, limitations on high frequency band as well as in the identification of specific kinds of modes indicate that numerical methods able to model the real cavity geometry and an acoustic experimental modal analysis may be necessary for a more complete analysis. Future works shall also consider the presence of passive acoustic devices such as baffles and resonators capable of introducing damping and avoiding or limiting acoustic instabilities.

  18. Data readout system for multiwire proportional chambers

    International Nuclear Information System (INIS)

    An electronic system for data readout from multiwire proportional chambers is described. The system will be used in a magnetic spectrometer for investigation into rare processes in an ITEP accelerating complex. Schematic solutions, used in the system allow one to maximally use the 'VECTOR' standard interface fast operation. The system assembly is completely made of domestic parts. The readout system structure developed allows one to easily reduce or increase the number of MPC channels questioned. The mean time, required for preparing data on cluster, does not exceed 1.5 μs

  19. Optimization studies on pulse ionization chambers

    International Nuclear Information System (INIS)

    The results are presented of optimization studies on two models of an air-filled, pulse, ionization chamber intended for detecting air impurities. Studies were conducted on the effect of dosage grids, procedure of controlling them, field configuration, type of radioactive source, surface of collecting electrode, and length of dosage pulse. The most critical parameters that have an effect upon the pulse shape, i.t. upon the pulse-amplitude and -length are: procedure of controlling the dosage grid, dosage dosage-pulse length and electric-field intensity. (author)

  20. Ion feedback suppression in Time Projection Chambers

    CERN Document Server

    Sauli, Fabio; Everaerts, P

    2006-01-01

    A controlled-voltage Gas Electron Multiplier (GEM) can be used to block the re-injection of positive ions in large volume Time Projection Chambers. With proper choice of geometry, gas filling and external fields, good electron transmission can be obtained at very low GEM voltages; pulsed ion gating is then much easier than with conventional wire grids, requiring hundreds of volts. Gating schemes suited for the TPC detector planned for the International Linear Collider detector are described. The possibility of GEM-based DC-operated ion filters, exploiting the difference in diffusion properties of ions and electrons, is also discussed.

  1. Bubble Chamber Research Group Microcomputer Unit

    International Nuclear Information System (INIS)

    A distributed data acquisition system has been developed by the Bubble Chamber Research Group at the Rutherford Appleton laboratory for use with their film measuring machines. The system is based upon a set of microcomputers linked together with a VAX 11/780 computer, in a local area computer network. This network is of the star type and uses a packet switching technique. Each film measuring machine is equipped with a microcomputer which controls the function of the table, buffers data and enhances the interface between operators and machines. This paper provides a detailed description of each microcomputer and can be used as a reference manual for these computers. (author)

  2. Observation of light from resistive plate chambers

    International Nuclear Information System (INIS)

    Electrically induced signals and light emissions from restrictive plate chamber (RPC) are simultaneously measured using a glass RPC with transparent high-voltage planes, operating in the streamer mode. With one exception, good correspondence is seen in between the electrical and optical signals in every aspect: signal shapes, pulse heights, timing and afterpulses. The one exception is a possible limiting effect observed on the optical signal pulse height for a given pulse height of electrically induced signal. Shapes of the signal visually observed by eye are also described. (orig.)

  3. Frederic Chopin's Chamber Music and Polish Songs

    OpenAIRE

    Rezaei, Ramin

    2010-01-01

    My purpose in writing this thesis is to represent Chopin and his music in a different light than usual. Most people are only familiar with Chopin’s works for piano solo and the few works for piano and orchestra. I know many music students and even some professional musicians and teachers who consider Chopin only as a piano composer. Chopin’s chamber works and Polish songs are seldom performed, though in my opinion they are extremely beautiful and deserve much more attention. Through writing t...

  4. Performance of large area Micro Pixel Chamber

    OpenAIRE

    Nagayoshi, T.; Kubo, H.; Miuchi, K; Ochi, A.; Orito, R.; Takada, A; Tanimori, T.; Ueno, M

    2003-01-01

    A novel gaseous two-dimensional imaging detector "Micro Pixel Chamber (micro-PIC)" has been developed. This detector is based on double sided printed circuit board (PCB). We have developed large area (10cm x 10cm) micro-PICs with 65536 pixel anodes of 400um pitch on a 100um thick insulating substrate. Achieved energy resolution was 30% (FWHM) at 5.9keV, and a gas gain of 7000 was obtained with argon ethane (8:2) gas mixture. This gain is high enough to detect minimum ionizing particles with s...

  5. Holography in a freon bubble chamber

    International Nuclear Information System (INIS)

    After some tests in a PS beam in the summer of 1981, the run took place in October 1981 in the H2 beam of the SPS. Although some problems of heat dissipation in freon limited the expansion rate of the bubble chamber, more than 11000 holograms were taken, showing 10 μm bubble tracks, with very good image quality and contrast. More than 100 tracks can be stored on a hologram without affecting the quality if all the bubbles are small. In addition, the analysis of the holograms does not look more complex than the exploitation of conventional high-resolution pictures. (orig./HSI)

  6. Liquid Engine Design: Effect of Chamber Dimensions on Specific Impulse

    Science.gov (United States)

    Hoggard, Lindsay; Leahy, Joe

    2009-01-01

    Which assumption of combustion chemistry - frozen or equilibrium - should be used in the prediction of liquid rocket engine performance calculations? Can a correlation be developed for this? A literature search using the LaSSe tool, an online repository of old rocket data and reports, was completed. Test results of NTO/Aerozine-50 and Lox/LH2 subscale and full-scale injector and combustion chamber test results were found and studied for this task. NASA code, Chemical Equilibrium with Applications (CEA) was used to predict engine performance using both chemistry assumptions, defined here. Frozen- composition remains frozen during expansion through the nozzle. Equilibrium- instantaneous chemical equilibrium during nozzle expansion. Chamber parameters were varied to understand what dimensions drive chamber C* and Isp. Contraction Ratio is the ratio of the nozzle throat area to the area of the chamber. L is the length of the chamber. Characteristic chamber length, L*, is the length that the chamber would be if it were a straight tube and had no converging nozzle. Goal: Develop a qualitative and quantitative correlation for performance parameters - Specific Impulse (Isp) and Characteristic Velocity (C*) - as a function of one or more chamber dimensions - Contraction Ratio (CR), Chamber Length (L ) and/or Characteristic Chamber Length (L*). Determine if chamber dimensions can be correlated to frozen or equilibrium chemistry.

  7. New development of holography in particle detectors: application to bubble chambers and streamer chambers

    International Nuclear Information System (INIS)

    This thesis describes the contribution of holography in two particle detectors well used in high energy physics. A first part presents the possibilities of a double beam holographic set up with diffuse illumination in the case of large scale bubble chamber (more than 1000 litres). The second part introduces the results obtained by the use of an in-line holographic recording in a streamer chamber (a streamer is the electroluminescent state of an electronic avalanche). In both cases, the new possibilities offered by these developments are discussed (resolution and depth of field of holographic images)

  8. Golden Jubilee photos: The first CERN bubble chamber

    CERN Multimedia

    2004-01-01

    In the 1950s and 1960s, bubble and spark chambers were the dominant experimental tools in high-energy physics. While spark chambers were usually built and fitted to specific experiments, bubble chambers were constructed as general purpose devices that could be used for a variety of experiments. At CERN, the bubble chamber programme started under Charles Peyrou in the late 1950s. The first of CERN's bubble chambers, a 30 cm hydrogen chamber, is seen here being inserted into its vacuum tank. The HBC30, as it was called, took its first beam from the SC in 1959. One of the first pictures taken, of a positive pion-proton interaction, began a long series of pretty images for which bubble chambers would become famous. When it stopped operating in spring 1962, the HBC30 had consumed 150 km of film in its 3 years of operation.

  9. Design and commissioning of a semi-confined blast chamber

    Institute of Scientific and Technical Information of China (English)

    I.M. SNYMAN; F.J. MOSTERT; W. GRUNDLING

    2016-01-01

    This paper presents the design, test and analysis of a scaled cylindrical blast chamber. The blast chamber is a one-fifth dimensional size replica of the full-scale blast chamber (Emily). The blast chamber is semi-confined as one end is open. The scaled blast chamber is used to test concepts for closing the open end and allows the gas to vent at the same time. ANSYS AUTODYN calculated the pressure time histories for different closure scenarios. Comparing the results suggested a viable scenario, namely a structure consisting of a circular disc and a frame positioned at the open end of the blast chamber. The structure and cylindrical blast chamber were subjected to scaled blast tests and the pressure results are presented and discussed.

  10. Contamination of ionization chamber due to tritium exposure

    International Nuclear Information System (INIS)

    The contamination of three ionization chambers (Cu, Ni-plated, and Au-plated chambers) due to exposure to HT or HTO was measured. Considerable contamination took place for all of the chambers due to exposure to HTO. This is caused by the physical adsorption of HTO. The extent of the contamination differed from each other (Ni > Au > Cu), being considered due to difference in their surface roughness. In case of the exposure to HT, the Cu-chamber was contaminated in room air, whereas the Ni-chamber did in dry air atmosphere. This is considered due to the adsorption of HTO (being formed with catalytic exchange reaction between HT and H2O) on the Cuchamber and that of HT on the Ni-chamber. The Au-chamber was not contaminated with the exposure to HT. This is because neither the adsorption of HT nor the catalytic exchange reaction takes place on this surface

  11. Performance of the SLD Central Drift Chamber

    International Nuclear Information System (INIS)

    We report for the first time on the performance of the SLD Central Drift Chamber (CDC) at SLC, which has been recording data since 1992. The low mass of the chamber and the use of a gas characterized by both a low drift velocity and low diffusion constant help to minimize the drift-distance measurement errors. We describe some of the calibrations and corrections applied to the data, and report on the resolutions achieved thus far. We measure an intrinsic drift resolution of 55-110 μm in the region of uniform field. Analysis of the full drift-pulse waveform allows for efficient double-hit resolution of about 1 mm. Momentum resolution is characterized by the formula (dpt/pt2)2 = 0.00502 + (0.010/pt)2. Used in conjunction with the SLD vertex detector, the CDC permits measurements of impact parameters of high-momentum tracks to the level of 10 μm in the r-φ plane and 36 μm the r-z plane. A resolution of 6.4% is achieved in the measurement of dE/dx for the electrons in Bhabha scattering events

  12. Liquid xenon multiwire chamber for positron tomography

    International Nuclear Information System (INIS)

    The liquid xenon multiwire chamber has been proposed as a detector of 511 keV gamma-photons for positron emission tomography (PET). Both the scintillation and the ionization signal, read from the anode wires, are used. A test chamber of about 300 cm3 and containing six multiwire ionization cells has been built. The cell is formed by two plane cathodes, 10 mm apart, and 20 anode wires spaced by 2.5 mm tied to pairs resulting in 10 channels, read out independently. The first experiments were performed for a single cell. The number of the anode wire on which the signal is induced gives the depth of interaction in the detector with a precision of 5 mm. This is important information allowing one to reduce the parallax error and, therefore, to decrease the tomograph size and improve the solid angle. The position sensitivity across the cell (or along the tomograph ring) is achieved by measurement of the drift time of the electrons from the point of primary ionization to the anode, triggered by the scintillation detected with a photomultiplier tube. The scintillation also supplies a fast trigger for the coincidence analysis. (orig.)

  13. LET measurements with a liquid ionization chamber

    International Nuclear Information System (INIS)

    Deep-seated tumors can be efficiently treated with heavy charged particles. The characteristic depth dose profile inside the tissue (Bragg peak) allows to deliver a high dose inside the tumor, while sparing the neighboring healthy tissue. As compared to protons, heavy ions like carbon or oxygen produce a higher amount of ionization events along their track (and in particular at the end of the ion beam path), resulting in an irreparable damage to the DNA of the tumor cells. The density of such ionization events is described in terms of Linear Energy Transfer (LET), an important physical quantity, but difficult to be measured directly. The aim of this work is to determine LET of hadrontherapy beams by using Liquid Ionization Chambers (LIC). The ionization signal in LICs is affected by recombination effects that depend on the LET of the incident radiation. Differences in recombination effects in LICs and air-filled ionization chambers can be exploited to obtain the recombination index, which can be related to the LET, calculated by Monte Carlo methods. We thus developed a method to construct a calibration curve, which relates the recombination index with the LET at each depth in water. The result of this work can be used for online monitoring of the ion beam quality.

  14. COLDDIAG: A Cold Vacuum Chamber for Diagnostics

    CERN Document Server

    Casalbuoni, S; Gerstl, S; Grau, A W; Hagelstein, M; Saez de Jauregui, D; Boffo, C; Sikler, G; Baglin, V; Cox, M P; Schouten, J C; Cimino, R; Commisso, M; Spataro, B; Mostacci, A; Wallen, E J; Weigel, R; Clarke, J; Scott, D; Bradshaw, T; Jones, R; Shinton, I

    2011-01-01

    One of the still open issues for the development of superconducting insertion devices is the understanding of the beam heat load. With the aim of measuring the beam heat load to a cold bore and the hope to gain a deeper understanding in the beam heat load mechanisms, a cold vacuum chamber for diagnostics is under construction. The following diagnostics will be implemented: i) retarding field analyzers to measure the electron energy and flux, ii) temperature sensors to measure the total heat load, iii) pressure gauges, iv) and mass spectrometers to measure the gas content. The inner vacuum chamber will be removable in order to test different geometries and materials. This will allow the installation of the cryostat in different synchrotron light sources. COLDDIAG will be built to fit in a short straight section at ANKA. A first installation at the synchrotron light source Diamond is foreseen in June 2011. Here we describe the technical design report of this device and the planned measurements with beam.

  15. Description of new vacuum chamber correction concept

    Energy Technology Data Exchange (ETDEWEB)

    Danby, G.T.; Jackson, J.W.

    1989-01-01

    For rapid cycled accelerators eddy currents induced in vacuum chambers (VC) are typically the dominant source of systematic and random field aberrations. Complex thin wall VC are expensive and delicate where bakeout is required, as in the AGS Booster under construction. Thick wall VC are rugged and economical but produce large eddy currents. A ''Self-Correction'' concept has been developed and tested which corrects automatically by transformer action, even for variable /dot B/ cycles. Coils attached to the outside of the VC cancel eddy current aberrations over the entire ''good field'' aperture. The (inexpensive) correction coils follow the local contour of the VC, so large transverse VC movements are tolerated; both the aberrations and their corrections have the same displaced coordinates. Experimental results are presented for Booster correction coil designs demonstrating both self-correction and excitation by a separate power supply. Analytic results applicable to the Booster and other fast cycling accelerators are discussed. The eddy current field aberrations induced in a pre-production full size vacuum chamber inserted in an AGS Booster dipole have been successfully eliminated by the ''self correction'' coils attached to its surface. The voltage induced in a two-turns per pole ''back leg'' winding is sufficient to supply the necessary current through the correction winding. A nichrome wire attached in series provides adjustable resistance for current control. 2 refs., 7 figs.

  16. Wire chamber radiation detector with discharge control

    International Nuclear Information System (INIS)

    A wire chamber radiation detector has spaced apart parallel electrodes and grids defining an ignition region in which charged particles or other ionizing radiations initiate brief localized avalanche discharges and defining an adjacent memory region in which sustained glow discharges are initiated by the primary discharges. Conductors of the grids at each side of the memory section extend in orthogonal directions enabling readout of the X-Y coordinates of locations at which charged particles were detected by sequentially transmitting pulses to the conductors of one grid while detecting transmissions of the pulses to the orthogonal conductors of the other grid through glow discharges. One of the grids bounding the memory region is defined by an array of conductive elements each of which is connected to the associated readout conductor through a separate resistance. The wire chamber avoids ambiguities and imprecisions in the readout of coordinates when large numbers of simultaneous or near simultaneous charged particles have been detected. Down time between detection periods and the generation of radio frequency noise are also reduced

  17. BEBC, the Big European Bubble Chamber

    CERN Multimedia

    1971-01-01

    The vessel of the Big European Bubble Chamber, BEBC, was installed at the beginning of the 1970s. The large stainless-steel vessel, measuring 3.7 metres in diameter and 4 metres in height, was filled with 35 cubic metres of liquid (hydrogen, deuterium or a neon-hydrogen mixture), whose sensitivity was regulated by means of a huge piston weighing 2 tonnes. During each expansion, the trajectories of the charged particles were marked by a trail of bubbles, where liquid reached boiling point as they passed through it. The first images were recorded in 1973 when BEBC, equipped with the largest superconducting magnet in service at the time, first received beam from the PS. In 1977, the bubble chamber was exposed to neutrino and hadron beams at higher energies of up to 450 GeV after the SPS came into operation. By the end of its active life in 1984, BEBC had delivered a total of 6.3 million photographs to 22 experiments devoted to neutrino or hadron physics. Around 600 scientists from some fifty laboratories through...

  18. Aging Investigation of CMS EMU Prototype Chambers

    CERN Document Server

    Ferguson*, T; Krivshich, Anatoli; Kuznetsova, Ekaterina; Lobachev, Evgeny; Mitselmakher, Guenakh; Schipunov, L

    1999-01-01

    The aging investigation results of CMS EMU prototype chambers are presented. Aging tests under sustained irradiation by a 90Sr 2 Ci were performed with three working gas mixtures Ar( 30%)+CO2( 50%)+CF4( 20%), Ar( 30%)+CO2( 70%) and Ar( 40%)+CO2( 50%)+CF4( 10%). For Ar( 30%)+CO2( 50%)+CF4( 20%) mixture gas gain reduction was not observed up to the accumulated charge Q = 13.56 C/cm. However, the dark current in the chamber was noticeable starting already from Q = 2 C/cm. The absence of the CF4 ( in the Ar/CO2 gas mixture) caused fast aging deterioration, and Q = 0.2 C/cm was enough to obtain 50% of the gas gain reduction. In the test with Ar( 40%)+CO2( 50%)+CF4( 10%) mixture the gas gain reduction and the dark current increase were not observed up to Q = 13.35 C/cm. Reduction of the gas flow rate to 0.1 volume per day caused 50% of the gain decrease due to the gas pollution by fragments of dissociated gas molecules. The gain restored after switching back to the 1 volume per day flow rate. Studies with electroni...

  19. Bubble chambers for experiments in nuclear astrophysics

    Science.gov (United States)

    DiGiovine, B.; Henderson, D.; Holt, R. J.; Raut, R.; Rehm, K. E.; Robinson, A.; Sonnenschein, A.; Rusev, G.; Tonchev, A. P.; Ugalde, C.

    2015-05-01

    A bubble chamber has been developed to be used as an active target system for low energy nuclear astrophysics experiments. Adopting ideas from dark matter detection with superheated liquids, a detector system compatible with γ-ray beams has been developed. This detector alleviates some of the limitations encountered in standard measurements of the minute cross-sections of interest to stellar environments. While the astrophysically relevant nuclear reaction processes at hydrostatic burning temperatures are dominated by radiative captures, in this experimental scheme we measure the time-reversed processes. Such photodisintegrations allow us to compute the radiative capture cross-sections when transitions to excited states of the reaction products are negligible. Due to the transformation of phase space, the photodisintegration cross-sections are up to two orders of magnitude higher. The main advantage of the new target-detector system is a density several orders of magnitude higher than conventional gas targets. Also, the detector is virtually insensitive to the γ-ray beam itself, thus allowing us to detect only the products of the nuclear reaction of interest. The development and the operation as well as the advantages and disadvantages of the bubble chamber are discussed.

  20. Bubble chambers for experiments in nuclear astrophysics

    International Nuclear Information System (INIS)

    A bubble chamber has been developed to be used as an active target system for low energy nuclear astrophysics experiments. Adopting ideas from dark matter detection with superheated liquids, a detector system compatible with γ-ray beams has been developed. This detector alleviates some of the limitations encountered in standard measurements of the minute cross-sections of interest to stellar environments. While the astrophysically relevant nuclear reaction processes at hydrostatic burning temperatures are dominated by radiative captures, in this experimental scheme we measure the time-reversed processes. Such photodisintegrations allow us to compute the radiative capture cross-sections when transitions to excited states of the reaction products are negligible. Due to the transformation of phase space, the photodisintegration cross-sections are up to two orders of magnitude higher. The main advantage of the new target-detector system is a density several orders of magnitude higher than conventional gas targets. Also, the detector is virtually insensitive to the γ-ray beam itself, thus allowing us to detect only the products of the nuclear reaction of interest. The development and the operation as well as the advantages and disadvantages of the bubble chamber are discussed

  1. Neutron measurements with miniature fission chambers

    International Nuclear Information System (INIS)

    This report analyses the use and qualification of miniature fission chambers for two types of neutron measurements: 1) relative measurements in nuclear power reactors, or nuclear irradiation reactors. We consider the problem of burnable fissile material in detectors, under important neutron exposures and conclude on recommending the use of regenerating neutron detectors. 2) Measurements of integral physical parameters in experimental reactors. This method has been applied to measurements of fission rates in detectors with strong alpha-rays emitter deposits in order to establish standard tables of physical parameters. It has been used in particular for detectors including very radioactive actinium series. After a discussion of the instrumentation choice and data processing, specific to each measurements, we provide results on: 1) the technological and neutron behaviour of regenerating miniature fission chambers, in the swimming pool reactor 'TRITON', under a neutron exposure of 7.1020 n cm-2 and a gamma-rays exposure of 1,5.1011 rads about. The fissile material is 235U and the fertile material 234U. 2) The integral measurements of effective cross sections for 241Am and 238Pu in the experimental reactor 'MINERVE' use for study of problems of fast neutron reactors

  2. Advanced hydrogen/oxygen thrust chamber design analysis

    Science.gov (United States)

    Shoji, J. M.

    1973-01-01

    The results are reported of the advanced hydrogen/oxygen thrust chamber design analysis program. The primary objectives of this program were to: (1) provide an in-depth analytical investigation to develop thrust chamber cooling and fatigue life limitations of an advanced, high pressure, high performance H2/O2 engine design of 20,000-pounds (88960.0 N) thrust; and (2) integrate the existing heat transfer analysis, thermal fatigue and stress aspects for advanced chambers into a comprehensive computer program. Thrust chamber designs and analyses were performed to evaluate various combustor materials, coolant passage configurations (tubes and channels), and cooling circuits to define the nominal 1900 psia (1.31 x 10 to the 7th power N/sq m) chamber pressure, 300-cycle life thrust chamber. The cycle life capability of the selected configuration was then determined for three duty cycles. Also the influence of cycle life and chamber pressure on thrust chamber design was investigated by varying in cycle life requirements at the nominal chamber pressure and by varying the chamber pressure at the nominal cycle life requirement.

  3. Magma chambers: Formation, local stresses, excess pressures, and compartments

    Science.gov (United States)

    Gudmundsson, Agust

    2012-09-01

    An existing magma chamber is normally a necessary condition for the generation of a large volcanic edifice. Most magma chambers form through repeated magma injections, commonly sills, and gradually expand and change their shapes. Highly irregular magma-chamber shapes are thermo-mechanically unstable; common long-term equilibrium shapes are comparatively smooth and approximate those of ellipsoids of revolution. Some chambers, particularly small and sill-like, may be totally molten. Most chambers, however, are only partially molten, the main part of the chamber being crystal mush, a porous material. During an eruption, magma is drawn from the crystal mush towards a molten zone beneath the lower end of the feeder dyke. Magma transport to the feeder dyke, however, depends on the chamber's internal structure; in particular on whether the chamber contains pressure compartments that are, to a degree, isolated from other compartments. It is only during large drops in the hydraulic potential beneath the feeder dyke that other compartments become likely to supply magma to the erupting compartment, thereby contributing to its excess pressure (the pressure needed to rupture a magma chamber) and the duration of the eruption. Simple analytical models suggest that during a typical eruption, the excess-pressure in the chamber decreases exponentially. This result applies to a magma chamber that (a) is homogeneous and totally fluid (contains no compartments), (b) is not subject to significant replenishment (inflow of new magma into the chamber) during the eruption, and (c) contains magma where exsolution of gas has no significant effect on the excess pressure. For a chamber consisting of pressure compartments, the exponential excess-pressure decline applies primarily to a single erupting compartment. When more than one compartment contributes magma to the eruption, the excess pressure may decline much more slowly and irregularly. Excess pressure is normally similar to the in

  4. Compatibility results of some diagnostic ionization chambers

    International Nuclear Information System (INIS)

    The most important task of the National Laboratory for Metrology of the Ionizing Radiations at the Institute for Radiation Protection and Dosimetry - LNMRI/IRD-CNEN/MCT is to realize and maintain the legal units in compliance with the International System of Units - Si and disseminate them, above all within the framework of legal and scientific metrology. The LNMRI/IRD thus is on top of the metrological hierarchy in Brazil. Calibration certificates issued is the document that was result of the calibrations, that is, the instrument was calibrated and now it is traceable to national standards. Groups of a similar model of the ion chambers design specific for using at conventional diagnostic dosimetric, attenuated and no attenuated and dental applications, are placed under similar calibration condition at the LNMRI/IRD. The main objective is to observe how is the compatibilities' measurements obtained through 10 equipment set dedicated for clinical dosimetry, and how are the dispersion conclusion for these. (author)

  5. Development of an optical digital ionisation chamber

    International Nuclear Information System (INIS)

    We are developing a new device for optically detecting and imaging the track of a charged particle in a gas. The electrons in the particle track are made to oscillate rapidly by the application of an external, short duration, high voltage, RF electric field. The excited electrons produce additional ionisation and electronic excitation of the gas molecules in their immediate vicinity, leading to copious light emission (fluorescence) from the selected gas, allowing the location of the electrons along the track to be determined. Two digital cameras simultaneously scan the emitted light across two perpendicular planes outside the chamber containing the gas. The information thus obtained for a given track can be used to infer relevant quantities for microdosimetry and dosimetry, e.g. energy deposited, LET, and track structure in the gas. The design of such a device now being constructed and methods of obtaining the dosimetric data from the digital output will be described. (author)

  6. Resistive Plate Chambers: electron transport and modeling

    International Nuclear Information System (INIS)

    We study the electron transport in gas mixtures used by Resistive Plate Chambers (RPCs) in high energy physics experiments at CERN. Calculations are performed using a multi term theory for solving the Boltzmann equation. We identify the effects induced by non-conservative nature of electron attachment, including attachment heating of electrons and negative differential conductivity (NDC). NDC was observed only in the bulk component of drift velocity. Using our Monte Carlo technique, we calculate the spatially resolved transport properties in order to investigate the origin of these effects. We also present our microscopic approach to modeling of RPCs which is based on Monte Carlo method. Calculated results for a timing RPC show good agreement with an analytical model and experimental data. Different cross section sets for electron scattering in C2H2F4 are used for comparison and analysis

  7. Gamma sensitivity of thin gap chamber

    International Nuclear Information System (INIS)

    The Large Hadron Collider (LHC) at the European Laboratory for Particle Physics (CERN) is expected to operate at lower luminosity (1033 cm-2s-1) for the first three years and at the full luminosity of 1034 cm-2s-1 by year 2008 and on. Thin Gap Chamber (TGC) must operate under this high luminosity. Therefore there will be enormous background whose effect have to be estimated. The main particles in the background radiation are neutrons and photons. In this report, the sensitivity of TGC for gammas with energy from 20 keV to 1.8 MeV have been measured using radioactive sources. The measured sensitivity was compared with results from calculations of the Monte Carlo simulation code called EGS4 (Electron Gamma Shower). The average sensitivity of the TGC for gammas is about 1%. (author)

  8. Echo chambers in the age of misinformation

    CERN Document Server

    Del Vicario, Michela; Zollo, Fabiana; Petroni, Fabio; Scala, Antonio; Caldarelli, Guido; Stanley, H Eugene; Quattrociocchi, Walter

    2015-01-01

    The wide availability of user-provided content in online social media facilitates the aggregation of people around common interests, worldviews, and narratives. Despite the enthusiastic rhetoric on the part of some that this process generates "collective intelligence", the WWW also allows the rapid dissemination of unsubstantiated conspiracy theories that often elicite rapid, large, but naive social responses such as the recent case of Jade Helm 15 -- where a simple military exercise turned out to be perceived as the beginning of the civil war in the US. We study how Facebook users consume information related to two different kinds of narrative: scientific and conspiracy news. We find that although consumers of scientific and conspiracy stories present similar consumption patterns with respect to content, the sizes of the spreading cascades differ. Homogeneity appears to be the primary driver for the diffusion of contents, but each echo chamber has its own cascade dynamics. To mimic these dynamics, we introdu...

  9. Development of an optical digital ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Turner, J.E.; Hunter, S.R.; Hamm, R.N.; Wright, H.A.; Hurst, G.S.; Gibson, W.A.

    1988-01-01

    We are developing a new device for optically detecting and imaging the track of a charged particle in a gas. The electrons in the particle track are made to oscillate rapidly by the application of an external, short-duration, high-voltage, RF electric field. The excited electrons produce additional ionization and electronic excitation of the gas molecules in their immediate vicinity, leading to copious light emission (fluorescence) from the selected gas, allowing the location of the electrons along the track to be determined. Two digital cameras simultaneously scan the emitted light across two perpendicular planes outside the chamber containing gas. The information thus obtained for a given track can be used to infer relevant quantities for microdosimetry and dosimetry, e.g., energy deposited, LET, and track structure in the gas. The design of such a device now being constructed and methods of obtaining the dosimetric data from the digital output will be described. 4 refs., 4 figs.

  10. Emulsion chamber observations and interpretation (HE 3)

    Science.gov (United States)

    Shibata, M.

    1986-01-01

    Experimental results from Emulsion Chamber (EC) experiments at mountain altitudes or at higher levels using flying carriers are examined. The physical interest in this field is concentrated on the strong interaction at the very high energy region exceeding the accelerator energy, also on the primary cosmic ray intensity and its chemical composition. Those experiments which observed cosmic ray secondaries gave information on high energy interaction characteristics through the analyses of secondary spectra, gamma-hadron families and C-jets (direct observation of the particle production occuring at the carbon target). Problems of scaling violation in fragmentation region, interaction cross section, transverse momentum of produced secondaries, and some peculiar features of exotic events are discussed.

  11. The coated cathode conductive layer chamber

    International Nuclear Information System (INIS)

    We describe a gaseous detector consisting of thin anode strips vacuum-evaporated on one side of a 100 μ thick plastic layer, alternating on the back side of the same foil with wider parallel cathode strips. Ionizatin released in a drift space on the anode side is amplified and detected much in the same way as in the microstrip gas chamber; in our detector however spontaenous breakdown due to surface currents is completely avoided by the presence of the insulating layer between anodes and cathodes. To reduce surface and volume charging up, we have used polymer foils with a moderate volume resistivity. The first results show good efficiency, good plateaux and time resolution in detecting low-rate minimum ionizing electrons. Although not suited for high rate or good energy resolution applications, this kind of detector seems rather promising for realizing cheaply large active surfaces. (orig.)

  12. RETAINED STONE PIECE IN ANTERIOR CHAMBER

    Directory of Open Access Journals (Sweden)

    ZvornicaninJasmin, Nadarevic-VodencarevicAmra

    2015-04-01

    Full Text Available ABSTRACT We read with interest the article by Surekha et al. regarding the retained stone piece in anterior chamber. Similar to the results of previous studies, the authors found that delayed intraocular foreign body (IOFB management can result in good visual outcome without an apparent increased risk of endophthalmitis or other deleterious side effects. However, the authors failed to explain the exact reason for the diminution of vision in patients left eye. It is unclear what the uncorrected visual acuity was and what kind of correction was used, more precisely type and amount of cylinder, given the presence of the corneal opacity. Since the size of the IOFB is approximately 4x4x1mm, significant irido-corneal angle changes resulting in intraocular pressure raise and optic nerve head damage can be expected. Traumatic glaucoma following open globe injury can occur in 2.7 to 19% of cases, with several risk factors associated with glaucoma development (advanced age, poor visual acuity at presentation,perforating rather than penetrating ocular injury,lens injury, presence of vitreous hemorrhage and presence of an IOFB. Earlier reportsof latetraumaticoptic neuropathy onset, even after several years, indicate that this possibility cannot be completely ruled out too. Therefore, repeated intraocular pressure measurements, gonioscopy, pupillary reaction assessment, together with through posterior segment examination including visual field and optical coherence tomography examinations can be useful in determining the possible optic nerve damage as one of the possible reasons for visual acuity reduction. The authors did not suggest any operative treatment at this time. However, it should bear in mind that the inert anterior chamber IOFB could be a risk factor for non-infectious endophthalmitis development even after many years. Also, long term retained anterior chamber foreign body leads to permanent endothelial cell loss and can even result in a corneal

  13. Aging studies of CMS muon chamber prototypes

    International Nuclear Information System (INIS)

    Aging of CMS muon cathode strip chamber prototypes under sustained irradiation was studied. The tests were performed with three prototypes of different gas seal designs and with three gas mixtures Ar(30%)+CO2(50%)+CF4(20%), Ar(30%)+CO2(70%) and Ar(40%)+CO2(50%)+CF4(10%). The CF4-containing mixtures showed no or little aging for an overall accumulated charge per unit of wire length in excess of 13 C/cm. In comparison, the performance deterioration in the Ar-CO2 mixture proved to be very dramatic: the gas gain falls by a factor of 2 for each 0.25 C/cm of accumulated charge

  14. Bubble Chambers for Experiments in Nuclear Astrophysics

    CERN Document Server

    DiGiovine, B; Holt, R J; Rehm, K E; Raut, R; Robinson, A; Sonnenschein, A; Rusev, G; Tonchev, A P; Ugalde, C

    2015-01-01

    A bubble chamber has been developed to be used as an active target system for low energy nuclear astrophysics experiments. Adopting ideas from dark matter detection with superheated liquids, a detector system compatible with gamma-ray beams has been developed. This detector alleviates some of the limitations encountered in standard measurements of the minute cross sections of interest to stellar environments. While the astrophysically relevant nuclear reaction processes at hydrostatic burning temperatures are dominated by radiative captures, in this experimental scheme we measure the time-reversed processes. Such photodisintegrations allow us to compute the radiative capture cross sections when transitions to excited states of the reaction products are negligible. Due to the transformation of phase space, the photodisintegration cross sections are up to two orders of magnitude higher. The main advantage of the new target-detector system is a density several orders of magnitude higher than conventional gas tar...

  15. Foreign Body Embedded in Anterior Chamber Angle

    Directory of Open Access Journals (Sweden)

    Shmuel Graffi

    2012-01-01

    Full Text Available Introduction. We present a case of a metallic foreign body embedded in the anterior chamber angle. After standing in close proximity to a construction worker breaking a tile, a 26-year-old woman using soft contact lens for the correction of mild myopia presented to emergency department for evaluation of a foreign body sensation of her right eye. Methods and Results. Diagnosis was confirmed by gonioscopic examination and a noncontrast CT scan of head and orbits. The foreign body was removed by an external approach without utilizing a magnet. The patient's final outcome was favorable. Discussion. The above is a rare clinical situation, which is impossible to detect on slit-lamp examination without a gonioscopic view. Proper imaging and a specific management are mandatory in order to achieve favorable outcome.

  16. Construction and performance of the PHENIX pad chambers

    International Nuclear Information System (INIS)

    We present the Pad Chamber detector system in the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The three station system provides space points along each track in the spectrometer arms at mid-rapidity and covers a total area of 88 m2. Its main functions are to provide the track coordinate along the beam and to ensure reliable pattern recognition at very high particle multiplicity. A new concept for two dimensional wire chamber readout via its finely segmented cathode was developed. The full readout system, comprising 172 800 electronic channels, is described together with the challenging design of the chambers. The electronics, mounted on the outer chamber face, together with the chamber itself amounts to 1.2% of a radiation length. Results from cosmic ray tests, showing an average efficiency better than 99.5% for all chambers are presented. The experiences from the full scale operation in the first run are reported

  17. Ballistic-neutralized chamber transport of intense heavy ion beams

    International Nuclear Information System (INIS)

    Two-dimensional particle-in-cell simulations of intense heavy ion beams propagating in an inertial confinement fusion (ICF) reactor chamber are presented. The ballistic-neutralized transport scheme studied uses 4 GeV Pb+1 ion beams injected into a low-density, gas-filled reactor chamber and the beam is ballistically focused onto an ICF target before entering the chamber. Charge and current neutralization of the beam is provided by the low-density background gas. The ballistic-neutralized simulations include stripping of the beam ions as the beam traverses the chamber as well as ionization of the background plasma. In addition, a series of simulations are presented that explore the charge and current neutralization of the ion beam in an evacuated chamber. For this vacuum transport mode, neutralizing electrons are only drawn from sources near the chamber entrance

  18. Construction and performance of the PHENIX pad chambers

    Energy Technology Data Exchange (ETDEWEB)

    Adcox, K.; Ajitanand, J.; Alexander, J.; Barrette, J.; Belkin, R.; Borland, D.; Bryan, W.L.; Rietz, R. du; El Chenawi, K.; Cherlin, A.; Fellenstein, J.; Filimonov, K.; Fraenkel, Z.; Gan, D.; Garpman, S.; Gil, Y.; Greene, S.V.; Gustafsson, H.-A.; Holzmann, W.; Issah, M.; Jagadish, U.; Lacey, R.; Lauret, J.; Liccardi, W.; Mark, S.K.; Milan, J.; Miller, T.E.; Milov, A.; Mitchell, J.T.; Nilsson, P.; Nikkinen, L.; Nystrand, J.; O' Brien, E.; Oskarsson, A. E-mail: anders.oskarsson@kosufy.lu.se; Oesterman, L.; Otterlund, I.; Qi, Y.; Pasmantirer, B.; Pinkenburg, C.; Ravinovich, I.; Rosati, M.; Rose, A.; Silvermyr, D.; Sivertz, M.; Smith, M.C.; Starinsky, N.; Stenlund, E.; Teodorescu, O.; Tserruya, I.; Tydesjoe, H.; Xie, W.; Young, G.R.; Yurevich, V

    2003-02-01

    We present the Pad Chamber detector system in the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The three station system provides space points along each track in the spectrometer arms at mid-rapidity and covers a total area of 88 m{sup 2}. Its main functions are to provide the track coordinate along the beam and to ensure reliable pattern recognition at very high particle multiplicity. A new concept for two dimensional wire chamber readout via its finely segmented cathode was developed. The full readout system, comprising 172 800 electronic channels, is described together with the challenging design of the chambers. The electronics, mounted on the outer chamber face, together with the chamber itself amounts to 1.2% of a radiation length. Results from cosmic ray tests, showing an average efficiency better than 99.5% for all chambers are presented. The experiences from the full scale operation in the first run are reported.

  19. PERIODIC DYADIC GREEN'S FUNCTION FOR FIELD ANALYSIS IN EMC CHAMBER

    Institute of Scientific and Technical Information of China (English)

    Lv Feiyan; Ding Jianjin; Sha Fei

    2006-01-01

    Herein a novel Dyadic Green's Function (DGF) is presented to calculate the field in ElectroMagnetic Compatibility (EMC) chamber. Due to the difficulty of simulating the whole chamber environment, the analysis combines the DGF formulation and the FEM method, with the latter deals with the reflection from absorbers. With DGF formulation for infinite periodic array structures, this paper investigates electromagnetic field in chamber with truncated arrays. The reflection from the absorber serves as the virtual source contributing to the total field. Hence the whole chamber field calculation can be separated from the work of absorber model set-up. Practically the field homogeneity test and Normal Site Attenuation (NSA) test are carried out to evaluate the chamber performance. Based on the method in this paper, the simulation results agree well with the test, and predict successfully the victim frequency points of the chamber.

  20. Double anterior chamber in a patient with glaucoma and microspherophakia

    Directory of Open Access Journals (Sweden)

    Hamid Khakshoor

    2011-01-01

    Full Text Available We report the case of a 16-year-old woman with microspherophakia and secondary open angle glaucoma. The patient presented with a membrane dividing the anterior chamber into two segments without edema or Descemet′s membrane detachment. Slit lamp biomicroscopy, Pentacam, and specular microscopy images were obtained. Double anterior chamber is primarily found in patients with anterior chamber anomalies when there is no history of surgery or trauma.

  1. CFD Simulation Evaluation for Flow Distribution of the Closed Chamber

    OpenAIRE

    Hong Bin; Wang Hongmei

    2016-01-01

    Taking a closed chamber flow field as object, this paper establishes the 3D model of the Closed Chamber. With the conclusion of flow distribution and gasoline vapor concentration distribution of the Closed Chamber reached via the CFD software of Fluent and experiment research, this paper analyzes the flow distribution and concentration distribution of gasoline vapor. Several improvement projects are proposed, such as improving the wind circulation system to optimize the indoor gas concentrati...

  2. Construction of radon/radon daughter calibraton chamber

    International Nuclear Information System (INIS)

    The radon/radon daughter test chamber is a copper lined room 1.65x1.75x2.75m with an effective volume of 8000 litres. The air residence time is controlled by circulating the air in the chamber through absolute filters which remove 99.9% of particulates. Radon is drawn into the chamber from a 17 μCi 226RaCl source using the pressure differential across the blowers (<3 psi)

  3. Reconstruction of data in low-mass magnetostrictive chambers

    International Nuclear Information System (INIS)

    The reconstruction of spark positions in a set of low-mass spark chambers with remote magnetostrictive readout, used in a study of the reaction π-p → K0 Λ, is described. The main detectors used were optical spark chambers but in order to provide information close to the vertices low-mass magnetostrictive chambers were fitted inside the cone of the superconducting polarised target magnet. (U.K.)

  4. THERMAL RADIATION LOAD ON TEMPERATURE REGIMES IN PLANT GROWTH CHAMBERS

    OpenAIRE

    Hamasaki, T; Okada, Masumi

    2000-01-01

    In enclosed environments such as a plant growth chamber, thermal radiation plays an important role in determining heat balance and therefore the resultant temperature regimes. In artificially illuminated chambers, a significant level of thermal radiation is emitted from the lamps and/or the lamp house surface. Though there are both shortwave and longwave components in thermal radiation, our measurements in two different chamber designs, with and without thermal radiation filters, showed the l...

  5. Tests of a novel design of Resistive Plate Chambers

    International Nuclear Information System (INIS)

    A novel design of Resistive Plate Chambers (RPCs), using only a single resistive plate, is being proposed. Based on this design, two large size prototype chambers were constructed and were tested with cosmic rays and in particle beams. The tests confirmed the viability of this new approach. In addition to showing an improved single-particle response compared to the traditional 2-plate design, the novel chambers also prove to be suitable for calorimetric applications

  6. Development of Beryllium Vacuum Chamber Technology for the LHC

    CERN Document Server

    Veness, R; Dorn, C

    2011-01-01

    Beryllium is the material of choice for the beam vacuum chambers around collision points in particle colliders due to a combination of transparency to particles, high specific stiffness and compatibility with ultra-high vacuum. New requirements for these chambers in the LHC experiments have driven the development of new methods for the manufacture of beryllium chambers. This paper reviews the requirements for experimental vacuum chambers. It describes the new beryllium technology adopted for the LHC and experience gained in the manufacture and installation.

  7. Numerical solutions of differential equations of an ionization chamber

    International Nuclear Information System (INIS)

    A system of reduced differential equations generally valid for plane-parallel, cylindrical, and spherical ionization chambers filled with air, which is appropriate for numerical solution, has been derived. The system has been solved for all three geometries. The comparison of the calculated results of Armstrong and Tate, for plane-parallel ionization chambers, and Sprinkle and Tate, for spherical ionization chambers, with the present calculations has shown a good agreement. The calculated values for ionization chambers filled with CO2 were also in good agreement with the experimental data of Moriuchi et al (author)

  8. Shock tubes: compressions in the low pressure chamber

    International Nuclear Information System (INIS)

    The gas shock tube used in these experiments consists of a low pressure chamber and a high pressure chamber, divided by a metal-diaphragm-to-rupture. In contrast to the shock mode of operation, where incident and reflected shocks in the low pressure chamber are studied which occur within 3.5 ms, in this work the compression mode of operation was studied, whose maxima occur (in the low pressure chamber) about 9 ms after rupture. Theoretical analysis was done with the finite element computer code EURDYN-1M, where the computation was carried out to 30 ms

  9. Procurement specification high vacuum test chamber and pumping system

    International Nuclear Information System (INIS)

    The specification establishes requirements for a high-vacuum test chamber, associated vacuum pumps, valves, controls, and instrumentation that shall be designed and fabricated for use as a test chamber for testing a closed loop Brayton Isotope Power System (BIPS) Ground Demonstration System (GDS). The vacuum system shall include all instrumentation required for pressure measurement and control of the vacuum pumping system. A general outline of the BIPS-GDS in the vacuum chamber and the preliminary piping and instrumentation interface to the vacuum chamber are shown

  10. Procurement specification high vacuum test chamber and pumping system

    Energy Technology Data Exchange (ETDEWEB)

    Cormick, J. E.

    1976-05-31

    The specification establishes requirements for a high-vacuum test chamber, associated vacuum pumps, valves, controls, and instrumentation that shall be designed and fabricated for use as a test chamber for testing a closed loop Brayton Isotope Power System (BIPS) Ground Demonstration System (GDS). The vacuum system shall include all instrumentation required for pressure measurement and control of the vacuum pumping system. A general outline of the BIPS-GDS in the vacuum chamber and the preliminary piping and instrumentation interface to the vacuum chamber are shown.

  11. Vacuum Chamber for the Measurement System of the Beam Energy

    Science.gov (United States)

    Abakumova, E.; Achasov, M.; Dong, HaiYi; Qu, HuaMin; Krasnov, A.; Kosarev, A.; Muchnoi, N.; Pyata, E.; Xiao, Qiong; Mo, XiaoHu; Wang, YiFang; Zhukov, A.

    Vacuum chamber for the beam energy measurement system based on the Compton backscattering method is presented. The main elements of the chamber are GaAs entrance viewport and a copper mirror. The viewport design provides baking out of the vacuum chamber up to 250 °C. To produce the viewport, an original technology based on brazing GaAs plate by lead has been developed. The vacuum chambers were installed at the BEPC-II and VEPP-4 M colliders. After installation the residual gas pressure is about 10-10 Torr.

  12. Propagation of the trip behavior in the VENUS vertex chamber

    International Nuclear Information System (INIS)

    The high voltage system of the VENUS vertex chamber occasionally trips by a discharge somewhere among cathode electrodes during data taking. This trip behavior induces often additional trips at other electrodes such as the skin and the grid electrodes in the vertex chamber. This propagation mechanism of trips is so complicated in this system related with multi-electrodes. Although the vertex chamber is already installed inside the VENUS detector and consequently the discharge is not able to observe directly, a trial to estimate the propagation has been done using only the information which appears around the trip circuits and the power supply of the vertex chamber. (author)

  13. Laboratory implantation for well type ionization chambers calibration

    International Nuclear Information System (INIS)

    The Radiological Science Laboratory is implanting a service for calibration of well type chambers by IAEA training program. The kerma rate in the air (mu Gy/h) of the linear Cs-137 reference source CDCS-J4 have been determined using a well type chamber Standard Imaging HDR-1000 model, which have been calibrated at Secondary Standard Laboratory Calibration of IAEA, whereas two HDR-1000 Plus chambers were calibrated too, following the same standards. The results were compared with Wisconsin University calibration certification and has demonstrated that well type ionization chamber calibration can be used in brachytherapy for several kinds of radionuclides. (Author)

  14. Explosive Containment Chamber Vulnerability to Chemical Munition Fragment Impact

    Energy Technology Data Exchange (ETDEWEB)

    Benham, R.A.; Fischer, S.H.; Kipp, M.E.; Martinez, R.R.

    1999-02-01

    Scenarios in which the explosive burster charge in a chemical munition accidentally detonates inside demilitarization containment chambers are analyzed. The vulnerability of an inner Auxiliary Pressure Vessel and the primary Explosive Containment Chamber to impact by fragments from the largest explosive charge expected to be placed in these chambers (M426, 8 inch, chemical, 7 lbs Comp B) is evaluated. Numerical (CTH) and empirical (ConWep) codes are used to characterize the munition fragments, and assess the consequences of their impact and penetration on the walls of these vessels. Both pristine and corroded configurations of the munition have been considered, with and without liquid agent fill. When the munition burster charge detonates, munition case fragments impact and perforate the Auxiliary Pressure Vessel wall, resulting in extensive breakup of this inner chamber and the formation of additional fragments. These residual munition case and Auxiliary Pressure Vessel fragments have sufficient mass and velocity to crater the Explosive Containment Chamber inner wall layer, with accompanying localized permanent deformation (bulging) of both the inner and outer chamber walls. The integrity of the Explosive Containment Chamber was retained under all of the APV / munition configurations considered in this study, with no evidence that primary (munition) or secondary (munition and Auxiliary Pressure Vessel) fragments will perforate the inner chamber wall. Limited analyses of munition detonation without the Auxiliary Pressure Vessel present indicate that some munition span fragments could form under those conditions that have sufficient mass and velocity to perforate the inner wall of the Explosive Containment Chamber.

  15. Radiation Target Area Sample Environmental Chamber (RTASEC) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Payload Systems Inc. proposes the Radiation Target Area Sample Environmental Chamber (RTASEC) as an innovative approach enabling radiobiologists to investigate the...

  16. Development of Master Chamber Software for Data Acquisition of Ionization Chamber for Indus 2 RRCAT

    Directory of Open Access Journals (Sweden)

    Priyesh Soni

    2013-02-01

    Full Text Available The main goal of this paper was to Develop Master control software for DAQ of ionization chamber for INDUS-2 beam lines for detection of X-ray flux by an Ionization chamber that will remotely control and monitor the ultra low current signal detection analog module precisely. This application will be useful to measure the intensity of X-ray flux through ionization chamber in a beam line of synchrotron radiation source which is mounted in INDUS-2. It is one of new technique of detection. Beam line area is highly restricted because of hazardous radiation, so through this application remote interfacing is provided for the ultra low current signal detection card that can be controlled by Master software. The development of such type arrangement we used software in C#.NET there are many issues like develop code, Design forms, to achieve the specified response from the CPU card, code developed in C# .NET. Initially, I explored and gained the knowledge of C#.NET. I practices some small modular projects as part to learn how the system works. I used programming language C#.NET architecture version 3.5 in Visual Studio 2008

  17. Quantifying the "chamber effect" in CO2 flux measurements

    Science.gov (United States)

    Vihermaa, Leena; Childs, Amy; Long, Hazel; Waldron, Susan

    2014-05-01

    The significance of aquatic CO2 emissions has received attention in recent years. For example annual aquatic emissions in the Amazon basin have been estimated as 500 Mt of carbon1. Methods for determining the flux rates include eddy covariance flux tower measurements, flux estimates calculated from partial pressure of CO2 (pCO2) in water and the use floating flux chambers connected to an infra-red gas analyser. The flux chamber method is often used because it is portable, cheaper and allows smaller scale measurements. It is also a direct method and hence avoids problems related to the estimation of the gas transfer coefficient that is required when fluxes are calculated from pCO2. However, the use of a floating chamber may influence the flux measurements obtained. The chamber shields the water underneath from effects of wind which could lead to lower flux estimates. Wind increases the flux rate by i) causing waves which increase the surface area for efflux, and ii) removing CO2 build up above the water surface, hence maintaining a higher concentration gradient. Many floating chambers have an underwater extension of the chamber below the float to ensure better seal to water surface and to prevent any ingress of atmospheric air when waves rock the chamber. This extension may cause additional turbulence in flowing water and hence lead to overestimation of flux rates. Some groups have also used a small fan in the chamber headspace to ensure thorough mixing of air in the chamber. This may create turbulence inside the chamber which could increase the flux rate. Here we present results on the effects of different chamber designs on the detected flux rates. 1Richey et al. 2002. Outgassing from Amazonian rivers and wetlands as a large tropical source of atmospheric CO2. Nature 416: 617-620.

  18. ALICE Time Projection Chamber (TPC) Readout Sector in Lab

    CERN Multimedia

    2003-01-01

    The Time Projection Chamber (TPC) is the main particle tracking detector in ALICE. Charged particles crossing the gas of the TPC knock electrons out of their atoms, which drift in the eletric field. By measuring the arrival of electrons at the end of the chamber, at segments such as the one shown here, the TPC will reconstruct the paths of the original charged particles.

  19. Monte Carlo Simulation Optimizing Design of Grid Ionization Chamber

    Institute of Scientific and Technical Information of China (English)

    ZHENG; Yu-lai; WANG; Qiang; YANG; Lu

    2013-01-01

    The grid ionization chamber detector is often used for measuring charged particles.Based on Monte Carlo simulation method,the energy loss distribution and electron ion pairs of alpha particle with different energy have been calculated to determine suitable filling gas in the ionization chamber filled with

  20. Mycocardial perfusion scintigraphy using a new technique, the mesh chamber

    International Nuclear Information System (INIS)

    The 10cm x 10cm chamber has been used in conjunction with a new reconstruction algorithm. Ongoing investigations are testing system performance, including three-dimensional resolution and contrast ratio for various objects. The chambers have had some reliability problems. 30 references, 7 figures

  1. Damage Diagnosis for High Temperature Coke-oven Chamber Walls

    Science.gov (United States)

    Sugiura, Masato; Sakaida, Michitaka; Fujikake, Yohichi; Irie, Keisuke

    Metallurgical coke is needed as reducing reagent and energy source in blast furnaces. Most of coke ovens in Japan have been working over 30 years and have become gradually decrepit. A coke oven consists of many coking chambers, and each chamber is 6 m high, 16 m long and 0.4m wide. Uneven damage at the chamber-wall surface such as brick erosion and carbon deposition disturbs production because the coke is pushed horizontally when discharged from the chamber. To diagnose the chamber wall which is constantly sustained at a high temperature, we have developed a water-cooling heat-resistance probe. Line scan cameras mounted in the probe obtain thermal images of the entire chamber-wall surfaces with high resolution. In addition, to measure topographical information of the wall, a laser light-section method combined with line-scan-camera imaging has been considered. It is emphasized that the diagnosis probe works under enormously severe conditions, such as at a temperature of over 1000°C and inside a width of only 0.4m. Clarifying the appearance of chamber-wall damages in operating aged coke ovens, we proposed the index relating unevenness of a chamber-wall surface to pushing load. The index is utilized for the guidance enabling effective repairs of damaged oven walls.

  2. Cataract Surgery in Eyes with Shallow Anterior Chamber

    OpenAIRE

    Hüseyin Bayramlar; Remzi Karadağ; Ünsal Sarı

    2014-01-01

    Shallow anterior chamber may be encountered in an eye planned for cataract surgery as well as during phacoemulsification. In both situations, cataract surgery is a challenging case. In this article, we tried to review the situations and management of shallow anterior chamber in cataract surgery. (Turk J Ophthalmol 2014; 44: 388-91

  3. Cataract Surgery in Eyes with Shallow Anterior Chamber

    Directory of Open Access Journals (Sweden)

    Hüseyin Bayramlar

    2014-10-01

    Full Text Available Shallow anterior chamber may be encountered in an eye planned for cataract surgery as well as during phacoemulsification. In both situations, cataract surgery is a challenging case. In this article, we tried to review the situations and management of shallow anterior chamber in cataract surgery. (Turk J Ophthalmol 2014; 44: 388-91

  4. Application of virtual instrument in radon chamber temperature monitor system

    International Nuclear Information System (INIS)

    Application of virtual instrument in radon chamber temperature monitor system is studied. Taking a kind of radon chamber temperature signal acquisition interface device based on micro-controller as example, application software is developed on virtual instrument platform LabVIEW. Full and accurate diagram block and virtual instrument panel are given. (authors)

  5. Characterisation of an ionization chamber of the radioisotope metrology laboratory

    International Nuclear Information System (INIS)

    The sensitivity as a function of the photon energy up to 1.9 MeV has been studied for a special ionization chamber (50 cm length, stainless steel, high pressure Ar). The response of the chamber to 16 of the most frequently used radionuclides has been also determined. (author)

  6. Construction of a drift chamber prototype for the CMS experiment

    International Nuclear Information System (INIS)

    General design features of a small size drift chamber prototype are described in this report. Prototype construction has taken place at CIEMAT and we explain in detail the assembly procedure. This activity is part of a long term project to mass produce chambers for the muon barrel detector of the CMS experiment which will be installed at CERN. (Author)

  7. Multi-step avalanche chambers for FNAL experiment E605

    International Nuclear Information System (INIS)

    Physical processes in multi-step avalanche chambers, detector properties, and difficulties in operation are discussed. Advantages of multi-step chambers over classical MWPC for specific experimental problems encountered in experiment E605 (high-flux environment and CERENKOV imaging) are described. Some details of detector design are presented

  8. Anterior chamber cholesterolosis in a patient with retinoblastoma.

    Science.gov (United States)

    Hong, Bryan K; Say, Emil Anthony T; Chévez-Barrios, Patricia; Lee, Thomas C; Kim, Jonathan W

    2016-01-01

    Anterior chamber cholesterolosis is a rare phenomenon typically associated with non-neoplastic conditions such as hyphema or Coats disease; it has never been reported to be associated with intraocular malignancy. We report a case of anterior chamber cholesterolosis presenting in the setting of retinoblastoma and discuss clinical features relevant for its differentiation from Coats disease. PMID:27330481

  9. The muon chambers take centre stage at CMS

    CERN Multimedia

    2003-01-01

    The CMS muon chambers are now starting to arrive at CERN in significant numbers. All in all, the muon system of the CMS detector will comprise some 1400 of these chambers. Twenty percent of those for the endcaps have already been installed, while the assembly of those for the barrel will start in December.

  10. Performance test of a triple GEM chamber with Cosmics

    International Nuclear Information System (INIS)

    In this paper, the response of the detector to the cosmic muons is reported and the efficiency of charged particle detection of the chamber at different GEM voltages is estimated . This study would help in optimizing the operating conditions of the triple GEM chamber

  11. A cylindrical drift chamber with azimuthal and axial position readout

    International Nuclear Information System (INIS)

    A cylindrical multiwire drift chamber with axial charge-division has been constructed and used in experiment E852 at Brookhaven National Laboratory. It serves as a trigger element and as a tracking device for recoil protons in π-p interactions. We describe the chamber's design considerations, details of its construction, electronics, and performance characteristics. (orig.)

  12. Dynamic chamber armor behavior in IFE and MFE

    International Nuclear Information System (INIS)

    The chamber wall armor is subject to demanding conditions in both inertial fusion energy (IFE) and magnetic fusion energy (MFE) chambers. This paper assesses the requirements on armor imposed by the operating conditions in IFE and MFE, including energy deposition density, time of deposition and frequencies, and discusses their impact on the performance of the candidate armor materials

  13. Influence of chamber misalignment on cased telescoped (CT ammunition accuracy

    Directory of Open Access Journals (Sweden)

    D. Corriveau

    2016-04-01

    Full Text Available As part of a research program, it was desired to better understand the impact of the rotating chamber alignment with the barrel throat on the precision and accuracy of a novel cased telescoped (CT ammunition firing rifle. In order to perform the study, a baseline CT ammunition chamber which was concentric with a Mann barrel bore was manufactured. Additionally, six chambers were manufactured with an offset relative to the barrel bore. These chambers were used to simulate a misaligned chamber relative to the bore axis. Precision and accuracy tests were then performed at 200 m in an indoor range under controlled conditions. For this project, 5.56 mm CT ammunition was used. As the chamber axis offset relative to the gun bore was increased, the mean point of impact was displaced away from the target center. The shift in the impact location is explained by the presence of in-bore yaw which results in lateral throw-off and aerodynamic jump components. The linear theory of ballistics is used to establish a relationship between the chamber misalignment and the resulting projectile mean point of impact for a rifle developed to fire CT ammunition. This relationship allows for the prediction of the mean point of impact given a chamber misalignment.

  14. Description and calibration beamline SEM/Ion Chamber Current Digitizer

    International Nuclear Information System (INIS)

    This report discusses the following on beamline SEM/ion chamber current digitizers: Module description; testing and calibration; common setup procedures; summary of fault indications and associated causes; summary of input and output connections; SEM conversion constant table; ion chamber conversion constant table; hexadecimal to decimal conversion table; and schematic diagram

  15. 78 FR 76750 - Drawbridge Operation Regulation; Chambers Creek, Steilacoom, WA

    Science.gov (United States)

    2013-12-19

    ...The Coast Guard has issued a temporary deviation from the operating schedule that governs the Burlington Northern Santa Fe (BNSF) Chambers Creek Railway Bridge across Chambers Creek, mile 0.0, at Steilacoom, WA. The deviation is necessary to allow BNSF to perform maintenance and upgrade items to this vertical lift bridge in support of Positive Train Control requirements per the Rail Safety......

  16. Application of Chaboche Model in Rocket Thrust Chamber Analysis

    Science.gov (United States)

    Asraff, Ahmedul Kabir; Suresh Babu, Sheela; Babu, Aneena; Eapen, Reeba

    2015-12-01

    Liquid Propellant Rocket Engines are commonly used in space technology. Thrust chamber is one of the most important subsystems of a rocket engine. The thrust chamber generates propulsive thrust force for flight of the rocket by ejection of combustion products at supersonic speeds. Often double walled construction is employed for these chambers. The thrust chamber investigated here has its hot inner wall fabricated out of a high thermal conductive material like copper alloy and outer wall made of stainless steel. Inner wall is subjected to high thermal and pressure loads during operation of engine due to which it will be in the plastic regime. Main reasons for the failure of such chambers are fatigue in the plastic range (called as low cycle fatigue since the number of cycles to failure will be low in plastic range), creep and thermal ratcheting. Elasto plastic material models are required to simulate the above effects through a cyclic stress analysis. This paper gives the details of cyclic stress analysis carried out for the thrust chamber using different plasticity model combinations available in ANSYS (Version 15) FE code. The best model among the above is applied in the cyclic stress analysis of two dimensional (plane strain and axisymmetric) and three dimensional finite element models of thrust chamber. Cyclic life of the chamber is calculated from stress-strain graph obtained from above analyses.

  17. The electronics readout system for the OPAL Vertex Drift Chamber

    International Nuclear Information System (INIS)

    The Vertex Drift Chamber for the OPAL experiment at LEP provides high quality track co-ordinates using multi-hit sub-nanosecond timing to detect the drifted electrons. This paper explains the electronic techniques that have been devised and implemented for the detector. The overall performance of the system is demonstrated with measurements from the final OPAL chamber. (author)

  18. Some Features of Aerodynamics of Cyclonic Chamber with Free Exit

    Directory of Open Access Journals (Sweden)

    A. N. Orekhov

    2014-06-01

    Full Text Available The paper cites results of an experimental research in aerodynamics of a cyclonic chamber with a free exit that has a large relative length. Distributions of aerodynamic stream characteristics depending on geometry of working volume of the cyclonic chamber are given in the paper. Calculative dependences are proposed in the paper.

  19. A compact gas ionization chamber for VERA

    International Nuclear Information System (INIS)

    Full text: The increasing demand for measuring long-lived radionuclides with small AMS machines at energies below 1 MeV per nucleon raises the need for compact detectors which still have a decent energy resolution and allow for a clear identification of the incident particles. Based on a design by the AMS group at the ETH Zurich a compact gas ionization chamber was built and installed at the VERA 3 MV AMS facility. Due to its compact design, the detector easily fits into a DN100 cross-piece and can be inserted and retracted without breaking the vacuum. The anode is split into two active regions which allows the simultaneous measurement of ΔE and ERES. An identification of the incident particles is therefore possible via their different stopping powers. For the entrance window silicon nitride foils are used. These foils are remarkably homogeneous and can be obtained pinhole-free with thicknesses down to 50 nm. In this work the setup of the detector together with the results of first measurements of the previously difficult to measure AMS-relevant radionuclides 10Be, 36Cl and 41Ca will be presented. (author)

  20. Dosimetry of Cobalt 60 Gamma Chamber

    Directory of Open Access Journals (Sweden)

    S.N. Upadhyay

    1999-07-01

    Full Text Available Ferrous sulphate-benzoic acid-xylen(tl orange (FBX dosimetric system is linear in the range fl|0m 0.01 Gy to 10 Gy and can be used in the case of a nuclear accident, for documenting clinical doses in total-body irradiations in radiation therapy as well as for measuring daily radiation dose during external beam therapy because of its tissue-equivallency. FBX system is stable up to 15 days in the range 15 - 60 degree centigrade. It is independent of photon energy up to 3 ke V and is fairly dose rate in dependent in the range from 0.01 to 2.5 Gy/min. Besides its use in radiation therapy, external beam therapy and nuclear accidents, the present study shows that this dosimeter can be effectively used for determining positional variation inside the gamma chamber. This has been detected by placing dosimetric solutions in small bottles kept in two racks of the phantom in a symmetrical fashion. Average variations in two tracks were found to be 2.74 per cent, 0.33 per cent, 4 per cent and 4.83 per cent.

  1. OPERA Resistive Plate Chambers underground test results

    Energy Technology Data Exchange (ETDEWEB)

    Bergnoli, A. [Padova University and INFN, Padova (Italy); Brugnera, R. [Padova University and INFN, Padova (Italy); Candela, A. [INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Carrara, E. [Padova University and INFN, Padova (Italy); Ciesielski, R. [Padova University and INFN, Padova (Italy); Dal Corso, F. [Padova University and INFN, Padova (Italy); Degli Esposti, L. [Bologna University and INFN, Bologna (Italy); Di Giovanni, A. [INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); D' Incecco, M. [INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Di Troia, C. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Dusini, S. [Padova University and INFN, Padova (Italy); Fanin, C. [Padova University and INFN, Padova (Italy); Felici, G. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Gambarara, A. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Garfagnini, A. [Padova University and INFN, Padova (Italy); Gatta, M.; Grianti, F. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Gustavino, C.; Lindozzi, M. [INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Longhin, A. [Padova University and INFN, Padova (Italy)]. E-mail: longhin@pd.infn.it; Mengucci, A. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Monacelli, P. [L' Aquila University and INFN, l' Aquila (Italy)]|[INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Paoloni, A. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Stanco, L. [Padova University and INFN, Padova (Italy); Tatananni, E. [INFN Laboratori Nazionali del Gran Sasso, Assergi (Italy); Terranova, F.; Spinetti, M. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Stipcevic, M.; Sugonyaev, V. [Rudjer Boskovic Institute (IRB), Zagreb (Croatia); Terminiello, L.; Ventura, M.; Votano, L. [INFN Laboratori Nazionali di Frascati, Frascati (Italy)

    2006-08-15

    The OPERA experiment [M. Guler et al., CERN/SPSC 2000-028, SPSC/P318, LNGS P25/2000, July 10, 2000; M. Guler et al., CERN/SPSC 2001-025, SPSC/M668, LNGS-EXP 30/2001 Add. 1/01, August 21, 2001] will study {nu}{sub {mu}}->{nu}{sub {tau}} oscillations through {tau} appearance on the 732 Km long CERN to Gran Sasso baseline. The magnet yokes of the two muon spectrometers are instrumented with 44 layers of high resistivity bakelite Resistive Plate Chambers (RPCs) operated in streamer mode. Each layer covers about 70 m{sup 2}. Four RPC planes were instrumented and the first tests were performed confirming a good behaviour of the installed RPCs in terms of intrinsic noise and operating currents. The measured noise maps agree with those obtained in the extensive quality tests performed at surface. Counting rates are below 20 Hz/m{sup 2}. Single an multiple cosmic muon tracks were also reconstructed. The estimated efficiency is close to the geometrical limit and the very first measurements of the absolute and differential muon flux are in agreement with expectations.

  2. OPERA Resistive Plate Chambers underground test results

    International Nuclear Information System (INIS)

    The OPERA experiment [M. Guler et al., CERN/SPSC 2000-028, SPSC/P318, LNGS P25/2000, July 10, 2000; M. Guler et al., CERN/SPSC 2001-025, SPSC/M668, LNGS-EXP 30/2001 Add. 1/01, August 21, 2001] will study νμ->ντ oscillations through τ appearance on the 732 Km long CERN to Gran Sasso baseline. The magnet yokes of the two muon spectrometers are instrumented with 44 layers of high resistivity bakelite Resistive Plate Chambers (RPCs) operated in streamer mode. Each layer covers about 70 m2. Four RPC planes were instrumented and the first tests were performed confirming a good behaviour of the installed RPCs in terms of intrinsic noise and operating currents. The measured noise maps agree with those obtained in the extensive quality tests performed at surface. Counting rates are below 20 Hz/m2. Single an multiple cosmic muon tracks were also reconstructed. The estimated efficiency is close to the geometrical limit and the very first measurements of the absolute and differential muon flux are in agreement with expectations

  3. Resistive plate chambers in positron emission tomography

    Science.gov (United States)

    Crespo, Paulo; Blanco, Alberto; Couceiro, Miguel; Ferreira, Nuno C.; Lopes, Luís; Martins, Paulo; Ferreira Marques, Rui; Fonte, Paulo

    2013-07-01

    Resistive plate chambers (RPC) were originally deployed for high energy physics. Realizing how their properties match the needs of nuclear medicine, a LIP team proposed applying RPCs to both preclinical and clinical positron emission tomography (RPC-PET). We show a large-area RPC-PET simulated scanner covering an axial length of 2.4m —slightly superior to the height of the human body— allowing for whole-body, single-bed RPC-PET acquisitions. Simulations following NEMA (National Electrical Manufacturers Association, USA) protocols yield a system sensitivity at least one order of magnitude larger than present-day, commercial PET systems. Reconstruction of whole-body simulated data is feasible by using a dedicated, direct time-of-flight-based algorithm implemented onto an ordered subsets estimation maximization parallelized strategy. Whole-body RPC-PET patient images following the injection of only 2mCi of 18-fluorodesoxyglucose (FDG) are expected to be ready 7 minutes after the 6 minutes necessary for data acquisition. This compares to the 10-20mCi FDG presently injected for a PET scan, and to the uncomfortable 20-30minutes necessary for its data acquisition. In the preclinical field, two fully instrumented detector heads have been assembled aiming at a four-head-based, small-animal RPC-PET system. Images of a disk-shaped and a needle-like 22Na source show unprecedented sub-millimeter spatial resolution.

  4. Detector Physics of Resistive Plate Chambers

    CERN Document Server

    Lippmann, Christian; Riegler, W

    2003-01-01

    Resistive Plate Chambers (RPCs) are gaseous parallel plate avalanche detectors that implement electrodes made from a material with a high volume resistivity between 10^7 and 10^12 Ohm cm. Large area RPCs with 2mm single gaps operated in avalanche mode provide above 98% efficiency and a time resolution of around 1ns up to a flux of several kHz/cm2. These Trigger RPCs will, as an example, equip the muon detector system of the ATLAS experiment at CERN on an area of 3650m2 and with 355.000 independent read out channels. Timing RPCs with a gas gap of 0.2 to 0.3mm are widely used in multi gap configurations and provide 99% efficiency and time resolution down to 50ps. While their performance is comparable to existing scintillator-based Time-Of-Flight (TOF) technology, Timing RPCs feature a significantly, up to an order of magnitude, lower price per channel. They will for example equip the 176m2 TOF barrel of the ALICE experiment at CERN with 160.000 independent read out cells. RPCs were originally operated in stream...

  5. Data acquisition system for a deuteration chamber

    International Nuclear Information System (INIS)

    The work present is focusing auxiliary in the experiment the reaction of fusion in cold in the laboratory of Physical of Plasmas of Instituto Nacional de Investigaciones Nucleares. These systems of acquisition of data concrete to register in line surface of pressure and temperature in the gap of 5.6 x 10-4 to 1 x 103 and -270 to 1300 Centigrade degrees with help of personal computer. The manner of purchase in chamber of Deuterium is per middle of thermocouple with the object of whereas any control of the temperature in different point in the some of manner the signal of in for the system is the thermocouple (milli volts), the conversion analogy a digital is mean of Cad of 12 bits rate double slope the out is mean the PPI to send the signal to P C of these manner the read of the thermocouples is translate graphic or digital in the screen of the P C. In the phase of pressure element sensor is measure type Pirani, the measure is of manner of temperature. (Author)

  6. Radiofrequency spark chambers and delay line resonators

    International Nuclear Information System (INIS)

    According to a suggestion of A. Kastler, a spark chamber was excited by an undamped radiofrequency pulse and tracks about 1 mm wide obtained; the result was interpreted by computation of the coefficients of electronic amplification and partial ambipolar diffusion. This work led us to the construction of a new fast triggering undamped wave-train generator of very high tension (patent taken out by the C.E.A. under the no.: EN 7 134 650 the 27.9.1971). Since this apparatus uses a resonant storage line, its design implied a precise knowledge of high impedance delay lines. The experimental radiofrequency spectra of the input impedance of opened or short-circuited lines were plotted completely and analysed by the circuits theory, new measuring methods were established, dispersion relations accurately checked and the equivalence of the formulas, within the third order, with theses of Debye's Dipolar Absorption demonstrated. General properties of Hilbert's transform were also investigated. From the experimental point of view, the electromagnetic energy storage process was extended to the case of a liquid nitrogen-immersed resonant delay line. The good behavior of the cryogenic experiment, where the main difficulty of icing was overcame by the construction of special electrodes, offers great promise for extrapolation to superconductivity. (author)

  7. Pseudoexfoliation material on posterior chamber intraocular lenses

    Directory of Open Access Journals (Sweden)

    Rocha-Bastos RA

    2014-08-01

    Full Text Available Ricardo António da Rocha-Bastos,1 Sérgio Estrela Silva,1 Flávio Prézia,1 Fernando Falcão-Reis,1,2 António B Melo11Department of Ophthalmology, Hospital São João, Alameda Prof Hernâni Monteiro, Porto, Portugal; 2Department of Sense Organs, Faculty of Medicine, University of Porto, Alameda Prof Hernâni Monteiro, Porto, PortugalAbstract: The presence of pseudoexfoliation material on the surface of an intraocular lens (IOL is a rare finding. We report a series of seven cases with different patterns of pseudoexfoliation material deposition on the posterior chamber IOLs, recognized 2–20 years after cataract surgery. Six patients had an IOL implanted in the capsular bag and one in the ciliary sulcus. Two patients had undergone posterior capsulotomy. Although the pathophysiological mechanisms and clinical significance of this finding remain unknown, the careful follow-up of pseudophakic patients with known or suspected pseudoexfoliation syndrome is essential to monitor the development or progression of glaucoma, since deposition of pseudoexfoliation material continues even after cataract surgery.Keywords: intraocular lens, glaucoma, exfoliation syndrome, cataract

  8. Monolithic JFET preamplifier for ionization chamber calorimeters

    International Nuclear Information System (INIS)

    A prototype preamplifier circuit is presented for use in SSC ionization chamber calorimeters. It consists of a new type of silicon integrated circuit comprised of very low noise junction FET (JFET) components. Presently, monolithic preamplifier circuits for use in highly segmented detectors are made of implanted channel JFETs or MOS devices. While such circuits solve the density problems, they do not perform to the same level of low noise characteristics as found in discrete JFET components. The JFETs which comprise this new integrated circuit preserve the excellent low noise performance normally found only in discrete JFETs. JFETs also are much more radiation resistant and less prone to damage by electromagnetic discharges than MOS transistors. Two innovative fabrication processes are discussed. They solve the difficult gate-to-gate isolation problem needed to manufacture JFET integrated circuits. Both allow the use of an epitaxially formed channel and a diffused gate, as in standard discrete JFET processing. This, presumably, results in JFETs which exhibit lower noise than those made with implanted channels. 11 refs., 9 figs

  9. Performance of large area Micro Pixel Chamber

    CERN Document Server

    Nagayoshi, T; Miuchi, K; Ochi, A; Orito, R; Takada, A; Tanimori, T; Ueno, M

    2003-01-01

    A novel gaseous two-dimensional imaging detector "Micro Pixel Chamber (micro-PIC)" has been developed. This detector is based on double sided printed circuit board (PCB). We have developed large area (10cm x 10cm) micro-PICs with 65536 pixel anodes of 400um pitch on a 100um thick insulating substrate. Achieved energy resolution was 30% (FWHM) at 5.9keV, and a gas gain of 7000 was obtained with argon ethane (8:2) gas mixture. This gain is high enough to detect minimum ionizing particles with such a small electrode pitch. Although several discharges occurred during 65 hours continuous operation, the detectors have kept stable operation with high gain. The micro-PIC is a useful detector for many applications e.g. X-ray, gamma ray, and charged particle imaging. The micro electrode structure allows us to measure directions of primary electrons due to incident X-rays or gamma rays, which provide a strong method for X-ray polarimetry and gamma-ray imaging.

  10. Chemistry of radiation damage to wire chambers

    International Nuclear Information System (INIS)

    Proportional counters are used to study aspects of radiation damage to wire chambers (wire aging). Principles of low-pressure, rf plasma chemistry are used to predict the plasma chemistry in electron avalanches (1 atm, dc). (1) Aging is studied in CF4/iC4H10 gas mixtures. Wire deposits are analyzed by Auger electron spectroscopy. An apparent cathode aging process resulting in loss of gain rather than in a self-sustained current is observed in CF4-rich gases. A four-part model considering plasma polymerization of the hydrocarbon, etching of wire deposits by CF4, acceleration of deposition processes in strongly etching environments, and reactivity of the wire surface is developed to understand anode wire aging in CF4/iC4H10 gases. Practical guidelines suggested by the model are discussed. (2) Data are presented to suggest that trace amounts of Freons do not affect aging rates in either dimethyl ether or Ar/C2H6. Apparent loss of gain is explained by attachment of primary electrons to a continuously increasing concentration of Freon 11 (CCl3F) in the counter gas. An increase in the concentration of Freon 11 in dimethyl ether is caused by a distillation process in the gas supply bottle and is a natural consequence of the unequal volatilities of the two compounds

  11. A Proportional Wire Chamber Array: GRAND's Status

    CERN Document Server

    Poirier, J; Puerto, M L; Strahler, E A; Vermedahl, J

    2003-01-01

    Project GRAND is a 100m x 100m air shower array of position sensitive proportional wire chambers (PWCs) located at 41.7 degrees North and 86.2 degrees West at an elevation of 220m above sea level. Its convenient location adjacent to the campus of the University of Notre Dame makes it a good training ground for students. There are 64 stations each with eight 1.29 m^2 PWCs. The geometry of the stations allows for the angles of charged secondaries to be determined to within 0.26 degrees in each of two orthogonal planes; muons are differentiated from electrons and hadrons by means of a steel plate. Two triggers are run simultaneously: a multiple hit coincidence trigger, rich in extensive air showers, and a single track trigger, rich in secondary muon tracks. The former trigger is sensitive to primary energies greater than ~100 TeV, the latter to energies greater than ~10 GeV.

  12. Performance of ionization chambers in X radiation beams, radioprotection level

    International Nuclear Information System (INIS)

    Narrow beams, radioprotection level, were implanted in an X ray system, based on ISO 4037-1, as recommended by IAEA (SRS 16). Energy dependency tests were carried out and short-term stability in ionization chambers for use in radiation protection of trademark Physikalisch-Technische Werkstaetten (PTW), 32002 and 23361 models. The ionization chambers were studied with regard to short-term stability within the program of quality control of the laboratory, with a 90Sr + 90Y. The results of the short-term stability test were compared with the recommendations of IEC 60731, respect to dosemeters used in radiotherapy, since this standard presents the more restrictive limits with regard to the behaviour of ionization chambers. All cameras showed results within the limits recommended by this standard. With respect to the energy dependency of the response, the model Chamber 32002 presented a maximum dependence of only 2.7%, and the model Chamber 23361, 4.5%

  13. Limited streamer chamber testing and quality evaluation in ASTRA

    International Nuclear Information System (INIS)

    Limited streamer chambers are extensively used for high-energy and nuclear physics experiments in accelerator and underground laboratories. The tracking system of LVD, an underground experiment to study muons and nutrino astronomy, will use roughly 15000 limited streamer chambers and 100000 external pickup strips with digital readout electronics. In the article the different aspects of chamber operation that serve to establish a testing procedure and to define acceptance criteria for selecting reliable and long-life devices, are discussed. The procedures and the results obtained from a long-term test to evaluate streamer chamber quality, based upon a sample of 2900 items, are described. The selection tests and the long-term observations have been performed in the ASTRA laboratory, established at the Laboratori Nazionali di Frascati to carry out quality control procedures for streamer chambers on a large scale and in a controlled environment

  14. He leak testing of Indus-2 dipole vacuum chambers

    International Nuclear Information System (INIS)

    Full text: Centre for Advanced Technology is developing its second synchrotron radiation source INDUS-2 which is a 2.5 GeV electron storage ring. Dipole vacuum chambers are the vital components of Indus-2 vacuum system. Each of these chambers is approx. 3.6 m long and 0.67 m wide with 24 nos. of ports of various sizes. The dipole chambers were made by machining two halves and they are then lip welded together. The dipole chamber has approx. 14 m of total weld length and it was leak tested for leak tightness of the order of 10-10 mbar 1/s. Helium mass spectrometer leak detector (HMSLD) was utilized for the leak testing. Subsequently the leaks of various orders in welding joints were repaired and leak tightness achieved. This paper describes the experiences during leak testing of 20 nos. of aluminum dipole chambers for INDUS-2

  15. Calibration of PICO Bubble Chamber Dark Matter Detectors

    Science.gov (United States)

    Jin, Miaotianzi; PICO Collaboration

    2016-03-01

    The PICO Collaboration builds bubble chambers for the direct detection of WIMP dark matter. I will present the suite of calibration experiments performed to measure the sensitivity of these chambers to nuclear recoils (the expected WIMP signal) and to gamma rays (a common background to the WIMP signal). These calibrations include measurements with a 10-ml C3F8 bubble chamber at Northwestern University and with a 30-ml C3F8 bubble chamber deployed in the University of Montreal's tandem Van de Graaf facility, giving the bubble chamber response to a variety of gamma rays, broad-spectrum neutron sources, and mono-energetic low energy neutrons. I will compare our measured sensitivities to those predicted by a simple thermodynamic model and will show how the results impact our ability to detect dark matter, with a focus on light WIMP searches. Supported by DOE Grant: DE-SC0012161.

  16. Electrode module of the ''RISK'' spectrometer streamer chamber

    International Nuclear Information System (INIS)

    The design of an electrode module of the bipolar streamer chamber of the RISK magnetic spectrometer is described. The electrode module has two independent chambers of the working volume of 153 cm and 293 cm length, separated by a 20 cm gap. Both chambers are located in the vessel of 600 cm length. Each of the working chambers of the electrode module is made of 1.5 cm thick viniplast and it comprises three sections. Four grid electrodes are installed in every working chamber of the module. The grid electrode is a metal gid frame of stainless steel with 1x1 mm cell and 80 mkm thick wire. The geomettric transparency of the grid equals 85%. Special attention is paid to calculation of the stress of the grid electrodes. The vessel of the electrode module is described in detail

  17. Study of large drift chambers with high precision

    International Nuclear Information System (INIS)

    Among the measuring instruments used in high energy physics for detecting particles, drift chambers are being universally employed on an increasing scale because of their outstanding properties. With this type of chamber it is possible to determine the position in space of a trace left by a charged particle to within a few hundred microns and with very easy coding and recording of the data. As part of an experiment carried out in the CERN (ISR) proton collision rings, a set of 24 large drift chambers was assembled. The great accuracy of these chambers enabled a reduction to be made in the distances over which the determinations would have been made with conventional chambers and thereby to benefit from a wide solid angle of detection without the apparatus reaching prohibitive dimensions

  18. Summary on Titanium Nitride Coating of SNS Ring Vacuum Chambers

    CERN Document Server

    Todd, Robert J; Hseuh Hsiao Chaun; Weiss, Daniel

    2005-01-01

    The inner surfaces of the 248 m Spallation Neutron Source (SNS) accumulator ring vacuum chambers are coated with ~100 nm of titanium nitride (TiN) to reduce the secondary electron yield (SEY) of the chamber walls. There are approximately 100 chambers and kicker modules, some up to 5 m in length and 36 cm in diameter, coated with TiN. The coating is deposited by means of reactive DC magnetron sputtering using a cylindrical magnetron with internal permanent magnets. This cathode configuration generates a deposition rate sufficient to meet the required production schedule and produces stoichiometric films with good adhesion, low SEY and acceptable outgassing. Moreover, the cathode magnet configuration allows for simple changes in length and has been adapted to coat the wide variety of chambers and components contained within the arc, injection, extraction, collimation and RF regions. Chamber types, quantities and the cathode configurations used to coat them are presented herein. A brief summary of the salient co...

  19. Effects of air humidity on ionization chamber response

    International Nuclear Information System (INIS)

    A study of the effect of air humidity on four different ionization chamber cap materials verified earlier studies (Kristensen and Sundbom, 1981; Mijnheer et al., 1983) and extended our understanding of the problem. We found nylon and A-150 plastic caps swell as they absorb water from the air. This accounts for as much as 2.5% increase in ionization response. Graphite chambers readily absorb and desorb water from the air. This creates a problem in maintaining dry air in a wet graphite chamber. Humid air has a different density and W value than dry air (Niatel, 1969, 1975). This decreases the charge collected in a wet graphite chamber. We observe a decrease in response of approximately 2%, a value greater than can be accounted for by these effects alone. Polyethylene chambers are unaffected by humid air. 4 refs., 9 figs

  20. Ionization chamber gradient effects in nonstandard beam configurations

    International Nuclear Information System (INIS)

    Purpose: For the purpose of nonstandard beam reference dosimetry, the current concept of reporting absorbed dose at a point in water located at a representative position in the chamber volume is investigated in detail. As new nonstandard beam reference dosimetry protocols are under development, an evaluation of the role played by the definition of point of measurement could lead to conceptual improvements prior to establishing measurement procedures. Methods: The present study uses the current definition of reporting absorbed dose to calculate ionization chamber perturbation factors for two cylindrical chamber models (Exradin A12 and A14) using the Monte Carlo method. The EGSnrc based user-code EGS lowbar chamber is used to calculate chamber dose responses of 14 IMRT beams chosen to cause considerable dose gradients over the chamber volume as previously used by Bouchard and Seuntjens [''Ionization chamber-based reference dosimetry of intensity modulated radiation beams,'' Med. Phys. 31(9), 2454-5465 (2004)]. Results: The study shows conclusively the relative importance of each physical effect involved in the nonstandard beam correction factors of 14 IMRT beams. Of all correction factors involved in the dosimetry of the beams studied, the gradient perturbation correction factor has the highest magnitude, on average, 11% higher compared to reference conditions for the Exradin A12 chamber and about 5% higher for the Extradin A14 chamber. Other perturbation correction factors (i.e., Pwall, Pstem, and Pcel) are, on average, less than 0.8% different from reference conditions for the chambers and beams studied. The current approach of reporting measured absorbed dose at a point in water coinciding with the location of the centroid of the chamber is the main factor responsible for large correction factors in nonstandard beam deliveries (e.g., intensity modulated radiation therapy) reported in literature. Conclusions: To reduce or eliminate the magnitude of perturbation

  1. Calibration of working standard ionization chambers and dose standardization

    International Nuclear Information System (INIS)

    Measurements were performed for the calibration of two working standard ionization chambers in the secondary standard dosimetry laboratory of Sudan. 600 cc cylindrical former type and 1800 cc cylindrical radical radiation protection level ionization chambers were calibrated against 1000 cc spherical reference standard ionization chamber. The chamber were calibrated at X-ray narrow spectrum series with beam energies ranged from (33-116 KeV) in addition to 1''3''7''Cs beam with 662 KeV energy. The chambers 0.6 cc and 0.3 cc therapy level ionization were used for dose standardization and beam output calibrations of cobalt-60 radiotherapy machine located at the National Cancer Institute, University of Gazira. Concerning beam output measurements for 6''0''Co radiotherapy machine, dosimetric measurements were performed in accordance with the relevant per IAEA dosimetry protocols TRS-277 and TRS-398. The kinetic energy released per unit mass in air (air kerma) were obtained by multiplying the corrected electrometer reading (nC/min) by the calibration factors (Gy/n C) of the chambers from given in the calibration certificate. The uncertainty of measurements of air kerma were calculated for the all ionization chambers (combined uncertainty) the calibration factors of these ionization chambers then were calculated by comparing the reading of air kerma of secondary standard ionization chambers to than from radical and farmer chambers. The result of calibration working standard ionization chambers showed different calibration factors ranged from 0.99 to 1.52 for different radiation energies and these differences were due to chambers response and specification. The absorbed dose to to water calculated for therapy ionization chamber using two code of practice TRS-277 and TRS-398 as beam output for 6''0''Co radiotherapy machine and it can be used as a reference for future beam output calibration in radiotherapy dosimetry. The measurement of absorbed dose to water showed that the

  2. Autoignition Chamber for Remote Testing of Pyrotechnic Devices

    Science.gov (United States)

    Harrington, Maureen L.; Steward, Gerald R.; Dartez, Toby W.

    2009-01-01

    The autoignition chamber (AIC) performs by remotely heating pyrotechnic devices that can fit the inner diameter of the tube furnace. Two methods, a cold start or a hot start, can be used with this device in autoignition testing of pyrotechnics. A cold start means extending a pyrotechnic device into the cold autoignition chamber and then heating the device until autoignition occurs. A hot start means heating the autoignition chamber to a specified temperature, and then extending the device into a hot autoignition chamber until autoignition occurs. Personnel are remote from the chamber during the extension into the hot chamber. The autoignition chamber, a commercially produced tubular furnace, has a 230-V, single-phase, 60-Hz electrical supply, with a total power output of 2,400 W. It has a 6-in. (15.2-cm) inner diameter, a 12-in. (30.4-cm) outer diameter and a 12-in.- long (30.4-cm), single-zone, solid tubular furnace (element) capable of heating to temperatures up to 2,012 F (1,100 C) in air.

  3. Electrode module of the RISC spectrometer streamer chamber

    International Nuclear Information System (INIS)

    The RISC spectrometer streamer chamber is one of the biggest among the acting in our days controlled track detectors of this type. Its feeling volume constitutes 3.5 m3. A bipolar scheme of its high-voltage power supply is another peculiarity of this chamber. This unit is the first streamer chamber with bipolar supply successfully operating on the accelerator. Studied is the operation of the six-meter module of grid electrodes which is the main part of the streamer chamber forming its feeling volume. The following problems are under consideration: choice of configuration and basic parameters of electrode module, estimation of high-voltage isolation strength, construction of the case and operation volumes of the chamber, calculation estimations and assembly technique of grid electrodes. The streamer regime in the given chamber was obtained during its first start in April, 1977. By now, some experiments with the RISC spectrometer streamer chamber have been carried out on the Serpuchov accelerator. The results of these experiments are under study

  4. A new TXRF vacuum chamber with sample changer for chemical analysis using silicon drift chamber detector

    International Nuclear Information System (INIS)

    Full text: Several TXRF spectrometers for chemical analysis as well as for wafer surface analysis are commercially available. But there is no one available for chemical analysis offering the possibility to measure the samples in vacuum conditions. Vacuum of 10-2 mbar in the sample environment helps to reduce the background due to scattering from air, thus to improve the detection limits as well as to reduce the absorption of low energy fluorescence radiation from low Z elements and extend the elemental range to be measured and removes the Ar lines from the spectrum. The x-ray group of the Atominstitut designed and fabricated a new vacuum chamber for TXRF equipped with a 12 position sample changer from Italstructures, Riva, Italy. The detector used was a 10 mm2 silicon drift detector (KETEK, Munich, Germany), offering the advantage of electrically cooling, so no LN2 is required. The chamber was designed to be attached to a diffraction tube housing, e.g. with a fine focus Mo-x-ray tube and uses a multilayer monochromator. Spectra are stored by a small AMTEK MCA and control between sample changer and MCA communication is done by a modified AMPTEK software. The performance is expressed in detection limits of 1 pg Rb for Mo Ka excitation with 50 kV, 40 mA excitation conditions, 1000 s lifetime, obtained from a sample containing 600 pg Rb as single element standard. Details on performance, reproducibility and light element excitation and detection are presented. (author)

  5. Calibration of ionization chambers used in LDR brachytherapy

    International Nuclear Information System (INIS)

    In this work was developed a calibration procedure of well-type ionization chambers used for measurements of I-125, seed type. It was used as a standard an ionization chamber Capintec CRC-15BT, with calibration certificate of the University of Wisconsin. It were calibrated two well-type ionization chambers of Capintec CRC-15R model. A source of I-125 was used in clinical use (18.5 to 7.4 MBq). The results showed that with the application of calibration factors was possible to decrease read deviate from 16% to just 1.0%

  6. The pixel readout system for the PHENIX pad chambers

    International Nuclear Information System (INIS)

    A new concept for two-dimensional position readout of wire chambers is described. The basic idea is to use a cathode segmented into small pixels that are read out in specific groups (pads). The electronics is mounted on the outer face of the chamber with a chip-on-board technique, pushing the material thickness to a minimum. The system described here, containing 210 000 readout channels, will be used to read out the pad chambers in the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC)

  7. Assembly of Drift Tubes (DT) Chambers at CIEMAT (Madrid)

    CERN Multimedia

    Jesus Puerta-Pelayo

    2003-01-01

    The construction of muon drift tube chambers (DT) has been carried out in four different european institutes: Aachen (Germany), CIEMAT-Madrid (Spain), Legnaro and Turin (Italy), all of them following similar procedures and quality tests. Each chamber is composed by three or two independent units called superlayers, with four layers of staggered drift cells each. The assembly of a superlayer is a succesive glueing of aluminium plates and I-beams with electrodes previously attached, forming a rectangular and gas-tight volume. These pictures illustrate the various processes of material preparation, construction, equipment and assembly of full chambers at CIEMAT (Madrid).

  8. Study and Application of Sealing Material for Coke Oven Chamber

    Institute of Scientific and Technical Information of China (English)

    GAN Feifang; TAI Li

    2005-01-01

    A kind of dry refractory sealing material has been developed to repair the fine cracks in coke oven chamber. With silica sand as the main raw material, the sealing material is blown into coke oven chamber by compressed air while being applied, and bonded to brick surface or filled in fine cracks of chamber under right pressure. The physical properties of the material are similar to those of silica bricks during its application. So it can be adapted to conditions of coke oven and has good service life. The study and application results of the sealing material are described in this paper.

  9. "Flat-Fish" vacuum chamber for the ISR

    CERN Multimedia

    1983-01-01

    The "Flat-Fish" vacuum chamber was a very special one for the ISR beam intersection I-4, inside the Split-Field Magnet. Technical descriptions are given with pictures 7802042 and 7712182. There were several generations of this chamber. This picture was taken during the last year of ISR operation. See also 7510230X, 7511123X, 7802039, 7802041. A flat-fish type vacuum chamber was also used at I-8, inside the Open Axial Field Magnet (OAFM, experiment 807 on large transverse momentum collision products), see 7901358.

  10. Use of a streamer chamber for low energy nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Van Bibber, K.; Pang, W.; Avery, M.; Bloemhof, E.

    1979-10-01

    A small streamer chamber has been implemented for low energy heavy ion reaction studies at the LBL 88-inch cyclotron. The response of the chamber to light and heavy ions below 35 MeV/nucleon has been examined. The limited sensitivity of light output as a function of ionization works to advantage in recording a wide variety of tracks in the same photograph whose energy loss may vary considerably. Furthermore, as gas targets are attractive for several reasons, we have investigated the suitability of Ar and Xe for use in streamer chambers.

  11. Vapor chambers for an atmospheric cloud physics laboratory

    Science.gov (United States)

    Fleischman, G. L.; Scollon, T. R., Jr.; Loose, J. D.

    1980-01-01

    The methanol/stainless steel vapor chambers (flat-plate heat pipes) discussed in this paper were developed for use in spaceborne atmospheric cloud chambers. This application imposed stringent thermal and mechanical requirements on the design. Flatness, low thermal mass, vibration, and structural integrity requirements were achieved in addition to precision temperature uniformity and thermal transport. Heat transfer coefficients on the order of 0.34 to 0.40 W/sq cm -C were measured. The vapor chambers are capable of transporting 170 W-cm per cm of width in either the axial or side-to-side direction.

  12. Cryogenic Chamber for Servo-Hydraulic Materials Testing

    Science.gov (United States)

    Francis, John J.; Tuttle, James

    2009-01-01

    A compact cryogenic test chamber can be cooled to approximately 5 to 6 Kelvin for materials testing. The system includes a temperature controller and multiple sensors to measure specimen temperature at different locations. The testing chamber provides a fast and easy method to perform materials testing at lower than liquid nitrogen temperature (77 K). The purpose of the chamber is to cool a composite lap shear specimen to approximately 20 K so that tensile test force and displacement data may be acquired at this cryogenic temperature range.

  13. MUSIC chamber for investigation of fusion processes with radioactive beams

    International Nuclear Information System (INIS)

    An improved model of a Multiple Sampling Ionization Chamber (MUSIC) has been achieved. An outline of the chamber is presented. One can distinguish the 11 pads of the anode, the cage allowing to obtain a uniform electric field inside the chamber, the 5 x 5 cm2 Silicon microstrip detector-target and the Veto silicon detector. The 11 channel preamplifier is coupled directly to the anode pads. Due to this arrangement, an important increase of the signal noise ratio was obtained. The preamplifier scheme is given also. The integrated circuit of the type AMP-3 has a special construction of hybrid type. The circuitry layout is also presented. (authors)

  14. HF production in CMS-Resistive Plate Chambers

    International Nuclear Information System (INIS)

    The formation of highly reactive compounds in the gas mixture during Resistive Plate Chambers (RPCs) operation at the CERN Gamma Irradiation Facility (GIF) is studied. Results from two different types of chambers are discussed: 50 x 50 cm2 RPC prototypes and two final CMS-RB1 chambers. The RB1 detectors were also connected to a closed loop gas system. Gas composition, possible additional impurities as well as fluoride ions have been monitored in different gamma irradiation conditions both in open and closed loop mode. The chemical composition of the RPC electrode surface has also been analyzed using an electron microscope equipped with an EDS/X-ray

  15. Simulations of explosion-induced damage to underground rock chambers

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A numerical approach is presented to study the explosion-induced pressure load on an underground rock chamber wall and its resultant damage to the rock chamber.Numerical simulations are carried out by using a modified version of the commercial software AUTODYN.Three different criteria,i.e.a peak particle velocity (PPV) criterion,an effective strain (ES) criterion,and a damage criterion,are employed to examine the explosion-induced damaged zones of the underground rock chamber.The results show that the charg...

  16. The pixel readout system for the PHENIX pad chambers

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Paul B., E-mail: paul.nilsson@kosufy.lu.se; Barrette, J.; Bryan, W.; Fraenkel, Z.; Greene, V.; Garpman, S.; Gustafsson, H.-A.; Jagadish, U.; Nikkinen, L.; Lacey, R.; Lauret, J.; Mark, S.K.; Milov, A.; O' Brien, E.; Oskarsson, A.; Oesterman, L.; Otterlund, I.; Pinkenburg, C.; Ravinovich, I.; Rose, A.; Silvermyr, D.; Sivertz, M.; Smith, M.; Stenlund, E.; Svensson, T.; Teodorescu, O.; Tserruya, I.; Xie, W.; Young, G.R

    1999-12-27

    A new concept for two-dimensional position readout of wire chambers is described. The basic idea is to use a cathode segmented into small pixels that are read out in specific groups (pads). The electronics is mounted on the outer face of the chamber with a chip-on-board technique, pushing the material thickness to a minimum. The system described here, containing 210 000 readout channels, will be used to read out the pad chambers in the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC)

  17. Temperature characterisation of the CLOUD chamber at CERN

    Science.gov (United States)

    Dias, A. M.; Almeida, J.; Kirkby, J.; Mathot, S.; Onnela, A.; Vogel, A.; Ehrhart, S.

    2014-12-01

    Temperature stability, uniformity and absolute scale inside the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN are important for experiments on aerosol particle nucleation and ice/liquid cloud formation. In order to measure the air temperature, a comprehensive set of arrays ("strings") of platinum resistance thermometers, thermocouples and optical sensors have been installed inside the 26 m3 chamber. The thermal sensors must meet several challenging design requirements: ultra-clean materials, 0.01 K measurement sensitivity, high absolute precision (thermometer strings and the thermal performance of the chamber during the CLOUD8 and CLOUD9 campaigns, 2013-2014, together with the planned upgrades of the CLOUD thermal system.

  18. Influence of aerosol upon radon concentration of radon chamber

    International Nuclear Information System (INIS)

    On the basis of theoretical analysis, the influence on the radon concentration of radon chamber by the experiment of filling the radon chamber with aerosol, and the absorption of radon daughter on aerosol under the condition of different radon concentration and aerosol concentration was described. The results of experiment showed that: Aerosol did not affect the stability of the radon concentration of the radon chamber, but different aerosol concentration will change the combination state of radon daughter, thus it will affect the diffusion coefficient of radon daughter, so it will affect the results of the measure of the gross measuring instrument. (authors)

  19. Chamber Quality Factors for the NACP-02 Chamber in 60Co Beams: Comparison of EGSnrc and PENELOPE Monte Carlo Simulations

    International Nuclear Information System (INIS)

    A new comparison of the values published for the chamber quality factor fc,Q0 of a NACP-02 plane-parallel chamber in 60Co, calculated with the Monte Carlo (MC) systems EGSnrc and PENELOPE, shows a difference of approximately 0.5%. The authors analyse possible reasons for this difference and recalculate the chamber quality factor with EGSnrc. Variations in the simulation transport parameters of EGSnrc result in changes smaller than the difference. An investigation of the most important uncertainties of cross-sectional data, considering variations in the mean excitation energy of stopping powers and in the total photon cross-sections, shows uncertainties comparable to the differences between the two codes for the chamber quality factor. Variations of the front wall thickness of the NACP-02 chamber, in the range of discrepancies with manufacturer data reported in the literature, result in significant changes in the calculated values. However, the difference in fc,Q0 cannot be explained in terms of these modifications. Hence, although both codes have been demonstrated to yield artefact free ion chamber simulations, a convergence of results for this particular problem cannot be achieved. An uncertainty estimate which takes into account the 0.5% difference for the MC calculated chamber quality factors seems to be a reasonable assumption. (author)

  20. IRIDIUM LINER FOR NASA 5 LBF CLASS MATERIAL TEST CHAMBER IRIDIUM LINER FOR ATLANTIC RESEARCH CORPORA

    Science.gov (United States)

    1995-01-01

    IRIDIUM LINER FOR NASA 5 LBF CLASS MATERIAL TEST CHAMBER IRIDIUM LINER FOR ATLANTIC RESEARCH CORPORATION 5 LBF CLASS ROCKET CHAMBER 25 LBF CLASS 75 HFC 25 TAC CERAMIC COMPOSITE ROCKET CHAMBER FROM REFRACTURY COMPOSITES INC. PURCHASE ORDER C-551941-

  1. A cylindrical drift chamber for the measurement of k → πνν-bar decay

    International Nuclear Information System (INIS)

    A cylindrical drift chamber has been constructed for the study of the rare kaon decay K/sup +/ → π/sup +/νν-bar. Data from two prototype chambers and initial results from the final chamber are presented

  2. Analysis of micro-particles in TRISTAN vacuum chambers

    International Nuclear Information System (INIS)

    Micro-particles in the beam chamber of a TRISTAN vacuum system were investigated from the point of view of suppressing micro-particles trapped in the accumulation ring. Micro-particles coming from ion pumps (IP) and distributed ion pumps (DIP), aluminium alloy particles produced during treatment of aluminium alloy chambers for welding, micro-particles from the environment, i.e.soil (granite rocks or amphiboles), particles of concrete and painting materials were identified. A molten iron particle found in a chamber suggests interaction between the particle and bunched electron beam. Most of the particles coming from outside the chambers can be avoided by using high class clean rooms. The particles from the ion pumps can be reduced using different pumps which do not emit particles. The particles produced during assembly of, for example, DIP must be suppressed by accepting different assembling from the traditional ones. (author)

  3. Technical Design Study for the PANDA Time Projection Chamber

    CERN Document Server

    Ball, M; Dørheim, S; Höppner, C; Ketzer, B; Konorov, I; Neubert, S; Paul, S; Rauch, J; Uhl, S; Vandenbroucke, M; Berger, M; Berger-Chen, J -C; Cusanno, F; Fabbietti, L; Münzer, R; Arora, R; Frühauf, J; Kiš, M; Leifels, Y; Kleipa, V; Hehner, J; Kunkel, J; Kurz, N; Peters, K; Risch, H; Schmidt, C J; Schmitt, L; Schwab, S; Soyk, D; Voss, B; Weinert, J; Beck, R; Kaiser, D; Lang, M; Schmitz, R; Walther, D; Bühler, P; Müllner, P; Zmeskal, J; Hermann, N

    2012-01-01

    This document illustrates the technical layout and the expected performance of a Time Projection Chamber as the central tracking system of the PANDA experiment. The detector is based on a continuously operating TPC with Gas Electron Multiplier (GEM) amplification.

  4. Radiological risk from Am-241 in ionisation smoke chambers

    International Nuclear Information System (INIS)

    The author discusses the risk to man from the use of ionisation smoke chamber detectors with an Am-241 radiation source. The estimated dose is compared with that due to natural radioactivity. (G.T.H.)

  5. Ducted combustion chamber for direct injection engines and method

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Charles

    2015-03-03

    An internal combustion engine includes an engine block having a cylinder bore and a cylinder head having a flame deck surface disposed at one end of the cylinder bore. A piston connected to a rotatable crankshaft and configured to reciprocate within the cylinder bore has a piston crown portion facing the flame deck surface such that a combustion chamber is defined within the cylinder bore and between the piston crown and the flame deck surface. A fuel injector having a nozzle tip disposed in fluid communication with the combustion chamber has at least one nozzle opening configured to inject a fuel jet into the combustion chamber along a fuel jet centerline. At least one duct defined in the combustion chamber between the piston crown and the flame deck surface has a generally rectangular cross section and extends in a radial direction relative to the cylinder bore substantially along the fuel jet centerline.

  6. Ultralightweight, Regeneratively Cooled Combustion Chamber for Mars Ascent Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a high-pressure, regeneratively-cooled combustion chamber that uses novel material selection for extreme reductions in mass. These materials are...

  7. Improved Rhenium Thrust Chambers for In-Space Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation-cooled, bipropellant thrust chambers are being considered for the ascent/descent engines and reaction control systems (RCS) for future NASA missions such...

  8. Stereo: cylindrical drift chamber for muon decay experiments at LAMPF

    International Nuclear Information System (INIS)

    A stereo, cylindrical drift chamber has been built for use in a search for rare decay modes of the muon at LAMPF. This chamber (part of the Crystal Box detector) has 728 cells on 8 concentric annuli at alternating angles of 100 to 160 from the chamber axis and with radii from 105 to 220 mm. The basic cell cross section is (9 x 10) mm2 and the inter-layer spacing is 4.7 mm. Preliminary results show the single-wire efficiencies to be greater than 99%. Based on results obtained from prototype chambers, we hope to achieve 170-μm resolution (including multiple scattering) when TDC offsets and sense-wire locations found in a careful inspection of the endplates are added to the track-finding algorithm

  9. Improved Rhenium Thrust Chambers for In-Space Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation-cooled, bipropellant thrust chambers are being considered for the ascent/descent engines and reaction control systems for NASA missions such as Mars...

  10. Oxford engineering students to study new solutions for vacuum chambers

    CERN Multimedia

    Department of Engineering Science - University of Oxford

    2012-01-01

    In April, eleven engineering science students in their third year at Oxford University were invited here to present their design ideas for new vacuum chamber materials to be used in accelerators. We publish below an abstract of the article that the University of Oxford featured on its website.   The 11 Oxford students who worked at CERN on alternatives to beryllium in vacuum chambers. (Photo courtesy of the Department of Engineering Science, University of Oxford.) Engineering Science students invited to design for CERN’s Large Hadron Collider In April, eleven Engineering Science students in their third year were invited to the CERN laboratory in Geneva to present their ideas for new vacuum chamber designs for the experiments of the Large Hadron Collider (LHC). Their design objectives were to propose alternatives to beryllium – the material used for some of the existing experimental vacuum chambers. Beryllium (chemical element with the symbol Be and atomic number 4) is to...

  11. Simulation of the heat transfer around the ATLAS muon chambers

    CERN Multimedia

    2005-01-01

    This 2D simulation recently carried out on the ATLAS muon chambers by a small team of CERN engineers specialises in the numerical computation of fluid dynamics, in other words the flow of fluids and heat.

  12. Development of standard ionization chamber counting system for activity measurements

    CERN Document Server

    Pyun, W B; Lee, H Y; Park, T S

    1998-01-01

    This study is to set up the activity measuring system using a 4 pi gamma ionization chamber as used mainly in national standards laboratories that are responsible for radionuclide metrology. The software for automatic control between the electrometer and personal computer is developed using Microsoft visual basic 4.0 and IEEE488 Interface. The reproducibility of this 4 pi gamma ionization chamber is about 0.02% and the background current is 0.054+-0.024 pA. this 4 pi gamma ionization chamber is calibrated by 6 standard gamma emitting radionuclides from KRISS. According to the result of this study, it is revealed that this 4 pi gamma ionization chamber counting system can be used as a secondary standard instrument for radioactivity measurement.

  13. Secret Chambers: The Insider Story of Cells and Complex Life

    OpenAIRE

    Farid Pazhoohi

    2014-01-01

    Review of Secret Chambers: The Insider Story of Cells and Complex Life. Martin Brasier. 2012. Oxford University Press, UK. Pp. 320 with 15 black and white illustrations and 8 pages of color plates. £16.99 (hardcover). ISBN 9780199644001.

  14. Development of fission chamber for nuclear reactors controlling

    International Nuclear Information System (INIS)

    Fission Chambers are gas-filled type detectors that operate in the ionization chamber regime, which is without electron multiplication. As the fill-gas is not directly ionized by neutrons, fission chambers are lined with fissile material that through interaction with neutrons fission products are produced, are highly ionizing particles. Pulse type operation of these detectors are used for neutron flux measurements during start up and shut-down reactor conditions in which pulses of high amplitude produced by fission products can be easily discriminated from those produced by alpha radiation from uranium and also from the external gamma field. With current or current fluctuation mode operation (Campbell) the use of these detectors can be extended for the whole range of reactor operation. In this work, it is presented the development and construction of a fission chamber at IPEN-CNEN/SP. Furthermore, the material and techniques used and also the operational characteristics obtained with the first prototype are given. (author)

  15. Novel method for cleaning a vacuum chamber from hydrocarbon contamination

    International Nuclear Information System (INIS)

    A novel method for cleaning a high vacuum chamber is presented. This method is based on concurrent in situ high-energetic UV light activation of contaminants located in the residual gas and at the vacuum chamber surfaces as well as the in situ generation of highly reactive ozone. Ozone oxidizes the contaminants to volatile species. Investigations by energy-dispersive x-ray analysis of residual gas depositions and mass-spectroscopy measurements of the residual gas in the vacuum chamber identify the contaminant species as hydrocarbons. After a cleaning period of 8 h, a decrease in measured chamber contamination by about 90% could be achieved according to atomic force microscope analysis. Mass spectroscopy measurements using a residual gas analyzer indicate the creation of volatile, carbonaceous species during the cleaning process.

  16. CFD Simulation Evaluation for Flow Distribution of the Closed Chamber

    Directory of Open Access Journals (Sweden)

    Hong Bin

    2016-01-01

    Full Text Available Taking a closed chamber flow field as object, this paper establishes the 3D model of the Closed Chamber. With the conclusion of flow distribution and gasoline vapor concentration distribution of the Closed Chamber reached via the CFD software of Fluent and experiment research, this paper analyzes the flow distribution and concentration distribution of gasoline vapor. Several improvement projects are proposed, such as improving the wind circulation system to optimize the indoor gas concentration. By improving the structure of wind circulation system, it makes flow distribution more reasonable and significantly improves the uniformity of indoor gas concentration. Through implementation of this improvement, the reliability and performance of the containment chamber obviously program to improve.

  17. Development of a sample chamber for micro-PIXE

    International Nuclear Information System (INIS)

    A new sample chamber for micro-PIXE analysis of geological thick samples has been successfully developed. A target in the sample chamber is normal to the beam and Si(Li) detectors are located at 135deg to the beam direction. For the sample observation, a normal viewing optics with the optical axis collinear with the beam is achieved by a combination of long working distance microscope and mirror with a central hole for the beam transmission. The normal incidence beam and normal viewing are essential to raise a spatial resolution of the thick target analysis. In addition, the sample chamber has fulfilled ten requirements as for material, driving stage, X-ray absorbers, space for another detector, etc. The information obtained by the development can give a new guide to manufacture the sample chamber for the micro-PIXE. (author)

  18. Suppression of bunch transverse instabilities by the chamber asymmetry

    International Nuclear Information System (INIS)

    Axial asymmetry of a vacuum chamber gives rise to wake forces producing betatron tune shifts for tail particles. In the result, the bunch transverse instabilities could be suppressed or even eliminated

  19. 'Reading' bubble chamber pictures with the Spiral Reader eyes.

    CERN Multimedia

    1974-01-01

    Interactive techniques were widely used to study bubble chamber pictures. After a visual scanning of the pictures and a vertex measurement on a Shivamatic, the Spiral Reader allowed the track polar coordinates to be easily measured. See photo 7408137X

  20. Dirofilaria in the anterior chamber: A rare occurrence

    Directory of Open Access Journals (Sweden)

    Rupali Chopra

    2012-01-01

    Full Text Available Dirofilariasis is a parasitic infection of the carvivores that may present as a zoonotic infestation in humans. Systemic involvement in man is subcutaneous, pulmonary, or ocular. We report a rare occurrence of ocular dirofilariasis in a 25-year-old male patient who presented with pain and redness in the eye. A live, white, coiled, and highly motile worm was present in the anterior chamber. The worm, however, could not be detected in the anterior chamber, posterior segment, or the angle of the anterior chamber when the patient was taken to the operating room for surgical removal of the worm. The patient was made to lie prone till the worm reappeared in the anterior chamber and was removed by paracentesis. The worm was identified as Dirofilaria repens on the basis of microscopic and histopathological examination.

  1. Factors controlling the structures of magma chambers in basaltic volcanoes

    Science.gov (United States)

    Wilson, L.; Head, James W.

    1991-01-01

    The depths, vertical extents, and lateral extents of magma chambers and their formation are discussed. The depth to the center of a magma chamber is most probably determined by the density structure of the lithosphere; this process is explained. It is commonly assumed that magma chambers grow until the stress on the roof, floor, and side-wall boundaries exceed the strength of the wall rocks. Attempts to grow further lead to dike propagation events which reduce the stresses below the critical values of rock failure. The tensile or compressive failure of the walls is discussed with respect to magma migration. The later growth of magma chambers is accomplished by lateral dike injection into the country rocks. The factors controlling the patterns of growth and cooling of such dikes are briefly mentioned.

  2. Development of exposure assessment method with the chamber

    Science.gov (United States)

    Kato, N.; Koyama, Y.; Yokoyama, H.; Matsui, Y.; Yoneda, M.

    2015-05-01

    This study aims at developing the measurement method of nanoparticle concentration and at getting a representative value of nanoparticle uniform concentration due to chamber ventilation. We conducted a chamber equipped with HEPA filter and control the background nanoparticles concentration by using an adequate ventilation. Then, we used generator to evaluate concentration in the chamber uniformity. We measured background value and source counts at the particle size distribution by SMPS. In addition, we performed numerical analysis with CFD model OpenFoam. As results, we found that there is no aggregate in experimental conditions in this study. Though we confirmed that it is difficult to uniformalise nanoparticle concentration, However we also found simulation results showed higher reproducibility. Therefore, we could assess nanoparticle size distribution and concentration in our chamber at this stage.

  3. Transport of Na48 Drift Chambers to Dubna

    CERN Multimedia

    GOLOVATYUK, V

    2010-01-01

    On 22 July, in the occasion of the departure of the Na48 Drift Chambers from CERN, Mikhail Itkis (acting Director of the JIINR) and Rolf Heuer (CERN Director General) visited the NA62 experimental area.

  4. An examination of medical linear accelerator ion-chamber performance

    International Nuclear Information System (INIS)

    Full text: The company ( Radiation Oncology Physics and Engineering Services Pty Ltd) provides medical physics services to four radiotherapy centres in NSW with a total of 6 high energy medical linear accelerators manufactured by three different companies. As part of the services, the stability of the accelerator ion chamber system is regularly examined for constancy and periodically for absolute calibration. Each accelerator ion chamber has exhibited undesirable behaviour from time to time, sometimes leading to its replacement. This presentation describes the performance of the ion chambers for some of the linacs over a period of 12-18 months and the steps taken by the manufacturer to address the problems encountered. As part of our commissioning procedure of new linacs, an absolute calibration of the accelerator output (photon and electron beams) is repeated several times over the period following examination of the physical properties of the radiation beams. These calibrations were undertaken in water using the groups calibrated ion chamber/electrometer system and were accompanied by constancy checks using an acrylic phantom and field instruments. Constancy checks were performed daily for a period of 8 weeks during the initial life of the accelerator and thereafter weekly. For one accelerator, the ion chamber was replaced 6 times in the first eighteen months of its life due to severe drifts in output, found to be due to pressure changes in one half of the chamber In another accelerator, erratic swings of 2% were observed for a period of nine months, particularly with the electron beams, before the manufacturer offered to change the chamber with another constructed from different materials. In yet another accelerator the ion chamber has shown consistent erratic behaviour, but this has not been addressed by the manufacturer. In another popular accelerator, the dosimetry was found to be very stable until some changes in the tuning were introduced resulting in small

  5. Field Statistics in a One-Dimensional Reverberation Chamber Model

    OpenAIRE

    Canavero, Flavio

    2009-01-01

    This work focuses on building a fairly simple yet physically appropriate 1D model for a Reverberation Chamber which claims to be able to analytically predict the statistical behavior of such a chamber, without forsaking to the benefits of deterministic models. The statistical properties are introduced by varying the size of a 1D stirrer or the cavity size itself. A validation analysis shows agreement with other theories and measured results on real RCs. Field statistics in undermoded regime i...

  6. Experimental and calculated calibration of ionization chambers with air circulation

    CERN Document Server

    Peetermans, A

    1972-01-01

    The reports describes the method followed in order to calibrate the different ionization chambers with air circulation, used by the 'Health Physics Group'. The calculations agree more precisely with isotopes cited previously (/sup 11/C, /sup 13/N, /sup 15/O, /sup 41 /Ar, /sup 14/O, /sup 38/Cl) as well as for /sup 85/Kr, /sup 133/Xe, /sup 14/C and tritium which are used for the experimental standardisation of different chambers.

  7. Progress toward a diffusion suppressed holographic streamer chamber

    International Nuclear Information System (INIS)

    We have been pursuing a research effort at Yale that has several aspects. These include holographic recording of streamer chamber tracks and suppression of the thermal diffusion of ionisation electrons on tracks. The diffusion of electrons away from the track site in the time between the passage of the ionizing particle and the arrival of the high voltage pulse is the dominant source of track width in high pressure streamer chambers. We report our progress in these two areas. (orig./HSI)

  8. Tracking simulation and wire chamber requirements for the SSC

    International Nuclear Information System (INIS)

    Limitations placed on wire chambers by radiation damage and rate requirements in the SSC environment are reviewed. Possible conceptual designs for wire chamber tracking systems which meet these requirements are discussed. Computer simulation studies of tracking in such systems are presented. Simulations of events from interesting physics at the SSC, including hits from minimum bias background events, are examined. Results of some preliminary pattern recognition studies are given. 16 refs., 16 figs., 2 tabs

  9. Tracking and vertex finding with drift chambers and neural networks

    International Nuclear Information System (INIS)

    Finding tracks, track vertices and event vertices with neural networks from drift chamber signals is discussed. Simulated feed-forward neural networks have been trained with back-propagation to give track parameters using Monte Carlo simulated tracks in one case and actual experimental data in another. Effects on network performance of limited weight resolution, noise and drift chamber resolution are given. Possible implementations in hardware are discussed. 7 refs., 10 figs

  10. Laser calibration system for the CERES Time Projection Chamber

    OpenAIRE

    Miskowiec, Dariusz; Braun-Munzinger, Peter

    2008-01-01

    A Nd:YAG laser was used to simulate charged particle tracks at known positions in the CERES Time Projection Chamber at the CERN SPS. The system was primarily developed to study the response of the readout electronics and to calibrate the electron drift velocity. Further applications were the determination of the gating grid transparency, the chamber position calibration, and long-term monitoring of drift properties of the gas in the detector.

  11. TA53:19 Reverb Chamber Quick-Look

    Energy Technology Data Exchange (ETDEWEB)

    Bishofberger, Kip A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-19

    Within Building 19 of TA-53, a screen room has been evaluated for use as a reverb chamber (with deep gratitude to Dale Dalmas and Greg Dale for their assistance). With minimal additional sealing of the chamber, we expect the Q to increase even more, and thus field levels for the same RF source power. Future studies need to determine leakage field levels, which will define maximum achievable field levels.

  12. Properties of a commercial extrapolation chamber in β radiation fields

    International Nuclear Information System (INIS)

    A commercial extrapolation chamber was tested in different β radiation fields and its properties investigated. Its usefulness for β radiation calibration and dosimetry was verified. Experiments were performed in order to obtain the main characteristics such as the calibration factors (and consequently the energy dependence) for all chamber collecting electrodes (between 10 and 40 mm diameter), the transmission factors in tissue and the useful source-detector distance range

  13. Nuclear Design Considerations for Z-IFE Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Meier, W R; Schmitt, R C; Abbott, R P; Latkowski, J F; Reyes, S

    2005-02-02

    Z-pinch driven IFE (Z-IFE) requires the design of a repetitive target insertion system that allows coupling of the pulsed power to the target with adequate standoff, and a chamber that can withstand blast and radiation effects from large yield targets. The present strategy for Z-IFE is to use high yield targets ({approx}2-3 GJ/shot), low repetition rate per chamber ({approx}0.1 Hz), and 10 chambers per power plant. In this study, we propose an alternative power plant configuration that uses very high yield targets (20 GJ/shot) in a single chamber operating at 0.1 Hz. A thick-liquid-wall chamber is proposed to absorb the target emission (x-rays, debris and neutrons) and mitigate the blast effects on the chamber wall. The target is attached to the end of a conical shaped Recyclable Transmission Line (RTL) made from a solid coolant (e.g., frozen flibe), or a material that is easily separable from the coolant (e.g., steel). The RTL/target assembly is inserted through a single opening at the top of the chamber for each shot. This study looks at the RTL material choice from a safety and environmental point of view. Materials were assessed according to waste disposal rating (WDR) and contact dose rate (CDR). Neutronics calculations, using the TART2002 Monte Carlo code from Lawrence Livermore National Laboratory (LLNL), were performed for the RTL and Z-IFE chamber, and key results reported here.

  14. Tracking simulation and wire chamber requirements for the SSC

    International Nuclear Information System (INIS)

    In this paper limitations placed on wire chambers by radiation damage and rate requirements in the SSC environment are reviewed. Possible conceptual designs for wire chamber tracking systems which meet these requirements are discussed. Computer simulation studies of tracking in such systems are presented. Simulations of events from interesting physics at the SSC, including hits from minimum bias background events, are examined. Results of some preliminary pattern recognition studies are given

  15. Cone penetration test in a virtual calibration chamber

    OpenAIRE

    Butlanska, Joanna

    2014-01-01

    Cone penetration test (CPT) is a fast and reliable site investigation tool for exploring soils and soft ground. While the interpretation of the test results in clay has advanced considerably from a theoretical and numerical viewpoint that of tests in sands still relies largely on empirical correlations. A major source of such correlations comes from tests done in calibration chambers (CC), where soil state and properties might be tightly controlled. Calibration chambers are relatively large p...

  16. Chamber technology concepts for inertial fusion energy: Three recent examples

    International Nuclear Information System (INIS)

    The most serious challenges in the design of chambers for inertial fusion energy (IFE) are 1) protecting the first wall from fusion energy pulses on the order of several hundred megajoules released in the form of x rays, target debris, and high energy neutrons, and 2) operating the chamber at a pulse repetition rate of 5-10 Hz (i.e., re-establishing, the wall protection and chamber conditions needed for beam propagation to the target between pulses). In meeting these challenges, designers have capitalized on the ability to separate the fusion burn physics from the geometry and environment of the fusion chamber. Most recent conceptual designs use gases or flowing liquids inside the chamber. Thin liquid layers of molten salt or metal and low pressure, high-Z gases can protect the first wall from x rays and target debris, while thick liquid layers have the added benefit of protecting structures from fusion neutrons thereby significantly reducing the radiation damage and activation. The use of thick liquid walls is predicted to 1) reduce the cost of electricity by avoiding the cost and down time of changing damaged structures, and 2) reduce the cost of development by avoiding the cost of developing a new, low-activation material. Various schemes have been proposed to assure chamber clearing and renewal of the protective features at the required pulse rate. Representative chamber concepts are described, and key technical feasibility issues are identified for each class of chamber. Experimental activities (past, current, and proposed) to address these issues and technology research and development needs are discussed

  17. The M.I.T. - Tohuku beam dump chamber

    International Nuclear Information System (INIS)

    A holographic bubble chamber is described that will search for the tau neutrino. Tests are described that demonstrate that with standard lasers photographs of 30 micron diameter bubbles can be taken throughout a 36 inches diameter x 33 inches deep chamber. It is shown that bubbles of this diameter are sufficient for this experiment and that a measurement of the impact parameter will yield the tau meson lifetime. (U.K.)

  18. Imploded test-chamber for an ISR intersection

    CERN Multimedia

    1977-01-01

    At the ISR intersection points the vacuum chambers had to be as "transparent" as possible, for the p-p collision product particles to reach the detectors with minimum hindrance. This meant the choice of a light, yet very strong, metal; minimum thickness; and corrugation for mechanical strength. The test-chamber seen here was made of 0.6 mm thick corrugated titanium, obviously not strong enough to withstand the atmospheric pressure.

  19. Central tracking chamber with inflated cathode-strip foils

    International Nuclear Information System (INIS)

    A new cylindrical low-mass central drift chamber has been constructed for the K+ → π+νν experiment at BNL (E787). The chamber consists of 12 layers of axial wire cells and 6 layers of thin cathode-strip foils, four of which are supported by differential gas pressure. The momentum resolution (RMS) for muons and pions in the range 150 to 250 MeV is found to be about 0.9%. (authors)

  20. Some recent results for nonlinear acoustics in combustion chambers

    OpenAIRE

    Culick, F. E. C.

    1990-01-01

    Conditions of high energy densities and low losses in combustion chambers encourage the excitation and sustenance of organized unsteady motions generically called combustion instabilities. The fluctuations, common in propulsion systems, often reach sufficient amplitudes to cause excessive rates of heat transfer to exposed surfaces and unacceptable structural vibrations, causing failure in extreme cases. In many cases, to avoid the occurrence of instabilities, combustion chambers are ...

  1. Drift chamber tracking with a VLSI neural network

    International Nuclear Information System (INIS)

    We have tested a commercial analog VLSI neural network chip for finding in real time the intercept and slope of charged particles traversing a drift chamber. Voltages proportional to the drift times were input to the Intel ETANN chip and the outputs were recorded and later compared off line to conventional track fits. We will discuss the chamber and test setup, the chip specifications, and results of recent tests. We'll briefly discuss possible applications in high energy physics detector triggers

  2. Identification of proteins in fluid collected from nerve regeneration chambers

    Directory of Open Access Journals (Sweden)

    Ye Yilin

    2014-01-01

    Full Text Available We examined whether there are novel neurotrophic factors (NTFs in nerve regeneration conditioned fluid (NRCF. Nerve regeneration chamber models were established in the sciatic nerves of 25 New Zealand rabbits, and NRCF was extracted from the chambers l week postoperatively. Proteins in NRCF were separated by native polyacrylamide gel electrophoresis (PAGE, and Western blot and ELISA were used to identify the proteins. A novel NTF was identified in a protein fraction corresponding to 220 kDa.

  3. Anterior chamber flare after trabeculectomy and after phacoemulsification

    OpenAIRE

    Siriwardena, D; Kotecha, A; Minassian, D; Dart, J.; KHAW, P.

    2000-01-01

    AIMS—To evaluate and compare prospectively the anterior chamber inflammatory response after phacoemulsification cataract surgery and after trabeculectomy with peripheral iridectomy.
METHODS—Anterior chamber inflammation was measured using the Kowa FM-500 laser flare meter in 131 patients undergoing trabeculectomy and 148 patients undergoing phacoemulsification cataract extraction with intraocular lens implantation. Flare was measured before surgery and on each postoperative visit up to 12 mon...

  4. Aging in the large CDF axial drift chamber

    Energy Technology Data Exchange (ETDEWEB)

    Allspach, D.; Ambrose, D.; Binkley, M.; /Fermilab; Bromberg, C.; /Michigan State U.; Burkett, K.; Kephart, R.; Madrak, R.; Miao, T.; Mukherjee, A.; Roser, R.; Wagner, R.L.

    2004-12-01

    The Central Outer Tracker (COT) is a large axial drift chamber in the Collider Detector at Fermilab operating with a gas mixture that is 50/50 argon/ethane with an admixture of 1.7% isopropanol. In its first two years of operation the COT showed unexpected aging with the worst parts of the chamber experiencing a gain loss of {approx}50% for an accumulated charge of {approx}35 mC/cm. By monitoring the pulse height of hits on good tracks, it was possible to determine the gain as a function of time and location in the chamber. In addition, the currents of the high voltage supplies gave another monitor of chamber gain and its dependence on the charge deposition rate. The aging was worse on the exhaust end of the chamber consistent with polymer buildup as the gas flows through the chamber. The distribution in azimuth suggests that aging is enhanced at lower temperatures, but other factors such as gas flow patterns may be involved. Elemental and molecular analysis of the sense wires found a coating that is mostly carbon and hydrogen with a small amount of oxygen; no silicon or other contaminants were identified. High resolution electron microscope pictures of the wire surface show that the coating is smooth with small sub-micron nodules. In the course of working with the chamber gas system, we discovered a small amount of O{sub 2} is enough to reverse the aging. Operating the chamber with {approx}100 ppm of O{sub 2} reversed almost two years of gain loss in less than 10 days while accumulating {le} 2 mC/cm.

  5. Nuclear design considerations for Z-IFE chambers

    International Nuclear Information System (INIS)

    Z-pinch driven IFE (Z-IFE) requires the design of a repetitive target insertion system that allows coupling of the pulsed power to the target with adequate standoff, and a chamber that can withstand blast and radiation effects from large yield targets. The present strategy for Z-IFE is to use high yield targets (∼2-3 GJ/shot), low repetition rate per chamber (∼0.1 Hz), and 10 chambers per power plant. In this study, we propose an alternative power plant configuration that uses very high yield targets (20 GJ/shot) in a single chamber operating at 0.1 Hz. A thick-liquid-wall chamber is proposed to absorb the target emission (X-rays, debris and neutrons) and mitigate the blast effects on the chamber wall. The target is attached to the end of a conical shaped recyclable transmission line (RTL) made from a solid coolant (e.g., frozen flibe), or a material that is easily separable from the coolant (e.g., steel). The RTL/target assembly is inserted through a single opening at the top of the chamber for each shot. This study looks at the RTL material choice from a safety and environmental point of view. Materials were assessed according to waste disposal rating (WDR) and contact dose rate (CDR). Neutronics calculations, using the TART2002 Monte Carlo code from Lawrence Livermore National Laboratory (LLNL), were performed for the RTL and Z-IFE chamber, and key results reported here

  6. A ring-shaped recombination chamber for hadron therapy dosimetry

    International Nuclear Information System (INIS)

    An innovative recombination chamber has been designed for estimation of stray radiation doses and quality factors in hadron therapy. The chamber allows for determination of absorbed dose and recombination index of radiation quality in phantoms at small distances from simulated organs. The chamber body and electrodes are ring shaped, so the beam may be directed through the empty centre of the ring. The ionisation of the filling gas is caused by secondary or scattered radiation and can be related to the dose absorbed in the tissues close to the irradiated target volume. A recently designed and constructed ring-shaped recombination chamber successfully passed first operational tests. The measurements performed on a proton eye therapy beam line showed potential usefulness of the chamber for determination of the scattered radiation dose in the vicinity of the beam. In the future, the chamber can be applied both for patient dosimetry and for monitoring changes in the scattered radiation field, associated with different configurations of the elements forming the proton beam line. (authors)

  7. Lifetime survivability of contaminated target-chamber optics

    International Nuclear Information System (INIS)

    Target chambers used for Inertial Confinement Fusion (ICF) expose laser optics to a very hostile environment, not only from high-fluence laser irradiation but also x-ray irradiation and particulate debris from targets and chamber wall materials. Expendable debris shields provide the first line of defense to more costly optics upstream in the laser beam path to contaminants generated within the target chamber. However, the replacement of a large number of debris shields is also an expensive proposition so that extending their usable lifetime within the chamber is important. We have conducted tests to show that optics can both be cleaned and damaged by laser irradiation at 355 nm after being contaminated with potential chamber-wall materials such as B4C and Al2O3. Such optics can survive from one to hundreds of laser shots, depending on degree of contamination and laser fluence levels. Similarly, we have studied the survivability of optics that have been exposed to direct contamination from representative target materials irradiated in the target chamber. We have also studied the effects on optics that were not directly exposed to targets, yet received secondary exposure from the above directly-exposed samples

  8. An improved chamber for direct visualisation of chemotaxis.

    Directory of Open Access Journals (Sweden)

    Andrew J Muinonen-Martin

    Full Text Available There has been a growing appreciation over the last decade that chemotaxis plays an important role in cancer migration, invasion and metastasis. Research into the field of cancer cell chemotaxis is still in its infancy and traditional investigative tools have been developed with other cell types and purposes in mind. Direct visualisation chambers are considered the gold standard for investigating the behaviour of cells migrating in a chemotactic gradient. We therefore drew up a list of key attributes that a chemotaxis chamber should have for investigating cancer cell chemotaxis. These include (1 compatibility with thin cover slips for optimal optical properties and to allow use of high numerical aperture (NA oil immersion objectives; (2 gradients that are relatively stable for at least 24 hours due to the slow migration of cancer cells; (3 gradients of different steepnesses in a single experiment, with defined, consistent directions to avoid the need for complicated analysis; and (4 simple handling and disposability for use with medical samples. Here we describe and characterise the Insall chamber, a novel direct visualisation chamber. We use it to show GFP-lifeact transfected MV3 melanoma cells chemotaxing using a 60x high NA oil immersion objective, which cannot usually be done with other chemotaxis chambers. Linear gradients gave very efficient chemotaxis, contradicting earlier results suggesting that only polynomial gradients were effective. In conclusion, the chamber satisfies our design criteria, most importantly allowing high NA oil immersion microscopy to track chemotaxing cancer cells in detail over 24 hours.

  9. Study of the PTW microLion chamber temperature dependence

    International Nuclear Information System (INIS)

    The use of liquid ionization chambers in radiotherapy has grown during the past few years. While for air ionization chambers the kTP correction for air mass density due to pressure and temperature variations is well known, less work has been done on the case of liquid ionization chambers, where there is still the need to take into account the influence of temperature in the free ion yield. We have measured the PTW microLion isooctane-filled ionization chamber temperature dependence in a ∼ ±10 °C interval around the standard 20 °C room temperature for three operation voltages, including the manufacturer recommended voltage, and two beam qualities, 60Co and 50 kV x-rays. Within the measured temperature range, the microLion signal exhibits a positive linear dependence, which is around 0.24% K−1 at 800 V with 60Co irradiation. This effect is of the same order of magnitude as the T dependence found in air ionization chambers, but its nature is completely different and its sign opposite to that of an air chamber. Onsager theory has been used to model the results and is consistent with this linear behaviour. However, some inconsistencies in the modelling of the 50 kV x-ray results have been found that are attributed to the failure of Onsager's isolated pair assumption for such radiation quality. (paper)

  10. Test chambers for cell culture in static magnetic field

    International Nuclear Information System (INIS)

    Article presents a test chamber intended to be used for in vitro cell culture in homogenous constant magnetic field with parametrically variable magnitude. We constructed test chambers with constant parameters of control homeostasis of cell culture for the different parameters of static magnetic field. The next step was the computer calculation of 2D and 3D simulation of the static magnetic field distribution in the chamber. The analysis of 2D and 3D calculations of magnetic induction in the cells' exposition plane reveals, in comparison to the detection results, the greater accuracy of 2D calculations (Figs. 9 and 10). The divergence in 2D method was 2–4% and 8 to 10% in 3D method (reaching 10% only out of the cells′ cultures margins). -- Highlights: ► We present test chamber to be used for in vitro cell culture in static magnetic field. ► The technical data of the chamber construction was presented. ► 2D versus 3D simulation of static magnetic field distribution in chamber was reported. ► We report the accuracy of 2D calculation than 3D

  11. Design and construction of an inexpensive homemade plant growth chamber.

    Science.gov (United States)

    Katagiri, Fumiaki; Canelon-Suarez, Dario; Griffin, Kelsey; Petersen, John; Meyer, Rachel K; Siegle, Megan; Mase, Keisuke

    2015-01-01

    Plant growth chambers produce controlled environments, which are crucial in making reproducible observations in experimental plant biology research. Commercial plant growth chambers can provide precise controls of environmental parameters, such as temperature, humidity, and light cycle, and the capability via complex programming to regulate these environmental parameters. But they are expensive. The high cost of maintaining a controlled growth environment is often a limiting factor when determining experiment size and feasibility. To overcome the limitation of commercial growth chambers, we designed and constructed an inexpensive plant growth chamber with consumer products for a material cost of $2,300. For a comparable growth space, a commercial plant growth chamber could cost $40,000 or more. Our plant growth chamber had outside dimensions of 1.5 m (W) x 1.8 m (D) x 2 m (H), providing a total growth area of 4.5 m2 with 40-cm high clearance. The dimensions of the growth area and height can be flexibly changed. Fluorescent lights with large reflectors provided a relatively spatially uniform photosynthetically active radiation intensity of 140-250 μmoles/m2/sec. A portable air conditioner provided an ample cooling capacity, and a cooling water mister acted as a powerful humidifier. Temperature, relative humidity, and light cycle inside the chamber were controlled via a z-wave home automation system, which allowed the environmental parameters to be monitored and programmed through the internet. In our setting, the temperature was tightly controlled: 22.2°C±0.8°C. The one-hour average relative humidity was maintained at 75%±7% with short spikes up to ±15%. Using the interaction between Arabidopsis and one of its bacterial pathogens as a test experimental system, we demonstrate that experimental results produced in our chamber were highly comparable to those obtained in a commercial growth chamber. In summary, our design of an inexpensive plant growth chamber

  12. Design and construction of an inexpensive homemade plant growth chamber.

    Directory of Open Access Journals (Sweden)

    Fumiaki Katagiri

    Full Text Available Plant growth chambers produce controlled environments, which are crucial in making reproducible observations in experimental plant biology research. Commercial plant growth chambers can provide precise controls of environmental parameters, such as temperature, humidity, and light cycle, and the capability via complex programming to regulate these environmental parameters. But they are expensive. The high cost of maintaining a controlled growth environment is often a limiting factor when determining experiment size and feasibility. To overcome the limitation of commercial growth chambers, we designed and constructed an inexpensive plant growth chamber with consumer products for a material cost of $2,300. For a comparable growth space, a commercial plant growth chamber could cost $40,000 or more. Our plant growth chamber had outside dimensions of 1.5 m (W x 1.8 m (D x 2 m (H, providing a total growth area of 4.5 m2 with 40-cm high clearance. The dimensions of the growth area and height can be flexibly changed. Fluorescent lights with large reflectors provided a relatively spatially uniform photosynthetically active radiation intensity of 140-250 μmoles/m2/sec. A portable air conditioner provided an ample cooling capacity, and a cooling water mister acted as a powerful humidifier. Temperature, relative humidity, and light cycle inside the chamber were controlled via a z-wave home automation system, which allowed the environmental parameters to be monitored and programmed through the internet. In our setting, the temperature was tightly controlled: 22.2°C±0.8°C. The one-hour average relative humidity was maintained at 75%±7% with short spikes up to ±15%. Using the interaction between Arabidopsis and one of its bacterial pathogens as a test experimental system, we demonstrate that experimental results produced in our chamber were highly comparable to those obtained in a commercial growth chamber. In summary, our design of an inexpensive plant

  13. Characterization and testing of a new environmental chamber

    Science.gov (United States)

    Leskinen, A.; Yli-Pirilä, P.; Kuuspalo, K.; Sippula, O.; Jalava, P.; Hirvonen, M.-R.; Jokiniemi, J.; Virtanen, A.; Komppula, M.; Lehtinen, K. E. J.

    2015-06-01

    A 29 m3 Teflon chamber, designed for studies on the aging of combustion aerosols, at the University of Eastern Finland is described and characterized. The chamber is part of a research facility, called Ilmari, where small-scale combustion devices, a dynamometer for vehicle exhaust studies, dilution systems, the chamber, and cell and animal exposure devices are located side by side under the same roof. The small surface-to-volume ratio of the chamber enables reasonably long experiment times, with particle wall loss rate constants of 0.088, 0.080, 0.045, and 0.040 h-1 for polydisperse, 50, 100, and 200 nm monodisperse aerosols, respectively. The NO2 photolysis rate can be adjusted from 0 to 0.62 min-1. The irradiance spectrum is centered at either 350 or 365 nm, and the maximum irradiance, produced by up to 160 blacklight lamps, is 29.7 W m-2, which corresponds to the ultraviolet (UV) irradiance in Central Finland at noon on a sunny day in the midsummer. The temperature inside the chamber is uniform and can be kept at 25±1 °C. The chamber is kept in an overpressure with a moving top frame, which reduces sample dilution and entrance of contamination during an experiment. The functionality of the chamber was tested with oxidation experiments of toluene, resulting in secondary organic aerosol (SOA) yields of 12-42%, depending on the initial conditions, such as NOx concentration and UV irradiation. The highest gaseous oxidation product yields of 12.4-19.5% and 5.8-19.5% were detected with ions corresponding to methyl glyoxal (m/z 73.029) and 4-oxo-2-pentenal (m/z 99.044), respectively. Overall, reasonable yields of SOA and gaseous reaction products, comparable to those obtained in other laboratories, were obtained.

  14. Radiological evaluation of coronary artery-cardiac chamber shunt

    Energy Technology Data Exchange (ETDEWEB)

    Matsunaga, Naofumi

    1987-09-01

    Coronary artery-cardiac chamber shunts were observed in 84 cases out of consecutive 1,126 cases in which coronary angiography was performed. This ''coronary artery-cardiac chamber shunt'' has no draining vein and contrast material directly escapes into the cardiac chamber, which is different from the so-called ''coronary arterio-venous fistula''. The angiographic features of coronary artery-cardiac chamber shunt were classified into three types; Type I (57 cases): Endocardium is diffusely opacified on distole, and contrast material escapes into the cardiac chamber on systole. Type II (13 cases): A small localized direct coronary artery-cardiac chamber shunt. Type III (20 cases): Contrast material escapes into the cardiac chamber in the area of mural thrombus of the left atrium or left ventricle. It is speculated that type I shunt is due to persistent arterio-sinusoidal vessel, and type II shunt is due to persistent arterio-luminal vessel. Type I and II shunts were observed in hypertrophic cardiomyopathy with high incidence (42.4 %). In hypertrophic cardiomyopathy, the degree of shunts was not correlated with the degree of the ventricular wall thickening. These shunts were not also correlated with the presence or absence of myocardial squeezing. These facts suggest that the shunts may be due to the abnormality of the microcirculation of the myocardium. Type III shunt was observed in the mural thrombus in the left ventricle (7 cases), left atrial thrombus (12 cases) and verruca of the mitral valve (1 case). Angiographic features of these shunts are described, and their pathophysiological significance is discussed.

  15. Dark matter limits froma 15 kg windowless bubble chamber

    Energy Technology Data Exchange (ETDEWEB)

    Szydagis, Matthew Mark [Univ. of Chicago, IL (United States)

    2011-03-01

    The COUPP collaboration has successfully used bubble chambers, a technology previously applied only to high-energy physics experiments, as direct dark matter detectors. It has produced the world's most stringent spin-dependent WIMP limits, and increasingly competitive spin-independent limits. These limits were achieved by capitalizing on an intrinsic rejection of the gamma background that all other direct detection experiments must address through high-density shielding and empirically-determined data cuts. The history of COUPP, including its earliest prototypes and latest results, is briefly discussed in this thesis. The feasibility of a new, windowless bubble chamber concept simpler and more inexpensive in design is discussed here as well. The dark matter limits achieved with a 15 kg windowless chamber, larger than any previous COUPP chamber (2 kg, 4 kg), are presented. Evidence of the greater radiopurity of synthetic quartz compared to natural is presented using the data from this 15 kg device, the first chamber to be made from synthetic quartz. The effective reconstruction of the three-dimensional positions of bubbles in a highly distorted optical field, with ninety-degree bottom lighting similar to cloud chamber lighting, is demonstrated. Another innovation described in this thesis is the use of the sound produced by bubbles recorded by an array of piezoelectric sensors as the primary means of bubble detection. In other COUPP chambers, cameras have been used as the primary trigger. Previous work on bubble acoustic signature differentiation using piezos is built upon in order to further demonstrate the ability to discriminate between alpha- and neutron-induced events.

  16. Design of basic chamber of the Main Control Valve

    Directory of Open Access Journals (Sweden)

    S.W. Lee

    2008-06-01

    Full Text Available Purpose: The development of a control valve for closed circuit requires comprehensive technologies in the overall precision machinery industry, from the development of casting materials for the housing to various types of parts. The development of a new type of control valve would have great advantage with a long lifecycle. Therefore, it is necessary to secure the MCV (Main Control Valve development technology that applies various sensors. This paper aims at providing a fundamental base for the establishment of design systems including the flow chamber design database of the MCV for wheel loaders, strength and rigidity design system, and the system for energy efficiency improvement. Particularly, this study set up the basic design database for the flow chamber design to establish the flow chamber design database, and secured the stability of the flow chamber from the basic design stage. In addition, major design variables were determined by utilizing a statistical technique in order to design such flow chamber.Design/methodology/approach: This study uses the I-DEAS to analyze the MCV structure characteristics. In addition, it uses the factorial design and sensitivity analysis to select important factors for the MCV design.Findings: This study establishes the unit flow chamber database for the MCV housing unit and the governing equation for the flow chamber.Research limitations/implications: Since the MCV damage often occurs due to the problem with the material itself and in the manufacturing process, it is difficult to tell clearly whether it occurred as the MCV reached the failure pressure.Practical implications: The basic data needed to design the MCV can be provided, and the required time for the design and the reliability of the design can be reduced and improved respectively.Originality/value: The verification of the design factors obtained from the flow analysis and structural analysis as well as the DOE was made by fabricating a sample

  17. Dark matter limits froma 15 kg windowless bubble chamber

    Energy Technology Data Exchange (ETDEWEB)

    Szydagis, Matthew Mark; /Chicago U.

    2010-12-01

    The COUPP collaboration has successfully used bubble chambers, a technology previously applied only to high-energy physics experiments, as direct dark matter detectors. It has produced the world's most stringent spin-dependent WIMP limits, and increasingly competitive spin-independent limits. These limits were achieved by capitalizing on an intrinsic rejection of the gamma background that all other direct detection experiments must address through high-density shielding and empirically-determined data cuts. The history of COUPP, including its earliest prototypes and latest results, is briefly discussed in this thesis. The feasibility of a new, windowless bubble chamber concept simpler and more inexpensive in design is discussed here as well. The dark matter limits achieved with a 15 kg windowless chamber, larger than any previous COUPP chamber (2 kg, 4 kg), are presented. Evidence of the greater radiopurity of synthetic quartz compared to natural is presented using the data from this 15 kg device, the first chamber to be made from synthetic quartz. The effective reconstruction of the three-dimensional positions of bubbles in a highly distorted optical field, with ninety-degree bottom lighting similar to cloud chamber lighting, is demonstrated. Another innovation described in this thesis is the use of the sound produced by bubbles recorded by an array of piezoelectric sensors as the primary means of bubble detection. In other COUPP chambers, cameras have been used as the primary trigger. Previous work on bubble acoustic signature differentiation using piezos is built upon in order to further demonstrate the ability to discriminate between alpha- and neutron-induced events.

  18. Practical electron dosimetry: a comparison of different types of ionization chambers

    International Nuclear Information System (INIS)

    Since Markus chambers are no longer recommended in the 1997 DIN 6800-2 version there are uncertainties as to the use of alternative chamber types for electron dosimetry. Therefore, we performed a comparison between different types of ionization chambers. In particular, the widespread Farmer and Roos chambers were compared with the Markus chamber for polarity effect, chamber-to-chamber variation, and deviations of the measured absorbed dose relative to the value obtained with the Roos chamber (which is regarded as an ideal Bragg-Gray-chamber). The perturbation correction factor at 60Co radiation was determined experimentally as 1,029 ± 0,5% (Roos chamber) and 1,018 ± 0,5% (Markus chamber) for the investigated plane-parallel chambers. In addition, we could show that the Roos chambers do not have a larger chamber-to-chamber variation than the Farmer chambers. Likewise, our results suggest that Farmer chambers could be used for electron energies above 6 MeV. (orig.)

  19. Magma Chambers, Thermal Energy, and the Unsuccessful Search for a Magma Chamber Thermostat

    Science.gov (United States)

    Glazner, A. F.

    2015-12-01

    Although the traditional concept that plutons are the frozen corpses of huge, highly liquid magma chambers ("big red blobs") is losing favor, the related notion that magma bodies can spend long periods of time (~106years) in a mushy, highly crystalline state is widely accepted. However, analysis of the thermal balance of magmatic systems indicates that it is difficult to maintain a significant portion in a simmering, mushy state, whether or not the system is eutectic-like. Magma bodies cool primarily by loss of heat to the Earth's surface. The balance between cooling via energy loss to the surface and heating via magma accretion can be denoted as M = ρLa/q, where ρ is magma density, L is latent heat of crystallization, a is the vertical rate of magma accretion, and q is surface heat flux. If M>1, then magma accretion outpaces cooling and a magma chamber forms. For reasonable values of ρ, L, and q, the rate of accretion amust be > ~15 mm/yr to form a persistent volume above the solidus. This rate is extremely high, an order of magnitude faster than estimated pluton-filling rates, and would produce a body 10 km thick in 700 ka, an order of magnitude faster than geochronology indicates. Regardless of the rate of magma supply, the proportion of crystals in the system must vary dramatically with depth at any given time owing to transfer of heat. Mechanical stirring (e.g., by convection) could serve to homogenize crystal content in a magma body, but this is unachievable in crystal-rich, locked-up magma. Without convection the lower part of the magma body becomes much hotter than the top—a process familiar to anyone who has scorched a pot of oatmeal. Thermal models that succeed in producing persistent, large bodies of magma rely on scenarios that are unrealistic (e.g., omitting heat loss to the planet's surface), self-fulfilling prophecies (e.g., setting unnaturally high temperatures as fixed boundary conditions), or physically unreasonable (e.g., magma is intruded

  20. UHV testing of upgraded vacuum chambers for Indus-1

    International Nuclear Information System (INIS)

    Indus-1 is a 450 MeV, 100 mA dedicated electron storage ring operating at pressure 10-10 mbar range without beam and 10-9 mbar range with beam using triode sputter ion pump (SIP) and titanium sublimation pump (TSP) combination. Indus-1 storage ring is presently working with six operational beam lines installed at three bending magnets. To accommodate two more beam lines and to reduce number of demountable joints, up-gradation of Indus-1 UHV system was planned. Salient features of upgraded vacuum system are bending magnet vacuum chambers with one extra port for additional beam line and straight section vacuum chambers with integrated TSP body. Half of the Indus-1 storage ring vacuum envelope with two bending magnet vacuum chamber and six straight section vacuum chambers were assembled with pumps, gauges etc, leak tested and tested for its UHV performance. Ultimate vacuum 5x10-10 mbar with SIP and 2x10-10 mbar after TSP pumping were achieved. Residual gas analyser (RGA) spectrum recorded for residual gas analysis indicated the imprints of a typical all metal UHV system having H2 as major gas. This paper describes UHV testing of upgraded, newly fabricated vacuum chambers for Indus-1 storage ring. (author)

  1. Inertial confinement fusion reaction chamber and power conversion system study

    International Nuclear Information System (INIS)

    GA Technologies has developed a conceptual ICF reactor system based on the Cascade rotating-bed reaction chamber concept. Unique features of the system design include the use of low activation SiC in a reaction chamber constructed of box-shaped tiles held together in compression by prestressing tendons to the vacuum chamber. Circulating Li2O granules serve as the tritium breeding and energy transport material, cascading down the sides of the reaction chamber to the power conversion system. The total tritium inventory of the system is 6 kg; tritium recovery is accomplished directly from the granules via the vacuum system. A system for centrifugal throw transport of the hot Li2O granules from the reaction chamber to the power conversion system has been developed. A number of issues were evaluated during the course of this study. These include the response of first-layer granules to the intense microexplosion surface heat flux, cost effective fabrication of Li2O granules, tritium inventory and recovery issues, the thermodynamics of solids-flow options, vacuum versus helium-medium heat transfer, and the tradeoffs of capital cost versus efficiency for alternate heat exchange and power conversion system option. The resultant design options appear to be economically competitive, safe, and environmentally attractive

  2. Integrated inertial fusion energy chamber dynamics and response

    Energy Technology Data Exchange (ETDEWEB)

    Uddin, Hasib, E-mail: uddin3@illinois.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana–Champaign, Urbana, IL 61801 (United States); Kramer, Richard; Pantano, Carlos [Department of Mechanical Science and Engineering, University of Illinois at Urbana–Champaign, Urbana, IL 61801 (United States); Kramer, Kevin; Tang, Vincent [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Sacks, Ryan; Moses, Gregory [Fusion Technology Institute, University of Wisconsin Madison, Madison, WI 53706 (United States); Hunt, Ryan; DeMuth, James; Scott, Howard; Dunne, A. Mike [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)

    2014-12-15

    Highlights: • LES with embedded geometry. • Repetitive IFE chamber state. • Sensitivity to blast modeling. - Abstract: This paper presents results of three-dimensional hydrodynamics simulations of the flow inside a model inertial fusion energy (IFE) fusion chamber. Turbulence modeling employing the large-eddy simulation approach is used to estimate the gas dynamics, state, and mixing after a sufficiently large number of target ignitions. The rich radiation-flow physics that takes place immediately after the lasers hit the hohlraum is modeled separately using a high-fidelity one-dimensional model, which provides reference conditions for the complex geometry three-dimensional turbulence simulations. The IFE geometry includes optical ports and recirculation openings as well as a duct to evacuate the debris produced after each energy deposition (as a model of a laser shot). Furthermore, a selected set of sensitivity studies are conducted to estimate the effect of uncertainty in radiative properties of the Xenon gas at the prevalent conditions in the chamber. The results provide guidance regarding the turbulence conditions in the chamber, which seem to have entered a decay state immediately before a new shot takes place. Computational estimates of the density variability within the chamber as well as pressure history at the approximate location of the laser optical ports is presented among other turbulence statistics.

  3. Integrated inertial fusion energy chamber dynamics and response

    International Nuclear Information System (INIS)

    Highlights: • LES with embedded geometry. • Repetitive IFE chamber state. • Sensitivity to blast modeling. - Abstract: This paper presents results of three-dimensional hydrodynamics simulations of the flow inside a model inertial fusion energy (IFE) fusion chamber. Turbulence modeling employing the large-eddy simulation approach is used to estimate the gas dynamics, state, and mixing after a sufficiently large number of target ignitions. The rich radiation-flow physics that takes place immediately after the lasers hit the hohlraum is modeled separately using a high-fidelity one-dimensional model, which provides reference conditions for the complex geometry three-dimensional turbulence simulations. The IFE geometry includes optical ports and recirculation openings as well as a duct to evacuate the debris produced after each energy deposition (as a model of a laser shot). Furthermore, a selected set of sensitivity studies are conducted to estimate the effect of uncertainty in radiative properties of the Xenon gas at the prevalent conditions in the chamber. The results provide guidance regarding the turbulence conditions in the chamber, which seem to have entered a decay state immediately before a new shot takes place. Computational estimates of the density variability within the chamber as well as pressure history at the approximate location of the laser optical ports is presented among other turbulence statistics

  4. Design and construction of the CLEO II drift chamber

    International Nuclear Information System (INIS)

    We have constructed a new large cylindrical drift chamber (2 m long and 2 m in diameter) for the CLEO II experiment at the Cornell Electron Storage Ring (CESR). The chamber contains 51 readout layers including 11 stereo layers, with 48480 (12240) total (sense) wires. Segmented cathode strips were used instead of field wires for the innermost and outermost layers to provide two accurate measurements of the longitudinal coordinate. Very low density support structures were developed to hold the cathode strips. Aluminium wire was used for the majority of the field wires to reduce multiple scattering and the tension load on the endplates. A semiautomatic apparatus was developed to string wires with the chamber mounted vertically. With this system, it was also possible to replace any wire in the chamber. A maximum stringing rate of 60 wires/h, was achieved. The tension on all wires was measured soon after they were strung; the failure rate due to improper tension was typically less than 2%. Hybrid preamplifiers were developed and mounted directly on the chamber on custom printed circuit boards. Each board also contains a pulser calibration system and a high voltage current monitor. High voltage power is individually supplied to each of the 51 layers under computer control. A new type of hardware track finder was developed for the trigger. (orig.)

  5. Low-Cost, High-Performance Combustion Chamber

    Science.gov (United States)

    Fortini, Arthur J.

    2015-01-01

    Ultramet designed and fabricated a lightweight, high-temperature combustion chamber for use with cryogenic LOX/CH4 propellants that can deliver a specific impulse of approx.355 seconds. This increase over the current 320-second baseline of nitrogen tetroxide/monomethylhydrazine (NTO/MMH) will result in a propellant mass decrease of 55 lb for a typical lunar mission. The material system was based on Ultramet's proven oxide-iridium/rhenium architecture, which has been hot-fire tested with stoichiometric oxygen/hydrogen for hours. Instead of rhenium, however, the structural material was a niobium or tantalum alloy that has excellent yield strength at both ambient and elevated temperatures. Phase I demonstrated alloys with yield strength-to-weight ratios more than three times that of rhenium, which will significantly reduce chamber weight. The starting materials were also two orders of magnitude less expensive than rhenium and were less expensive than the C103 niobium alloy commonly used in low-performance engines. Phase II focused on the design, fabrication, and hot-fire testing of a 12-lbf thrust class chamber with LOX/CH4, and a 100-lbf chamber for LOX/CH4. A 5-lbf chamber for NTO/MMH also was designed and fabricated.

  6. The Cathode Strip Chamber Data Acquisition System for CMS

    CERN Document Server

    Bylsma, B G; Gilmore, J R; Gu, J H; Ling, T Y

    2007-01-01

    The Cathode Strip Chamber (CSC) [1] Data Acquisition (DAQ) system for the CMS [2] experiment at the LHC [3] will be described. The CSC system is large, consisting of 218K cathode channels and 183K anode channels. This leads to a substantial data rate of ~1.5GByte/s at LHC design luminosity (1034cm-2s-1) and the CMS first level trigger (L1A) rate of 100KHz. The DAQ system consists of three parts. The first part is on-chamber Cathode Front End Boards (CFEB)[4], which amplify, shape, store, and digitise chamber cathode signals, and Anode Front End Boards (AFEB)[5], which amplify, shape and discriminate chamber anode signals. The second part is the Peripheral Crate Data Acquisition Motherboards (DAQMB), which control the onchamber electronics and the readout of the chamber. The third part is the off-detector DAQ interface boards, which perform real time error checking, electronics reset requests and data concentration. It passes the resulting data to a CSC local DAQ farm, as well as CMS main DAQ [6]. All electron...

  7. Thin wall vacuum reaction chamber for neutron measurement

    International Nuclear Information System (INIS)

    A thin wall (3 mm) stainless steel vacuum reaction chamber has been designed, fabricated and installed in the K500 superconducting beam hall at VECC for the in-beam experiment. The chamber is spherical in shape, with inner diameter 1010 mm, having three independent sections. The middle segment is fixed to the beam line, whereas the two hemispherical sections are removable type with the help of hydraulic trolleys. This specific design facilitates almost 360 degree access of the chamber for setting up an experiment. The typical vacuum ∼ 4 x 10-7 mbar is achieved by two 550 lit/sec air cooled turbo molecular pumps backed by two 35 m3/hr scroll pumps in ∼ 8 hours. PLC based control system has been developed for the operation of pumps. 12 rings are fabricated to mount detectors, each having 440 mm radius and separated by 30° from each other in polar angle. These rings are supported inside the chamber by two flanges placed along the beam line. These rings are properly calibrated in polar and azimuthal angles with respect to the centre of the chamber. (author)

  8. Calculation of longitudinal CSR impedance in curved chamber

    International Nuclear Information System (INIS)

    Coherent synchrotron radiation (CSR) fields are generated when a bunched beam moves along a curved trajectory. A new code, named CSRZ, was developed using finite difference method to calculate the longitudinal CSR impedance for a beam moving along a curved chamber. The method adopted in our code was originated by T. Agoh and K. Yokoya [1]. It solves the parabolic equation in the frequency domain in a curvilinear coordinate system. In our studies, the chamber has uniform rectangular crosssection along the beam trajectory, which is the same as that in [1]. But the curvature of the beam trajectory is freed, and then we can investigate the CSR impedance of a single or a series of bending magnets. The calculation results indicate that the shielding effect due to outer chamber wall can be well explained by a simple optical approximation model at high frequencies. With an approximation of a wiggling chamber inside a wiggler, the coherent wiggler radiation (CWR) impedance has also been studied. Due to chamber shielding, the CWR impedance exhibits narrow peaks at frequencies satisfying the resonant conditions. (author)

  9. Forecasting magma-chamber rupture at Santorini volcano, Greece

    Science.gov (United States)

    Browning, John; Drymoni, Kyriaki; Gudmundsson, Agust

    2015-10-01

    How much magma needs to be added to a shallow magma chamber to cause rupture, dyke injection, and a potential eruption? Models that yield reliable answers to this question are needed in order to facilitate eruption forecasting. Development of a long-lived shallow magma chamber requires periodic influx of magmas from a parental body at depth. This redistribution process does not necessarily cause an eruption but produces a net volume change that can be measured geodetically by inversion techniques. Using continuum-mechanics and fracture-mechanics principles, we calculate the amount of magma contained at shallow depth beneath Santorini volcano, Greece. We demonstrate through structural analysis of dykes exposed within the Santorini caldera, previously published data on the volume of recent eruptions, and geodetic measurements of the 2011-2012 unrest period, that the measured 0.02% increase in volume of Santorini’s shallow magma chamber was associated with magmatic excess pressure increase of around 1.1 MPa. This excess pressure was high enough to bring the chamber roof close to rupture and dyke injection. For volcanoes with known typical extrusion and intrusion (dyke) volumes, the new methodology presented here makes it possible to forecast the conditions for magma-chamber failure and dyke injection at any geodetically well-monitored volcano.

  10. Realization of radioactive equilibrium in the KRISS radon chamber

    International Nuclear Information System (INIS)

    The maintenance of radioactive equilibrium between radon and its decay products in a radon chamber is necessary to calibrate radon decay product monitors. In this study, the activity concentrations of radon decay products have been measured, and mosquito-repellent incense has been used to produce aerosol particles in the chamber. Filter papers with 8 μm pore size were used to collect aerosol in the chamber. The activity concentrations of radon decay products have been evaluated by the Modified Tsivoglou Method. The correction factors due to the differences in counting time requirements of the Modified Tsivoglou Method and the time delay between consecutive measurements have been determined. Finally, the radioactive equilibrium has been confirmed by applying the Bateman equation. - Highlights: • The activity concentrations of radon decay products are evaluated by the Modified Tsivoglou Method. • Mosquito-repellent incense is used to produce aerosol particles in the radon chamber. • The radioactive equilibrium in the chamber was achieved within 2 days and confirmed by the Bateman equation

  11. A recording chamber for small volume slice electrophysiology.

    Science.gov (United States)

    Dondzillo, Anna; Quinn, Kevin D; Cruickshank-Quinn, Charmion I; Reisdorph, Nichole; Lei, Tim C; Klug, Achim

    2015-09-01

    Electrophysiological recordings from brain slices are typically performed in small recording chambers that allow for the superfusion of the tissue with artificial extracellular solution (ECS), while the chamber holding the tissue is mounted in the optical path of a microscope to image neurons in the tissue. ECS itself is inexpensive, and thus superfusion rates and volumes of ECS consumed during an experiment using standard ECS are not critical. However, some experiments require the addition of expensive pharmacological agents or other chemical compounds to the ECS, creating a need to build superfusion systems that operate on small volumes while still delivering appropriate amounts of oxygen and other nutrients to the tissue. We developed a closed circulation tissue chamber for slice recordings that operates with small volumes of bath solution in the range of 1.0 to 2.6 ml and a constant oxygen/carbon dioxide delivery to the solution in the bath. In our chamber, the ECS is oxygenated and recirculated directly in the recording chamber, eliminating the need for tubes and external bottles/containers to recirculate and bubble ECS and greatly reducing the total ECS volume required for superfusion. At the same time, the efficiency of tissue oxygenation and health of the section are comparable to standard superfusion methods. We also determined that the small volume of ECS contains a sufficient amount of nutrients to support the health of a standard brain slice for several hours without concern for either depletion of nutrients or accumulation of waste products. PMID:26203105

  12. Initial Back-to-Back Fission Chamber Testing in ATRC

    Energy Technology Data Exchange (ETDEWEB)

    Benjamin Chase; Troy Unruh; Joy Rempe

    2014-06-01

    Development and testing of in-pile, real-time neutron sensors for use in Materials Test Reactor experiments is an ongoing project at Idaho National Laboratory. The Advanced Test Reactor National Scientific User Facility has sponsored a series of projects to evaluate neutron detector options in the Advanced Test Reactor Critical Facility (ATRC). Special hardware was designed and fabricated to enable testing of the detectors in the ATRC. Initial testing of Self-Powered Neutron Detectors and miniature fission chambers produced promising results. Follow-on testing required more experiment hardware to be developed. The follow-on testing used a Back-to-Back fission chamber with the intent to provide calibration data, and a means of measuring spectral indices. As indicated within this document, this is the first time in decades that BTB fission chambers have been used in INL facilities. Results from these fission chamber measurements provide a baseline reference for future measurements with Back-to-Back fission chambers.

  13. Principles of operation of multiwire proportional and drift chambers

    International Nuclear Information System (INIS)

    The first multiwire proportional chamber, in its modern conception, was constructed and operated in the years 1967-68. It was soon recognized that the main properties of a multiwire proportional chamber, i.e. very good time resolution, good position accuracy and self-triggered operation, are very attractive for the use of the new device in high-energy physics experiments. Today, most fast detectors contain a large number of proportional chambers, and their use has spread to many different fields of applied research, such as X-ray and heavy ion astronomy, nuclear medicine, and protein crystallography. In many respects, however, multiwire proportional chambers are still experimental devices, requiring continuous attention for good operation and sometimes reacting in unexpected ways to a change in the environmental conditions. Furthermore, in the fabrication and operation of a chamber people seem to use a mixture of competence, technical skill and magic rites, of the kind ''I do not know why I'm doing this but somebody told me to do so''. In these notes the authors illustrate the basic phenomena underlying the behaviour of a gas detector, with the hope that the reader will not only better understand the reasons for some irrational-seeming preferences (such as, for example, in the choice of the gas mixture), but will also be able better to design detectors for his specific experimental needs

  14. Forecasting magma-chamber rupture at Santorini volcano, Greece.

    Science.gov (United States)

    Browning, John; Drymoni, Kyriaki; Gudmundsson, Agust

    2015-01-01

    How much magma needs to be added to a shallow magma chamber to cause rupture, dyke injection, and a potential eruption? Models that yield reliable answers to this question are needed in order to facilitate eruption forecasting. Development of a long-lived shallow magma chamber requires periodic influx of magmas from a parental body at depth. This redistribution process does not necessarily cause an eruption but produces a net volume change that can be measured geodetically by inversion techniques. Using continuum-mechanics and fracture-mechanics principles, we calculate the amount of magma contained at shallow depth beneath Santorini volcano, Greece. We demonstrate through structural analysis of dykes exposed within the Santorini caldera, previously published data on the volume of recent eruptions, and geodetic measurements of the 2011-2012 unrest period, that the measured 0.02% increase in volume of Santorini's shallow magma chamber was associated with magmatic excess pressure increase of around 1.1 MPa. This excess pressure was high enough to bring the chamber roof close to rupture and dyke injection. For volcanoes with known typical extrusion and intrusion (dyke) volumes, the new methodology presented here makes it possible to forecast the conditions for magma-chamber failure and dyke injection at any geodetically well-monitored volcano. PMID:26507183

  15. Bluetooth Communication Interface for EEG Signal Recording in Hyperbaric Chambers.

    Science.gov (United States)

    Pastena, Lucio; Formaggio, Emanuela; Faralli, Fabio; Melucci, Massimo; Rossi, Marco; Gagliardi, Riccardo; Ricciardi, Lucio; Storti, Silvia F

    2015-07-01

    Recording biological signals inside a hyperbaric chamber poses technical challenges (the steel walls enclosing it greatly attenuate or completely block the signals as in a Faraday cage), practical (lengthy cables creating eddy currents), and safety (sparks hazard from power supply to the electronic apparatus inside the chamber) which can be overcome with new wireless technologies. In this technical report we present the design and implementation of a Bluetooth system for electroencephalographic (EEG) recording inside a hyperbaric chamber and describe the feasibility of EEG signal transmission outside the chamber. Differently from older systems, this technology allows the online recording of amplified signals, without interference from eddy currents. In an application of this technology, we measured EEG activity in professional divers under three experimental conditions in a hyperbaric chamber to determine how oxygen, assumed at a constant hyperbaric pressure of 2.8 ATA , affects the bioelectrical activity. The EEG spectral power estimated by fast Fourier transform and the cortical sources of the EEG rhythms estimated by low-resolution brain electromagnetic analysis were analyzed in three different EEG acquisitions: breathing air at sea level; breathing oxygen at a simulated depth of 18 msw, and breathing air at sea level after decompression. PMID:25608308

  16. Microbiological profile of anterior chamber aspirates following uncomplicated cataract surgery

    Directory of Open Access Journals (Sweden)

    Prajna N

    1998-01-01

    Full Text Available Anterior chamber aspirate cultures were done for 66 patients who underwent either an uncomplicated intracapsular cataract extraction, extracapsular cataract extraction with posterior-chamber intraocular lens implantation, or phacoemulsification with posterior-chamber intraocular lens implantation. The aspirate was obtained at the time of wound closure. The aspirates were immediately transferred to the microbiology laboratory where one drop of the aspirate was placed on a glass slide for gram stain, and the remainder was unequally divided and inoculated into blood agar, chocolate agar and thioglycolate broth. The cultures were incubated at 37° C with 5% CO2 and held for 5 days. Of 66 patients 4 (6%, had smear-positive anterior chamber aspirates. None of the aspirates showed any growth on any of the 3 culture media used. None of the eyes in the study developed endophthalmitis. This study concludes that there is no contamination of the anterior chamber by viable bacteria after cataract surgery, irrespective of the mode of intervention.

  17. Establishment of the RSS reentrant chamber as a reference standard for brachytherapy sources

    International Nuclear Information System (INIS)

    Re-entrant chambers provide a reliable, sensitive and easy method for calibrating the brachytherapy sources, at the hospital site. This work reports on the establishment of the RSS well chamber, as a reference chamber, for the routine calibration of the hospital well chambers

  18. Construction of an ionization chamber for buildup measurements in megavoltage X-ray beams

    International Nuclear Information System (INIS)

    The design and construction of a simple homemade ion chamber for brildup measurements in megavoltage beams is described. Tests indicate that the performance of the chamber is superior in some respects to a commercially available chamber. Results obtained using the chamber in a 6 MV beam are presented. (Author)

  19. Chamber Design for the Laser Inertial Fusion Energy (LIFE) Engine

    International Nuclear Information System (INIS)

    The Laser Inertial Fusion Energy (LIFE) concept is being designed to operate as either a pure fusion or hybrid fusion-fission system. The present work focuses on the pure fusion option. A key component of a LIFE engine is the fusion chamber subsystem. It must absorb the fusion energy, produce fusion fuel to replace that burned in previous targets, and enable both target and laser beam transport to the ignition point. The chamber system also must mitigate target emissions, including ions, x-rays and neutrons and reset itself to enable operation at 10-15 Hz. Finally, the chamber must offer a high level of availability, which implies both a reasonable lifetime and the ability to rapidly replace damaged components. An integrated design that meets all of these requirements is described herein.

  20. OPAL Central Detector (Including vertex, jet and Z chambers)

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. OPAL's central tracking system consists of (in order of increasing radius) a silicon microvertex detector, a vertex detector, a jet chamber, and z-chambers. All the tracking detectors work by observing the ionization of atoms by charged particles passing by: when the atoms are ionized, electrons are knocked out of their atomic orbitals, and are then able to move freely in the detector. These ionization electrons are detected in the different parts of the tracking system. (This piece includes the vertex, jet and Z chambers) In the picture above, the central detector is the piece being removed to the right.