Beam Tube Research Articles

Connection Performance of Bolted Aluminum Alloy Honeycomb Panel-Beam Composite Structure

A convenient and reliable connection between panels and beams was investigated for collaborative work of single-layer composite reticulated shell structure in which aluminum alloy honeycomb panels participate. In the paper, the "self-tapping bolt" connection was adopted to realize the "tight fit" performance of connection effectively in the composite structure. Through three groups of bearing capacity test on 1.5 m×3 m square meters of the aluminum alloy honeycomb panel-square tube beam combined structure, the force characteristics and failure mechanism of the structures were studied. The experimental results revealed that the connection method could ensure effective transmission between the panel and the beam which made them work in excellent condition. In order to simulate complex performance connection with the panel-beam composite structure, tangential and normal contact behavior were considered at the bolt connection point between the honeycomb panel and the beam in ABAQUS analysis. The analysis results illustrated that the finite element results had the highest matching degree with the experimental values when the friction coefficient of the joint boundary was 0.25. The finite element analysis of the connection bolts spacing indicated that the economic and excellent connection effect can be achieved when the spacing was about 90 mm.

Prefabricated connection for steel beam and concrete-filled steel tube column

A new type of connection system with steel beam and concrete-filled steel tube (CFST) column is proposed in this paper. This type of connection system uses internal stiffeners and high-strength threaded steel rods to connect the steel beams in two directions with the assistance of side plates pre-welded on the column, intending to serve for high-rise buildings where moderate or high ductility is required, and is geometrically possible to be covered within the wall or floor space therefore offering architectural pleasing. The force transfer mechanisms of the connection are important for the corresponding load-carrying capacities and may be different in the two beam directions. In order to investigate the mechanical properties of the connection system, four different specimens, including interior and exterior connections with corresponding columns and beams in two directions, were made and examined under monotonic loadings, further with comparison to FE modelling results. The results of experimental and numerical investigations indicate the proposed connection system offers satisfactory stiffness and load-carrying capacities. Force transfer mechanisms are discussed with assistance from stress and strain responses identified from validated FE modelling in details. Design considerations are further highlighted for implementation in practice.

Field Compensation in Electron-Ion Collider Magnets With a Passive Superconducting Shield

This paper presents work under a Small Business Innovation Research Phase I grant to Particle Beam Lasers, Inc. and Brookhaven National Laboratory to develop a passive superconducting shield as an alternative to the present design of an active shield with superconducting coils. This shielding provides a nearly field-free region for the electron beam near the high-gradient quadrupole for the proton beam in the interaction region (IR) of the proposed electron ion collider. Several materials are being examined for this shielding-tubes of low- or high-temperature superconductors (LTS or HTS), LTS sheets, and HTS tapes. Supplementing this shielding is an iron ring between the superconducting shield and beam tube to counter any decay in shielding currents. If successfully developed, demonstrated, and shown to be compatible with the magnet designs of all the IR magnets, this technique will provide an economical and technically excellent solution that reduces the need to operate IR magnets at higher current. This paper will summarize the latest design studies and test results both at 77 K for the shielding by the bulk-HTS tube and at 4 K for the shielding by tubes of HTS or LTS.

Optical detection in magnetic state-selection Cs beam tubes for transportable Cs beam clocks

Cs beam clocks are indispensable instruments for time and frequency measurements. We adopt an optical detection method, which employs an external distributed-feedback laser diode, for counting the number of Cs atoms in a Cs beam tube using magnetic state selection. Our method converts the number of Cs atoms into that of emitted fluorescent photons, thereby largely enhancing the signal amplitude so that it can be detected by common circuits without involving additional noises. The signal-to-noise ratio in this experiment reaches 3000 in a bandwidth of 1 Hz. In comparison to the traditional detection method that adopts magnetic state-selectors, ionizers, mass spectrometers and electron multipliers, the optical detection method can simplify the structure and extend the lifetime of the Cs beam tubes. A Cs beam clock adopting this detection method demonstrates a short-term stability of 9 × 10−12 τ−1/2 and has been operating continuously for more than nine months.

Simulation of a collimator and sapphire filter for PGAA facility of the Moroccan TRIGA MARK II research reactor

The Prompt Gamma Neutron Activation Analysis (PGAA) facility will be commissioned at the NB1 beam tube of the Moroccan TRIGA MARK II research reactor. PGAA is a non-destructive analytical technique used for multi-elemental analysis and especially for light element analysis. For better performances, PGAA requires small and focused beam, and high Фth/Фep and Фth/Фfast ratios, and low background gamma radiation. For this purpose, fast neutron filters are commonly used to reduce fast and epithermal components of neutron flux. In this paper, the impact of sapphire filter, introduced, within the collimator hole, at the beam port on neutron spectra was evaluated. Monte Carlo, MCNP6.2, code has been used with ENDF VII.1 neutron cross section library to perform this study. An approximate TRIGA MARK II reactor MCNP model has been used to generate neutron spectra at the entrance of the collimator. Then an independent model for both collimator and sapphire filter has been brought into calculation to fulfil our purpose. Results showed an increase of about 8 times for both Фth/Фep and Фth/Фfast ratios using a 10 cm length of sapphire.

Finite Element Study on Shear Performances of In-filled Bolt Joint of Assembled GRC Wall with Light Steel Skeleton Frame

A new in-filled wall is used in assembled steel structure buildings, which consists of two layers of glass fiber reinforced concrete (GRC) panels and a built-in light steel skeleton frame. To make this new wall fill in the main steel structure, a new in-filled bolt joint is used. In order to obtain the mechanical properties and failure modes under shear load, the shear performances of this joint were studied with the finite element (FE) software ABAQUS. The results show that before reaching the fracture failure strain, the in-filled bolt joint shows good elastic-plastic behaviour. When the strain of the in-filled bolt joint reaches the failure strain, the shear load reaches the peak value. Subsequently, due to the shear fracture of the bolt, the shear load drops rapidly. Throughout the loading process, the stress of steel beam and rectangular steel tube is always very small and the stress of the joint yields in a large area in the later stage.

The research reactor TRIGA Mainz – a strong and versatile neutron source for science and education

Abstract The TRIGA Mark II-reactor at the Johannes Gutenberg University Mainz (JGU) is one of three research reactors in Germany. The TRIGA Mainz became first critical on August 3rd, 1965. It can be operated in the steady state mode with a maximum power of 100 kWth and in the pulse mode with a peak power of 250 MWth and a pulse length of 30 ms. The TRIGA Mainz is equipped with a central thimble, a rotary specimen rack, three pneumatic transfer systems, four beam tubes, and a graphite thermal column. The TRIGA Mainz is intensively used both for basic and applied research in nuclear chemistry and nuclear physics. Two sources for ultra-cold neutrons (UCN) are operational at two beam ports. At a third beam port a Penning-Trap for highly precise mass measurements of exotic nuclides is installed. Education and training is another main field of activity. Here, various courses in nuclear and radiochemistry, reactor operation and reactor physics are held for scientists, advanced students, engineers, and technicians utilizing the TRIGA Mainz reactor.

Study on heat transfer between the High-Luminosity LHC beam screens and the He II-cooled beam tube

The new beam screens for the inner triplets in the HL-LHC are designed to intercept heat loads of up to 25 Wm−1 between 60 K and 80 K. The screens need to be mechanically supported by the beam tube at 1.9 K while limiting heat transfer to the same tube to less than 0.5 W m−1. Measurements for the thermal validation of the beam screens were carried out on a dedicated test stand at the Central Cryogenic Laboratory at CERN. This paper describes the first measurement campaign of a full-scale D1-type beam screen mock-up: several parameters such as base temperature and heating power were varied, and results include heat transfer mechanisms within the beam screen and more importantly to the 1.9 K beam tube that forms the physical boundary between beam screen and He II-cooled magnets.

Augmenting the fine beam tube: From hybrid measurements to magnetic field visualization

Since the emergence of augmented reality (AR), it has been a constant subject of educational research, as it can improve conceptual understanding and generally promote learning. In addition, a motivational effect and improved interaction and collaboration through AR were observed. Recently, AR technologies have taken a major leap forward in development, such that head-mounted devices or smartglasses in particular are now finding their first applications in STEM education, especially in experiments. In line with these developments, we here present an AR experiment in electrodynamics for undergraduate laboratory courses in physics using real-time physical data from and virtual tools on mobile devices to both analyze and visualize physical phenomena.

Field Quality of HD3—A Nb<inline-formula> <tex-math notation="LaTeX">$_3$</tex-math> </inline-formula>Sn Dipole Magnet Based on Block Design

Author(s): Wang, X; Cheng, DW; Dietderich, DR; DiMarco, J; Felice, H; Ferracin, P; Marchevsky, M; Prestemon, SO; Sabbi, G | Abstract: HD3 is the latest magnet of a series of block-type Nb3Sn dipole model magnets developed by the Superconducting Magnet Program at Lawrence Berkeley National Laboratory. The magnet is 1 m long with a clear aperture of 43 mm. As a model magnet designed with accelerator-quality features, each coil has flared ends to provide a clear bore for a beam tube. The magnet design was also optimized to minimize the geometric and saturation field errors. In 2013, HD3b reached a peak dipole field of 13.4 T at 4.4 K. As part of the magnet test, we measured field quality using rotating coils with lengths of 26 and 130 mm developed by Fermi National Accelerator Laboratory. Here, we report and analyze the measured static and dynamic field errors. We discuss the insight provided by the field quality study of HD3, which can be useful for the development of high-field block-type dipole magnets for next-generation circular colliders.

A neutron radiography beamline relying on the Isfahan Miniature Neutron Source Reactor

Abstract Concerning to the costs of the establishment of new research reactors and their waste issues, the world’s quest is to expand the capabilities of existing research reactors and to develop their application further. In this way, attempts have been made to extract an appropriate thermal neutron beam for neutron radiography purposes at the 30 kW Isfahan MNSR reactor. In this study, the result of calculations and experiments in support of the implementation of a thermal neutron radiography beamline at this reactor has been demonstrated. While many research reactors have beam tube equipment, the original design of the MNSR did not include beam tubes. Therefore, at first stage of our feasibility study, a vertical aluminum tube with a diameter of about 5 cm has been used as an external beam tube to validate calculated values of MCNP code with experimental measurements. The image quality has been determined using ASTM image quality indicators. It can conclude that the Isfahan MNSR is an appropriate reactor with suitable neutron flux for a neutron radiography system. Results show that it is possible to obtain an appropriate neutron radiography beam at this low power research reactor. Also, according to the physical restrictions of the MNSR and considering the least possible changes in the current reactor status, some beam tubes with larger beam diameters have been designed and the related beam parameters have been calculated and demonstrated.

Evolution characteristics of spontaneous combustion in three zones of the goaf when using the cutting roof and release pressure technique

AbstractThe changes associated with the cutting roof and release pressure mining method in the three zones that are susceptible to spontaneous combustion in the goaf with “Y” type ventilation system were studied. For the investigated underground coal mine working face, its three zones of spontaneous combustion have a “U” type ventilation system for the traditional mining method and a “Y” type ventilation system for the cutting roof and release pressure mining method. These systems were monitored using a beam tube method, and the evolution characteristics of spontaneous combustion of the three zones was analysed. The monitoring data showed that when using a traditional mining method with a “U” type ventilation system, the scattered tropical zone converts into the oxidation heating zone after 68.5 m in the goaf, and the suffocative zone presents after 85.5 m. For the cutting roof and release pressure mining method together with a “Y” type ventilation system, the scattered tropical zone converts into the oxidation heating zone after 84 m in the goaf, and the suffocative zone appears after 198.8 m. Compared to traditional mining, the width of the oxidation heating zone increases when using the cutting roof and release pressure method. To prevent spontaneous combustion of the goaf, the comprehensive techniques of the pressure balance for fire control, ground fissure sealing, working face sealing, retained roadways guniting and inert gas fire extinguishing have been used in the studied coal mine. The CO concentration of the goaf is less than 300 ppm during the mining process. Safe mining of the tested working face shows that the cutting roof and release pressure technique can be applied to control the coal seam spontaneous combustion.

CHALLENGES IN CLINICAL PRACTICE OF CR MAMMOGRAPHY IN TANZANIA.

The aim of this study was to evaluate the clinical practice of CR mammography in Tanzania. The equipment performance and operational conditions were studied; and mean glandular dose (DG) estimated to 75 women undergoing diagnosis at three mammography facilities. All mammograms during this study were reported to be useful for the intended diagnosis. The median DG for craniocaudal and mediolateral oblique projections ranged from 1.27 ± 0.18 mGy to 1.9 ± 0.27 mGy and from 1.3 ± 0.18 mGy to 1.9 ± 0.27 mGy, respectively, and were below the national regulatory guidance of 2.5 mGy. Despite this positive result, unavoidable inappropriate use of beam quality and tube loading settings which could have been through appropriate staff training and performing routine quality control were not uncommon. This work provides an insight of current operational conditions of CR in Tanzania and what strategy should be employed to this service to improve patient care in the country.

Diffraction-Beam Optics of Filamentation: I–Formalism of Diffraction Beams and Light Tubes

The concept of nonstationary diffraction-beam optics of high-power femtosecond laser pulses is presented. According to the concept, the power of a beam propagates along specific light structures—diffraction- beam tubes. These tubes do not intersect and do not exchange energy, but changes in their shape and cross sections during propagation show the effect of physical processes that occur with radiation in the medium. The nonstationary theory is supplemented with evolutionary equations for time-averaged diffraction rays and effective squared radii of diffraction tubes.

Diffraction-Beam Optics of Filamentation: II–Diffraction-Beam Pattern of Laser Pulse Filamentation

Based on the diffraction-ray representation of nonlinear propagation of laser pulses, some examples of visualization of the filamentation of high-power femtosecond laser pulses in air are considered in the form of evolutionary paths of diffraction beams and light tubes. It is ascertained that a filament is supported by the light energy of the part of the beam which is inside a beam tube with the initial peak power higher than the critical power of self-focusing. This light tube is an energy reservoir for the filament. The light beam periphery holds the diffraction-beam tube which includes the filament by means of formation of a “diffractive” waveguide.

The KATRIN superconducting magnets: overview and first performance results

The KATRIN experiment aims for the determination of the effective electron anti-neutrino mass from the tritium beta-decay with an unprecedented sub-eV sensitivity. The strong magnetic fields, designed for up to 6 T, adiabatically guide β-electrons from the source to the detector within a magnetic flux of 191 Tcm2. A chain of ten single solenoid magnets and two larger superconducting magnet systems have been designed, constructed, and installed in the 70-m-long KATRIN beam line. The beam diameter for the magnetic flux varies from 0.064 m to 9 m, depending on the magnetic flux density along the beam line. Two transport and tritium pumping sections are assembled with chicane beam tubes to avoid direct “line-of-sight” molecular beaming effect of gaseous tritium molecules into the next beam sections. The sophisticated beam alignment has been successfully cross-checked by electron sources. In addition, magnet safety systems were developed to protect the complex magnet systems against coil quenches or other system failures. The main functionality of the magnet safety systems has been successfully tested with the two large magnet systems. The complete chain of the magnets was operated for several weeks at 70% of the design fields for the first test measurements with radioactive krypton gas. The stability of the magnetic fields of the source magnets has been shown to be better than 0.01% per month at 70% of the design fields. This paper gives an overview of the KATRIN superconducting magnets and reports on the first performance results of the magnets.

Design of an atom source collimator for a compact frequency-stabilized laser.

A concise laser system for optically pumped cesium beam clocks is presented. The laser's frequency is locked by a fluorescence signal, produced by the interaction between a cesium atomic beam and laser. A cesium oven with a longer atom source collimator, formed by an array of channels, was used to reduce the divergence angle of the cesium atomic beam. The size of the cesium source collimator is 4 mm×0.6 mm, and the cesium expenditure rate is 2.4×10-1 g per year. A dense cesium atomic flux was used to interact with the laser to generate a fluorescence signal when the oven heating temperature is not too high. The cesium beam tube could have a longer lifetime. The optical structure of the laser system is compact. The measured frequency stability of the laser is ∼4×10-11 at 10,000s when the laser frequency is locked in the F=4→F'=5 transition of the cesium D2 line. The design of an atom oven and atom source may be used in other atomic beam clocks to improve their performance.

Чисельне моделювання теплообмінного апарата для різних систем вентиляції

The purpose of the research is to develop and numerical modeling of the shell-tube heat exchanger of a new design as an element of the microclimate maintenance system for various types of ventilation systems in the summer season. Materials and methods of research. As mentioned above, two types of ventilation systems are considered - tunnel and lateral. For these ventilation systems TA is projected. The poultry house is a traditional type. At the side walls there are openings with jackets in the total number of 80 pieces. with dimensions 0,3×0,85 m. And also on the front end walls are located evacuation cooling tapes with dimensions of 5,1×1,1 m. In place of the cassettes and louver we fit the HE. Consider the shell and tube heat exchanger with a shell of a rectangular cross section in the transverse flow of pipe beams. The geometry of the pipes with diameters d = 10 mm is peculiar, which differs from the traditional chess, corridor and compact beams. Neighboring pipes in such close beams are displaced one relative to the other at a distance of 1 mm. Moreover, we consider two types of beam construction, in which there is a displacement of pipes in a transverse direction along the entire length of the tube beam by 15 mm. All calculations are performed at a volume flow of air 1036 thousand m3/h. As a coolant air is selected with a temperature of +40 o С at the inlet, which flows in the channels for cooling the external heated air in the poultry house in the summer period of the year, where as the cooler is used water underground wells. In the soybean, cold water moving inside the pipes, which has an inlet temperature of +10 o C. The layout of the heat carrier movement is cross-linked. Research results and their discussion. The temperature change for different ventilation systems. For tunnel ventilation, the temperature in the TA decreases from +40 to +22.5 o C (Fig. 2), and for the side - from +40 to +19,7 o С. Conclusions and perspectives. 1. A new design of a shell-tube heat exchanger with a compact arrangement of pipes in tubular beams is proposed and developed. 2. Computer-aided mathematical modeling of heat and mass transfer processes in bundles of pipes of different geometries with compact placement of pipes using the software ANSYS Fluent. The fields of velocities, temperatures, and pressure in the studied channels are obtained. The conditions of the hydrodynamic flow in the channels were analyzed and estimates of the heat transfer intensity between the hot and cold coolant through the wall separating them. 3. It was determined that the tunnel ventilation system would be most effective and TA was designed for it.

Analysis and Simulation of a Gripper for Fuel Handling on China Lead-Based Research Reactor

The China lead-based research reactor (CLEAR-I) with 10 MW(thermal) will be built for the research of the accelerator-driven subcritical system (ADS) and lead-cooled fast reactor technology. Compared with other reactors, ADS has a spallation target placed in the reactor core center, which affects the refueling motion in the vessel. It is difficult to reach the fuel assemblies near the proton beam tube through the common vertical refueling gripper. In this technical note, a new cantilever-type and internal grasping gripper with defined refueling process was designed to handle all assemblies in CLEAR-I. The static and kinematics analyses of the gripper were carried out by ANSYS Workbench and MATLAB considering the influence of working in air and liquid metal. The structural and kinematic simulation results show that the design of the gripper is feasible for CLEAR-I. It provides an advanced refueling solution for the technical validation of ADS.

Lead shutter for the IFMIF LIPAc accelerator

The International Fusion Materials Irradiation Facility (IFMIF) aims to provide an accelerator-based, D-Li neutron source to produce high energy neutrons at sufficient intensity and irradiation volume for DEMO (Demonstration Fusion Power Plant) materials qualification. As part of the Broader Approach agreement between Japan and EURATOM, the goal of the IFMIF/EVEDA project is to work on the engineering design of IFMIF and to validate the main technological challenges which, among a wide diversity of hardware includes the LIPAc (Linear IFMIF Prototype Accelerator), a 125 mA continuous wave deuteron accelerator up to 9 MeV mainly designed and manufactured in Europe.The LIPAc beam is stopped in a copper cone involving a high production of neutron and gamma radiation and activation of its surface. A lead shutter has been designed to shield against the gamma radiation coming from the copper cone through the beam tube when the beam is off, in order to allow access inside the accelerator vault. The lead shutter is located in a multipurpose chamber that also contains a scraper and two vacuum ports. The function of the scraper is to protect the last part of the beam tube in case of abnormal beams.The requirements imposed on the lead shutter chamber include the motion of the lead shutter to locate it in open (beam on) and closed position (beam off), resistance to the radiation environment, vacuum and leak tightness, alignment capabilities of the scraper and leak tightness of its cooling circuit. In this article the radioprotection calculations demonstrating the shutter performance are presented and the mechanical system of the lead shutter and the layout of the different elements contained in the chamber are described, along with their functions.