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Sample records for atlas vacuum chamber

  1. First Half Of The ATLAS Vacuum Chamber Arrives

    CERN Multimedia

    2001-01-01

    The ATLAS detector, built to observe and record the products of head-on collisions of protons in the Large Hadron Collider, is one of the largest and most elaborate particle physics experiments ever designed. It is the product of a world-wide effort by over 1800 scientists from more than 150 laboratories and institutions in 34 countries. With the detector due to begin operation in 2005, its various components have started to arrive from their manufacturers around the world, the most recent being the first of the two vacuum chambers for the two end cap toroid magnets. As it is too big to transport all at once it is comes in two halves. Each half of the vacuum chamber weighs 40 tonnes and is about 11x5.5x5 cubic meters in size. The huge 500 cubic meter vacuum vessles are an in kind contribution to ATLAS from NIKHEF (the Netherlands Institute for High Energy Physics) following a design by the Rutherford Appleton Laboratory in the UK. The chamber was built and delivered by the Royal Schelde Exotech shipyards i...

  2. ATLAS Supplier Award for the ECT Vacuum Vessels

    CERN Multimedia

    Jenni, P

    On 12 February the Netherlands firm Schelde Exotech was awarded the ATLAS Supplier Award for the construction of the two vacuum vessels for the ATLAS End- Cap Toroid (ECT) magnets. ATLAS Supplier Award ceremonies have now become something of a tradition. For the third consecutive year, ATLAS has given best supplier awards for the most exceptional contributors to the construction of the detector. The Netherlands firm Schelde Exotech has just received the award for the construction of the two vacuum vessels for the ECTs. With a diameter of 11 metres and a volume of 550 cubic metres, the ECT vacuum vessels are obviously impressive in scale. They consist of large aluminium plates and a stainless steel central bore tube. In order to obtain the required undulations, the firm had to develop a special assembly and welding technique. Despite the chambers' imposing size, a very high degree of precision has been achieved in their geometry. Moreover, the chambers, which were delivered in July 2002 to CERN, were built i...

  3. Calculation of Wakefields and Higher Order Modes for the Vacuum Chamber of the ATLAS Experiment for the HL-LHC

    CERN Document Server

    Wanzenberg, R

    2013-01-01

    A design study for a High Luminosity Large Hadron Collider (HL-LHC) was started to extend the discovery potential of the Large Hadron Collider (LHC). The HL-LHC study implies also an upgraded configuration of the ATLAS detector with a new beam pipe. The trapped Higher Order Modes (HOMs) and the short range wakefields for the new design of the vacuum chamber are calculated using the computer codes MAFIA and ECHO2D. The short range wakefields are characterized in terms of kick and loss parameters. For the HOMs the frequency the R/Q and the Q-values are given which can directly converted into impedance data. The obtained data are intended to be included into the impedance database of the HL-LHC.

  4. Evacuation of the NET vacuum chamber

    International Nuclear Information System (INIS)

    Muller, R.A.

    1987-01-01

    Parametric calculations of the evacuation process were carried out for the NET-vacuum chamber involving two blanket designs. The results show that with an acceptable vacuum pumping capacity the required start vacuum conditions can be realized within reasonable time. The two blanket concepts do not differ remarkably in their evacuation behaviour. The remaining large pressure differences between the different locations of the vacuum chamber can be reduced if approximately 30% of the total gas flow is extracted from the heads of the blanket replacement ports

  5. Evacuation of the NET vacuum chamber

    International Nuclear Information System (INIS)

    Mueller, R.

    1986-01-01

    Parametric calculations of the evacuation process were carried out for the NET-vacuum chamber involving two blanket designs. The results show that with an acceptable vacuum pumping capacity the required start vacuum conditions can be realized within reasonable time. The two blanket concepts do not differ remarkably in their evacuation behaviour. The remaining large pressure differences between the different locations of the vacuum chamber can be reduced if approximately 30% of the total gas flow is extracted from the heads of the blanket replacement ports. (author)

  6. Procurement specification high vacuum test chamber and pumping system

    International Nuclear Information System (INIS)

    1976-01-01

    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

  7. Safety shield for vacuum/pressure-chamber windows

    Science.gov (United States)

    Shimansky, R. A.; Spencer, R.

    1980-01-01

    Optically-clear shatter-resistant safety shield protects workers from implosion and explosion of vacuum and pressure windows. Plastic shield is inexpensive and may be added to vacuum chambers, pressure chambers, and gas-filling systems.

  8. Vacuum chamber-free centrifuge with magnetic bearings.

    Science.gov (United States)

    Park, Cheol Hoon; Kim, Soohyun; Kim, Kyung-Soo

    2013-09-01

    Centrifuges are devices that separate particles of different densities and sizes through the application of a centrifugal force. If a centrifuge could be operated under atmospheric conditions, all vacuum-related components such as the vacuum chamber, vacuum pump, diffusion pump, and sealing could be removed from a conventional centrifuge system. The design and manufacturing procedure for centrifuges could then be greatly simplified to facilitate the production of lightweight centrifuge systems of smaller volume. Furthermore, the maintenance costs incurred owing to wear and tear due to conventional ball bearings would be eliminated. In this study, we describe a novel vacuum chamber-free centrifuge supported by magnetic bearings. We demonstrate the feasibility of the vacuum chamber-free centrifuge by presenting experimental results that verify its high-speed support capability and motoring power capacity.

  9. Venturi vacuum systems for hypobaric chamber operations.

    Science.gov (United States)

    Robinson, R; Swaby, G; Sutton, T; Fife, C; Powell, M; Butler, B D

    1997-11-01

    Physiological studies of the effects of high altitude on man often require the use of a hypobaric chamber to simulate the reduced ambient pressures. Typical "altitude" chambers in use today require complex mechanical vacuum systems to evacuate the chamber air, either directly or via reservoir system. Use of these pumps adds to the cost of both chamber procurement and maintenance, and service of these pumps requires trained support personnel and regular upkeep. In this report we describe use of venturi vacuum pumps to perform the function of mechanical vacuum pumps for human and experimental altitude chamber operations. Advantages of the venturi pumps include their relatively low procurement cost, small size and light weight, ease of installation and plumbing, lack of moving parts, and independence from electrical power sources, fossil fuels and lubricants. Conversion of three hyperbaric chambers to combined hyper/hypobaric use is described.

  10. "Flat-Fish" Vacuum Chamber

    CERN Multimedia

    CERN PhotoLab

    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.

  11. 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...

  12. The vacuum chamber in the interaction region of particle colliders a historical study and developments implementations in the LHCb experiment at CERN

    CERN Document Server

    Knaster, J R; Gamez-Mejias, L

    2004-01-01

    The history of particle colliders begins in the early 60's when an idea previously patented by R. Wideroe in 1953 is constructed. The design of the vacuum chamber in their experimental area became essential as it was the rst physical barrier that the particles to be detected needed to traverse. The interaction of the products of the collisions with the vacuum chamber structural materials, hindered the identification of the significative events. This Thesis analyses the historical evolution of the experimental vacuum chambers and summarizes the technical criteria that are to be fulfilled. The Large Hadron Collider (LHC) presently under construction at CERN is the last generation of particle colliders. Four big experiments will be in operation (ATLAS, CMS, ALICE and LHCb) in the LHC with diferent physics objectives. In particular, LHCb will be devoted to the study of CP violation and the design of its vacuum chamber is the scope of this Thesis. Physics simulations with an initial design consisting of a conical ...

  13. 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.

  14. 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.

  15. 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.

  16. Impedances in lossy elliptical vacuum chambers

    International Nuclear Information System (INIS)

    Piwinski, A.

    1994-04-01

    The wake fields of a bunched beam caused by the resistivity of the chamber walls are investigated for a vacuum chamber with elliptical cross section. The longitudinal and transverse impedances are calculated for arbitrary energies and for an arbitrary position of the beam in the chamber. (orig.)

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

    International Nuclear Information System (INIS)

    Sindal, B.K.; Kumar, K.V.A.N.P.S.; Ramshiroman; Bhange, Nilesh; Yadav, D.P.; Sridhar, R.; Shukla, S.K.

    2013-01-01

    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 H 2 as major gas. This paper describes UHV testing of upgraded, newly fabricated vacuum chambers for Indus-1 storage ring. (author)

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

    CERN Multimedia

    CERN PhotoLab

    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.

  19. 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.

  20. Bi-cone vacuum chamber in the ISR

    CERN Multimedia

    CERN PhotoLab

    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.

  1. Thermal and Alignment Analysis of the Instrument-Level ATLAS Thermal Vacuum Test

    Science.gov (United States)

    Bradshaw, Heather

    2012-01-01

    This paper describes the thermal analysis and test design performed in preparation for the ATLAS thermal vacuum test. NASA's Advanced Topographic Laser Altimeter System (ATLAS) will be flown as the sole instrument aboard the Ice, Cloud, and land Elevation Satellite-2 (ICESat-2). It will be used to take measurements of topography and ice thickness for Arctic and Antarctic regions, providing crucial data used to predict future changes in worldwide sea levels. Due to the precise measurements ATLAS is taking, the laser altimeter has very tight pointing requirements. Therefore, the instrument is very sensitive to temperature-induced thermal distortions. For this reason, it is necessary to perform a Structural, Thermal, Optical Performance (STOP) analysis not only for flight, but also to ensure performance requirements can be operationally met during instrument-level thermal vacuum testing. This paper describes the thermal model created for the chamber setup, which was used to generate inputs for the environmental STOP analysis. This paper also presents the results of the STOP analysis, which indicate that the test predictions adequately replicate the thermal distortions predicted for flight. This is a new application of an existing process, as STOP analyses are generally performed to predict flight behavior only. Another novel aspect of this test is that it presents the opportunity to verify pointing results of a STOP model, which is not generally done. It is possible in this case, however, because the actual pointing will be measured using flight hardware during thermal vacuum testing and can be compared to STOP predictions.

  2. ATLAS honours one of its suppliers

    CERN Multimedia

    2003-01-01

    On 12 February the Netherlands firm Schelde Exotech was awarded a prize for best ATLAS supplier for the construction of the two vacuum chambers for the ATLAS endcap toroid magnets. The award for best supplier is handed over to representatives of the firm Schelde Exotech in front of one of the two vacuum chambers built by the firm. From left to right: E. Baynham (RAL), H. Geerink (NIKHEF), Y. Lefevere (NIKHEF), J. Engelen (NIKHEF), P. Jenni (CERN), E. Holtom (RAL), R. Boddaert (Schelde Exotech), G. Luijckx (NIKHEF), H. Klumpus (Schelde Exotech), M. Nessi (CERN), H. ten Kate (CERN), M. Nordberg (CERN), H. Hoffmann (CERN).This ceremony has now become something of a tradition. For the third consecutive year, ATLAS has given best supplier awards for the most exceptional contributors to the construction of the future detector. The Netherlands firm Schelde Exotech has just received the award for the construction of the two vacuum chambers for the ATLAS endcap toroid magnets. With a diameter of 11 metres and a volum...

  3. LEP vacuum chamber, prototype

    CERN Multimedia

    CERN PhotoLab

    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.

  4. Development of secondary chamber for tar cracking-improvement of wood pyrolysis performance in pre-vacuum chamber

    Science.gov (United States)

    Siahaan, S.; Homma, H.; Homma, H.

    2018-02-01

    Energy crisis and global warming, in other words, climate change are critical topics discussed in various parts of the world. Global warming primarily result from too much emission of carbon dioxide (CO2) in the atmosphere. To mitigate global warming, or climate change and improve electrification in rural areas, wood pyrolysis technology is developed in a laboratory scale, of which gases are directly applicable to the gas engine generator. Our laboratory has developed a prototype of wood pyrolysis plant with a pre-vacuum chamber. However, tar yield was around 40 wt% of feedstock. This research aims to reduce tar yield by secondary tar cracking. For the secondary tar cracking, a secondary pre-vacuum chamber is installed after primary pre-vacuum chamber. Gases generated in the primary pre-vacuum chamber are lead into the secondary chamber that is heated up to 1000 K. This paper reports performance of the secondary chamber for secondary tar cracking in homogeneous mode and heterogeneous mode with char.

  5. The Impedance of Multi-layer Vacuum Chambers

    CERN Document Server

    Vos, L

    2003-01-01

    Many components of the LHC vacuum chamber have multi-layered walls : the copper coated cold beam screen, the titanium coated ceramic chamber of the dump kickers, the ceramic chamber of the injection kickers coated with copper stripes, only to name a few. Theories and computer programs are available for some time already to evaluate the impedance of these elements. Nevertheless, the algorithm developed in this paper is more convenient in its application and has been used extensively in the design phase of multi-layer LHC vacuum chamber elements. It is based on classical transmission line theory. Closed expressions are derived for simple layer configurations, while beam pipes involving many layers demand a chain calculation. The algorithm has been tested with a number of published examples and was verified with experimental data as well.

  6. Upgrades of the ATLAS Muon Spectrometer with sMDT Chambers

    CERN Document Server

    Ferretti, Claudio; The ATLAS collaboration

    2015-01-01

    With half the drift-tube diameter of the Monitored Drift Tube (MDT) chambers of the ATLAS muon spectrometer and otherwise unchanged operating parameters, small-diameter Muon Drift Tube (sMDT) chambers provide an order of magnitude higher rate capability and can be installed in detector regions where MDT chambers do not fit. The chamber assembly time has been reduced by a factor of seven to one working day and the sense wire positioning accuracy improved by a factor of two to better than ten microns. Two sMDT chambers have been installed in ATLAS in 2014 to improve the momentum resolution in the barrel part of the spectrometer. The construction of additional twelve chambers covering the feet regions of the ATLAS detector has started. It will be followed by the replacement of the MDT chambers at the ends of the barrel inner layer by sMDTs improving the Performance at the high expected background rates and providing space for additional RPC trigger chambers.

  7. Upgrades of the ATLAS Muon Spectrometer with sMDT Chambers

    CERN Document Server

    Ferretti, C

    2016-01-01

    With half the drift-tube diameter of the Monitored Drift Tube (MDT) chambers of the ATLAS muon spectrometer and otherwise unchanged operating parameters, small-diameter Muon Drift Tube (sMDT) chambers provide an order of magnitude higher rate capability and can be installed in detector regions where MDT chambers do not fit. The chamber assembly time has been reduced by a factor of seven to one working day and the sense wire positioning accuracy improved by a factor of two to better than ten microns. Two sMDT chambers have been installed in ATLAS in 2014 to improve the momentum resolution in the barrel part of the spectrometer. The construction of an additional twelve chambers covering the feet regions of the ATLAS detector has started. It will be followed by the replacement of the MDT chambers at the ends of the barrel inner layer by sMDTs improving the Performance at the high expected background rates and providing space for additional RPC trigger chambers.

  8. LEP vacuum chamber, early prototype

    CERN Multimedia

    CERN PhotoLab

    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).

  9. The PEP-II Lower Pressure HER Vacuum Chamber

    International Nuclear Information System (INIS)

    DeBarger, S.; Metcalfe, S.; Seeman, J.; Sullivan, M.; Wienands, U.; Wright, D.

    2006-01-01

    This new vacuum chamber has been installed from 12 to 21 meters upstream of the BaBar detector in the PEP-II High Energy Ring (HER) to reduce lost particle backgrounds. The backgrounds from HER now dominate the backgrounds in the BaBar detector and the present vacuum pressure is 1 x 10 -9 Torr. The new chamber will increase the pumping significantly by adding 18 x 2000 l/s titanium sublimation pumps to the existing 5 x 440 l/s ion pumps, and is expected to reduce the pressure by about a factor of five. Features of the chamber include improved water cooling, improved vacuum conductance through copper RF screens featuring over 15,000 small square holes and the ability to sublimate titanium while the beam is still on

  10. The thin-wall tube drift chamber operating in vacuum (prototype)

    Science.gov (United States)

    Alexeev, G. D.; Glonti, L. N.; Kekelidze, V. D.; Malyshev, V. L.; Piskun, A. A.; Potrbenikov, Yu. K.; Rodionov, V. K.; Samsonov, V. A.; Tokmenin, V. V.; Shkarovskiy, S. N.

    2013-08-01

    The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. "Self-centering" spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum.

  11. The thin-wall tube drift chamber operating in vacuum (prototype)

    International Nuclear Information System (INIS)

    Alexeev, G.D.; Glonti, L.N.; Kekelidze, V.D.; Malyshev, V.L.; Piskun, A.A.; Potrbenikov, Yu.K.; Rodionov, V.K.; Samsonov, V.A.; Tokmenin, V.V.; Shkarovskiy, S.N.

    2013-01-01

    The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. “Self-centering” spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum

  12. The thin-wall tube drift chamber operating in vacuum (prototype)

    Energy Technology Data Exchange (ETDEWEB)

    Alexeev, G.D. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Glonti, L.N., E-mail: glonti@sunse.jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); Kekelidze, V.D.; Malyshev, V.L.; Piskun, A.A.; Potrbenikov, Yu.K.; Rodionov, V.K.; Samsonov, V.A.; Tokmenin, V.V.; Shkarovskiy, S.N. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2013-08-01

    The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. “Self-centering” spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum.

  13. LEP vacuum chamber, cross-section

    CERN Multimedia

    CERN PhotoLab

    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.

  14. 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.

  15. Development of Aluminium Vacuum Chambers for the LHC Experiments at CERN

    CERN Document Server

    Gallilee, M; Costa-Pinto, P; Lepeule, P; Perez-Espinos, J; Marques Antunes Ferreira, L; Prever-Loiri, L; Sapountzis, A

    2014-01-01

    Beam losses may cause activation of vacuum chamber walls, in particular those of the Large Hadron Collider (LHC) experiments. For the High Luminosity (HL-LHC), the activation of such vacuum chambers will increase. It is therefore necessary to use a vacuum chamber material which interacts less with the circulating beam. While beryllium is reserved for the collision point, a good compromise between cost, availability and transparency is obtained with aluminium alloys; such materials are a preferred choice with respect to austenitic stainless steel. Manufacturing a thin-wall aluminium vacuum chamber presents several challenges as the material grade needs to be machinable, weldable, leak-tight for small thicknesses, and able to withstand heating to 250°C for extended periods of time. This paper presents some of the technical challenges during the manufacture of these vacuum chambers and the methods for overcoming production difficulties, including surface treatments and Non-Evaporable Getter (NEG) thin-film coat...

  16. Vacuum Chamber for the Booster Bending Magnets

    CERN Multimedia

    CERN PhotoLab

    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).

  17. Impedance analysis of the PEP-II vacuum chamber

    International Nuclear Information System (INIS)

    Ng, C.K.; Weiland, T.

    1995-05-01

    The PEP-II high energy ring (HER) vacuum chamber consists of a copper tube with periodically spaced pumping slots. The impedance of the vacuum chamber due to the slots is analyzed. Both narrow-band and broadband impedances are considered as well as longitudinal and transverse components thereof. It is found that although the broad-band impedance is tolerable, the narrow-band impedance may exceed the instability limit given by the natural damping with no feedback system on. Traveling wave modes in the chamber are the major source of this high value narrow-band impedance. We also study the dependences of the impedance on the slot length and the geometrical cross section

  18. 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...

  19. Tailored vacuum chambers for ac magnets

    International Nuclear Information System (INIS)

    Harvey, A.

    1985-01-01

    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

  20. Method for sequentially processing a multi-level interconnect circuit in a vacuum chamber

    Science.gov (United States)

    Routh, D. E.; Sharma, G. C. (Inventor)

    1984-01-01

    An apparatus is disclosed which includes a vacuum system having a vacuum chamber in which wafers are processed on rotating turntables. The vacuum chamber is provided with an RF sputtering system and a dc magnetron sputtering system. A gas inlet introduces various gases to the vacuum chamber and creates various gas plasma during the sputtering steps. The rotating turntables insure that the respective wafers are present under the sputtering guns for an average amount of time such that consistency in sputtering and deposition is achieved. By continuous and sequential processing of the wafers in a common vacuum chamber without removal, the adverse affects of exposure to atmospheric conditions are eliminated providing higher quality circuit contacts and functional device.

  1. Safety shield for vacuum/pressure chamber viewing port

    Science.gov (United States)

    Shimansky, R. A.; Spencer, R. S. (Inventor)

    1981-01-01

    Observers are protected from flying debris resulting from a failure of a vacuum or pressure chamber viewing port following an implosion or explosion by an optically clear shatter resistant safety shield which spaced apart from the viewing port on the outer surface of the chamber.

  2. Upgrades Of The ATLAS Muon Spectrometer With sMDT Chambers

    CERN Document Server

    Ferretti, Claudio; The ATLAS collaboration

    2015-01-01

    The Monitored Drift Tube (MDT) chambers of the ATLAS muon spectrometer demonstrated that they provide very precise and robust tracking over large areas. Goals of ATLAS muon detector upgrades are to increase the acceptance for precision muon momentum measurement and triggering and to improve the rate capability of the muon chambers in the high-background regions when the LHC luminosity increases. Small-diameter Muon Drift Tube (sMDT) chambers have been developed for these purposes. With half the drift-tube diameter of the MDT chambers and otherwise unchanged operating parameters, sMDT chambers share the advantages with the MDTs, but have more than ten times higher rate capability and can be installed in detector regions where MDT chambers do not fit in. The chamber assembly methods have been optimized for mass production, reducing cost and construction time considerably and improving the sense wire positioning accuracy to better than ten microns. Two sMDT chambers have been installed in 2014 to improve the mom...

  3. Bench measurement of vacuum chamber impedances with wires

    International Nuclear Information System (INIS)

    Shafer, R.E.

    1979-01-01

    Particle beams travelling in an accelerator or storage ring vacuum chamber produce electric and magnetic fields which interact with the walls of the chamber. The induced wall currents in turn generate secondary fields which can interact with the beam, giving rise to both energy loss and other effects which can cause beam instability. In many simple geometries these effects can be calculated. In more complex geometries the calculations are difficult and very approximate. For this reason it is important that the effects be measured if possible prior to installation. As accelerators become larger and the number of vacuum chamber components more numerous, and as more severe beam intensity and stability requirements are placing lower limits on the longitudinal and transverse impedances, a less than adequate component will be more likely to limit machine performance

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

    International Nuclear Information System (INIS)

    Sindal, B.K.; Bhavsar, S.T.; Shukla, S.K.

    2003-01-01

    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

  5. Construction and test of sMDT chambers for the ATLAS muon spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Takasugi, Eric; Schmidt-Sommerfeld, Korbinian; Kortner, Oliver; Kroha, Hubert [Max-Planck-Institut fuer Physik, Muenchen (Germany)

    2016-07-01

    In the ATLAS muon spectrometer, Monitored Drift Tube chambers (MDTs) are used for precise tracking measurements. In order to increase the geometric acceptance and rate capability, new chambers have been designed and are under construction to be installed in ATLAS during the winter shutdown of 2016/17 of the LHC. The new chambers have a drift tube diameter of 15 mm (compared to 30 mm of the other MDTs) and are therefore called sMDT chambers. This presentation reports on the progress of chamber construction and on the results of quality assurance tests.

  6. Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

    Science.gov (United States)

    Danby, Gordon T.; Jackson, John W.

    1991-01-01

    A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations in the particle beam.

  7. Achieving ultrahigh vacuum in an unbaked chamber with glow ...

    Indian Academy of Sciences (India)

    2016-12-06

    Dec 6, 2016 ... An ultimate vacuum in any leak-tight chamber with a given pumping speed and ... chamber is exposed to atmospheric pressure, water vapour gets sorbed ... A variable DC power supply of 0–1000 V was con- nected in series ...

  8. Vacuum chambers full of ideas for the Swedish synchrotron

    CERN Multimedia

    Corinne Pralavorio

    2016-01-01

    CERN’s Vacuum, Surfaces and Coatings group has contributed to the development of vacuum chambers for the MAX IV synchrotron, which has just been officially opened in Sweden.   A section of the new 3 GeV MAX IV synchrotron at the time of installation. In the centre of the magnets you can see the vacuum chamber developed in collaboration with CERN. (Photo: Marek Grabski, MAX IV Vacuum group) On 21 June, the King and the Prime Minister of Sweden officially opened MAX IV, a brand-new synchrotron in Lund, Sweden. The summer solstice, the longest day of the year, was deliberately chosen for the ceremony: MAX IV, a cutting-edge synchrotron, will deliver the brightest X-rays ever produced to more than 2000 users. Some 1500 kilometres away, a team at CERN followed the opening ceremony with a touch of pride. The Vacuum, Surfaces and Coatings group in the Technology department (TE-VSC) participated in the construction of this new synchrotron. Its contribution lies at the very hea...

  9. DEVELOPMENT OF TITANIUM NITRIDE COATING FOR SNS RING VACUUM CHAMBERS

    International Nuclear Information System (INIS)

    HE, P.; HSEUH, H.C.; MAPES, M.; TODD, R.; WEISS, D.

    2001-01-01

    The inner surface of the ring vacuum chambers of the US Spallation Neutron Source (SNS) will be coated with ∼100 nm of Titanium Nitride (TiN). This is to minimize the secondary electron yield (SEY) from the chamber wall, and thus avoid the so-called e-p instability caused by electron multipacting as observed in a few high-intensity proton storage rings. Both DC sputtering and DC-magnetron sputtering were conducted in a test chamber of relevant geometry to SNS ring vacuum chambers. Auger Electron Spectroscopy (AES) and Rutherford Back Scattering (RBS) were used to analyze the coatings for thickness, stoichiometry and impurity. Excellent results were obtained with magnetron sputtering. The development of the parameters for the coating process and the surface analysis results are presented

  10. 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...

  11. Large area window on vacuum chamber surface for neutron scattering instruments

    International Nuclear Information System (INIS)

    Itoh, Shinichi; Yokoo, Tetsuya; Ueno, Kenji; Suzuki, Junichi; Teraoku, Takuji; Tsuchiya, Masao

    2012-01-01

    The feasibility of a large area window using a thin aluminum plate on the surface of the vacuum chamber for neutron scattering instruments at a pulsed neutron source was investigated. In the prototype investigation for a window with an area of 1m×1.4m and a thickness of 1 mm, the measured pressure dependence of the displacement agreed well with a calculation using a nonlinear strain–stress curve up to the plastic deformation region. In addition, we confirmed the repetition test up to 2000 pressurization-and-release cycles, which is sufficient for the lifetime of the vacuum chamber for neutron scattering instruments. Based on these investigations, an actual model of the window to be mounted on the vacuum chamber of the High Resolution Chopper Spectrometer (HRC) at J-PARC was designed. By using a calculated stress distribution on the window, the clamping structure capable of balancing the tension in the window was determined. In a model with a structure identical to the actual window, we confirmed the repetition test over more than 7000 pressurization-and-release cycles, which shows a lifetime long enough for the actual usage of the vacuum chamber on the HRC.

  12. A system for the study of molecular contamination. [experimental vacuum chambers

    Science.gov (United States)

    Dillow, C. F.; Allen, T. H.; Linford, R. M. F.; Richmond, R. G.

    1975-01-01

    An experimental vacuum chambers was designed and fabricated to provide a wide range of experimental capability. This work chamber assembly (WCA) was conceived to establish the proof-of-principle of various techniques for studying the kinetics of contaminants and their effects. It incorporates the capability for depositing both optical and contaminant films on temperature-controlled samples, and for in-situ measurements of the vacuum ultraviolet reflectance. Ellipsometer optics are mounted on the chamber for film thickness determinations, and other features include access ports for radiation sources and instrumentation.

  13. Development of micromegas muon chambers for the ATLAS upgrade

    Science.gov (United States)

    Wotschack, J.

    2012-02-01

    Large-area particle detectors based on the bulk-micromegas technology are an attractive choice for the upgrade of LHC detectors and/or detectors for the ILC or other experiments. In the context of the R&D for the ATLAS Muon System upgrade, we have built detectors of order 1 m2. In order to overcome the spark problem in micromegas a novel protection scheme using resistive strips above the readout electrode has been developed. This technology has undergone extensive tests with hadron beams at the CERN-SPS, X-rays in the lab, as well as in a neutron beam. In addition, four 10 × 10 cm2 micromegas chambers have been installed in the ATLAS cavern and are taking data under LHC conditions. We will discuss the underlying design of the chambers and present results on the performance of these chambers.

  14. Development of micromegas muon chambers for the ATLAS upgrade

    International Nuclear Information System (INIS)

    Wotschack, J

    2012-01-01

    Large-area particle detectors based on the bulk-micromegas technology are an attractive choice for the upgrade of LHC detectors and/or detectors for the ILC or other experiments. In the context of the R and D for the ATLAS Muon System upgrade, we have built detectors of order 1 m 2 . In order to overcome the spark problem in micromegas a novel protection scheme using resistive strips above the readout electrode has been developed. This technology has undergone extensive tests with hadron beams at the CERN-SPS, X-rays in the lab, as well as in a neutron beam. In addition, four 10 × 10 cm 2 micromegas chambers have been installed in the ATLAS cavern and are taking data under LHC conditions. We will discuss the underlying design of the chambers and present results on the performance of these chambers.

  15. Distributed remote temperature monitoring system for INDUS-2 vacuum chambers

    International Nuclear Information System (INIS)

    Bhange, N.J.; Gothwal, P.; Fatnani, P.; Shukla, S.K.

    2011-01-01

    Indus-2, a 2.5 GeV Synchrotron Radiation Source (SRS) at Indore has a large vacuum system. The vacuum envelope of Indus-2 ring comprises of 16 dipole chambers as vital parts. Each chamber has 4 photon absorbers and three beam line ports blanked with end flanges. Temperature monitoring of critical vacuum components during operation of Indus-2 ring is an important requirement. The paper discusses a distributed, 160 channel remote temperature monitoring system developed and deployed for this purpose using microcontroller based, modular Temperature Monitoring Units (TMU). The cabling has been extensively minimized using RS485 system and keeping trip relay contacts of all units in series. For ensuring proper signal conditioning of thermocouple outputs (K-type) and successful operation over RS485 bus, many precautions were taken considering the close proximity to the storage ring. We also discuss the software for vacuum chamber temperature monitoring and safety system. The software developed using LabVIEW, has important features like modularity, client-server architecture, local and global database logging, alarms and trips, event and error logging, provision of various important configurations, communications handling etc. (author)

  16. Tokamak Fusion Test Reactor neutral beam injection system vacuum chamber

    International Nuclear Information System (INIS)

    Pedrotti, L.R.

    1977-01-01

    Most of the components of the Neutral Beam Lines of the Tokamak Fusion Test Reactor (TFTR) will be enclosed in a 50 cubic meter box-shaped vacuum chamber. The chamber will have a number of unorthodox features to accomodate both neutral beam and TFTR requirements. The design constraints, and the resulting chamber design, are presented

  17. Construction and test of high precision drift-tube (sMDT) chambers for the ATLAS muon spectrometer

    CERN Document Server

    Nowak, Sebastian; Kroha, Hubert; Schwegler, Philipp; Sforza, Federico

    2014-01-01

    For the upgrade of the ATLAS muon spectrometer in March 2014 new muon tracking chambers (sMDT) with drift-tubes of 15 mm diameter, half of the value of the standard ATLAS Monitored Drift-Tubes (MDT) chambers, and 10~$\\mu$m positioning accuracy of the sense wires have been constructed. The new chambers are designed to be fully compatible with the present ATLAS services but, with respect to the previously installed ATLAS MDT chambers, they are assembled in a more compact geometry and they deploy two additional tube layers that provide redundant rack information. The chambers are composed of 8 layers of in total 624 aluminium drift-tubes. The assembly of a chamber is completed within a week. A semi-automatized production line is used for the assembly of the drift-tubes prior to the chamber assembly. The production procedures and the quality control tests of the single components and of the complete chambers will be discussed. The wire position in the completed chambers have been measured by using a coordinate me...

  18. Streamlined Calibration of the ATLAS Muon Spectrometer Precision Chambers

    CERN Document Server

    Levin, DS; The ATLAS collaboration; Dai, T; Diehl, EB; Ferretti, C; Hindes, JM; Zhou, B

    2009-01-01

    The ATLAS Muon Spectrometer is comprised of nearly 1200 optically Monitored Drifttube Chambers (MDTs) containing 354,000 aluminum drift tubes. The chambers are configured in barrel and endcap regions. The momentum resolution required for the LHC physics reach (dp/p = 3% and 10% at 100 GeV and 1 TeV) demands rigorous MDT drift tube calibration with frequent updates. These calibrations (RT functions) convert the measured drift times to drift radii and are a critical component to the spectrometer performance. They are sensitive to the MDT gas composition: Ar 93%, CO2 7% at 3 bar, flowing through the detector at arate of 100,000 l hr−1. We report on the generation and application of Universal RT calibrations derived from an inline gas system monitor chamber. Results from ATLAS cosmic ray commissioning data are included. These Universal RTs are intended for muon track reconstuction in LHC startup phase.

  19. Temperature Studies for ATLAS MDT BOS Chambers

    CERN Document Server

    Engl, A.; Biebel, O.; Mameghani, R.; Merkl, D.; Rauscher, F.; Schaile, D.; Ströhmer, R.

    Data sets with high statistics taken at the cosmic ray facility, equipped with 3 ATLAS BOS MDT chambers, in Garching (Munich) have been used to study temperature and pressure effects on gas gain and drifttime. The deformation of a thermally expanded chamber was reconstructed using the internal RasNik alignment monitoring system and the tracks from cosmic data. For these studies a heating system was designed to increase the temperature of the middle chamber by up to 20 Kelvins over room temperature. For comparison the temperature effects on gas properties have been simulated with Garfield. The maximum drifttime decreased under temperature raise by -2.21 +- 0.08 ns/K, in agreement with the results of pressure variations and the Garfield simulation. The increased temperatures led to a linear increase of the gas gain of about 2.1% 1/K. The chamber deformation has been analyzed with the help of reconstructed tracks. By the comparison of the tracks through the reference chambers with these through the test chamber ...

  20. 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.

  1. High vacuum general purpose scattering chamber for nuclear reaction study

    International Nuclear Information System (INIS)

    Suresh Kumar; Ojha, S.C.

    2003-01-01

    To study the nuclear reactions induced by beam from medium energy accelerators, one of the most common facility required is a scattering chamber. In the scattering chamber, projectile collides with the target nucleus and the scattered reaction products are detected with various type of nuclear detector at different angles with respect to the beam. The experiments are performed under high vacuum to minimize the background reaction and the energy losses of the charged particles. To make the chamber general purpose various requirement of the experiments are incorporated into it. Changing of targets, changing angle of various detectors while in vacuum are the most desired features. The other features like ascertaining the beam spot size and position on the target, minimizing the background counts by proper beam dump, accurate positioning of the detector as per plan etc. are some of the important requirements

  2. Performance of the ATLAS Precision Muon Chambers under LHC Operating Conditions

    CERN Document Server

    Deile, M.; Dubbert, J; Horvat, S; Kortner, O; Kroha, H; Manz, A; Mohrdieck, S; Rauscher, F; Richter, Robert; Staude, A

    2004-01-01

    For the muon spectrometer of the ATLAS detector at the large hadron collider (LHC), large drift chambers consisting of 6 to 8 layers of pressurized drift tubes are used for precision tracking covering an active area of 5000 m2 in the toroidal ?eld of superconducting air core magnets. The chambers have to provide a spatial resolution of 41 microns with Ar:CO2 (93:7) gas mixture at an absolute pressure of 3 bar and gas gain of 2?104. The environment in which the chambers will be operated is characterized by high neutron and background with counting rates of up to 100 per square cm and second. The resolution and efficiency of a chamber from the serial production for ATLAS has been investigated in a 100 GeV muon beam at photon irradiation rates as expected during LHC operation. A silicon strip detector telescope was used as external reference in the beam. The spatial resolution of a chamber is degraded by 4 ?m at the highest background rate. The detection e?ciency of the drift tubes is unchanged under irradiation...

  3. ITER cryostat main chamber and vacuum vessel pressure suppression system design

    International Nuclear Information System (INIS)

    Ito, Akira; Nakahira, Masataka; Takahashi, Hiroyuki; Tada, Eisuke; Nakashima, Yoshitane; Ueno, Osamu

    1999-03-01

    Design of Cryostat Main Chamber and Vacuum Vessel Pressure Suppression System (VVPS) of International Thermonuclear Experimental Reactor (ITER) has been conducted. The cryostat is a cylindrical vessel that includes in-vessel component such as vacuum vessel, superconducting toroidal coils and poloidal coils. This cryostat provides the adiabatic vacuum about 10 -4 Pa for the superconducting coils operating at 4 K and forms the second confinement barrier to tritium. The adiabatic vacuum is to reduce thermal loads applied to the superconducting coils and their supports so as to keep their temperature 4 K. The VVPS consists of a suppression tank located under the lower bio-shield and 4 relief pipes to connect the vacuum vessel and the suppression tank. The VVPS is to keep the maximum pressure rise of the vacuum vessel below the design value of 0.5 MPa in case of the in-vessel LOCA (water spillage from in-vessel component). The spilled water and steam are lead to the suppression tank through the relief pipes when the internal pressure of vacuum vessel is over 0.2 MPa, and then the internal pressure is kept below 0.5 MPa. This report summarizes the structural design of the cryostat main chamber and pressure suppression system, together with their fabrication and installation. (author)

  4. ITER cryostat main chamber and vacuum vessel pressure suppression system design

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Akira; Nakahira, Masataka; Takahashi, Hiroyuki; Tada, Eisuke [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nakashima, Yoshitane; Ueno, Osamu

    1999-03-01

    Design of Cryostat Main Chamber and Vacuum Vessel Pressure Suppression System (VVPS) of International Thermonuclear Experimental Reactor (ITER) has been conducted. The cryostat is a cylindrical vessel that includes in-vessel component such as vacuum vessel, superconducting toroidal coils and poloidal coils. This cryostat provides the adiabatic vacuum about 10{sup -4} Pa for the superconducting coils operating at 4 K and forms the second confinement barrier to tritium. The adiabatic vacuum is to reduce thermal loads applied to the superconducting coils and their supports so as to keep their temperature 4 K. The VVPS consists of a suppression tank located under the lower bio-shield and 4 relief pipes to connect the vacuum vessel and the suppression tank. The VVPS is to keep the maximum pressure rise of the vacuum vessel below the design value of 0.5 MPa in case of the in-vessel LOCA (water spillage from in-vessel component). The spilled water and steam are lead to the suppression tank through the relief pipes when the internal pressure of vacuum vessel is over 0.2 MPa, and then the internal pressure is kept below 0.5 MPa. This report summarizes the structural design of the cryostat main chamber and pressure suppression system, together with their fabrication and installation. (author)

  5. Semi-automated high-efficiency reflectivity chamber for vacuum UV measurements

    Science.gov (United States)

    Wiley, James; Fleming, Brian; Renninger, Nicholas; Egan, Arika

    2017-08-01

    This paper presents the design and theory of operation for a semi-automated reflectivity chamber for ultraviolet optimized optics. A graphical user interface designed in LabVIEW controls the stages, interfaces with the detector system, takes semi-autonomous measurements, and monitors the system in case of error. Samples and an optical photodiode sit on an optics plate mounted to a rotation stage in the middle of the vacuum chamber. The optics plate rotates the samples and diode between an incident and reflected position to measure the absolute reflectivity of the samples at wavelengths limited by the monochromator operational bandpass of 70 nm to 550 nm. A collimating parabolic mirror on a fine steering tip-tilt motor enables beam steering for detector peak-ups. This chamber is designed to take measurements rapidly and with minimal oversight, increasing lab efficiency for high cadence and high accuracy vacuum UV reflectivity measurements.

  6. Open loop, auto reversing liquid nitrogen circulation thermal system for thermo vacuum chamber

    International Nuclear Information System (INIS)

    Naidu, M C A; Nolakha, Dinesh; Saharkar, B S; Kavani, K M; Patel, D R

    2012-01-01

    In a thermo vacuum chamber, attaining and controlling low and high temperatures (-100 Deg. C to +120 Deg. C) is a very important task. This paper describes the development of 'Open loop, auto reversing liquid nitrogen based thermal system'. System specifications, features, open loop auto reversing system, liquid nitrogen flow paths etc. are discussed in this paper. This thermal system consists of solenoid operated cryogenic valves, double embossed thermal plate (shroud), heating elements, temperature sensors and PLC. Bulky items like blowers, heating chambers, liquid nitrogen injection chambers, huge pipe lines and valves were not used. This entire thermal system is very simple to operate and PLC based, fully auto system with auto tuned to given set temperatures. This system requires a very nominal amount of liquid nitrogen (approx. 80 liters / hour) while conducting thermo vacuum tests. This system was integrated to 1.2m dia thermo vacuum chamber, as a part of its augmentation, to conduct extreme temperature cycling tests on passive antenna reflectors of satellites.

  7. Longitudinal coupling impedance of a double-step cross section change in the vacuum chamber

    International Nuclear Information System (INIS)

    Guidee, P.; Hahn, H.; Mizumachi, Y.

    1978-03-01

    The coupling impedance of a double-step cross section change in the vacuum chamber of an accelerator or storage ring is computed in first approximation. The character of the coupling impedance in the various frequency domains, that is low-frequency, above cut-off frequency of the vacuum chamber, and at resonances is discussed

  8. In situ measurement of ceramic vacuum chamber conductive coating quality

    International Nuclear Information System (INIS)

    Doose, C.; Harkay, K.; Kim, S.; Milton, S.

    1997-01-01

    A method for measuring the relative surface resistivity and quality of conductive coatings on ceramic vacuum chambers was developed. This method is unique in that it allows one to test the coating even after the ceramic chamber is installed in the accelerator and under vacuum; furthermore, the measurement provides a localized surface reading of the coating conductance. The method uses a magnetic probe is calibrated using the measured DC end-to-end resistance of the tube under test and by comparison to a high quality test surface. The measurement method has also been verified by comparison to high frequency impedance measurements. A detailed description, results, and sensitivity of the technique are given here

  9. VUV photoemission studies of candidate Large Hadron Collider vacuum chamber materials

    Directory of Open Access Journals (Sweden)

    R. Cimino

    1999-06-01

    Full Text Available In the context of future accelerators and, in particular, the beam vacuum of the Large Hadron Collider (LHC, a 27 km circumference proton collider to be built at CERN, VUV synchrotron radiation (SR has been used to study both qualitatively and quantitatively candidate vacuum chamber materials. Emphasis is given to show that angle and energy resolved photoemission is an extremely powerful tool to address important issues relevant to the LHC, such as the emission of electrons that contributes to the creation of an electron cloud which may cause serious beam instabilities and unmanageable heat loads on the cryogenic system. Here we present not only the measured photoelectron yields from the proposed materials, prepared on an industrial scale, but also the energy and in some cases the angular dependence of the emitted electrons when excited with either a white light (WL spectrum, simulating that in the arcs of the LHC, or monochromatic light in the photon energy range of interest. The effects on the materials examined of WL irradiation and /or ion sputtering, simulating the SR and ion bombardment expected in the LHC, were investigated. The studied samples exhibited significant modifications, in terms of electron emission, when exposed to the WL spectrum from the BESSY Toroidal Grating Monochromator beam line. Moreover, annealing and ion bombardment also induce substantial changes to the surface thereby indicating that such surfaces would not have a constant electron emission during machine operation. Such characteristics may be an important issue to define the surface properties of the LHC vacuum chamber material and are presented in detail for the various samples analyzed. It should be noted that all the measurements presented here were recorded at room temperature, whereas the majority of the LHC vacuum system will be maintained at temperatures below 20 K. The results cannot therefore be directly applied to these sections of the machine until

  10. Conditioning of vacuum chamber by RF plasma

    International Nuclear Information System (INIS)

    Elizondo, J.I.; Nascimento, I.C. do

    1985-01-01

    A new conditioning vaccum chamber system is presented. It consists in hydrogen plasm generation by microwaves with low electronic temperature (Te approx. 5eV) and low ionization degree. The ions and neutral atoms generated in the reaction: e + H 2 -> H+ H+ e, bomb the chamber walls combinig themselves to impurities of surface and generating several compounds: H 2 O, CO, CH 4 , CO 2 etc. The vacuum system operates continuosly and remove these compounds. A microwave system using magnetron valve (f=2,45 GHz, P=800W) was constructed for TBR (Brazilian tokamak). The gas partial pressures were monitored before, during and after conditioning showing the efficiency of the process. (M.C.K.) [pt

  11. Linear accelerator section alignment in a vacuum chamber

    International Nuclear Information System (INIS)

    Vengrov, R.M.; Vinogradskij, N.N.; Danil'tsev, E.N.; Iosseliani, D.D.; Kosyak, V.S.; Porubaj, N.I.; Ugarov, S.B.

    1989-01-01

    Alignment technique for multisectional accelerating structures, that may be used in designing new accelerators for experimental and applied purposes, is described. The accuracy of the alignment of four-chamber resonator sections directly in an accelerator vacuum volume without its depressurization is not less than 100 μm. 8 refs.; 5 figs.; 5 tabs

  12. Intensive irradiation studies, monitoring and commissioning data analysis on the ATLAS MDT chambers

    CERN Document Server

    AUTHOR|(CDS)2071390; Susinno, Giancarlo

    2007-01-01

    The ATLAS MDT chambers have been extensively studied, starting from irradiation test to commissioning activities. First, a detailed description of high rate and high background tests is given. These tests have been carried out on a small ATLAS-like MDT chamber, by the Cosenza and Roma TRE groups. The precision tracking chambers of the muon spectrometer, in fact, have to operate for more than 10 years in the harsh LHC background, due mainly to low energy neutrons and photons. Aging effects, such as the deterioration of the tube themselves can appear and difficulties in pattern recognition and tracking may occur. Moreover an upgrade to Super-LHC is foreseen. Then, there is an accurate description of the MDTGnam package, the official software for the on-line monitoring of MDT performances. When dealing with a complex apparatus, such as the ATLAS experiment, an on-line monitoring system is a fundamental tool. The GNAM project, developed by Cosenza, Pavia, Pisa and Napoli groups, is a monitoring framework to be us...

  13. Mega-bicone vacuum chamber for ISR intersections

    CERN Document Server

    CERN PhotoLab

    1975-01-01

    The cylindrical central part covered the collision region allowing secondary particles emitted at large angle to escape thanks to its very thin wall.The two conical parts are terminated by "transparent" thin windows for letting out forward emitted secondary particles. Vacuum chambers of this shape were made in their thin parts out of 0.3 mm stainless steel or 0.28 mm titanium alloy sheet. See also 7609219, 7609221, 7507132X.

  14. NEG coating of the non-standard LSS vacuum chambers

    CERN Document Server

    Costa-Pinto, P

    2005-01-01

    The vacuum chambers of nearly all the warm magnets of the LHC (MBXW, MQW, MSI, MSD, etc…) will be coated with a Ti-Zr-V thin film by magnetron sputtering. The NEG coating is necessary to provide uniform pumping speed along the chambers and to suppress electron cloud instabilities and dynamic outgassing. The about 300 chambers will be coated using the existing facility, developed for the production of the standard LSS chambers, after minor modifications mainly due to the different cross sections. In order to cope with the present installation schedule, the production planning will allow processing of different families of chambers in parallel by using two or three coating systems simultaneously. After a brief introduction to the Ti-Zr-V characteristics and performances, the coating facility and strategy will be illustrated as well as the possible conflicts due to uncertainties in the planning of the experimental beam pipes and the standard LSS chambers.

  15. High-vacuum chamber for the irradiation of targets

    International Nuclear Information System (INIS)

    Krimmel, E.; Dullnig, H.

    1975-01-01

    The high vacuum chamber for irradiating targets with X-rays, electron or ion beams is connected to a magazine storage vessel for the targets through a loading duct which can be evacuated. This duct is traversed by a carriage transporting a magazine to the irradiation position. The duct can be closed by a closing valve. Inside the chamber there is a grip attached to a swivel arm which takes a frame with a target from the magazine, or vice versa, and moves it into the irradiation position. This means that the chamber must always be kept at a constant internal pressure. The swiveling shaft for the swivel arm and the transport pinion of the carriage in addition are magnetically coupled to drive shafts located outside the chamber, which obviates the need for any seals. The grip may also deposit the frame on a goniometer, which allows the target to be aligned in the irradiation position. In addition, the measuring probes used to record the amount of reflected radiation are installed in the chamber under electrically insulated conditions relative to the chamber. (DG/RF) [de

  16. LHCb: Design of a Highly Optimised Vacuum Chamber Support for the LHCb Experiment

    CERN Multimedia

    Leduc, L; Veness, R

    2011-01-01

    The beam vacuum chamber in the LHCb experimental area passes through the centre of a large aperture dipole magnet. The vacuum chamber and all its support systems lie in the acceptance of the detector, so must be highly optimised for transparency to particles. As part of the upgrade programme for the LHCb vacuum system, the support system has been re-designed using advanced lightweight materials. In this paper we discuss the physics motivation for the modifications, the criteria for the selection of materials and tests performed to qualify them for the particular environment of a particle physics experiment. We also present the design of the re-optimised support system.

  17. 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.

  18. Status of COLDDIAG: A Cold Vacuum Chamber for Diagnostics

    CERN Document Server

    Gerstl, Stefan; Casalbuoni, Sara; Grau, Andreas; Hagelstein, Michael; Saez de Jauregui, David; Baglin, Vincent; Boffo, Cristian; Sikler, Gunther; Bradshaw, Thomas; Cimino, Roberto; Commisso, Mario; Spataro, Bruno; Clarke, James; Scott, Duncan; Cox, Matthew; Schouten, Jos; Jones, Roger; Shinton, Ian; Mostacci, Andrea; Wallen, Erik; Weigel, Ralf

    2010-01-01

    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.

  19. A drift chamber with a new type of straws for operation in vacuum

    Science.gov (United States)

    Azorskiy, N.; Glonti, L.; Gusakov, Yu.; Elsha, V.; Enik, T.; Kakurin, S.; Kekelidze, V.; Kislov, E.; Kolesnikov, A.; Madigozhin, D.; Movchan, S.; Polenkevich, I.; Potrebenikov, Yu.; Samsonov, V.; Shkarovskiy, S.; Sotnikov, S.; Zinchenko, A.; Danielsson, H.; Bendotti, J.; Degrange, J.; Dixon, N.; Lichard, P.; Morant, J.; Palladino, V.; Gomez, F. Perez; Ruggiero, G.; Vergain, M.

    2016-07-01

    A 2150×2150 mm2 registration area drift chamber capable of working in vacuum is presented. Thin-wall tubes (straws) of a new type are used in the chamber. A large share of these 9.80 mm diameter drift tubes are made in Dubna from metalized 36 μm Mylar film welded along the generatrix using an ultrasonic welding machine created at JINR. The main features of the chamber and some characteristics of the drift tubes are described. Four such chambers with the X, Y, U, V coordinates each, containing 7168 straws in total, are designed and produced at JINR and CERN. They are installed in the vacuum volume of the NA62 setup in order to study the ultra-rare decay K+ →π+ vv bar and to search for and study rare meson decays. In autumn 2014 the chambers were used for the first time for the data taking in the experimental run of the NA62 at CERN's SPS.

  20. Dutch supplier rewarded for manufacture of the two vacuum vessels for the ATLAS end-cap toroids

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    The ATLAS collaboration has presented an award for outstanding supplier performance to Dutch firm Schelde Exotech. Based on a design by Rutherford Appleton Laboratory, UK, Schelde Exotech manufactured under a NIKHEF contract the two 500 m3 large vacuum vessels for the cryostats of the ATLAS end-cap toroids. These 11-metre diameter castellated aluminium vessels with stainless-steel bore tube are essentially made up of 40-mm-thick plates for the shells, 75-mm-thick plates for the endplates, and 150-mm-thick bars for the flanges. Because of transport constraints, the vessels were made in halves, temporarily sealed and vacuum tested at the works, then transported to CERN for final assembly and acceptance tests. Both vessels were vacuum-tight and the meticulous and clean way of working ensured that a high vacuum was obtained within a few days of pumping. The delivery to CERN was completed in July 2002. Representatives of Schelde Exotech are seen here receiving their award in the ATLAS assembly hall. In the backgro...

  1. LHC Detector Vacuum System Consolidation for Long Shutdown 1 (LS1) in 2013-2014

    CERN Document Server

    Gallilee, M; Cruikshank, P; Gallagher, J; Garion, C; Jimenez, J M; Kersevan, R; Kos, H; Leduc, L; Lepeule, P; Provot, N; Rambeau, H; Veness, R

    2012-01-01

    The LHC has ventured into unchartered territory for Particle Physics accelerators. A dedicated consolidation program is required between 2013 and 2014 to ensure optimal physics performance. The experiments, ALICE, ATLAS, CMS, and LHCb, will utilise this shutdown, along with the gained experience of three years of physics running, to make optimisations to their detectors. New vacuum technologies have been developed for the experimental areas, to be integrated during this first phase shutdown. These technologies include bellows, vacuum chambers and ion pumps in aluminium, new beryllium vacuum chambers, and composite mechanical supports. An overview of this first phase consolidation program for the LHC experiments is presented.

  2. Study of the performance of the Micromegas chambers for the ATLAS Muon Spectrometer upgrade

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00237763; The ATLAS Muon collaboration

    2017-01-01

    Micromegas (MICRO MEsh GAseous Structure) chambers are Micro-Pattern Gaseous Detectors designed to provide a high spatial resolution in highly irradiated environments. In 2007 an ambitious long-term R&D activity was started in the context of the ATLAS experiment, at CERN: the Muon ATLAS Micromegas Activity (MAMMA). After years of tests on prototypes and technology breakthroughs, Micromegas chambers were chosen as tracking detectors for an upgrade of the ATLAS Muon Spectrometer. These novel detectors will be installed in 2018 and 2019 during the second long shutdown of the Large Hadron Collider, and will serve as precision detectors in the innermost part of the ATLAS Muon Spectrometer. Eight layers of Micromegas modules of unprecedented size, up to 3 $\\rm{{m^2}}$, will cover a surface of 150 $\\rm{{m^2}}$ for a total active area of about 1200 $\\rm{{m^2}}$. This upgrade will be crucial to ensure high quality performance for the ATLAS Muon Spectrometer in view of the third run of the Large Hadron Collider and...

  3. Construction of monitored drift tube chambers for ATLAS end-cap muon spectrometer at IHEP (Protvino)

    CERN Document Server

    Bensinger, J; Borisov, A; Fakhrutdinov, R M; Goryatchev, S; Goryachev, V N; Gushchin, V; Hashemi, K S; Kojine, A; Kononov, A I; Larionov, A; Paramoshkina, E; Pilaev, A; Skvorodnev, N; Tchougouev, A; Wellenstein, H

    2002-01-01

    Trapezoidal-shaped Monitored Drift Tube (MDT) chambers will be used in end-caps of ATLAS muon spectrometer. Design and construction technology of such chambers in IHEP (Protvino) is presented. X-ray tomography results confirm desirable 20 mum precision of wire location in the chamber.

  4. Large-Scale Production of Monitored Drift Tube Chambers for the ATLAS Muon Spectrometer

    CERN Document Server

    Bauer, F.; Kortner, O; Kroha, H; Manz, A; Mohrdieck, S; Richter, R; Zhuravlov, V

    2016-01-01

    Precision drift tube chambers with a sense wire positioning accuracy of better than 20 microns are under construction for the ATLAS muon spectrometer. 70% of the 88 large chambers for the outermost layer of the central part of the spectrometer have been assembled. Measurements during chamber construction of the positions of the sense wires and of the sensors for the optical alignment monitoring system demonstrate that the requirements for the mechanical precision of the chambers are fulfilled.

  5. Correlation of photon beam motion with vacuum chamber cooling on the NSLS x-ray ring

    International Nuclear Information System (INIS)

    Johnson, E.D.; Fauchet, A.M.; Zhang, Xiaohao.

    1991-01-01

    The NSLS X-ray ring exhibits a direct correlation between photon beam motion, and distortion of the ring vacuum chamber induced by fluctuations in the cooling system. We have made long term measurements of photon beam vertical position, accelerator vacuum chamber motion, process water temperatures, and angular motions of the magnets around one superperiod of the NSLS x-ray ring. Short term transients in water temperature cause deflection of the ring vacuum chamber which have in turn been shown to induce very small angular rotations of the magnets, on the order of 10 micro-radians. A larger and more difficult to correct effect is the drift in beam position over the course of a fill. This problem has been shown to be related to the thermal gradients that develop across the vacuum chamber which, as a consequence of the configuration of the chamber cooling, depend upon stored current. Orbit simulations based upon the measured rotations are in agreement with the observed beam motions, and reveal that certain patterns of correlated motions of the magnets can produce much larger errors than random motion or concerted motion of all the magnets. During the course of these measurements global orbit feedback was installed, and found to significantly reduce the orbit errors which could not be corrected at their source

  6. Short description of BMS/BMF MDT chamber production for the muon spectrometer of the ATLAS experiment

    International Nuclear Information System (INIS)

    Barashkov, A.V.; Glonti, G.L.; Gongadze, A.L.; Gongadze, I.B.; Gostkin, M.I.; Gus'kov, A.V.; Dedovich, D.V.; Demichev, M.A.; Evtukhovich, P.G.; Elagin, A.L.; Zhemchugov, A.S.; Il'yushenko, E.N.; Kotov, S.A.; Kotova, T.I.; Korolevich, Ya.V.; Kruchonok, V.G.; Krumshtejn, Z.V.; Kuznetsov, N.K.; Lomidze, D.D.; Nikolaev, K.V.; Potrap, I.N.; Rudenko, T.O.; Kharchenko, D.V.; Tskhadadze, Eh.G.; Chepurnov, V.F.; Shelkov, G.A.; Shiyakova, M.M.; Shcherbakov, A.A.; Podkladkin, S.Yu.

    2005-01-01

    The method of assembly of the MDT chambers for the muon spectrometer of the ATLAS experiment is described. During 2000-2004 ∼ 25000 drift tubes were produced at the DLNP, JINR. The tubes were assembled into 84 muon chambers of BMS/BMF type, one of the six main types for the barrel part of the ATLAS muon spectrometer. Particle momenta must be measured in the ATLAS spectrometer with very high precision (2% at 100 GeV/c and 10% at 1000 GeV/c), which required to produce the coordinate detectors with very high (∼80 μm) precision. We describe the method of assembly of large-scale 5-10 m 2 muon chambers with the signal wire mean deviation from the nominal position less than 20 μm

  7. Development of fast heating electron beam annealing setup for ultra high vacuum chamber

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sadhan Chandra [UGC-DAE Consortium For Scientific Research, University Campus, Khandwa Road, Indore 452 001, MP (India); School of Electronics, Devi Ahilya University, Indore 452001, MP (India); Institute of Physics, University of Greifswald, Felix Hausdroff Str. 6 (Germany); Majumdar, Abhijit, E-mail: majuabhijit@gmail.com, E-mail: majumdar@uni-greifswald.de; Hippler, R. [Institute of Physics, University of Greifswald, Felix Hausdroff Str. 6 (Germany); Katiyal, Sumant [School of Electronics, Devi Ahilya University, Indore 452001, MP (India); Shripathi, T. [UGC-DAE Consortium For Scientific Research, University Campus, Khandwa Road, Indore 452 001, MP (India)

    2014-02-15

    We report the design and development of a simple, electrically low powered and fast heating versatile electron beam annealing setup (up to 1000 °C) working with ultra high vacuum (UHV) chamber for annealing thin films and multilayer structures. The important features of the system are constant temperature control in UHV conditions for the temperature range from room temperature to 1000 ºC with sufficient power of 330 W, at constant vacuum during annealing treatment. It takes approximately 6 min to reach 1000 °C from room temperature (∼10{sup −6} mbar) and 45 min to cool down without any extra cooling. The annealing setup consists of a UHV chamber, sample holder, heating arrangement mounted on suitable UHV electrical feed-through and electronic control and feedback systems to control the temperature within ±1 ºC of set value. The outside of the vacuum chamber is cooled by cold air of 20 °C of air conditioning machine used for the laboratory, so that chamber temperature does not go beyond 50 °C when target temperature is maximum. The probability of surface oxidation or surface contamination during annealing is examined by means of x-ray photoelectron spectroscopy of virgin Cu sample annealed at 1000 °C.

  8. Development of fast heating electron beam annealing setup for ultra high vacuum chamber

    International Nuclear Information System (INIS)

    Das, Sadhan Chandra; Majumdar, Abhijit; Hippler, R.; Katiyal, Sumant; Shripathi, T.

    2014-01-01

    We report the design and development of a simple, electrically low powered and fast heating versatile electron beam annealing setup (up to 1000 °C) working with ultra high vacuum (UHV) chamber for annealing thin films and multilayer structures. The important features of the system are constant temperature control in UHV conditions for the temperature range from room temperature to 1000 ºC with sufficient power of 330 W, at constant vacuum during annealing treatment. It takes approximately 6 min to reach 1000 °C from room temperature (∼10 −6 mbar) and 45 min to cool down without any extra cooling. The annealing setup consists of a UHV chamber, sample holder, heating arrangement mounted on suitable UHV electrical feed-through and electronic control and feedback systems to control the temperature within ±1 ºC of set value. The outside of the vacuum chamber is cooled by cold air of 20 °C of air conditioning machine used for the laboratory, so that chamber temperature does not go beyond 50 °C when target temperature is maximum. The probability of surface oxidation or surface contamination during annealing is examined by means of x-ray photoelectron spectroscopy of virgin Cu sample annealed at 1000 °C

  9. Using the method of statistic tests for determining the pressure in the UNC-600 vacuum chamber

    International Nuclear Information System (INIS)

    Kiver, A.M.; Mirzoev, K.G.

    1998-01-01

    The aim of the paper is to simulate the process of pumping-out the UNC-600 vacuum chamber. The simulation is carried out by the Monte-Carlo statistic test method. It is shown that the pressure value in every liner of the chamber may be determined from the pressure in the pump branch pipe, determined by the discharge current of this pump. Therefore, it is possible to precise the working pressure in the ion guide of the UNC-600 vacuum chamber [ru

  10. Measurement of resonance modes causative of beam position monitor signal noise in vacuum chamber of storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Youngdo; Hwang, Ilmoon; Park, Sungju [Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Kim, Changbum, E-mail: chbkim@postech.ac.k [Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

    2011-05-11

    It is known that the position reading obtained from the beam position monitor (BPM) mounted at the storage ring can be corrupted by the resonance mode. We carried out a three dimensional finite-difference time-domain (FDTD) simulation of vacuum chambers of the storage ring of the Pohang Light Source (PLS) without simplified modeling to measure the frequencies of resonance modes excited in the vacuum chamber. The frequencies of resonance modes obtained by the eigenmode simulation are well matched with the peak frequencies of RF transmission scattering matrix (S{sub 21}) graph of sector vacuum chamber measured using a network analyzer. It is found that a transverse electric (TE) resonance mode exists in the operation frequency band of BPM and the vertically oriented electric field of TE resonance mode is linked to the BPM position reading noise. Based on this study, we can easily design a vacuum chamber free from the BPM position reading noise caused by the TE resonance mode.

  11. Measurement of resonance modes causative of beam position monitor signal noise in vacuum chamber of storage ring

    International Nuclear Information System (INIS)

    Joo, Youngdo; Hwang, Ilmoon; Park, Sungju; Kim, Changbum

    2011-01-01

    It is known that the position reading obtained from the beam position monitor (BPM) mounted at the storage ring can be corrupted by the resonance mode. We carried out a three dimensional finite-difference time-domain (FDTD) simulation of vacuum chambers of the storage ring of the Pohang Light Source (PLS) without simplified modeling to measure the frequencies of resonance modes excited in the vacuum chamber. The frequencies of resonance modes obtained by the eigenmode simulation are well matched with the peak frequencies of RF transmission scattering matrix (S 21 ) graph of sector vacuum chamber measured using a network analyzer. It is found that a transverse electric (TE) resonance mode exists in the operation frequency band of BPM and the vertically oriented electric field of TE resonance mode is linked to the BPM position reading noise. Based on this study, we can easily design a vacuum chamber free from the BPM position reading noise caused by the TE resonance mode.

  12. Application of EB welding to fabrication of vacuum chamber of heliotron E

    International Nuclear Information System (INIS)

    Kita, Hisanao; Wada, Tatsuji; Nakazaki, Takamitsu; Akutsu, Yoji; Kazawa, Yoshiaki

    1981-01-01

    Heliotron E, which is a large-scaled device of Heliotron series, is in operation in Kyoto University. Target plasma parameters of this machine are as follows; plasma density 1 x 10 20 m -3 , electron temperature 1 keV, ion temperature 0.8 keV and n tau 10 18 -- 10 19 sec/m 3 . Plasma confining magnetic fields are produced by the helical coil current. To assure the accuracy of the helical coils, the high level of accuracy was required to the profile of the vacuum chamber. The vacuum chamber twists around the torus by 9.5 times and its poloidal cross section shows a race-track shape in any toroidal position. Major radius is 2200 mm and minor radius is 215.5 mm. The material is the high-strength non-magnetic steel which has low permeability (μ = 40 kgf/mm 2 ) and special chemical composition (25Cr-12Ni-0.3N). The thickness of the wall is from 20 to 33 mm. To make the vacuum chamber, 190 pieces were joined together by EB welding after the hot press forming. A giant apparatus (6.5 m x 6.5 m x 3.5 m) was prepared and applied and a special re-focusing coil was used for the long beam welding. The profile accuracy of the vacuum chamber has been controlled as follows; major radius +-3 mm, minor radius sub(-1.5)sup(+4.5)mm, where minus means the inner side. X-ray and dye-penetrant quality of all welds was acceptable for ASME pressure vessel code and JIS. The laekage was less than 1.3 x 10 -8 Torr. 1/sec. The final pressure is 2 x 10 -8 Torr. (author)

  13. The Read-Out Driver for the ATLAS MDT Muon Precision Chambers

    CERN Document Server

    Boterenbrood, H; Kieft, G; König, A; Vermeulen, J C; Wijnen, T A M; 14th IEEE - NPSS Real Time Conference 2005 Nuclear Plasma Sciences Society

    2006-01-01

    Some 200 MDT Read Out Drivers (MRODs) will be built to read out the 1200 MDT precision chambers of the muon spectrometer of the ATLAS experiment at the LHC. The MRODs receive event data via optical links (one per chamber, up to 8 per MROD), build event fragments at a maximum rate of 100 kHz, output these to the ATLAS data-acquisition system and take care of monitoring and error checking, handling and flagging. The design of the MROD-1 prototype (a 9U VME64 module in which this functionality is implemented using FPGAs and ADSP-21160 Digital Signal Processors programmed in C++) is described, followed by a presentation of results of performance measurements. Then the implications for the production version (called MROD-X) and the experience with pre-production modules of the MROD-X are discussed.

  14. Mechanical behaviour of vacuum chambers and beam screens under quench conditions in dipole and quadrupole fields

    CERN Document Server

    Rathjen, C

    2002-01-01

    A method based on analytical formulas is described to calculate bending moments, stresses, and deformations of vacuum chambers and beam screens in dipole and in quadrupole fields during a magnet quench. Solutions are given for circular and racetrack shaped structures. Without the need of time consuming calculations the solutions enable a quick design and verification of vacuum chambers and beam screens.

  15. Measurements of x-ray scattering from accelerator vacuum chamber surfaces, and comparison with an analytical model

    Directory of Open Access Journals (Sweden)

    G. F. Dugan

    2015-04-01

    Full Text Available This paper compares measurements and calculations of scattering of photons from technical vacuum chamber surfaces typical of accelerators. Synchrotron radiation generated by a charged particle beam in the accelerator is either absorbed, specularly reflected, or scattered by the vacuum chamber surface. This phenomenon has important implications on the operation of the accelerator. Measurements of photon scattering were made at the BESSY-II synchrotron radiation facility using samples of aluminum vacuum chamber from Cornell electron storage ring (CESR. A description of the analytic model used in the calculation is given, which takes into account the reflectivity of the material, the surface features of the sample, the wavelengths and the incident angles of the photons. The surface properties used in these calculations were obtained from measurements made from an atomic force microscope.

  16. Second generation "Flat-Fish" vacuum chamber for an ISR intersection

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    The picture shows the part of the "Flat-Fish" chamber covering one side of the beam intersection region. The other side is covered by an equal part and both are welded toghether at their small end. 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 stainless steel strings to the Split Field Magnet poles in order to take the atmospheric pressure forces. This was the thinnest vacuum chamber made for the ISR. Inconel material was chosen for its high elastic modulus and strenght at chamber bake-out temperature.

  17. On-chamber readout system for the ATLAS MDT Muon Spectrometer

    CERN Document Server

    Chapman, J; Ball, R; Brandenburg, G; Hazen, E; Oliver, J; Posch, C

    2004-01-01

    The ATLAS MDT Muon Spectrometer is a system of approximately 380,000 pressurized cylindrical drift tubes of 3 cm diameter and up to 6 meters in length. These Monitored Drift Tubes (MDTs) are precision- glued to form super-layers, which in turn are assembled into precision chambers of up to 432 tubes each. Each chamber is equipped with a set of mezzanine cards containing analog and digital readout circuitry sufficient to read out 24 MDTs per card. Up to 18 of these cards are connected to an on-chamber DAQ element referred to as a Chamber Service Module, or CSM. The CSM multiplexes data from the mezzanine cards and outputs this data on an optical fiber which is received by the off-chamber DAQ system. Thus, the chamber forms a highly self-contained unit with DC power in and a single optical fiber out. The Monitored Drift Tubes, due to their length, require a terminating resistor at their far end to prevent reflections. The readout system has been designed so that thermal noise from this resistor remains the domi...

  18. Conditioning of the vacuum chamber of the Tokamak Novillo

    International Nuclear Information System (INIS)

    Valencia A, R.; Lopez C, R.; Melendez L, L.; Chavez A, E.; Colunga S, S.; Gaytan G, E.

    1992-03-01

    The obtained experimental results of the implementation of two techniques of present time for the conditioning of the internal wall of the chamber of discharges of the Tokamak Novillo are presented, which has been designed, built and put in operation in the Laboratory of Plasma Physics of the National Institute of Nuclear Research (ININ). These techniques are: the vacuum baking and the low energy pulsed discharges, which were applied after having reached an initial pressure of the order of 10 -7 Torr. with a system of turbomolecular pumping previous preparation of surfaces and vacuum seals. The analysis of residual gases was carried out with a mass spectrometer before and after conditioning. The obtained results show that the vacuum baking it was of great effectiveness to reduce the value of the initial pressure in short time, in more of a magnitude order and the low energy discharges reduced the oxygen at worthless levels with regard to the initial values. (Author)

  19. Algorithm for study on the stressed-strained state of thermonuclear device vacuum chambers under dynamic loads

    International Nuclear Information System (INIS)

    Zhuravleva, A.M.; Litvinov, V.B.

    1982-01-01

    The problem of dynamic analysis of stressed-strained state of vacuum chambers is vital for large thermonuclear devices during the stall of the plasma-filament apd other tpansitional operation regimes when loading for a chamber are nonstationary. To plot a mathematical model the design of the vacuum chamber is discreted on the basis of the method of final elements. To approximate vacuum shell, a plate triangular element with 3 joint points and 5 parameters in the joint is used. It is obtained due to the unity of the bemded element and the element for the flat problem. To investigate nonstationary oscillations of vacuum chambers discreted on the basis of the method of final elements, it is suggested to use the numeric conversion of the Japlace transformation. On the basis of the algorithm suggested a program of numerical function conversion is developed. Test calculations have shown a good stability of the algorithm when selecting the values of transformation parameter in the range of lower intrinsic system frequencies. The advantage of the above method is in the fact that the time-structure shift function is found instantly in the form of the series for the whole time interval and does not require temporary steps, which bring about large expenses of counting time and error accumulation

  20. Construction and Test of New Precision Drift-Tube Chambers for Upgrades of the ATLAS Muon Spectrometer in 2016/17

    CERN Document Server

    INSPIRE-00218480; Kortner, O.; Müller, F.; Nowak, S.; Schmidt-Sommerfeld, K.

    2016-01-01

    Small-diameter Muon Drift Tube (sMDT) chambers have been developed for the ATLAS muon detector upgrade. They possess an improved rate capability and a more compact design with respect to the existing chambers, which allows to equip detector regions uninstrument at present. The chamber assembly methods have been optimized for mass production, while the sense wire positioning accuracy is improved to below ten microns. The chambers will be ready for installation in the winter shutdown 2016/17 of the Large Hadron Collider. The design and construction of the new sMDT chambers for ATLAS will be discussed as well as measurements of their precision and performance.

  1. Things One Can Learn by Putting a Quadcopter in a Vacuum Chamber

    Science.gov (United States)

    Ayars, Eric; Goff, Tori; Williams, Kirk

    2018-05-01

    Quadcopters (also known as "drones") do not fly in vacuum. This is obvious enough that experimenting on one in a vacuum chamber would seem rather uninteresting, but there is one question that may be usefully addressed by such an experiment: the mechanism for yaw control. Quadcopters control yaw (rotation about the vertical axis) by differential rotor speed, and the question of whether those changes in rotor speed create yaw torque via conservation of angular momentum or via atmospheric drag can be addressed by "flying" a quadcopter in a vacuum where there is effectively zero atmospheric drag.

  2. 2001, the ATLAS Cryostat Odyssey

    CERN Multimedia

    2001-01-01

    After a journey of several thousand kilometres, over sea and land, by canal and highway, the cryogenics barrel of the ATLAS electromagnetic calorimeter finally arrived at CERN last week. Installed in Hall 180, the cryogenics barrel of the ATLAS electromagnetic calorimeter will be fitted out to take the central superconducting solenoid and the electromagnetic calorimeter. On Monday 2 July, different French police units and EDF officials were once again keeping careful watch around the hairpin bends of the road twisting down from the Col de la Faucille: a special load weighing 100 tonnes, 7 metres high, 5.8 metres wide and 7.2 metres long was being brought down into the Pays de Gex to the Meyrin site of CERN. This time the destination was the ATLAS experiment. A huge blue tarpaulin cover concealed the cryogenics barrel of the experiment's liquid argon electromagnetic calorimeter. The cryostat consists of a vacuum chamber, a cylinder that is 5.5 metres in diameter, 7 metres long, and a concentric cold chamber ...

  3. RF HEATING AND TEMPERATURE OSCILLATIONS DUE TO A SMALL GAP IN A PEP-II VACUUM CHAMBER

    International Nuclear Information System (INIS)

    Novokhatski, Alexander

    2003-01-01

    Wake fields excited in a small gap of a vacuum chamber by ampere beams can have enough amplitude to heat the chamber. The electric component of these fields can be above the arcing limit. Usually flange connections in a vacuum chamber contain a vacuum gasket and an inner RF gasket. If a small gap occurs between the RF gasket and flange surface, wake fields can heat the flanges. The flanges are usually made of stainless steel, which efficiently absorbs RF power. Some flanges consist of two parts (like a vacuum valve flange) and are mechanically connected but have poor thermal contact. A temperature rise can lengthen the inner part of the flange and make firmer the thermal contact to the outer part of the flange. The heat will then flow to the outer part of the flange, which is air and water-cooled. This cooling lowers the flange temperature and the thermal contact becomes poor again. This ''quasi'' periodic mechanism can explain the nature of temperature oscillations observed at several locations in PEP-II, the SLAC B-factory

  4. All-metal vacuum chamber for the ZT-40 experiment

    International Nuclear Information System (INIS)

    Dike, R.S.; Downing, J.N.

    1981-10-01

    We discuss the design and fabrication of the all-metal vacuum chamber presently in use in the ZT-40 device. ZT-40 is the current experiment in the Los Alamos Reversed-Field Pinch (RFP) program. The new vessel, which replaces a ceramic one, is made of Inconel 625 and has major and minor diameters of 228 cm and 40 cm, respectively. It consists of 24 convoluted and straight sections welded into a single toroidal geometry. Presented are several design features showing diagnostic and vacuum port tubulations and thermal-electrical insulation isolating the unit from its conducting shell. We also discuss fabrication techniques and our procedure for cleaning and heat treatment designed to eliminate residual gas contamination in the Inconel material

  5. Sag compensation system for assembly of MDT-chambers for the ATLAS experiment

    International Nuclear Information System (INIS)

    Barashkov, A.V.; Glonti, G.L.; Gongadze, A.L.; Evtukhovich, P.G.; Il'yushenko, E.N.; Kotov, S.A.; Kruchonok, V.G.; Tskhadadze, Eh.G.; Chepurnov, V.F.; Shelkov, G.A.

    2005-01-01

    The description of a system of the devices created for compensation of the gravitational deflection of the drift chamber during its assembly is presented. By means of this system during stage-by-stage gluing of layers of tube drift detectors to the chamber the transversal deflection considerably decreases and by that high accuracy of mutual position of separate tubes is provided. The devices were applied at assembly of 74 MDT-chambers of the ATLAS experiment. Design values of deformation of the chambers as well as the results of measurement of transversal deflections obtained during the assembly with the use of the system of sag compensation are given. Testing of chambers on the X-ray tomograph at CERN has shown that the accuracy of the positions of separate signal wires inside the assembled chambers is within the limits of the required 20 μm

  6. A Large High Vacuum Reaction Chamber for Nuclear Physics Research at VECC, Kolkata

    International Nuclear Information System (INIS)

    Kundu, S; Bhattacharya, S; Meena, J K; Ghosh, T K; Bhattacharjee, T; Mukhopadhyay, P; Bhattacharya, C; Rana, T K; Banerjee, K; Mukherjee, G; Banerjee, S R; Bandyopadhyay, D L; Ahammed, M; Bhattacharya, P

    2012-01-01

    A large, segmented, horizontal axis, reaction chamber (SHARC) has recently been fabricated, installed and integrated with the beam line in the VECC superconducting cyclotron (SCC) experimental area. It is a cylindrical, three segment, stainless steel chamber of length 2.2 m, diameter 1 m. Two pairs of parallel rails have been provided internally for placement of the target assembly and detector systems within the chamber. The whole target assembly can be placed anywhere on the rail to facilitate optimum flight path. The nominal vacuum of ∼1×10 −7 mbar has been obtained in ∼8 hrs by means of two turbo molecular (1000 l/s) and two cryo pumps (2500 l/s) backed by mechanical pumps. The whole vacuum system as well as the target positioning (vertical and rotational movements) operations are fully automated with manual override option; both are monitored and controlled locally as well as remotely through the local and remote control units providing real time status display.

  7. Ultimate pressures achieved in TiZrV sputter-coated vacuum chambers

    CERN Document Server

    Benvenuti, Cristoforo; Ruzinov, V

    2001-01-01

    Two metre long, cylindrical vacuum chambers of diameter ranging from 34 to 100 mm, coated with TiZrV getter films by sputtering, have been baked for about 24 h at temperatures from 120 to 250 degrees C. The ultimate pressures achieved after bakeout were found to correspond to the ratio of the pressure gauge degassing to the effective pumping speed provided by the chamber at the location of the gauge. The results covering a pressure range from 10/sup -11/ Torr down to 10 /sup -13/ Torr are presented and discussed. (6 refs).

  8. An ultra-high-vacuum multiple grating chamber and scan drive with improved grating change

    International Nuclear Information System (INIS)

    Hulbert, S.L.; Holly, D.J.; Middleton, F.H.; Wallace, D.J.; Wisconsin Univ., Stoughton, WI; Wisconsin Univ., Stoughton, WI

    1989-01-01

    We describe a new grating chamber and scan drive which has been designed, built, and tested by Physical Sciences Laboratory of the University of Wisconsin for the new high flux, high-resolution spectroscopy branch line of the TOK hybrid wiggler/undulator on the NSLS VUV ring. The chamber will contain spherical gratings to be used in the Spherical Grating Monochromator (SGM) configuration introduced by Chen and Sette. The grating chamber houses five 180 mm x 35 mm x 30 mm gratings capable of scanning a range of 12 degree (-14 degree to +8 degree with respect to the incoming beam direction) for VUV and soft X-ray diffraction. The gratings can be switched and precisely indexed while under ultra-high vacuum (UHV) at any scan angle and are mechanically isolated from the vacuum chamber to prevent inaccuracies due to chamber distortions. The gratings can separately be adjusted for height, yaw, pitch, and roll, with the latter three performed while in vacuo. The scan drive provides a resolution of 0.03 arc sec with linearity over the 12 degree range of ∼1.5 arc sec and absolute reproducibility of 1 arc sec. 5 refs., 5 figs

  9. Performance of the ATLAS Muon Drift-Tube Chambers at High Background Rates and in Magnetic Fields

    CERN Document Server

    INSPIRE-00213689; Horvat, S.; Legger, F.; Kortner, O.; Kroha, H.; Richter, R.; Valderanis, Ch.; Rauscher, F.; Staude, A.

    2016-01-01

    The ATLAS muon spectrometer uses drift-tube chambers for precision tracking. The performance of these chambers in the presence of magnetic field and high radiation fluxes is studied in this article using test-beam data recorded in the Gamma Irradiation Facility at CERN. The measurements are compared to detailed predictions provided by the Garfield drift-chamber simulation programme.

  10. Historical review of the vacuum chamber technology for INS-ES

    International Nuclear Information System (INIS)

    Yoshida, Katsuhide

    2006-01-01

    The INS (Institute for Nuclear Study), University of Tokyo, was founded in 1955. Construction of the ES (electron synchrotron) was approved in 1956 and finished in 1961. 1.3 GeV INS-ES consists of 8 electric magnets with 3.14m length at intervals of 1.2m. It used resonant exciting current. The vacuum chamber was called donut made of ceramics at first and changed by araldite in 1964, and metal in 1970's. 53% of troubles were caused by the vacuum system in 1966. The metal donut with stainless steel welding bellows was changed by the stainless steel from SUS304 to SUS316L. These improvement methods solved the vacuum problems. The donut made of araldite, a trial piece of stainless steel welding bellows, increase of beam intensity of INS-ES and position of stainless steel welding bellows in section are shown. (S.Y.)

  11. Construction of a Thermal Vacuum Chamber for Environment Test of Triple CubeSat Mission TRIO-CINEMA

    Science.gov (United States)

    Jeon, Jeheon; Lee, Seongwhan; Yoon, Seyoung; Seon, Jongho; Jin, Ho; Lee, Donghun; Lin, Robert P.

    2013-12-01

    TRiplet Ionospheric Observatory-CubeSat for Ion, Neutron, Electron & MAgnetic fields (TRIO-CINEMA) is a CubeSat with 3.14 kg in weight and 3-U (10 × 10 × 30 cm) in size, jointly developed by Kyung Hee University and UC Berkeley to measure magnetic fields of near Earth space and detect plasma particles. When a satellite is launched into orbit, it encounters ultrahigh vacuum and extreme temperature. To verify the operation and survivability of the satellite in such an extreme space environment, experimental tests are conducted on the ground using thermal vacuum chamber. This paper describes the temperature control device and monitoring system suitable for CubeSat test environment using the thermal vacuum chamber of the School of Space Research, Kyung Hee University. To build the chamber, we use a general purpose thermal analysis program and NX 6.0 TMG program. We carry out thermal vacuum tests on the two flight models developed by Kyung Hee University based on the thermal model of the TRIO-CINEMA satellite. It is expected from this experiment that proper operation of the satellite in the space environment will be achieved.

  12. Construction of a Thermal Vacuum Chamber for Environment Test of Triple CubeSat Mission TRIO-CINEMA

    Directory of Open Access Journals (Sweden)

    Jeheon Jeon

    2013-09-01

    Full Text Available TRiplet Ionospheric Observatory-CubeSat for Ion, Neutron, Electron & MAgnetic fields (TRIO-CINEMA is a CubeSat with 3.14 kg in weight and 3-U (10 × 10 × 30 cm in size, jointly developed by Kyung Hee University and UC Berkeley to measure magnetic fields of near Earth space and detect plasma particles. When a satellite is launched into orbit, it encounters ultrahigh vacuum and extreme temperature. To verify the operation and survivability of the satellite in such an extreme space environment, experimental tests are conducted on the ground using thermal vacuum chamber. This paper describes the temperature control device and monitoring system suitable for CubeSat test environment using the thermal vacuum chamber of the School of Space Research, Kyung Hee University. To build the chamber, we use a general purpose thermal analysis program and NX 6.0 TMG program. We carry out thermal vacuum tests on the two flight models developed by Kyung Hee University based on the thermal model of the TRIO-CINEMA satellite. It is expected from this experiment that proper operation of the satellite in the space environment will be achieved.

  13. Elastomer seal for a large toroidal vacuum chamber

    International Nuclear Information System (INIS)

    Skellett, S.; Casey, F.; Blake, H.

    1978-07-01

    An aluminium toroidal vacuum chamber for use at 10(-6) torr, whose overall diameter is in the region of 5 metres, was built from 4 component parts which resulted in joint lines in the horizontal and vertical planes crossing each other in 4 places. A viton seal was developed which allows a vacuum tight joint to be made without the need for tightly toleranced fitting of the mating faces and also overcomes the difficulty of ensuring a reliable seal at cross-over joints. Ease of maintenance and repair in situ are important factors of the design. An assembly which presented the geometry of the sealing problem was tested and is described here. Various adhesives for bonding viton were examined for the manufacture of the seal. The most suitable adhesive was found to be Loctite S496, chosen for its bond strength and convenience in use. A device for preparing and bonding the viton in situ is described. (author)

  14. Residual gas analysis of a cryostat vacuum chamber during the cool down of SST - 1 superconducting magnet field coil

    International Nuclear Information System (INIS)

    Semwal, P.; Joshi, K.S.; Thankey, P.L.; Pathan, F.S.; Raval, D.C.; Patel, R.J.; Pathak, H.A.

    2005-01-01

    One of the most important feature of Steady state Superconducting Tokamak -1 (SST-l) is the Nb-Ti superconducting magnet field coils. The coils will be kept in a high vacuum chamber (Cryostat) and liquid Helium will be flown through it to cool it down to its critical temperature of 4.5K. The coil along with its hydraulics has four types of joints (1) Stainless Steel (S.S.) to Copper (Cu) weld joints (2) S. S. to S. S. weld joints (3) Cu to Cu brazed joints and (4) G-10 to S. S. joints with Sti-cast as the binding material. The joints were leak tested with a Helium mass spectrometer leak detector in vacuum as well as in sniffer mode. However during the cool-down of the coil, these joints may develop leaks. This would deteriorate the vacuum inside the cryostat and coil cool-down would subsequently become more difficult. To study the effect of cooling on the vacuum condition of the Cryostat, a dummy Cryostat chamber was fabricated and a toroidal Field (TF) magnet was kept inside this chamber and cooled down to 4.5 K.A residual gas analyzer (RGA) was connected to the Cryostat chamber to study the behaviour of major gases inside this chamber with temperature. An analysis of the RGA data acquired during the coo-down has been presented in this chamber. (author)

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

    International Nuclear Information System (INIS)

    Streli, C.; Wobrauschek, P.; Zoeger, N.; Pepponi, G.

    2003-01-01

    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 mm 2 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)

  16. True and measured outgassing rates of a vacuum chamber with a reversibly adsorbed phase

    Energy Technology Data Exchange (ETDEWEB)

    Akaishi, K. [National Inst. for Fusion Science, Toki, Gifu (Japan); Nakasuga, M. [Graduate School of Energy Science, Kyoto Univ., Uji, Kyoto (Japan); Funato, Y. [Suzuka National College of Technology, Suzuka, Mie (Japan)

    2000-03-01

    A pump down model for a vacuum chamber with a reversibly adsorbed phase is presented. The outgassing equation which predicts the variation of coverage at the wall surface of a vacuum chamber with time is derived. Then the measured and the true outgassing rates are defined. The theoretical measured outgassing rate shows only a very weak dependence for pumping speed. This prediction is opposite to the experimental result that the measured outgassing rate depends significantly on pumping speed. It is discussed that the experimental measured outgassing rate must be described as the product of the effective pumping speed and the measured pressure in the pumped chamber, in which the measured pressure is equivalent to the equilibrium pressure of the wall surface described by the equilibrium adsorption isotherm as a function of the shifted surface coverage {theta}-{delta}{theta} by a small coverage {delta}{theta} from the coverage of a pumping point {delta}. (author)

  17. True and measured outgassing rates of a vacuum chamber with a reversibly adsorbed phase

    International Nuclear Information System (INIS)

    Akaishi, K.; Nakasuga, M.; Funato, Y.

    2000-03-01

    A pump down model for a vacuum chamber with a reversibly adsorbed phase is presented. The outgassing equation which predicts the variation of coverage at the wall surface of a vacuum chamber with time is derived. Then the measured and the true outgassing rates are defined. The theoretical measured outgassing rate shows only a very weak dependence for pumping speed. This prediction is opposite to the experimental result that the measured outgassing rate depends significantly on pumping speed. It is discussed that the experimental measured outgassing rate must be described as the product of the effective pumping speed and the measured pressure in the pumped chamber, in which the measured pressure is equivalent to the equilibrium pressure of the wall surface described by the equilibrium adsorption isotherm as a function of the shifted surface coverage θ-Δθ by a small coverage Δθ from the coverage of a pumping point Δ. (author)

  18. Development of a Methodology for Conducting Hall Thruster EMI Tests in Metal Vacuum Chambers of Arbitrary Shape and Size

    Science.gov (United States)

    Gallimore, Alec D.

    2000-01-01

    While the closed-drift Hall thruster (CDT) offers significant improvement in performance over conventional chemical rockets and other advanced propulsion systems such as the arcjet, its potential impact on spacecraft communication signals must be carefully assessed before widespread use of this device can take place. To this end, many of the potentially unique issues that are associated with these thrusters center on its plume plasma characteristics and the its interaction with electromagnetic waves. Although a great deal of experiments have been made in characterizing the electromagnetic interference (EMI) potential of these thrusters, the interpretation of the resulting data is difficult because most of these measurements have been made in vacuum chambers with metal walls which reflect radio waves emanating from the thruster. This project developed a means of assessing the impact of metal vacuum chambers of arbitrary size or shape on EMI experiments, thereby allowing for test results to be interpreted properly. Chamber calibration techniques were developed and initially tested at RIAME using their vacuum chamber. Calibration experiments were to have been made at Tank 5 of NASA GRC and the 6 m by 9 m vacuum chamber at the University of Michigan to test the new procedure, however the subcontract to RIAME was cancelled by NASA memorandum on Feb. 26. 1999.

  19. Techniques developed for the ATLAS Thin Gap Chambers mass production in Japan

    CERN Document Server

    Tanaka, S; Ishii, K; Iwasaki, H; Arataki, Y; Bando, T; Homma, Y; Ishino, M; Kondo, T; Kobayashi, T; Kurashige, H; Mikenberg, G; Miyazaki, Y; Nakagawa, Y; Nanjo, H; Ikeno, M; Nozaki, M; Ochi, A; Sasaki, O; Shoa, M; Sugimoto, T; Takeda, H; Takeshita, T; Yokoyama, C

    2004-01-01

    The Thin Gap Chambers (TGCs) are used for the muon trigger system in the end-cap regions of the ATLAS detector. The TGC mass production phase at High Energy Accelerator Research Organization (KEK) started in January 2001. As the anode-cathode distance is small, 1.4 mm, chamber flatness is essential to achieve a uniform gas gain over the chamber. In order to perform a stable production with high quality we developed a chamber closing system. When we glue two half-chambers together, we sandwich them between a granite table and an aluminum honeycomb panel to keep the chamber flat from both sides. By using silk screens, we control the quantity of epoxy adhesive that affects the chamber thickness. Due to these developments, we can achieve the flatness of less than 100 µm. Uniformity of detection efficiency of the TGC is measured with a cosmic-ray test bench at Kobe University. So far we have tested 300 TGCs. Position dependence of the efficiency is measured with a granularity of 5mm-by-5mm. The average efficiency...

  20. Estimating teat canal cross-sectional area to determine the effects of teat-end and mouthpiece chamber vacuum on teat congestion.

    Science.gov (United States)

    Penry, J F; Upton, J; Mein, G A; Rasmussen, M D; Ohnstad, I; Thompson, P D; Reinemann, D J

    2017-01-01

    The primary objective of this experiment was to assess the effect of mouthpiece chamber vacuum on teat-end congestion. The secondary objective was to assess the interactive effects of mouthpiece chamber vacuum with teat-end vacuum and pulsation setting on teat-end congestion. The influence of system vacuum, pulsation settings, mouthpiece chamber vacuum, and teat-end vacuum on teat-end congestion were tested in a 2×2 factorial design. The low-risk conditions for teat-end congestion (TEL) were 40 kPa system vacuum (Vs) and 400-ms pulsation b-phase. The high-risk conditions for teat-end congestion (TEH) were 49 kPa Vs and 700-ms b-phase. The low-risk condition for teat-barrel congestion (TBL) was created by venting the liner mouthpiece chamber to atmosphere. In the high-risk condition for teat-barrel congestion (TBH) the mouthpiece chamber was connected to short milk tube vacuum. Eight cows (32 quarters) were used in the experiment conducted during 0400 h milkings. All cows received all treatments over the entire experimental period. Teatcups were removed after 150 s for all treatments to standardize the exposure period. Calculated teat canal cross-sectional area (CA) was used to assess congestion of teat tissue. The main effect of the teat-end treatment was a reduction in CA of 9.9% between TEL and TEH conditions, for both levels of teat-barrel congestion risk. The main effect of the teat-barrel treatment was remarkably similar, with a decrease of 9.7% in CA between TBL and TBH conditions for both levels of teat-end congestion risk. No interaction between treatments was detected, hence the main effects are additive. The most aggressive of the 4 treatment combinations (TEH plus TBH) had a CA estimate 20% smaller than for the most gentle treatment combination (TEL plus TBL). The conditions designed to impair circulation in the teat barrel also had a deleterious effect on circulation at the teat end. This experiment highlights the importance of elevated mouthpiece

  1. Design and Qualification of Transparent Beam Vacuum Chamber Supports for the LHCb Experiment

    CERN Document Server

    Bosch, JL; Garion, C

    2014-01-01

    Three beryllium beam vacuum chambers pass through the aperture of the large dipole magnet and particle acceptance region of the LHCb experiment, coaxial to the LHC beam. At the interior of the magnet, a system of rods and cables supports the chambers, holding them rigidly in place, in opposition to the vacuum forces caused by their conical geometry. In the scope of the current upgrade programme, the steel and aluminium structural components are replaced by a newly designed system, making use of beryllium, in addition to a number of organic materials, and are optimised for overall transparency to incident particles. Presented in this paper are the design criteria, along with the unique design developments carried out at CERN, and furthermore, a description of the technologies procured from industrial partners, specifically in obtaining the best solution for the cable components.

  2. Bending-magnet vacuum chambers for VUV ring at LNLS

    International Nuclear Information System (INIS)

    Castro, A.R.B. de; Rodrigues, A.R.D.; Gomes, P.A.P.; Baptista, C.A.R.

    1990-01-01

    We discuss design criteria dictated by optical, thermal, electrical impedance and structural considerations. The proposed chambers will provide 3 conventional light ports. A fourth port will allow extraction of back scattered soft X-rays. Cooled absorbers will collect the unused radiation while confining the photo-stimulated desorption to a vacuum antechamber away from the electron beam path. We describe the thermal considerations relating to the cooled sapphire filters needed in the visible light ports and the cooling requirements for the copper radiation absorbers. (author)

  3. Bending-magnet vacuum chambers for VUV ring at LNLS

    International Nuclear Information System (INIS)

    de Castro, A.R.B.; Rodrigues, A.R.D.; Gomes, P.A.P.; Baptista, C.A.R.P.

    1990-01-01

    This paper discusses design criteria dictated by optical, thermal, electrical impedance and structural considerations. The proposed chambers will provide 3 conventional light ports. A fourth port will allow extraction of back scattered soft X-rays. Cooled absorbers will collect the unused radiation while confining the photo-stimulated desorption to a vacuum antechamber away from the electron beam path. The authors describe the thermal considerations relating to the cooled sapphire filters needed in the visible light ports and the cooling requirements for the copper radiation absorbers

  4. Construction and Test of New Precision Drift-Tube Chambers for the ATLAS Muon Spectrometer

    CERN Document Server

    INSPIRE-00218480

    2017-02-11

    ATLAS muon detector upgrades aim for increased acceptance for muon triggering and precision tracking and for improved rate capability of the muon chambers in the high-background regions of the detector with increasing LHC luminosity. The small-diameter Muon Drift Tube (sMDT) chambers have been developed for these purposes. With half of the drift-tube diameter of the MDT chambers and otherwise unchanged operating parameters, sMDT chambers share the advantages of the MDTs, but have an order of magnitude higher rate capability and can be installed in detector regions where MDT chambers do not fit in. The chamber assembly methods have been optimized for mass production, minimizing construction time and personnel. Sense wire positioning accuracies of 5 ?micons have been achieved in serial production for large-size chambers comprising several hundred drift tubes. The construction of new sMDT chambers for installation in the 2016/17 winter shutdown of the LHC and the design of sMDT chambers in combination with new R...

  5. An accurate interference refractometer based on a permanent vacuum chamber : development and results

    NARCIS (Netherlands)

    Renkens, M.J.M.; Schellekens, P.H.J.

    1993-01-01

    A new accurate interference refractometer, without pumping device, has been developed. The refractometer is based on a commercially available laser measurement system and uses a prismatic measuring cell, containing a permanent vacuum chamber. Measurements of the refractive index of air can be

  6. Optimization and Calibration of the Drift-Tube Chambers for the ATLAS Muon Spectrometer

    CERN Document Server

    AUTHOR|(CDS)2067746

    2000-01-01

    The final phase of preparations for the ATLAS experiment at the future Large Hadron Collider (LHC) has begun. In the last decade the collaboration has carried out various test-beam experiments to study and optimize prototypes of all subdetectors under more and more realistic conditions. To enhance the detector-physical understanding, these hardware activities were complemented by detailed simulations. In parallel the development of reconstruction software has made important progress. The present work focusses on some advanced aspects of optimizing the Monitored Drift Tube Chambers (MDT) for operation as precision chambers in the Muon Spectrometer. It will be shown how this system has been tuned for maximum performance in order to meet the ambitious goals defined by the objectives of LHC particle physics. After defining the basic detector parameters, the tubes' capability of running in ATLAS's high-rate gamma radiation background was verified. Both tasks necessitated several years of gathering experience in mu...

  7. Streamlined calibrations of the ATLAS precision muon chambers for initial LHC running

    Energy Technology Data Exchange (ETDEWEB)

    Amram, N. [Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, 69978 Tel Aviv (Israel); Ball, R. [Department of Physics, The University of Michigan, Ann Arbor, MI 48109-1120 (United States); Benhammou, Y.; Ben Moshe, M. [Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, 69978 Tel Aviv (Israel); Dai, T.; Diehl, E.B. [Department of Physics, The University of Michigan, Ann Arbor, MI 48109-1120 (United States); Dubbert, J. [Max-Planck-Institut fuer Physik, Werner-Heisenberg-Institut, Muenchen (Germany); Etzion, E., E-mail: erez@cern.ch [Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, 69978 Tel Aviv (Israel); Ferretti, C.; Gregory, J. [Department of Physics, The University of Michigan, Ann Arbor, MI 48109-1120 (United States); Haider, S. [CERN, CH-1211 Geneva 23 (Switzerland); Hindes, J.; Levin, D.S.; Manilow, E.; Thun, R.; Wilson, A.; Weaverdyck, C.; Wu, Y.; Yang, H.; Zhou, B. [Department of Physics, The University of Michigan, Ann Arbor, MI 48109-1120 (United States); and others

    2012-04-11

    The ATLAS Muon Spectrometer is designed to measure the momentum of muons with a resolution of dp/p=3% at 100 GeV and 10% at 1 TeV. For this task, the spectrometer employs 355,000 Monitored Drift Tubes (MDTs) arrayed in 1200 chambers. Calibration (RT) functions convert drift time measurements into tube-centered impact parameters for track segment reconstruction. RT functions depend on MDT environmental parameters and so must be appropriately calibrated for local chamber conditions. We report on the creation and application of a gas monitor system based calibration program for muon track reconstruction in the LHC startup phase.

  8. Development of a Micro Pixel Chamber for the ATLAS Upgrade

    CERN Document Server

    Ochi, Atsuhiko; Komai, Hidetoshi; Edo, Yuki; Yamaguchi, Takahiro

    2012-01-01

    The Micro Pixel Chamber (μ-PIC) is being developed a sacandidate for the muon system of the ATLAS detector for upgrading in LHC experiments. The μ-PIC is a micro-pattern gaseous detector that doesn’t have floating structure such as wires, mesh, or foil. This detector can be made by printed-circuit-board (PCB) technology, which is commercially available and suited for mass production. Operation tests have been performed under high flux neutrons under similar conditions to the ATLAS cavern. Spark rates are measured using several gas mixtures under 7 MeV neutron irradiation, and good properties were observed using neon, ethane, and CF4 mixture of gases.Using resistive materials as electrodes, we are also developing a new μ-PIC, which is not expected to damage the electrodes in the case of discharge sparks.

  9. An overview of the mechanical design of the Atlas pulsed power machine

    CERN Document Server

    Bowman, D W; Barr, G W; Bennett, G A; Cochrane, J C; Davis, H A; Davis, T O; Dorr, G; Gribble, R F; Griego, J R; Hood, M; Kimerly, H J; Martínez, A; McCuistian, B T; Miller, R B; Ney, S A; Nielsen, K; Pankuch, P; Parsons, W M; Potter, C; Ricketts, R L; Salazar, H R; Scudder, D W; Shapiro, C; Thompson, M C; Trainor, R J; Valdez, G A; Yonemoto, W; Kirbie, H C

    1999-01-01

    Atlas is a pulsed-power facility being designed at Los Alamos National Laboratory to perform high-energy density experiments in support of Science-Based Stockpile Stewardship and basic research programs. Atlas will consist of 24 individual maintenance units, each consisting of 4 240-kV Marx units. Maintenance units are contained in large oil tanks arrayed in a circle about a central target chamber. Total stored energy of the capacitor bank will be 23 MJ. Maintenance units will discharge through an output shorting switch into a vertical tri-plate transmission line, and from there into a transition area/collector inside a large vacuum chamber. An overview of mechanical design aspects of the Atlas machine is presented. These include maintenance unit design and design of the tri-plate transmission line and transition region. Findings from fabrication and testing of prototype systems are discussed. (2 refs).

  10. Construction and test of new precision drift-tube chambers for the ATLAS muon spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Kroha, H., E-mail: kroha@mpp.mpg.de; Kortner, O.; Schmidt-Sommerfeld, K.; Takasugi, E.

    2017-02-11

    ATLAS muon detector upgrades aim for increased acceptance for muon triggering and precision tracking and for improved rate capability of the muon chambers in the high-background regions of the detector with increasing LHC luminosity. The small-diameter Muon Drift Tube (sMDT) chambers have been developed for these purposes. With half of the drift-tube diameter of the MDT chambers and otherwise unchanged operating parameters, sMDT chambers share the advantages of the MDTs, but have an order of magnitude higher rate capability and can be installed in detector regions where MDT chambers do not fit in. The chamber assembly methods have been optimized for mass production, minimizing construction time and personnel. Sense wire positioning accuracies of 5 μm have been achieved in serial production for large-size chambers comprising several hundred drift tubes. The construction of new sMDT chambers for installation in the 2016/17 winter shutdown of the LHC and the design of sMDT chambers in combination with new RPC trigger chambers for replacement of the inner layer of the barrel muon spectrometer are in progress.

  11. Construction and test of new precision drift-tube chambers for the ATLAS muon spectrometer

    Science.gov (United States)

    Kroha, H.; Kortner, O.; Schmidt-Sommerfeld, K.; Takasugi, E.

    2017-02-01

    ATLAS muon detector upgrades aim for increased acceptance for muon triggering and precision tracking and for improved rate capability of the muon chambers in the high-background regions of the detector with increasing LHC luminosity. The small-diameter Muon Drift Tube (sMDT) chambers have been developed for these purposes. With half of the drift-tube diameter of the MDT chambers and otherwise unchanged operating parameters, sMDT chambers share the advantages of the MDTs, but have an order of magnitude higher rate capability and can be installed in detector regions where MDT chambers do not fit in. The chamber assembly methods have been optimized for mass production, minimizing construction time and personnel. Sense wire positioning accuracies of 5 μm have been achieved in serial production for large-size chambers comprising several hundred drift tubes. The construction of new sMDT chambers for installation in the 2016/17 winter shutdown of the LHC and the design of sMDT chambers in combination with new RPC trigger chambers for replacement of the inner layer of the barrel muon spectrometer are in progress.

  12. Development of mass-production technique of the ATLAS thin gap chamber in Japan

    CERN Document Server

    Tanaka, S; Ishii, K; Iwasaki, H; Arataki, Y; Bando, T; Homma, Y; Ishino, M; Kondo, T; Kobayashi, T; Kurashige, H; Mikenberg, G; Miyazaki, Y; Nakagawa, Y; Nanjo, H; Ikeno, M; Nozaki, M; Ochi, A; Sasaki, O; Shoa, M; Sugimoto, T; Takeda, H; Takeshita, T; Yokoyama, C

    2004-01-01

    The thin gap chambers (TGCs) are used for the muon trigger system in the end-cap regions of the ATLAS detector. As the anode-cathode distance is small, 1.4 mm, chamber flatness is essential to achieve a uniform gas gain over the chamber. The TGC mass production phase at High Energy Accelerator Research Organization (KEK) started in January 2001. In order to perform a stable production with high quality we developed a chamber closing system. When we glue two half- chambers together, we sandwich them with a granite table and an aluminum honeycomb panel that keep the chamber flat from both sides. By using silk screens, we also control the quantity of epoxy adhesive that affects the chamber thickness. Owing to these developments, we can achieve the flatness of less than 100 mu m. Uniformity of detection efficiency of the TGC is measured with a cosmic-ray test bench at Kobe University. We have tested 300 TGCs so far. Position dependence of the efficiency is measured with a granularity of 5 mm- by-5 mm. The average...

  13. Super heated water generator for baking of vacuum chambers of INDUS-2

    International Nuclear Information System (INIS)

    Bhatnagar, Prateek; Yadav, D.P.; Sindal, B.K.; Sharma, H.K.; Shukla, S.K.

    2005-01-01

    It is proposed to use superheated water bake out system for in-situ baking of aluminum alloy dipole and straight section chambers of INDUS-2. Heat load calculations have shown that power requirements for an in-situ bake out at 150 degC is 0.64 kW mt - 1 and 3.2 kWmt -l for straight section and dipole chamber respectively (for one baking segment 60 kW. Baking of vacuum chambers by Nichrome flexible heating tapes at 150 degC has lot of practical problems such as non uniform temperature, non accessibility of heaters to inside parts etc. This paper presents various design objectives, mechanical, electrical and instrumentation design parameters including the safety devices in the system in order to achieve a fail safe baking operation ranging almost for 72 hrs. (author)

  14. Cold vacuum chamber for diagnostics: Instrumentation and first results

    Directory of Open Access Journals (Sweden)

    S. Gerstl

    2014-10-01

    Full Text Available For a proper design of the cryogenic layout of superconducting insertion devices it is necessary to take into account the heat load from the beam to the cold beam tube. In order to measure and possibly understand the beam heat load to a cold bore, a cold vacuum chamber for diagnostics (COLDDIAG has been built. COLDDIAG is designed in a flexible way, to allow its installation in different light sources. In order to study the beam heat load and the influence of the cryosorbed gas layer, the instrumentation comprises temperature sensors, pressure gauges, and mass spectrometers as well as retarding field analyzers with which it is possible to measure the beam heat load, total pressure, and gas content as well as the flux of particles hitting the chamber walls. In this paper we describe the experimental equipment, the installation of COLDDIAG in the Diamond Light Source and selected examples of the measurements performed to show the capabilities of this unique instrument.

  15. Cold vacuum chamber for diagnostics: Instrumentation and first results

    Science.gov (United States)

    Gerstl, S.; Voutta, R.; Casalbuoni, S.; Grau, A. W.; Holubek, T.; de Jauregui, D. Saez; Bartolini, R.; Cox, M. P.; Longhi, E. C.; Rehm, G.; Schouten, J. C.; Walker, R. P.; Sikler, G.; Migliorati, M.; Spataro, B.

    2014-10-01

    For a proper design of the cryogenic layout of superconducting insertion devices it is necessary to take into account the heat load from the beam to the cold beam tube. In order to measure and possibly understand the beam heat load to a cold bore, a cold vacuum chamber for diagnostics (COLDDIAG) has been built. COLDDIAG is designed in a flexible way, to allow its installation in different light sources. In order to study the beam heat load and the influence of the cryosorbed gas layer, the instrumentation comprises temperature sensors, pressure gauges, and mass spectrometers as well as retarding field analyzers with which it is possible to measure the beam heat load, total pressure, and gas content as well as the flux of particles hitting the chamber walls. In this paper we describe the experimental equipment, the installation of COLDDIAG in the Diamond Light Source and selected examples of the measurements performed to show the capabilities of this unique instrument.

  16. Construction and test of a full-scale prototype of an ATLAS muon spectrometer tracking chamber

    International Nuclear Information System (INIS)

    Biscossa, A.; Cambiaghi, M.; Conta, C.; Ferrari, R.; Fraternali, M.; Freddi, A.; Iuvino, G.; Lanza, A.; Livan, M.; Negri, A.; Polesello, G.; Rimoldi, A.; Vercellati, F.; Vercesi, V.; Bagnaia, P.; Bini, C.; Capradossi, G.; Ciapetti, G.; Creti, P.; De Zorzi, G.; Iannone, M.; Lacava, F.; Mattei, A.; Nisati, L.; Oberson, P.; Pontecorvo, L.; Rosati, S.; Veneziano, S.; Zullo, A.; Daly, C.H.; Davisson, R.; Guldenmann, H.; Lubatti, H.J.; Zhao, T.

    1999-01-01

    We have built a full scale prototype of the precision tracking chambers (Monitored Drift Tubes, MDT) for the muon spectrometer of the Atlas Experiment at the LHC collider. This article describes in detail the procedures used in constructing the drift tubes and in assembling the chamber. It presents data showing that the required mechanical precision has been achieved as well as test beam results displaying the over all chamber performance. The article presents data demonstrating the derivation of the space-time relation of the drift tubes by the autocalibration procedure using real data from the tracks crossing the chamber. Autocalibration is the procedure which must be used during run time

  17. He leaks in the CERN LHC beam vacuum chambers operating at cryogenic temperatures

    CERN Document Server

    Baglin, V

    2007-01-01

    The 27 km long large hadron collider (LHC), currently under construction at CERN, will collide protons beam at 14 TeV in the centre of mass. In the 8 arcs, the superconducting dipoles and quadrupoles of the FODO cells operate with superfluid He at 1.9 K. In the 8 long straight sections, the cold bores of the superconducting magnets are held at 1.9 or 4.5 K. Thus, in the LHC, 75% of the beam tube vacuum chamber is cooled with He. In many areas of the machine, He leaks could appear in the beam tube. At cryogenic temperature, the gas condenses onto the cold bores or beam screens, and interacts with the circulating beam. He leaks creates a He front propagating along the vacuum chambers, which might cause magnet quench. We discuss the consequences of He leaks, the possible means of detections, the strategies to localise them and the methods to measure their size.

  18. Hermeticity control system for the BMS/BMF-MDT chambers of the muon spectrometer of ATLAS experiment

    International Nuclear Information System (INIS)

    Barashkov, A.V.; Glonti, G.L.; Gongadze, A.L.; Dedovich, D.V.; Demichev, M.A.; Zhemchugov, A.S.; Il'yushenko, E.N.; Korolevich, Ya.V.; Kruchonok, V.G.; Lomidze, D.D.; Nikolaev, K.V.; Kharchenko, D.V.; Tskhadadze, Eh.G.; Chepurnov, V.F.; Shelkov, G.A.; Shcherbakov, A.A.

    2005-01-01

    Description of hermeticity certification of the JINR made muon chambers for the ATLAS experiment is presented. A high precision stand was installed in the production area of the DLNP, JINR. The description of the stand and results of the measurements and the description and results of the second testing of the drift chambers carried out after transportation to CERN are presented

  19. Molecular desorption of stainless steel vacuum chambers irradiated with 4.2  MeV/u lead ions

    Directory of Open Access Journals (Sweden)

    E. Mahner

    2003-01-01

    Full Text Available In preparation for the heavy ion program of the Large Hadron Collider at CERN, accumulation and cooling tests with lead ion beams have been performed in the Low Energy Antiproton Ring. These tests have revealed that due to the unexpected large outgassing of the vacuum system, the dynamic pressure of the ring could not be maintained low enough to reach the required beam intensities. To determine the actions necessary to lower the dynamic pressure rise, an experimental program has been initiated for measuring the molecular desorption yields of stainless steel vacuum chambers by the impact of 4.2  MeV/u lead ions with the charge states +27 and +53. The test chambers were exposed either at grazing or at perpendicular incidence. Different surface treatments (glow discharges, nonevaporable getter coating are reported in terms of the molecular desorption yields for H_{2}, CH_{4}, CO, Ar, and CO_{2}. Unexpected large values of molecular yields per incident ion up to 2×10^{4} molecules/ion have been observed. The reduction of the ion-induced desorption yield due to continuous bombardment with lead ions (beam cleaning has been investigated for five different stainless steel vacuum chambers. The implications of these results for the vacuum system of the future Low Energy Ion Ring and possible remedies to reduce the vacuum degradation are discussed.

  20. Mimicking Mars: a vacuum simulation chamber for testing environmental instrumentation for Mars exploration.

    Science.gov (United States)

    Sobrado, J M; Martín-Soler, J; Martín-Gago, J A

    2014-03-01

    We have built a Mars environmental simulation chamber, designed to test new electromechanical devices and instruments that could be used in space missions. We have developed this environmental system aiming at validating the meteorological station Rover Environment Monitoring Station of NASA's Mars Science Laboratory mission currently installed on Curiosity rover. The vacuum chamber has been built following a modular configuration and operates at pressures ranging from 1000 to 10(-6) mbars, and it is possible to control the gas composition (the atmosphere) within this pressure range. The device (or sample) under study can be irradiated by an ultraviolet source and its temperature can be controlled in the range from 108 to 423 K. As an important improvement with respect to other simulation chambers, the atmospheric gas into the experimental chamber is cooled at the walls by the use of liquid-nitrogen heat exchangers. This chamber incorporates a dust generation mechanism designed to study Martian-dust deposition while modifying the conditions of temperature, and UV irradiated.

  1. Performance, operation and detector studies with the ATLAS Resistive Plate Chambers

    International Nuclear Information System (INIS)

    Aielli, G; Bindi, M; Polini, A

    2013-01-01

    Resistive Plate Chambers provide the barrel region of the ATLAS detector with an independent muon trigger and a two-coordinate measurement. The chambers, arranged in three concentric double layers, are operated in a strong magnetic toroidal field and cover a surface area of about 4000 m 2 . During 2011 the LHC has provided proton-proton collisions at 7 TeV in the center-of-mass frame with a steady increase in instantaneous luminosity, summing up to about 5 fb −1 . The operational experience for this running period is presented along with studies of the detector performance as a function of luminosity, environmental conditions and working point settings. Non-event based information including in particular the large number of gas gap currents, individually monitored with nA accuracy, have been used to study the detector behavior with growing luminosity and beam currents. These data are shown to provide, when calibrated, an independent luminosity measurement and a crucial handle for understanding the ATLAS backgrounds well beyond the scope of muon triggering and detection. The measurements presented here allow to plan a strategy for the data taking in the next years and make some predictions about the detector performance at higher luminosities. They also improve the knowledge on RPC detector physics.

  2. Modernization of NASA's Johnson Space Center Chamber: A Payload Transport Rail System to Support Cryogenic Vacuum Optical Testing of the James Webb Space Telescope (JWST)

    Science.gov (United States)

    Garcia, Sam; Homan, Jonathan; Speed, John

    2016-01-01

    NASA is the mission lead for the James Webb Space Telescope (JWST), the next of the "Great Observatories", scheduled for launch in 2018. It is directly responsible for the integration and test (I&T) program that will culminate in an end-to-end cryo vacuum optical test of the flight telescope and instrument module in Chamber A at NASA Johnson Space Center. Historic Chamber A is the largest thermal vacuum chamber at Johnson Space Center and one of the largest space simulation chambers in the world. Chamber A has undergone a major modernization effort to support the deep cryogenic, vacuum and cleanliness requirements for testing the JWST. This paper describe the challenges of developing, integrating and modifying new payload rails capable of transporting payloads within the thermal vacuum chamber up to 65,000 pounds. Ambient and Cryogenic Operations required to configure for testing will be explained. Lastly review historical payload configurations stretching from the Apollo program era to current James Webb Space Telescope testing.

  3. Streamlined Calibrations of the ATLAS Precision Muon Chambers for Initial LHC Running

    CERN Document Server

    Amram, N; Benhammou, Y; Moshe, M Ben; Dai, T; Diehl, E B; Dubbert, J; Etzion, E; Ferretti, C; Gregory, J; Haider, S; Hindes, J; Levin, D S; Thun, R; Wilson, A; Weaverdyck, C; Wu, Y; Yang, H; Zhou, B; Zimmermann, S

    2012-01-01

    The ATLAS Muon Spectrometer is designed to measure the momentum of muons with a resolution of dp/p = 3% and 10% at 100 GeV and 1 TeV momentum respectively. For this task, the spectrometer employs 355,000 Monitored Drift Tubes (MDTs) arrayed in 1200 Chambers. Calibration (RT) functions convert drift time measurements into tube-centered impact parameters for track segment reconstruction. RT functions depend on MDT environmental parameters and so must be appropriately calibrated for local chamber conditions. We report on the creation and application of a gas monitor system based calibration program for muon track reconstruction in the LHC startup phase.

  4. Experimental measurement of magnetic field null in the vacuum chamber of KTM tokamak based on matrix of 2D Hall sensors

    Energy Technology Data Exchange (ETDEWEB)

    Shapovalov, G.; Chektybayev, B., E-mail: chektybaev@nnc.kz; Sadykov, A.; Skakov, M.; Kupishev, E.

    2016-11-15

    Experimental technique of measurement of magnetic field null region inside of the KTM tokamak vacuum chamber has been developed. Square matrix of 36 2D Hall sensors, which used in the technique, allows carrying out direct measurements of poloidal magnetic field dynamics in the vacuum chamber. To better measuring accuracy, Hall sensor’s matrix was calibrated with commercial Helmholtz coils and in situ measurement of defined magnetic field from poloidal and toroidal coils. Standard KTM Data-Acquisition System has been used to collect data from Hall sensors. Experimental results of measurement of magnetic field null in the vacuum chamber of KTM are shown in the paper. Additionally results of the magnetic field null reconstruction from signals of inductive total flux loops are shown in the paper.

  5. ATLAS magnet common cryogenic, vacuum, electrical and control systems

    CERN Document Server

    Miele, P; Delruelle, N; Geich-Gimbel, C; Haug, F; Olesen, G; Pengo, R; Sbrissa, E; Tyrvainen, H; ten Kate, H H J

    2004-01-01

    The superconducting Magnet System for the ATLAS detector at the LHC at CERN comprises a Barrel Toroid, two End Cap Toroids and a Central Solenoid with overall dimensions of 20 m diameter by 26 m length and a stored energy of 1.6 GJ. Common proximity cryogenic and electrical systems for the toroids are implemented. The Cryogenic System provides the cooling power for the 3 toroid magnets considered as a single cold mass (600 tons) and for the CS. The 21 kA toroid and the 8 kA solenoid electrical circuits comprise both a switch-mode power supply, two circuit breakers, water cooled bus bars, He cooled current leads and the diode resistor ramp-down unit. The Vacuum System consists of a group of primary rotary pumps and sets of high vacuum diffusion pumps connected to each individual cryostat. The Magnet Safety System guarantees the magnet protection and human safety through slow and fast dump treatment. The Magnet Control System ensures control, regulation and monitoring of the operation of the magnets. The update...

  6. Proposal of a Self-baking Single-wall Design for the VI Section of the ATLAS Beam Pipe

    CERN Document Server

    Marco Olcese, MO

    2002-01-01

    A single-wall design for the VI section of the ATLAS beam vacuum chamber is presented. This design would allow for a major cost saving with respect to the current double-wall baseline. All the thermal implications and impact on the B-layer mudules are discussed.

  7. Eddy Current Effect of the BNL-AGS Vacuum Chamber on the Optics of the BNL-AGS Synchrotron

    International Nuclear Information System (INIS)

    Tsoupas, N.; Ahrens, L.; Brown, K. A.; Glenn, J. W.; Gardner, K.

    1999-01-01

    During the acceleration cycle of the AGS synchrotron, eddy currents are generated within the walls of the vacuum chambers of the AGS main magnets. The vacuum chambers have elliptical cross section, are made of inconel material with a wall thickness of 2 mm and are placed within the gap of the combined-function main magnets of the AGS synchrotron. The generation of eddy currents in the walls of the vacuum chambers, creates various magnetic multipoles, which affect the optics of the AGS machine. In this report these magnetic multipoles are calculated for various time interval starting at the acceleration cycle, where the magnetic field of the main magnet is ∼0.1 T, and ending before the beam extraction process, where the magnetic field of the main magnet is almost constant at ∼ 1.1 T. The calculations show that the magnetic multipoles generated by the eddy-currents affect the optics of the AGS synchrotron during the acceleration cycle and in particular at low magnetic fields of the main magnet. Their effect is too weak to affect the optics of the AGS machine during beam extraction at the nominal energies

  8. High vacuum test of the dynamic components of the cyclotron dee chamber at the 224 cm variable energy cyclotron

    International Nuclear Information System (INIS)

    Chintalapudi, S.N.; Bandopadhyay, D.K.; Ghosh, D.K.; Gowariker, S.R.

    1979-01-01

    The 224 cm Variable Energy Cyclotron constructed and commissioned at Calcutta comprises a number of dynamic components in the high vacuum Dee Chamber. The static and dynamic conditions of these components have to be tested for high vacuum worthiness prior to their installation in the Dee Tank. A special set up was fabricated and used for simulating the Dee Chamber conditions and testing the components. A high vacuum of the order of 1 x 10 -5 torr was achieved under both dynamic and static conditions with and without coolant hydraulic pressures. The details of the set up, methods employed for the various tests carried out and the results obtained are described. (auth.)

  9. Modernization of NASA's Johnson Space Center Chamber: A Liquid Nitrogen System to Support Cryogenic Vacuum Optical Testing of the James Webb Space Telescope (JWST)

    Science.gov (United States)

    Garcia, Sammy; Homan, Jonathan; Montz, Michael

    2016-01-01

    NASA is the mission lead for the James Webb Space Telescope (JWST), the next of the “Great Observatories”, scheduled for launch in 2018. It is directly responsible for the integration and test (I&T) program that will culminate in an end-to-end cryo vacuum optical test of the flight telescope and instrument module in Chamber A at NASA Johnson Space Center. Historic Chamber A is the largest thermal vacuum chamber at Johnson Space Center and one of the largest space simulation chambers in the world. Chamber A has undergone a major modernization effort to support the deep cryogenic, vacuum and cleanliness requirements for testing the JWST. This paper describes the steps performed in efforts to convert the existing the 60’s era Liquid Nitrogen System from a forced flow (pumped) process to a natural circulation (thermo-siphon) process. In addition, the paper will describe the dramatic conservation of liquid nitrogen to support the long duration thermal vacuum testing. Lastly, describe the simplistic and effective control system which results in zero to minimal human inputs during steady state conditions.

  10. Glow discharge processing vs bakeout for aluminum storage ring vacuum chambers

    International Nuclear Information System (INIS)

    Dean, N.R.; Hoyt, E.W.; Palrang, M.T.; Walker, B.G.

    1977-11-01

    Experiments were carried out on laboratory and prototype scale systems in order to establish the feasibility of argon discharge processing the PEP storage ring aluminum vacuum chambers. Electron-induced desorption rates showed significant reductions following bakeout and/or argon glow discharge treatment (>10 19 ions cm -1 ). Data are presented and discussed in relation to advantages and problems associated with: water removal, argon trapping and subsequent release, electron energy dependence, discharge distribution, and surface plasma chemical effects

  11. Mimicking Mars: A vacuum simulation chamber for testing environmental instrumentation for Mars exploration

    Energy Technology Data Exchange (ETDEWEB)

    Sobrado, J. M., E-mail: sobradovj@inta.es; Martín-Soler, J. [Centro de Astrobiología (CAB), INTA-CSIC, Torrejón de Ardoz, 28850 Madrid (Spain); Martín-Gago, J. A. [Centro de Astrobiología (CAB), INTA-CSIC, Torrejón de Ardoz, 28850 Madrid (Spain); Instituto de Ciencias de Materiales de Madrid (ICMM-CSIC), Cantoblanco, 28049 Madrid (Spain)

    2014-03-15

    We have built a Mars environmental simulation chamber, designed to test new electromechanical devices and instruments that could be used in space missions. We have developed this environmental system aiming at validating the meteorological station Rover Environment Monitoring Station of NASA's Mars Science Laboratory mission currently installed on Curiosity rover. The vacuum chamber has been built following a modular configuration and operates at pressures ranging from 1000 to 10{sup −6} mbars, and it is possible to control the gas composition (the atmosphere) within this pressure range. The device (or sample) under study can be irradiated by an ultraviolet source and its temperature can be controlled in the range from 108 to 423 K. As an important improvement with respect to other simulation chambers, the atmospheric gas into the experimental chamber is cooled at the walls by the use of liquid-nitrogen heat exchangers. This chamber incorporates a dust generation mechanism designed to study Martian-dust deposition while modifying the conditions of temperature, and UV irradiated.

  12. Specification for the delivery of special sections made of aluminum alloy for use as vacuum chambers

    International Nuclear Information System (INIS)

    Possible extension of the research facility by a large storage-ring facility is presently being planned at DESY. For preliminary engineering tests concerning the dimensions of the vacuum system, there is a need for two extruded special sections made of an aluminum alloy, which are to be fabricated as vacuum chambers in deflecting magnets and in focussing magnets. Conditions of the contract and technical requirements of the special sections are given

  13. Final Test at the Surface of the ATLAS Endcap Muon Trigger Chamber Electronics

    CERN Document Server

    Kubota, T; Kanaya, N; Kawamoto, T; Kobayashi, T; Kuwabara, T; Nomoto, H; Sakamoto, H; Yamaguchi, T; Fukunaga, C; Ikeno, M; Iwasaki, H; Nagano, K; Nozaki, M; Sasaki, O; Tanaka, S; Yasu, Y; Hasegawa, Y; Oshita, H; Takeshita, T; Nomachi, M; Sugaya, Y; Sugimoto, T; Okumura, Y; Takahashi, Y; Tomoto, M; Kadosaka, T; Kawagoe, K; Kiyamura, H; Kurashige, H; Niwa, T; Ochi, A; Omachi, C; Takeda, H; Lifshitz, R; Lupu, N; Bressler, S; Tarem, S; Kajomovitz, E; Ben Ami, S; Bahat Treidel, O; Benhammou, Ya; Etzion, E; Lellouch, D; Levinson, L; Mikenberg, G; Roich, A

    2007-01-01

    For the detector commissioning planned in 2007, sector assembly of the ATLAS muon-endcap trigger chambers and final test at the surface for the assembled electronics are being done in CERN and almost completed. For the test, we built up the Data Acquisition (DAQ) system using test pulse of two types and cosmic rays in order to check functionality of the various aspects of the electronics mounted on a sector. So far, 99% of all 320,000 channels have been tested and most of them were installed into the ATLAS cavern. In this presentation, we will describe the DAQ systems and mass-test procedure in detail, and report the result of electronics test with some actual experiences

  14. A high-precision X-ray tomograph for quality control of the ATLAS Muon Monitored Drift Tube Chambers

    CERN Document Server

    Schuh, S; Banhidi, Z; Fabjan, Christian Wolfgang; Lampl, W; Marchesotti, M; Rangod, Stephane; Sbrissa, E; Smirnov, Y; Voss, Rüdiger; Woudstra, M; Zhuravlov, V

    2004-01-01

    A dedicated X-ray tomograph has been developed at CERN to control the required wire placement accuracy of better than 20mum of the 1200 Monitored Drift Tube Chambers which make up most of the precision chamber part of the ATLAS Muon Spectrometer. The tomograph allows the chamber wire positions to be measured with a 2mum statistical and 2mum systematic uncertainty over the full chamber cross-section of 2.2 multiplied by 0.6m**2. Consistent chamber production quality over the 4-year construction phase is ensured with a similar to 15% sampling rate. Measurements of about 70 of the 650 MDT chambers so far produced have been essential in assessing the validity and consistency of the various construction procedures.

  15. Photoelectron Yield and Photon Reflectivity from Candidate LHC Vacuum Chamber Materials with Implications to the Vacuum Chamber Design

    CERN Document Server

    Baglin, V; Gröbner, Oswald

    1998-01-01

    Studies of the photoelectron yield and photon reflectivity at grazing incidence (11 mrad) from candidate LHC vacuum chamber materials have been made on a dedicated beam line on the Electron Positron A ccumulator (EPA) ring at CERN. These measurements provide realistic input toward a better understanding of the electron cloud phenomena expected in the LHC. The measurements were made using synchrotro n radiation with critical photon energies of 194 eV and 45 eV; the latter corresponding to that of the LHC at the design energy of 7 TeV. The test materials are mainly copper, either, i) coated by co- lamination or by electroplating onto stainless steel, or ii) bulk copper prepared by special machining. The key parameters explored were the effect of surface roughness on the reflectivity and the pho toelectron yield at grazing photon incidence, and the effect of magnetic field direction on the yields measured at normal photon incidence. The implications of the results on the electron cloud phenom ena, and thus the L...

  16. Ion-stimulated gas desorption yields of coated (Au, Ag, Pd) stainless steel vacuum chambers irradiated with 4.2 MeV/u lead ions

    CERN Document Server

    Mahner, E; Küchler, D; Malabaila, M; Taborelli, M

    2005-01-01

    The ion-induced desorption experiment, installed in the CERN Heavy Ion Accelerator (LINAC 3), has been used to measure molecular desorption yields for 4.2 MeV/u lead ions impacting on different accelerator-type vacuum chambers. In order to study the effect of the surface oxide layer on the gas desorption, gold-, silver-, and palladium-coated 316LN stainless steel chambers and similarly prepared samples were tested for desorption at LINAC 3 and analysed for chemical composition by X-ray Photoemission Spectroscopy (XPS). The large effective desorption yield of 2 x 10**4 molecules/ion, previously measured for uncoated, vacuum fired stainless steel, was reduced after noble metal coating by up to 2 orders of magnitude. In addition, the effectiveness of beam scrubbing with heavy ions and the consequence of a subsequent venting on the desorption yields of a beam-scrubbed vacuum chamber are described. Practical consequences for the vacuum system of the future Low Energy Ion Ring (LEIR) are discussed.

  17. Molecular desorption of stainless steel vacuum chambers irradiated with 42 MeV/u lead ions

    CERN Document Server

    Mahner, E; Laurent, Jean Michel; Madsen, N

    2003-01-01

    In preparation for the heavy ion program of the Large Hadron Collider at CERN, accumulation and cooling tests with lead ion beams have been performed in the Low Energy Antiproton Ring. These tests have revealed that due to the unexpected large outgassing of the vacuum system, the dynamic pressure of the ring could not be maintained low enough to reach the required beam intensities. To determine the actions necessary to lower the dynamic pressure rise, an experimental program has been initiated for measuring the molecular desorption yields of stainless steel vacuum chambers by the impact of 4.2 MeV/u lead ions with the charge states +27 and +53. The test chambers were exposed either at grazing or at perpendicular incidence. Different surface treatments (glow discharges, nonevaporable getter coating) are reported in terms of the molecular desorption yields for H/sub 2 /, CH/sub 4/, CO, Ar, and CO/sub 2/. (16 refs).

  18. The Use of the Molecular Adsorber Coating Technology to Mitigate Vacuum Chamber Contamination During Pathfinder Testing for the James Webb Space Telescope

    Science.gov (United States)

    Abraham, Nithin S.; Hasegawa, Mark M.; Wooldridge, Eve M.; Henderson-Nelson, Kelly A.

    2016-01-01

    As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground based space applications, in particular, for vacuum chamber environments. This paper describes the recent use of the MAC technology during Pathfinder testing of the Optical Ground Support Equipment (OGSE) for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap persistent outgassed contaminants, specifically silicone based diffusion pump oil, from within JSC's cryogenic optical vacuum chamber test facility called Chamber A. This paper summarizes the sample fabrication, installation, laboratory testing, post-test chemical analysis results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination.

  19. The Mobile Chamber

    Science.gov (United States)

    Scharfstein, Gregory; Cox, Russell

    2012-01-01

    A document discusses a simulation chamber that represents a shift from the thermal-vacuum chamber stereotype. This innovation, currently in development, combines the capabilities of space simulation chambers, the user-friendliness of modern-day electronics, and the modularity of plug-and-play computing. The Mobile Chamber is a customized test chamber that can be deployed with great ease, and is capable of bringing payloads at temperatures down to 20 K, in high vacuum, and with the desired metrology instruments integrated to the systems control. Flexure plans to lease Mobile Chambers, making them affordable for smaller budgets and available to a larger customer base. A key feature of this design will be an Apple iPad-like user interface that allows someone with minimal training to control the environment inside the chamber, and to simulate the required extreme environments. The feedback of thermal, pressure, and other measurements is delivered in a 3D CAD model of the chamber's payload and support hardware. This GUI will provide the user with a better understanding of the payload than any existing thermal-vacuum system.

  20. VUV photoemission studies of candidate Large Hadron Collider vacuum chamber materials

    CERN Document Server

    Cimino, R; Baglin, V

    1999-01-01

    In the context of future accelerators and, in particular, the beam vacuum of the Large Hadron Collider (LHC), a 27 km circumference proton collider to be built at CERN, VUV synchrotron radiation (SR) has been used to study both qualitatively and quantitatively candidate vacuum chamber materials. Emphasis is given to show that angle and energy resolved photoemission is an extremely powerful tool to address important issues relevant to the LHC, such as the emission of electrons that contributes to the creation of an electron cloud which may cause serious beam instabilities and unmanageable heat loads on the cryogenic system. Here we present not only the measured photoelectron yields from the proposed materials, prepared on an industrial scale, but also the energy and in some cases the angular dependence of the emitted electrons when excited with either a white light (WL) spectrum, simulating that in the arcs of the LHC, or monochromatic light in the photon energy range of interest. The effects on the materials ...

  1. A new Highly Selective First Level ATLAS Muon Trigger With MDT Chamber Data for HL-LHC

    CERN Document Server

    Nowak, Sebastian; The ATLAS collaboration

    2015-01-01

    Highly selective first level triggers are essential for the physics programme of the ATLAS experiment at the HL-LHC where the instantaneous luminosity will exceed the LHC's instantaneous luminosity by almost an order of magnitude. The ATLAS first level muon trigger rate is dominated by low momentum sub-trigger threshold muons due to the poor momentum resolution at trigger level caused by the moderate spatial resolution of the resistive plate and thin gap trigger chambers. This limitation can be overcome by including the data of the precision muon drift tube chambers in the first level trigger decision. This requires the implementation of a fast MDT read-out chain and a fast MDT track reconstruction. A hardware demonstrator of the fast read-out chain was successfully tested under HL-LHC operating conditions at CERN's Gamma Irradiation Facility. It could be shown that the data provided by the demonstrator can be processed with a fast track reconstruction algorithm on an ARM CPU within the 6 microseconds latency...

  2. Vacuum chamber 'bicone'

    CERN Multimedia

    1977-01-01

    This chamber is now in the National Museum of History and Technology, Smithsonian Institution, Washington, DC, USA, where it was exposed in an exhibit on the History of High Energy Accelerators (1977).

  3. Quality control results of the drift tubes for the ATLAS MDT-BIS chambers

    International Nuclear Information System (INIS)

    Alexopoulos, T.; Avramidou, R.; Dris, M.; Filippas, T.A.; Gazis, E.N.; Katsoufis, E.; Maltezos, S.; Savva, P.; Tsipolitis, G.; Tzamariudaki, E.

    2006-01-01

    ATLAS (A Toroidal LHC ApparatuS) is a general purpose experiment, which will start its operation at the Large Hadron Collider (LHC) at CERN in 2007. The ATLAS detector is designed to study the products of proton-proton collisions at c.m.s. energies of up to 14 TeV. Three Greek Universities have taken the responsibility to construct 112 BIS-MDT (Barrel Inner Small) chambers using 29 000 drift tubes of 170 cm length and 3 cm diameter that have been quality tested before assembly. This work describes the Quality Assurance and Quality Control (QA Q C) procedures for the drift tubes, followed at the High Energy Physics Laboratory of the National Technical University of Athens, while emphasis is given on the obtained results for the above mentioned number of tubes

  4. Study of the performance of ATLAS muon drift-tube chambers in magntic fields and at high irradiation rates

    Energy Technology Data Exchange (ETDEWEB)

    Valderanis, Chrysostomos

    2012-07-26

    The performance of ATLAS muon drift-tube (MDT) chambers has been studied in detail using high-energy muon beams. The measurements of the drift tube properties in magnetic fields showed that inelastic collisions of the drifting electrons with the CO{sub 2} molecules in the Ar:CO{sub 2} (93:7) gas mixture of the MDT chambers have to be taken into account in the simulation of the drift properties. Such inelastic collisions are now correctly treated by the Garfield simulation programme from version 9 providing an accurate description of the behaviour of the ATLAS muon drift tubes, in particular in the magnetic field. Measurements at the Gamma Irradiation Facility at CERN were performed to study the performance of the MDT chambers in the presence of high {gamma} ray background fluences. The chambers have a spatial resolution better than 40 {mu}m at the nominal background rates expected at the Large Hadron Collider design luminosity of 10{sup 34} cm{sup -2}s{sup -1} and a resolution better than 50 {mu}m for up to five times higher background rates. Efficient muon detection up to background counting rates of 500 kHz per tube corresponding to 35% occupancy was demonstrated.

  5. Tokamak DEMO-FNS: Concept of magnet system and vacuum chamber

    Energy Technology Data Exchange (ETDEWEB)

    Azizov, E. A., E-mail: Azizov-EA@nrcki.ru; Ananyev, S. S. [National Research Center Kurchatov Institute (Russian Federation); Belyakov, V. A.; Bondarchuk, E. N.; Voronova, A. A. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (Russian Federation); Golikov, A. A. [National Research Center Kurchatov Institute (Russian Federation); Goncharov, P. R. [Peter the Great St. Petersburg Polytechnic University (Russian Federation); Dnestrovskij, A. Yu. [National Research Center Kurchatov Institute (Russian Federation); Zapretilina, E. R. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (Russian Federation); Ivanov, D. P. [National Research Center Kurchatov Institute (Russian Federation); Kavin, A. A.; Kedrov, I. V. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (Russian Federation); Klischenko, A. V.; Kolbasov, B. N. [National Research Center Kurchatov Institute (Russian Federation); Krasnov, S. V. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (Russian Federation); Krylov, A. I. [National Research Center Kurchatov Institute (Russian Federation); Krylov, V. A.; Kuzmin, E. G. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (Russian Federation); Kuteev, B. V. [National Research Center Kurchatov Institute (Russian Federation); Labusov, A. N. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (Russian Federation); and others

    2016-12-15

    The level of knowledge accumulated to date in the physics and technologies of controlled thermonuclear fusion (CTF) makes it possible to begin designing fusion—fission hybrid systems that would involve a fusion neutron source (FNS) and which would admit employment for the production of fissile materials and for the transmutation of spent nuclear fuel. Modern Russian strategies for CTF development plan the construction to 2023 of tokamak-based demonstration hybrid FNS for implementing steady-state plasma burning, testing hybrid blankets, and evolving nuclear technologies. Work on designing the DEMO-FNS facility is still in its infancy. The Efremov Institute began designing its magnet system and vacuum chamber, while the Kurchatov Institute developed plasma-physics design aspects and determined basic parameters of the facility. The major radius of the plasma in the DEMO-FNS facility is R = 2.75 m, while its minor radius is a = 1 m; the plasma elongation is k{sub 95} = 2. The fusion power is P{sub FUS} = 40 MW. The toroidal magnetic field on the plasma-filament axis is B{sub t0} = 5 T. The plasma current is I{sub p} = 5 MA. The application of superconductors in the magnet system permits drastically reducing the power consumed by its magnets but requires arranging a thick radiation shield between the plasma and magnet system. The central solenoid, toroidal-field coils, and poloidal-field coils are manufactured from, respectively, Nb{sub 3}Sn, NbTi and Nb{sub 3}Sn, and NbTi. The vacuum chamber is a double-wall vessel. The space between the walls manufactured from 316L austenitic steel is filled with an iron—water radiation shield (70% of stainless steel and 30% of water).

  6. Proposal for the award of a contract for the supply of ceramic vacuum chambers for the LHC beam dumping system

    CERN Document Server

    2001-01-01

    This document concerns the award of a contract for the supply of ceramic vacuum chambers for the LHC beam dumping system. Following a market survey carried out among 22 firms in seven Member States and one firm in the United States, a call for tenders (IT-2765/SL/LHC) was sent on 13 September 2001 to one firm. By the closing date, CERN had received a tender. The Finance Committee is invited to agree to the negotiation of a contract with KYOCERA FINECERAMICS (DE) for the supply of 36 ceramic vacuum chambers for the LHC beam dumping system for a total amount of 681 530 euros (1 013 094 Swiss francs), not subject to revision, with options for six additional vacuum chambers, for an additional amount of 146 768 euros (218 171 Swiss francs), not subject to revision, bringing the total amount to 828 298 euros (1 231 265 Swiss francs), not subject to revision. The rate of exchange which has been used is that applying on the closing date of the call for tenders. The firm has indicated the following distribution by cou...

  7. Studies of cosmic ray events in ATLAS sTGC muon chamber prototypes

    CERN Document Server

    AUTHOR|(CDS)2097847; Warburton, Andreas

    Four years after its first long shutdown in 2015, the Large Hadron Collider (LHC) will be shut down once more for a luminosity upgrade. During that time, the ATLAS detector on the LHC ring will also follow an upgrade program, one upgrade being the replacement of the Small Muon Wheels for a New Small Wheel containing small-strip Thin Gap Chambers (sTGCs). The sTGCs built in Canada will be tested at McGill University before their installation in ATLAS. A testing facility has been constructed and a 40 × 60 cm^2 sTGC prototype has been used to deliver preliminary measurements from cosmic rays. This thesis will present the development of a robust tracking algorithm which can handle extra clusters and multiple tracks in an sTGC detector. This algorithm also categorizes events based on their number of clusters and tracks. By modifying the trigger time window of the sTGC prototype, the evolution of the distribution of events over this categorization is shown.

  8. A Muon Trigger with high pT-resolution for Phase-II of the LHC Upgrade, based on the ATLAS Muon Drift Tube Chambers

    CERN Document Server

    Nowak, S; The ATLAS collaboration

    2014-01-01

    The ATLAS Muon Trigger in the ATLAS end-cap region is based on Thin Gap Chambers (TGC) which have an excellent time resolution but a moderate spatial resolution. The Muon Trigger efficiency curves show that for a transverse momentum ($p_{t}$) threshold of 20 GeVc$^{-1}$ the trigger rate is mainly dominated by muons with a $p_{t}$ between 10 GeVc$^{-1}$ and 20 GeVc$^{-1}$. To cope with the expected Muon Trigger rate at HL-LHC luminosities, we propose to include the precision tracking chambers (MDT) in the Muon Trigger. According to a potential study based on ATLAS data and assuming the HL-LHC scenario, this leads to a dramatical reduction of the Muon Trigger rate below the nominal threshold. As the already existing MDT chamber read-out chain is not capable of reading out the MDT fast enough to be used for the Muon Trigger, an additional fast read-out (FRO) chain with moderate spatial resolution but low latency is necessary. To conduct fast track reconstruction and muon $p_{t}$ determination with the data acqui...

  9. Design and Construction of Large Size Micromegas Chambers for the Upgrade of the ATLAS Muon Spectrometer

    CERN Document Server

    Lösel, Philipp; Müller, Ralph

    2015-01-01

    Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. A total surface of about $\\mathbf{150~m^2}$ of the forward regions of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each layer covers more than $\\mathbf{2~m^2}$ for a total active area of $\\mathbf{1200~m^2}$. Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS endcap muon tracking system in the 2018/19 shutdown. In order to achieve a 15$\\mathbf{\\%}$ transverse momentum resolution for $\\mathbf{1~TeV}$ muons, in addition to an excellent intrinsic resolution, the mechanical precision of each plane of the assembled module must be as good as $\\mathbf{30~\\mu m}$ along the precision coordinate and $\\mathbf{80~\\mu m}$ perpendicular to the chamber. The design and construction procedure of the Micromegas modules will be presented, as well as the design for the assembly ...

  10. Design and Construction of Large Size Micromegas Chambers for the ATLAS Upgrade of the Muon Spectrometer

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00380308; The ATLAS collaboration

    2016-01-01

    Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. A total surface area of about 150 m$^2$ of the forward regions (pseudo-rapidity coverage -- 1.3 $\\boldsymbol{< |\\eta| <}$ 2.7) of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each module extends over a surface from 2 to 3 m$^2$ for a total active area of 1200 m$^2$. Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels (NSW), which will replace the innermost stations of the ATLAS endcap muon tracking system in the 2018/19 shutdown. In order to achieve a 15\\% transverse momentum resolution for 1 TeV muons, in addition to an excellent intrinsic position resolution, the mechanical precision of each plane of the assembled module must be $\\boldsymbol{30{\\mu}m}$ along the precision coordinate and $\\boldsymbol{80{\\mu}m}$ perpendicular to the chamber. All readout planes are segmented into strips with a pitch of $\\bold...

  11. Vacuum system for HIMAC synchrotrons

    International Nuclear Information System (INIS)

    Kanazawa, M.; Sudou, M.; Sato, K.

    1994-01-01

    HIMAC synchrotrons are now under construction, which require vacuum chambers of large aperture and high vacuum of about 10 -9 torr. Wide thin wall vacuum chamber of 0.3 mm thickness reinforced with ribs has been developed as the chamber at dipole magnet. We have just now started to evacuate the lower ring. The obtained average value was about 5x10 -8 torr with turbo-molecular and sputter ion pumps, and 1.1x10 -9 torr after baking. (author)

  12. CFD Analysis of Evaporation-Condensation Phenomenon In an Evaporation Chamber of Natural Vacuum Solar Desalination

    Science.gov (United States)

    Ambarita, H.; Ronowikarto, A. D.; Siregar, R. E. T.; Setyawan, E. Y.

    2018-01-01

    Desalination technologies is one of solutions for water scarcity. With using renewable energy, like solar energy, wind energy, and geothermal energy, expected will reduce the energy demand. This required study on the modeling and transport parameters determination of natural vacuum solar desalination by using computational fluid dynamics (CFD) method to simulate the model. A three-dimensional case, two-phase model was developed for evaporation-condensation phenomenon in natural vacuum solar desalination. The CFD simulation results were compared with the avalaible experimental data. The simulation results shows inthat there is a phenomenon of evaporation-condensation in an evaporation chamber. From the simulation, the fresh water productivity is 2.21 litre, and from the experimental is 2.1 litre. This study shows there’s an error of magnitude 0.4%. The CFD results also show that, vacuum pressure will degrade the saturation temperature of sea water.

  13. Vacuum-insulated catalytic converter

    Science.gov (United States)

    Benson, David K.

    2001-01-01

    A catalytic converter has an inner canister that contains catalyst-coated substrates and an outer canister that encloses an annular, variable vacuum insulation chamber surrounding the inner canister. An annular tank containing phase-change material for heat storage and release is positioned in the variable vacuum insulation chamber a distance spaced part from the inner canister. A reversible hydrogen getter in the variable vacuum insulation chamber, preferably on a surface of the heat storage tank, releases hydrogen into the variable vacuum insulation chamber to conduct heat when the phase-change material is hot and absorbs the hydrogen to limit heat transfer to radiation when the phase-change material is cool. A porous zeolite trap in the inner canister absorbs and retains hydrocarbons from the exhaust gases when the catalyst-coated substrates and zeolite trap are cold and releases the hydrocarbons for reaction on the catalyst-coated substrate when the zeolite trap and catalyst-coated substrate get hot.

  14. Study of cavity effect in micro-Pirani gauge chamber with improved sensitivity for high vacuum regime

    Directory of Open Access Journals (Sweden)

    Guohe Zhang

    2018-05-01

    Full Text Available Ultra-low pressure application of Pirani gauge needs significant improvement of sensitivity and expansion of measureable low pressure limit. However, the performance of Pirani gauge in high vacuum regime remains critical concerns since gaseous thermal conduction with high percentage is essential requirement. In this work, the heat transfer mechanism of micro-Pirani gauge packaged in a non-hermetic chamber was investigated and analyzed compared with the one before wafer-level packaging. The cavity effect, extremely important for the efficient detection of low pressure, was numerically and experimentally analyzed considering the influence of the pressure, the temperature and the effective heat transfer area in micro-Pirani gauge chamber. The thermal conduction model is validated by experiment data of MEMS Pirani gauges with and without capping. It is found that nature gaseous convection in chamber, determined by the Rayleigh number, should be taken into consideration. The experiment and model calculated results show that thermal resistance increases in the molecule regime, and further increases after capping due to the suppression of gaseous convection. The gaseous thermal conduction accounts for an increasing percentage of thermal conduction at low pressure while little changes at high pressure after capping because of the existence of cavity effect improving the sensitivity of cavity-effect-influenced Pirani gauge for high vacuum regime.

  15. Molecular desorption of stainless steel vacuum chambers irradiated with 4.2 MeV/u lead ions

    CERN Document Server

    Mahner, E; Laurent, Jean Michel; Madsen, N

    2003-01-01

    In preparation for the heavy ion program of the Large Hadron Collider (LHC) at CERN, accumulation and cooling tests with lead ion beams have been performed in the Low Energy Antiproton Ring (LEAR). These tests have revealed that due to the unexpected large outgassing of the vacuum system, the dynamic pressure of the ring could not be maintained low enough to reach the required beam intensities. To determine the actions necessary to lower the dynamic pressure rise, an experimental program has been initiated for measuring the molecular desorption yields of stainless steel vacuum chambers by the impact of 4.2 MeV/u lead ions with the charge states +27 and +53. The test chambers were exposed either at grazing or at perpendicular incidence. Different surface treatments (glow-discharges, non-evaporable getter coating) are reported in terms of the molecular desorption yields for H2, CH4, CO, Ar and CO2. Unexpected large values of molecular yields per incident ion up to 2 104 molecules/ion have been observed. The red...

  16. Resolution and Efficiency of the ATLAS Muon Drift-Tube Chambers at High Background Rates

    CERN Document Server

    Deile, M.; Horvat, S.; Kortner, O.; Kroha, H.; Manz, A.; Mohrdieck-Mock, S.; Rauscher, F.; Richter, Robert; Staude, A.; Stiller, W.

    2016-01-01

    The resolution and efficiency of a precision drift-tube chamber for the ATLAS muon spectrometer with final read-out electronics was tested at the Gamma Irradiation Facility at CERN in a 100 GeV muon beam and at photon irradiation rates of up to 990 Hz/square cm which corresponds to twice the highest background rate expected in ATLAS. A silicon strip detector telescope was used as external reference in the beam. The pulse-height measurement of the read-out electronics was used to perform time-slewing corrections which lead to an improvement of the average drift-tube resolution from 104 microns to 82 microns without irradiation and from 128 microns to 108 microns at the maximum expected rate. The measured drift-tube efficiency agrees with the expectation from the dead time of the read-out electronics up to the maximum expected rate.

  17. Common support and integration of the BMS/BMF type MDT/RPC chambers of the muon spectrometer of the ATLAS experiment

    International Nuclear Information System (INIS)

    Barashkov, A.V.; Glonti, G.L.; Gongadze, A.L.; Gostkin, M.I.; Gus'kov, A.V.; Dedovich, D.V.; Demichev, M.A.; Zhemchugov, A.S.; Il'yushenko, E.N.; Kotov, S.A.; Korolevich, Ya.V.; Kruchonok, V.G.; Krumshtejn, Z.V.; Kuznetsov, N.K.; Lomidze, D.D.; Potrap, I.N.; Kharchenko, D.V.; Tskhadadze, Eh.G.; Chepurnov, V.F.; Shelkov, G.A.; Podkladkin, S.Yu.; Sekhniaidze, G.G.

    2005-01-01

    The common support system for muon BMS/BMF drift chambers with trigger RPC chambers for the muon spectrometer of the ATLAS experiment is described. The support systems are intended for the chambers integration into combined modules and for the subsequent installation in the experimental set-up. The technology of chambers integration is described. The sagging of the drift chambers was tested by tilting the modules at different angles. The measurements were performed by means of the RASNIK optical system. The normal operation of kinematic supports was confirmed. We also present the method of the sag regulation for the BMS/BMF chambers lying in the horizontal plane which provides the minimum difference between signal wire and detector tube body sags when the modules are later installed in their working positions

  18. Design and Construction of Large Size Micromegas Chambers for the ATLAS Upgrade of the Muon Spectrometer

    CERN Document Server

    Jeanneau, Fabien; The ATLAS collaboration

    2015-01-01

    Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. A total surface of about 150 m2 of the forward regions of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each module extends over a surface from 2 to 3 m2 for a total active area of 1200 m2. Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS endcap muon tracking system in the 2018/19 shutdown. In order to achieve a 15% transverse momentum resolution for 1 TeV muons, in addition to an excellent intrinsic resolution, the mechanical precision of each plane of the assembled module must be as good as 30 μm along the precision coordinate and 80 μm perpendicular to the chamber. In the prototyping towards the final configuration two similar quadruplets with dimensions 1.2×0.5 m2 have been built with the same structure as foreseen for the NSW upgrade. It represents ...

  19. Design and Construction of Large Size Micromegas Chambers for the ATLAS Upgrade of the Muon Spectrometer

    CERN Document Server

    Jeanneau, Fabien; The ATLAS collaboration

    2015-01-01

    Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. A total surface of about 150 m2 of the forward regions of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each module extends over a surface from 2 to 3 m2 for a total active area of 1200 m2. Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS endcap muon tracking system in the 2018/19 shutdown. In order to achieve a 15% transverse momentum resolution for 1 TeV muons, in addition to an excellent intrinsic resolution, the mechanical precision of each plane of the assembled module must be as good as 30 μm along the precision coordinate and 80 μm perpendicular to the chamber. All readout planes are segmented into strips with a pitch of 400 μm for a total of 4096 strips. In two of the four planes the strips are inclined by 1.5 ◦ and provide a measurement of the...

  20. Design and Construction of Large Size Micromegas Chambers for the ATLAS Upgrade of the Muon Spectrometer

    CERN Document Server

    Losel, Philipp Jonathan; The ATLAS collaboration

    2014-01-01

    Large area Micromegas detectors will be employed fo r the first time in high-energy physics experiments. A total surface of about 150 m$^2$ of the forward regions of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each module extends over a surface from 2 to 3 m$^2$ for a total active area of 1200 m$^2$. Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS endcap muon tracking system in the 2018/19 shutdown. In order to achieve a 15% transverse momentum resol ution for 1 TeV muons, in addition to an excellent intrinsic resolution, the mechanical prec ision of each plane of the assembled module must be as good as 30 $\\mu$m along the precision coordi nate and 80 $\\mu$m perpendicular to the chamber. The design and construction procedure of the microm egas modules will be presented, as well as the design for the assembly of modules onto the New Small Wheel. Emphasis wi...

  1. VUV photoemission studies of candidate LHC vacuum chamber materials

    CERN Document Server

    Baglin, V; Collins, I R

    1998-01-01

    In the context of future accelerators and, in particular, the beam vacuum of the LargeHadron Collider (LHC), a 27 km circumference proton collider to be built at CERN, VUVsynchrotron radiation (SR) has been used to study both qualitatively and quantitatively candidatevacuum chamber materials. Emphasis is given to show that angle and energy resolvedphotoemission is an extremely powerful tool to address important issues relevant to the LHC, suchas the emission of electrons that contribute to the creation of an electron cloud which may causeserious beam instabilities. Here we present not only the measured photoelectron yields (PY)from the proposed materials, prepared on an industrial scale, but also the energy and, in some cases,the angular dependence of the emitted electrons when excited with either a white light (WL)spectrum, simulating that in the arcs of the LHC or monochromatic light in the photon energy rangeof interest. The effects on the materials examined of WL irradiation and/or ion sputtering,simulati...

  2. Factors determining the choice of the beam tube material and the vacuum chamber design for a superconducting high energy storage accelerator

    International Nuclear Information System (INIS)

    Aggus, J.; Edwards, D. Jr.; Halama, H.J.; Herrera, J.

    1979-01-01

    The factors which determine the choice of the material and the basic design for the vacuum chamber of the ISABELLE Colliding Storage Accelerator are reviewed. When the physical, thermal, electrical, and mechanical properties of the bulk material, as well as the various surface characteristics, are considered, it appears that a stainless tube covered with a copper sleeve is the best choice for the chambers in the magnet lattice of the rings. Aluminum is probably the most desirable material for those chambers in the experimental straight sections

  3. Vacuum leak detector and method

    Science.gov (United States)

    Edwards, Jr., David

    1983-01-01

    Apparatus and method for detecting leakage in a vacuum system involves a moisture trap chamber connected to the vacuum system and to a pressure gauge. Moisture in the trap chamber is captured by freezing or by a moisture adsorbent to reduce the residual water vapor pressure therein to a negligible amount. The pressure gauge is then read to determine whether the vacuum system is leaky. By directing a stream of carbon dioxide or helium at potentially leaky parts of the vacuum system, the apparatus can be used with supplemental means to locate leaks.

  4. A full assembly and bakeout have just been successfully completed on the conical ALICE Absorber beam vacuum chambers

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    Pictures 01 & 02 : a good example of cooperation: Several of the 70 people involved in the project pose in front of the ALICE Absorber containing the beam pipe. Six CERN departments and six sub-contracting companies have participated in the design, production and testing of this vacuum chamber.

  5. Development of a pulse magnet of a superconducting storage ring and degradation of the pulse magnetic field by the vacuum chamber

    International Nuclear Information System (INIS)

    Tsukishima, Chihiro; Nakata, Shuhei

    1993-01-01

    A pulse magnet and its modulator are developed for a superconducting storage ring commissioning at Mitsubishi Electric Corp. The magnet is a window flame type one and uses a ceramic chamber with thin metallic coating for the vacuum shielding. The modulator generates a pulse current of 5.5 kA and the magnetic field is up to 1,300 G. The rise time of the field should be less than 300 ns in order to obtain enough injection efficiency to the storage ring. The shielding effects of the pulse magnetic field by the vacuum chamber are estimated using a three dimensional transient analysis program. The program solves the magnetic charge on the yoke surface of the magnet using the boundary element method and the eddy currents on the vacuum chamber using the network circuits method. The degradation of the magnetic field is measured by the search coil for different coating thickness to check the calculations results, and the results show good agreement with the calculation results. The calculation and the measurement results show the thickness should be less than 10 nm when the pulse width of the field is 600 ns. The dependence of the ununiformity of the coating thickness on the shielding effects is also estimated and the requirements for the uniformity are not so strict when the thickness is less than 10 nm. (author)

  6. The AGS Booster vacuum systems

    International Nuclear Information System (INIS)

    Hseuh, H.C.

    1989-01-01

    The AGS Booster is a synchrotron for the acceleration of both protons and heavy ions. The design pressure of low 10 -11 mbar is required to minimize beam loss of the partially stripped heavy ions. To remove contaminants and to reduce outgassing, the vacuum chambers and the components located in them will be chemically cleaned, vacuum fired, baked then treated with nitric oxide. The vacuum sector will be insitu baked to a minimum of 200 degree C and pumped by the combination of sputter ion pumps and titanium sublimation pumps. This paper describes the design and the processing of this ultra high vacuum system, and the performance of some half-cell vacuum chambers. 9 refs., 7 figs

  7. Vacuum systems for the ILC helical undulator

    CERN Document Server

    Malyshev, O B; Clarke, J A; Bailey, I R; Dainton, J B; Malysheva, L I; Barber, D P; Cooke, P; Baynham, E; Bradshaw, T; Brummitt, A; Carr, S; Ivanyushenkov, Y; Rochford, J; Moortgat-Pick, G A

    2007-01-01

    The International Linear Collider (ILC) positron source uses a helical undulator to generate polarized photons of ∼10MeV∼10MeV at the first harmonic. Unlike many undulators used in synchrotron radiation sources, the ILC helical undulator vacuum chamber will be bombarded by photons, generated by the undulator, with energies mostly below that of the first harmonic. Achieving the vacuum specification of ∼100nTorr∼100nTorr in a narrow chamber of 4–6mm4–6mm inner diameter, with a long length of 100–200m100–200m, makes the design of the vacuum system challenging. This article describes the vacuum specifications and calculations of the flux and energy of photons irradiating the undulator vacuum chamber and considers possible vacuum system design solutions for two cases: cryogenic and room temperature.

  8. Cold vacuum chamber for diagnostics: Analysis of the measurements at the Diamond Light Source and impedance bench measurements

    Science.gov (United States)

    Voutta, R.; Gerstl, S.; Casalbuoni, S.; Grau, A. W.; Holubek, T.; Saez de Jauregui, D.; Bartolini, R.; Cox, M. P.; Longhi, E. C.; Rehm, G.; Schouten, J. C.; Walker, R. P.; Migliorati, M.; Spataro, B.

    2016-05-01

    The beam heat load is an important input parameter needed for the cryogenic design of superconducting insertion devices. Theoretical models taking into account the different heating mechanisms of an electron beam to a cold bore predict smaller values than the ones measured with several superconducting insertion devices installed in different electron storage rings. In order to measure and possibly understand the beam heat load to a cold bore, a cold vacuum chamber for diagnostics (COLDDIAG) has been built. COLDDIAG is equipped with temperature sensors, pressure gauges, mass spectrometers as well as retarding field analyzers which allow to measure the beam heat load, total pressure, and gas content as well as the flux of particles hitting the chamber walls. COLDDIAG was installed in a straight section of the Diamond Light Source (DLS). In a previous paper the experimental equipment as well as the installation of COLDDIAG in the DLS are described [S. Gerstl et al., Phys. Rev. ST Accel. Beams 17, 103201 (2014)]. In this paper we present an overview of all the measurements performed with COLDDIAG at the DLS and their detailed analysis, as well as impedance bench measurements of the cold beam vacuum chamber performed at the Karlsruhe Institute of Technology after removal from the DLS. Relevant conclusions for the cryogenic design of superconducting insertion devices are drawn from the obtained results.

  9. Cold vacuum chamber for diagnostics: Analysis of the measurements at the Diamond Light Source and impedance bench measurements

    Directory of Open Access Journals (Sweden)

    R. Voutta

    2016-05-01

    Full Text Available The beam heat load is an important input parameter needed for the cryogenic design of superconducting insertion devices. Theoretical models taking into account the different heating mechanisms of an electron beam to a cold bore predict smaller values than the ones measured with several superconducting insertion devices installed in different electron storage rings. In order to measure and possibly understand the beam heat load to a cold bore, a cold vacuum chamber for diagnostics (COLDDIAG has been built. COLDDIAG is equipped with temperature sensors, pressure gauges, mass spectrometers as well as retarding field analyzers which allow to measure the beam heat load, total pressure, and gas content as well as the flux of particles hitting the chamber walls. COLDDIAG was installed in a straight section of the Diamond Light Source (DLS. In a previous paper the experimental equipment as well as the installation of COLDDIAG in the DLS are described [S. Gerstl et al., Phys. Rev. ST Accel. Beams 17, 103201 (2014]. In this paper we present an overview of all the measurements performed with COLDDIAG at the DLS and their detailed analysis, as well as impedance bench measurements of the cold beam vacuum chamber performed at the Karlsruhe Institute of Technology after removal from the DLS. Relevant conclusions for the cryogenic design of superconducting insertion devices are drawn from the obtained results.

  10. Calibration of the ATLAS precision muon chambers and study of the decay {tau} {yields} {mu}{mu}{mu} at the large hadron collider

    Energy Technology Data Exchange (ETDEWEB)

    Loeben, Joerg Horst Jochen von

    2010-07-07

    The Large Hadron Collider (LHC) is designed to collide protons at centre-of-mass energies of up to 14 TeV. One of the two general purpose experiments at the LHC is ATLAS, built to probe a broad spectrum of physics processes of the Standard Model of particle physics and beyond. ATLAS is equipped with a muon spectrometer comprising three superconducting air-core toroid magnets and 1150 precision drift tube (MDT) chambers measuring muon trajectories with better than 50 {mu}m position resolution. The accuracy of the space-to-drift-time relationships of the MDT chambers is one of the main contributions to the momentum resolution. In this thesis, an improved method for the calibration of the precision drift tube chambers in magnetic fields has been developed and tested using curved muon track segments. An accuracy of the drift distance measurement of better than 20 {mu}m is achieved leading to negligible deterioration of the muon momentum resolution. The second part of this work is dedicated to the study of the lepton flavour violating decay {tau}{yields}{mu}{mu}{mu}. Lepton flavour violation is predicted by almost every extension of the Standard Model. About 10{sup 12}{tau} leptons are produced per year at an instantaneous luminosity of 10{sup 33} cm{sup -2}s{sup -1} and a centre-of-mass energy of 14 TeV. Simulated data samples have been used to evaluate the sensitivity of the ATLAS experiment for {tau}{yields}{mu}{mu}{mu} decays with an integrated luminosity of 10 fb{sup -1}. Taking theoretical and experimental systematic uncertainties into account an upper limit on the signal branching ratio of B({tau}{yields}{mu}{mu}{mu}) <5.9 x 10{sup -7} at 90% confidence level is achievable. This result represents the first estimation in ATLAS. (orig.)

  11. Re-circulating linac vacuum system

    International Nuclear Information System (INIS)

    Wells, Russell P.; Corlett, John N.; Zholents, Alexander A.

    2003-01-01

    The vacuum system for a proposed 2.5 GeV, 10ΜA recirculating linac synchrotron light source [1] is readily achievable with conventional vacuum hardware and established fabrication processes. Some of the difficult technical challenges associated with synchrotron light source storage rings are sidestepped by the relatively low beam current and short beam lifetime requirements of a re-circulating linac. This minimal lifetime requirement leads directly to relatively high limits on the background gas pressure through much of the facility. The 10ΜA average beam current produces very little synchrotron radiation induced gas desorption and thus the need for an ante-chamber in the vacuum chamber is eliminated. In the arc bend magnets, and the insertion devices, the vacuum chamber dimensions can be selected to balance the coherent synchrotron radiation and resistive wall wakefield effects, while maintaining the modest limits on the gas pressure and minimal outgassing

  12. Beam heat load investigations with a cold vacuum chamber for diagnostics in a synchrotron light source

    Energy Technology Data Exchange (ETDEWEB)

    Voutta, Robert

    2016-04-22

    The beam heat load is a crucial input parameter for the cryogenic design of superconducting insertion devices. To understand the discrepancies between the predicted heat load of an electron beam to a cold bore and the heat load observed in superconducting devices, a cold vacuum chamber for diagnostics has been built. Extensive beam heat load measurements were performed at the Diamond light source. They are analysed systematically and combined with complementary impedance bench measurements.

  13. Construction of vacuum system for Tristan accumulation ring

    International Nuclear Information System (INIS)

    Ishimaru, H.; Horikoshi, G.; Kobayashi, M.; Kubo, T.; Mizuno, H.; Momose, T.; Narushima, K.; Watanabe, H.; Yamaguchi, H.

    1983-01-01

    An all aluminum-alloy vacuum system for the TRISTAN accumulation ring is now under construction. Aluminum and aluminum alloys are preferred materials for ultrahigh vacuum systems of large electron storage rings because of their good thermal conductivity, extremely low outgassing rate, and low residual radioactivity. Vacuum beam chambers for the dipole and quadrupole magnets are extruded using porthole dies. The aluminum alloy 6063-T6 provides superior performance in extrusion. For ultrahigh vacuum performance, a special extrusion technique is applied which, along with the outgassing procedure used, is described in detail. Aluminum alloy 3004 seamless elliptical bellows are inserted between the dipole and quadrupole magnet chambers. These bellows are produced by the hydraulic forming of a seamless tube. The seamless bellows and the beam chambers are joined by fully automatic welding. The ceramic chambers for the kicker magnets, the fast bump magnets, and the slow beam intensity monitor are inserted in the aluminum alloy beam chambers. The ceramic chamber (98% alumina) and elliptical bellows are brazed with brazing sheets (4003-3003-4003) in a vacuum furnace. The brazing technique is described. The inner surface of the ceramic chamber is coated with a TiMo alloy by vacuum evaporation to permit a smooth flow of the RF wall current. Other suitable aluminum alloy components, including fittings, feedthroughs, gauges, optical windows, sputter ion pumps, turbomolecular pumps, and valves have been developed; their fabrication is described

  14. Baking of SST-1 vacuum vessel modules and sectors

    International Nuclear Information System (INIS)

    Pathan, Firozkhan S; Khan, Ziauddin; Yuvakiran, Paravastu; George, Siju; Ramesh, Gattu; Manthena, Himabindu; Shah, Virendrakumar; Raval, Dilip C; Thankey, Prashant L; Dhanani, Kalpesh R; Pradhan, Subrata

    2012-01-01

    SST-1 Tokamak is a steady state super-conducting tokamak for plasma discharge of 1000 sec duration. The plasma discharge of such long time duration can be obtained by reducing the impurities level, which will be possible only when SST-1 vacuum chamber is pumped to ultra high vacuum. In order to achieve UHV inside the chamber, the baking of complete vacuum chamber has to be carried out during pumping. For this purpose the C-channels are welded inside the vacuum vessel. During baking of vacuum vessel, these welded channels should be helium leak tight. Further, these U-channels will be in accessible under operational condition of SST-1. So, it will not possible to repair if any leak is developed during experiment. To avoid such circumstances, a dedicated high vacuum chamber is used for baking of the individual vacuum modules and sectors before assembly so that any fault during welding of the channels will be obtained and repaired. This paper represents the baking of vacuum vessel modules and sectors and their temperature distribution along the entire surface before assembly.

  15. An automatic control of the pumping system for the vacuum chamber of the cyclotron

    International Nuclear Information System (INIS)

    Ikegami, Kumio; Kageyama, Tadashi; Kohno, Isao

    1979-01-01

    The main pumping system of the 160 cm cyclotron is composed of 32'', 14'', and 6'' oil difusion pumps connected in series and rough pumping system which consists of 1500 l/min rotary pump and 300 m 3 /h roots pump with 650 l/min rotary backing pump. Instead of manual operation an automatic control devise of the pumping system was developed and many valves were replaced with pneumatic ones. In the new control system, pumps and valves are operated automatically, according to the indication of pirani detectors, to evacuate the chamber of the cyclotron up to the pressure of 0.7 - 1.0 x 10 -6 Torr, and also to protect the pumping system against vacuum failure by accidental leakage in the chamber. The graphic handling board of the pumping system is installed on the control panel and each switch is provided with a name card showing its function briefly. (author)

  16. Understand ATLAS NSW Thin Gap Chamber from Garfield Simulation

    CERN Document Server

    Chapman, J; Diehl, E; Feng, H; Guan, L; Mikenberg, G; Smakhtin, V; Yu, J M; Zhou, B; Zhu, J; Zhao, Z

    2014-01-01

    The LHC will be upgraded in several phases with the goal of obtaining an instantaneous lumi- nosity of 5-7 x 10^34 cm-2s-s at the center of mass energy of 14 TeV and integrated luminosity of 3000 fb-1. In order to profit from the high luminosity and high energy runs of the LHC, the ATLAS collaboration plans to upgrade the present endcap small wheel muon spectrometer to im- prove the muon triggering as well as precision tracking. The proposed New Small Wheel (nSW) will be composed of two four-layer Micromegas detectors (MM) detector sandwiched between two four-layer small-strip Thin Gap Chambers (sTGC) quadruplets, where MM for precision tracking and sTGC for Level-1 triggering. In this paper, we focus on the Garfield [ 1 ] simulation of the sTGC detector to understand its timing performance and charge production. We also stud- ied the sTGC timing under different magnetic fields and high voltages. These studies provide important guide lines for the sTGC detector and electronics development.

  17. X-ray induced gas desorption within a prototype LEP vacuum chamber

    International Nuclear Information System (INIS)

    Williams, E.M.; Le Normand, F.; Hilleret, N.; Dominichini, G.

    1982-12-01

    The present report is concerned with an experimental simulation of the process of photon induced desorption within an aluminium vacuum chamber of the same basic form as proposed for the LEP accelerator. The objectives in the work can be described in the following three-fold manner: Firstly, to establish the levels of photon induced desorption efficiency for identified gas species. Secondly, to examine the contribution of surface treatments as bakeout and glow discharge cleaning, and to correlate these responses with changes in surface activity induced by beam cleaning. Thirdly, to gain insight into the energy dependence of the desorption process so as to provide a reasonable basis for predicting conditions at the levels of critical energy in excess of 100 keV which are applicable at the full design energy of the LEP accelerator. (orig./HSI)

  18. One of the two end-cap vacuum chambers for the CMS experiment has been completed.

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    This 7.5-metre-long cone-shaped object is the fruit of many years' development and its machining and assembly were performed with the utmost precision. Part of the team involved in the design and production of the end-cap vacuum chamber for CMS, standing behind the completed segment. Picture 02 from left to right : Thierry Tardy (TS/MME), Luigi Leggiero (TS/MME), Patrick Lepeule (AT/VAC), Gérard Faber (ETH Zürich), Stefano Bongiovani (CINEL Project Manager), Giuseppe Foffano (TS/MME) and Marc Thiebert (TS/MME).

  19. ATLAS MPGD production status

    CERN Document Server

    Schioppa, Marco; The ATLAS collaboration

    2018-01-01

    Micromegas (MICRO MEsh GAseous Structure) chambers are Micro-Pattern Gaseous Detectors designed to provide a high spatial resolution and reasonable good time resolution in highly irradiated environments. In 2007 an ambitious long-term R\\&D activity was started in the context of the ATLAS experiment, at CERN: the Muon ATLAS Micromegas Activity (MAMMA). After years of tests on prototypes and technology breakthroughs, Micromegas chambers were chosen as tracking detectors for an upgrade of the ATLAS Muon Spectrometer. These novel detectors will be installed in 2020 at the end of the second long shutdown of the Large Hadron Collider, and will serve mainly as precision detectors in the innermost part of the forward ATLAS Muon Spectrometer. Four different types of Micromegas modules, eight layers each, up to $3 m^2$ area (of unprecedented size), will cover a surface of $150 m^2$ for a total active area of about $1200 m^2$. With this upgrade the ATLAS muon system will maintain the full acceptance of its excellent...

  20. The fine art of preparing a vacuum

    CERN Multimedia

    2006-01-01

    The vacuum chambers, or beam pipes, of the LHC experiments are located right at the interface between the detectors and the accelerator, and are therefore crucial to the LHC project as a whole. In this domain, the ALICE and CMS experiments have just passed an important milestone, with the completion of the first of CMS's two end-cap vacuum chambers, together with the completion and bakeout of an 18-metre section of the ALICE vacuum chamber. These complex projects, for which CERN's AT/VAC Group is responsible, involved dozens of people over a number of years.

  1. Upgrade of the Level-1 muon trigger of the ATLAS detector in the barrel-endcap transition region with RPC chambers

    CERN Document Server

    Massa, L; The ATLAS collaboration

    2014-01-01

    This report presents a project for the upgrade of the Level-1 muon trigger in the barrel-endcap transition region (1.01) caused by charged particles originating from secondary interactions downstream of the interaction point. After the LHC phase-1 upgrade, forseen for 2018, the Level-1 muon trigger rate would saturate the allocated bandwidth unless new measures are adopted to improve the rejection of fake triggers. ATLAS is going to improve the trigger selectivity in the region |$\\eta$|>1.3 with the addition of the New Small Wheel detector as an inner trigger plane. To obtain a similar trigger selectivity in the barrel-endcap transition region 1.0<|$\\eta$|<1.3, it is proposed to add new RPC chambers at the edge of the inner layer of the barrel muon spectrometer. These chambers will be based on a three layer structure with thinner gas gaps and electrodes with respect to the ATLAS standard and a new low-profile light-weight mechanical structure that will allow the installation in the limited available spa...

  2. ATLAS Muon Drift Tube Electronics

    CERN Document Server

    Arai, Y; Beretta, M; Boterenbrood, H; Brandenburg, G W; Ceradini, F; Chapman, J W; Dai, T; Ferretti, C; Fries, T; Gregory, J; Guimarães da Costa, J; Harder, S; Hazen, E; Huth, J; Jansweijer, P P M; Kirsch, L E; König, A C; Lanza, A; Mikenberg, G; Oliver, J; Posch, C; Richter, R; Riegler, W; Spiriti, E; Taylor, F E; Vermeulen, J; Wadsworth, B; Wijnen, T A M

    2008-01-01

    This paper describes the electronics used for the ATLAS monitored drift tube (MDT) chambers. These chambers are the main component of the precision tracking system in the ATLAS muon spectrometer. The MDT detector system consists of 1,150 chambers containing a total of 354,000 drift tubes. It is capable of measuring the sagitta of muon tracks to an accuracy of 60 microns, which corresponds to a momentum accuracy of about 10% at pT = 1 TeV. The design and performance of the MDT readout electronics as well as the electronics for controlling, monitoring and powering the detector will be discussed. These electronics have been extensively tested under simulated running conditions and have undergone radiation testing certifying them for more than 10 years of LHC operation. They are now installed on the ATLAS detector and are operating during cosmic ray commissioning runs.

  3. Conditioning of the vacuum chamber of the Tokamak Novillo; Acondicionamiento de la camara de vacio del Tokamak Novillo

    Energy Technology Data Exchange (ETDEWEB)

    Valencia A, R; Lopez C, R; Melendez L, L; Chavez A, E; Colunga S, S; Gaytan G, E

    1992-03-15

    The obtained experimental results of the implementation of two techniques of present time for the conditioning of the internal wall of the chamber of discharges of the Tokamak Novillo are presented, which has been designed, built and put in operation in the Laboratory of Plasma Physics of the National Institute of Nuclear Research (ININ). These techniques are: the vacuum baking and the low energy pulsed discharges, which were applied after having reached an initial pressure of the order of 10{sup -7} Torr. with a system of turbomolecular pumping previous preparation of surfaces and vacuum seals. The analysis of residual gases was carried out with a mass spectrometer before and after conditioning. The obtained results show that the vacuum baking it was of great effectiveness to reduce the value of the initial pressure in short time, in more of a magnitude order and the low energy discharges reduced the oxygen at worthless levels with regard to the initial values. (Author)

  4. BEBC Big European Bubble Chamber

    CERN Multimedia

    CERN PhotoLab

    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.

  5. ATLAS Muon Drift Tube Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Arai, Y [KEK, High Energy Accelerator Research Organisation, Tsukuba (Japan); Ball, B; Chapman, J W; Dai, T; Ferretti, C; Gregory, J [University of Michigan, Department of Physics, Ann Arbor, MI (United States); Beretta, M [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Boterenbrood, H; Jansweijer, P P M [Nikhef National Institute for Subatomic Physics, Amsterdam (Netherlands); Brandenburg, G W; Fries, T; Costa, J Guimaraes da; Harder, S; Huth, J [Harvard University, Laboratory for Particle Physics and Cosmology, Cambridge, MA (United States); Ceradini, F [INFN Roma Tre and Universita Roma Tre, Dipartimento di Fisica, Roma (Italy); Hazen, E [Boston University, Physics Department, Boston, MA (United States); Kirsch, L E [Brandeis University, Department of Physics, Waltham, MA (United States); Koenig, A C [Radboud University Nijmegen/Nikhef, Dept. of Exp. High Energy Physics, Nijmegen (Netherlands); Lanza, A [INFN Pavia, Pavia (Italy); Mikenberg, G [Weizmann Institute of Science, Department of Particle Physics, Rehovot (Israel)], E-mail: brandenburg@physics.harvard.edu (and others)

    2008-09-15

    This paper describes the electronics used for the ATLAS monitored drift tube (MDT) chambers. These chambers are the main component of the precision tracking system in the ATLAS muon spectrometer. The MDT detector system consists of 1,150 chambers containing a total of 354,000 drift tubes. It is capable of measuring the sagitta of muon tracks to an accuracy of 60 {mu}m, which corresponds to a momentum accuracy of about 10% at p{sub T}= 1 TeV. The design and performance of the MDT readout electronics as well as the electronics for controlling, monitoring and powering the detector will be discussed. These electronics have been extensively tested under simulated running conditions and have undergone radiation testing certifying them for more than 10 years of LHC operation. They are now installed on the ATLAS detector and are operating during cosmic ray commissioning runs.

  6. ATLAS solenoid operates underground

    CERN Multimedia

    2006-01-01

    A new phase for the ATLAS collaboration started with the first operation of a completed sub-system: the Central Solenoid. Teams monitoring the cooling and powering of the ATLAS solenoid in the control room. The solenoid was cooled down to 4.5 K from 17 to 23 May. The first current was established the same evening that the solenoid became cold and superconductive. 'This makes the ATLAS Central Solenoid the very first cold and superconducting magnet to be operated in the LHC underground areas!', said Takahiko Kondo, professor at KEK. Though the current was limited to 1 kA, the cool-down and powering of the solenoid was a major milestone for all of the control, cryogenic, power and vacuum systems-a milestone reached by the hard work and many long evenings invested by various teams from ATLAS, all of CERN's departments and several large and small companies. Since the Central Solenoid and the barrel liquid argon (LAr) calorimeter share the same cryostat vacuum vessel, this achievement was only possible in perfe...

  7. Technical Capability Upgrades to the NASA Langley Research Center 8 ft. by 15 ft. Thermal Vacuum Chamber

    Science.gov (United States)

    Thornblom, Mark N.; Beverly, Joshua; O'Connell, Joseph J.; Duncan, Dwight L.

    2016-01-01

    The 8 ft. by 15 ft. thermal vacuum chamber (TVAC), housed in Building 1250 at the NASA Langley Research Center (LaRC), and managed by the Systems Integration and Test Branch within the Engineering Directorate, has undergone several significant modifications to increase testing capability, safety, and quality of measurements of articles under environmental test. Significant modifications include: a new nitrogen distribution manifold for supplying the shroud and other cold surfaces to liquid nitrogen temperatures; a new power supply and distribution system for accurately controlling a quartz IR lamp suite; a suite of contamination monitoring sensors for outgassing measurements and species identification; a new test article support system; signal and power feed-throughs; elimination of unnecessary penetrations; and a new data acquisition and control commanding system including safety interlocks. This paper will provide a general overview of the LaRC 8 ft. by 15 ft. TVAC chamber, an overview of the new technical capabilities, and will illustrate each upgrade in detail, in terms of mechanical design and predicted performance. Additionally, an overview of the scope of tests currently being performed in the chamber will be documented, and sensor plots from tests will be provided to show chamber temperature and pressure performance with actual flight hardware under test.

  8. Technical Capability Upgrades to the NASA Langley Research Center 6 ft. by 6 ft. Thermal Vacuum Chamber

    Science.gov (United States)

    Thornblom, Mark N.; Beverly, Joshua; O'Connell, Joseph J.; Mau, Johnny C.; Duncan, Dwight L.

    2014-01-01

    The 6 ft. by 6 ft. thermal vacuum chamber (TVAC), housed in Building 1250 at the NASA Langley Research Center (LaRC), and managed by the Systems Integration and Test Branch within the Engineering Directorate, has undergone several significant modifications to increase testing capability, safety, and quality of measurements of articles under environmental test. Significant modifications include: a new nitrogen thermal conditioning unit for controlling shroud temperatures from -150degC to +150degC; two horizontal auxiliary cold plates for independent temperature control from -150degC to +200degC; a suite of contamination monitoring sensors for outgassing measurements and species identification; signal and power feed-throughs; new pressure gauges; and a new data acquisition and control commanding system including safety interlocks. This presentation will provide a general overview of the LaRC 6 ft. by 6 ft. TVAC chamber, an overview of the new technical capabilities, and illustrate each upgrade in detail, in terms of mechanical design and predicted performance. Additionally, an overview of the scope of tests currently being performed in the chamber will be documented, and sensor plots from tests will be provided to show chamber temperature and pressure performance with actual flight hardware under test.

  9. Small-Strip Thin Gap Chambers for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00221766; The ATLAS collaboration

    2016-01-01

    The ATLAS muon system upgrade to be installed during the LHC long shutdown in 2018/19, the so called New Small Wheel (NSW), is designed to cope with the increased instantaneous luminosity in LHC Run 3. The small-strip Thin Gap Chambers (sTGC) will provide the NSW with fast trigger and high precision tracking. The construction protocol has been validated by test beam experiments on a full-size prototype sTGC detector, showing the performance requirements are met. The intrinsic spatial resolution for a single layer has been found to be about 50$\\mu$m at perpendicular incident angle, and the pads transition region has been measured to be about 4mm.

  10. MDT Commissioning Procedures Guidelines for Certifying RFI Chambers

    CERN Document Server

    Beretta, M; Branchini, P; Kourkoumelis, C; Dubbert, J; Gazis, E N; Hertenberger, R; Hurst, P; Kojine, A; Lanza, A; Marin, A; Mockett, P; Petridou, C; Tskhadadze, E G; Valente, P; Wotschack, J; Xie, Y; Zhao, Z

    2004-01-01

    Aim of the document is the definition of a common set of guidelines and test procedures for commissioning the MDT chambers. Commissioning is different for Barrel and Endcap chambers. The former will be tested at a single chamber level before going to the ATLAS pit, ready for the last quick test before final installation, while the latter will be first tested at a single chamber level (phase one), then installed into the Small and Big Wheel sectors (SW and BW), tested after the integration (phase two) and transported to the ATLAS pit for final wheel installation. The present document concerns all tests, including those of phase two for Endcap chambers, but it is possible that some specific tests, at the moment not planned, will be implemented during the Endcap phase two commissioning. It is composed of three sections: 1 â€" Guidelines for checking chamber conformity, where the main rules for declaring that chambers conform to the reference drawings and requirements are described; 2 â€" Commissioning tests,...

  11. Preliminary hazard analysis for the Brayton Isotope Ground Demonstration System (including vacuum test chamber)

    International Nuclear Information System (INIS)

    Miller, L.G.

    1975-01-01

    The Preliminary Hazard Analysis (PHA) of the BIPS-GDS is a tabular summary of hazards and undesired events which may lead to system damage or failure and/or hazard to personnel. The PHA reviews the GDS as it is envisioned to operate in the Vacuum Test Chamber (VTC) of the GDS Test Facility. The VTC and other equipment which will comprise the test facility are presently in an early stage of preliminary design and will undoubtedly undergo numerous changes before the design is frozen. The PHA and the FMECA to follow are intended to aid the design effort by identifying areas of concern which are critical to the safety and reliability of the BIPS-GDS and test facility

  12. Manufacture of the ALS storage ring vacuum system

    International Nuclear Information System (INIS)

    Kennedy, K.

    1990-11-01

    The Advanced Light Source (ALS) storage rings has a 4.9 meter magnetic radius and an antechamber type vacuum chamber. These two requirements makes conventional bent tube manufacturing techniques difficult. The ALS sector vacuum chambers have been made by matching two halves out of aluminum plate and welding at the mid plane. Each of these chambers have over 50 penetrations with metal sealed flanges and seven metal sealed poppet valves which use the chamber wall as the valve seat. The sector chambers are 10 meter long and some features in the chambers must be located to .25 mm. This paper describes how and how successfully these features have been achieved. 2 refs., 5 figs

  13. ATLAS RPC Quality Assurance results at INFN Lecce

    CERN Document Server

    INSPIRE-00211509; Borjanovic, I.; Cataldi, G.; Cazzato, A.; Chiodini, G.; Coluccia, M. R.; Creti, P.; Gorini, E.; Grancagnolo, F.; Perrino, R.; Primavera, M.; Spagnolo, S.; Tassielli, G.; Ventura, A.

    2006-01-01

    The main results of the quality assurance tests performed on the Resistive Plate Chamber used by the ATLAS experiment at LHC as muon trigger chambers are reported and discussed. Since July 2004, about 270 RPC units has been certified at INFN Lecce site and delivered to CERN, for being integrated in the final muon station of the ATLAS barrel region. We show the key RPC characteristics which qualify the performance of this detector technology as muon trigger chamber in the harsh LHC enviroments. These are dark current, chamber efficiency, noise rate, gas volume tomography, and gas leakage.

  14. Performance studies of resistive Micromegas chambers for the upgrade of the ATLAS Muon Spectrometer

    Science.gov (United States)

    Ntekas, Konstantinos

    2018-02-01

    The ATLAS collaboration at LHC has endorsed the resistive Micromegas technology (MM), along with the small-strip Thin Gap Chambers (sTGC), for the high luminosity upgrade of the first muon station in the high-rapidity region, the so called New Small Wheel (NSW) project. The NSW requires fully efficient MM chambers, up to a particle rate of ˜ 15 kHz/cm2, with spatial resolution better than 100 μm independent of the track incidence angle and the magnetic field (B ≤ 0.3 T). Along with the precise tracking the MM should be able to provide a trigger signal, complementary to the sTGC, thus a decent timing resolution is required. Several tests have been performed on small (10 × 10 cm2) MM chambers using medium (10 GeV/c) and high (150 GeV/c) momentum hadron beams at CERN. Results on the efficiency and position resolution measured during these tests are presented demonstrating the excellent characteristics of the MM that fulfil the NSW requirements. Exploiting the ability of the MM to work as a Time Projection Chamber a novel method, called the μTPC, has been developed for the case of inclined tracks, allowing for a precise segment reconstruction using a single detection plane. A detailed description of the method along with thorough studies towards refining the method's performance are shown. Finally, during 2014 the first MM quadruplet (MMSW) following the NSW design scheme, comprising four detection planes in a stereo readout configuration, has been realised at CERN. Test-beam results of this prototype are discussed and compared to theoretical expectations.

  15. Structural Analysis of Extended Plasma Focus Chamber

    International Nuclear Information System (INIS)

    Mohd Azhar Ahmad; Abdul Halim Baijan; Siti Aiasah Hashim

    2016-01-01

    Accelerator Development Centre (ADC) of Nuclear Malaysia intends to upgrade the plasma focus device. It involves the extension part placed on top of the existing plasma focus vacuum chamber. This extended vacuum chamber purposely to give an extra space in conducting experiments on the existing plasma focus chamber. The aim of upgrading the plasma focus device is to solve the limitation in research and analysis of sample due to its done in an open system that cause analysis of samples is limited and less optimal. This extended chamber was design in considering the ease of fabrication as well as durability of its structural. Thus, this paper discusses the structural analysis in term of pressure loading effect in extended chamber. (author)

  16. A Highly Selective First-Level Muon Trigger With MDT Chamber Data for ATLAS at HL-LHC

    CERN Document Server

    INSPIRE-00390105

    2016-07-11

    Highly selective triggers are essential for the physics programme of the ATLAS experiment at HL-LHC where the instantaneous luminosity will be about an order of magnitude larger than the LHC instantaneous luminosity in Run 1. The first level muon trigger rate is dominated by low momentum muons below the nominal trigger threshold due to the moderate momentum resolution of the Resistive Plate and Thin Gap trigger chambers. The resulting high trigger rates at HL-LHC can be su?ciently reduced by using the data of the precision Muon Drift Tube chambers for the trigger decision. This requires the implementation of a fast MDT read-out chain and of a fast MDT track reconstruction algorithm with a latency of at most 6 microseconds. A hardware demonstrator of the fast read-out chain has been successfully tested at the HL-LHC operating conditions at the CERN Gamma Irradiation Facility. The fast track reconstruction algorithm has been implemented on a fast trigger processor.

  17. A Highly Selective First-Level Muon Trigger With MDT Chamber Data for ATLAS at HL-LHC

    CERN Document Server

    Nowak, Sebastian; The ATLAS collaboration

    2015-01-01

    Highly selective triggers are essential for the physics programme of the ATLAS experiment at HL-LHC where the instantaneous luminosity will be about an order of magnitude larger than the LHC design luminosity. The Level-1 muon trigger rate is dominated by low momentum muons below the nominal trigger threshold due to the limited momentum resolution of the Resistive Plate and Thin Gap trigger chambers. The resulting high trigger rates at HL-LHC can be sufficient reduced by using the data of the precision Muon Drift Tube chambers for the trigger decision. This requires the implementation of a fast MDT read-out chain and of a fast MDT track reconstruction algorithm with a latency of at most 6~$\\mu$s. A hardware demonstrator of the fast read-out chain has been successfully tested at the high HL-LHC background rates at the CERN Gamma Irradiation Facility. The fast track reconstruction algorithm has been implemented on a fas trigger processor.

  18. ALICE's first vacuum bakeout a success

    CERN Multimedia

    2007-01-01

    At the beginning of April, the ALICE central beryllium beam pipe and absorber beam pipes were successfully conditioned. The installation and bakeout shell surround the beam pipe (lower left), running through the middle of the ITS and TPC. Notice the high-tech cooling system, an additional precaution to avoid overheating the ALICE detection equipment.One end of the vacuum sector during the bakeout and pure gas refill. It is unusual for a vacuum sector to end as it does in the middle of a non-accessible detector and made the installation and cabling of the bakeout equipment a more difficult procedure. Just before Easter, the first bakeout and NEG activation of experimental chambers in the LHC was carried out, followed by ultra pure gas refill. The bakeout consisted of externally heating the chambers under vacuum in order to lower their outgassing. This same heating process also activates the NEG, a coating on the inside surface of the beam vacuum chambers, which pumps the residual gas. ALICE's bakeout was pa...

  19. ASD IC for the thin gap chambers in the LHC Atlas experiment

    International Nuclear Information System (INIS)

    Sasaki, Osamu; Yoshida, Mitsuhiro

    1999-01-01

    An amplifier-shaper-discriminator (ASD) chip was designed and built for Thin Gap Chambers in the forward muon trigger system of the LHC Atlas experiment. The ASD IC uses SONY Analog Master Slice bipolar technology. The IC contains 4 channels in a QFP48 package. The gain of its first stage (preamplifier) is approximately 0.8V/pC and output from the preamplifier is received by a shaper (main-amplifier) with a gain of 7. The baseline restoration circuit is incorporated in the main-amplifier. The threshold voltage for discriminator section is common to the 4 channels and their digital output level is LVDS-compatible. The IC also has analog output of the preamplifier. The equivalent noise charge at input capacitance of 150 pF is around 7,500 electrons. The power dissipation with LDVS outputs (100 Omega load) is 59mW/ch

  20. ASD IC for the thin gap chambers in the LHC ATLAS experiment

    CERN Document Server

    Sasaki, O

    1998-01-01

    An amplifier-shaper-discriminator (ASD) chip was designed and built for Thin Gap Chambers in the forward muon trigger system of the LHC ATLAS experiment. The ASD IC uses SONY Analog Master Slice bipolar technology. The IC contains 4 $9 channels in a QFP48 package. The gain of its first stage (preamplifier) is approximately 0.8 V/pC and output from the preamplifier is received by a shaper (main-amplifier) with a gain of 7. The baseline restoration circuit is $9 incorporated in the main-amplifier. The threshold voltage for the discriminator section is common to the 4 channels and their digital output level is LVDS-compatible. The IC also has analog output for the preamplifier. The equivalent $9 noise charge at input capacitance of 150 pF is around 7500 electrons. The power dissipation with LDVS outputs (100 Omega load) is 59 mW/ch. (8 refs).

  1. ASD IC for the thin gap chambers in the LHC ATLAS Experiment

    CERN Document Server

    Sasaki, O

    1999-01-01

    An amplifier-shaper-discriminator (ASD) chip was designed and built for Thin Gap Chambers in the forward muon trigger system of the LHC Atlas experiment. The ASD IC uses SONY Analog Master Slice bipolar technology. The IC contains 4 channels in a QFP48 package. The gain of its first stage (preamplifier) is approximately 0.8 V/pC and output from the preamplifier is received by a shaper (main-amplifier) with a gain of 7. The baseline restoration circuit is incorporated in the main-amplifier. The threshold voltage for discriminator section is common to the 4 channels and their digital output level is LVDS- compatible. The IC also has analog output of the preamplifier. The equivalent noise charge at input capacitance of 150 pF is around 7500 electrons. The power dissipation with LDVS outputs (100 Omega load) is 59 mW/ch.

  2. Analysis of the steady-state operation of vacuum systems for fusion machines

    International Nuclear Information System (INIS)

    Roose, T.R.; Hoffman, M.A.; Carlson, G.A.

    1975-01-01

    A computer code named GASBAL was written to calculate the steady-state vacuum system performance of multi-chamber mirror machines as well as rather complex conventional multichamber vacuum systems. Application of the code, with some modifications, to the quasi-steady tokamak operating period should also be possible. Basically, GASBAL analyzes free molecular gas flow in a system consisting of a central chamber (the plasma chamber) connected by conductances to an arbitrary number of one- or two-chamber peripheral tanks. Each of the peripheral tanks may have vacuum pumping capability (pumping speed), sources of cold gas, and sources of energetic atoms. The central chamber may have actual vacuum pumping capability, as well as a plasma capable of ionizing injected atoms and impinging gas molecules and ''pumping'' them to a peripheral chamber. The GASBAL code was used in the preliminary design of a large mirror machine experiment--LLL's MX

  3. X-ray fluorescence in Member States: Austria and Sri Lanka. A new attachment module for secondary target excitation with sample changer and vacuum chamber

    International Nuclear Information System (INIS)

    Wobrauschek, P.; Smolek, S.; Streli, C.; Waduge, V.A.; Seneviratne, S.

    2009-01-01

    A new secondary target attachment vacuum chamber was developed, designed and constructed at the Atomic Institute of Vienna Technical University X ray Laboratory and installed at the Atomic Energy Authorities, Colombo, Sri Lanka. The prerequisites were that the new system had to fit physically next to the Wobistrax TXRF spectrometer and to use the same existing X ray tube and an existing uplooking LN2 cooled Si(Li) detector. This new spectrometer replaces a simple secondary target system previously installed. The new system offers a 10 position sample changer integrated in a vacuum chamber. The secondary targets are exchangeable, and Mo, Zr, Ti, Al, KBr and Teflon as Barkla polarizer are available. The system is designed for the emission-transmission method for quantification but can also be used for air filter samples where the thin film model for the quantification is applicable

  4. High efficient vacuum arc plant for coating deposition

    International Nuclear Information System (INIS)

    Aksenov, I.I.; Belous, V.A.

    2008-01-01

    A number of progressive technical solutions are used in the 'Bulat-9' machine designed for vacuum arc coating deposition. The features of the machine are: a dome shaped working chamber that allows to 'wash' its inner surfaces with hot nitrogen or argon gas; a system of automatic loading/unloading of articles to be treated into the chamber through its bottom; shielding of the inner surfaces of the chamber by heated panels; improved vacuum arc plasma sources including filtered one; four ported power supply for the vacuum arc discharges; LC oscillatory circuits suppressing microarcs on the substrate; the system of automatic control of a working process. The said technical features cause the apparatus originality and novelty preserved up to-day

  5. Shiva and Argus target diagnostics vacuum systems

    International Nuclear Information System (INIS)

    Glaros, S.S.; Mayo, S.E.; Campbell, D.; Holeman, D.

    1978-09-01

    The normal operation of LLL's Argus and Shiva laser irradiation facilities demand a main vacuum system for the target chamber and a separate local vacuum system for each of the larger appendage dianostics. This paper will describe the Argus and Shiva main vacuum systems, their respective auxiliary vacuum systems and the individual diagnostics with their respective special vacuum requirements and subsequent vacuum systems. Our latest approach to automatic computer-controlled vacuum systems will be presented

  6. ATLAS Muon DCS Upgrades and Optimizations

    CERN Document Server

    Bakalis, Christos; The ATLAS collaboration

    2017-01-01

    The Muon subsystem is comprised of four detector types: Resistive Plate Chambers (RPC) and Thin Gap Chambers (TGC) for trigger purposes, and Cathode Strip Chambers (CSC) and Muon Drift Tubes (MDT) for muon track reconstruction. The MDTs cover a large area at the outer part of the detector. In total, there are over a 1’000 MDT chambers, which are made of about 350’000 tubes. The luminosity upgrade of the HL-LHC is expected to pose a serious challenge to the MDTs. The expected increase of particle flux will set new, higher standards regarding the operation and control of the chambers. A step towards optimizing the ATLAS Muon Detector Control System (DCS) was to develop several DCS tools, namely a High Luminosity vs Trip Limit panel with its accompanying scripts and managers. The ultimate goal of this tool is to protect the MDT chambers from the rising particle flux and its associated increase in chamber current. In addition to optimizing the ATLAS Muon DCS, several tasks to accommodate the newly installed B...

  7. Physicist makes muon chamber sing

    CERN Multimedia

    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...

  8. The vacuum system for insertion devices at the Advanced Photon Source

    International Nuclear Information System (INIS)

    Trakhtenberg, E.; Gluskin, E.; Den Hartog, P.; Klippert, T.; Wiemerslage, G.; Xu, S.

    1995-01-01

    A vacuum system for the insertion devices at the Advanced Photon Source was designed, and chambers of this design were successfully manufactured and tested. Three different versions of the vacuum chamber have been developed with vertical apertures of 12 mm, 8mm, and 5 mm, respectively. The chambers are fabricated by extruding 6063 aluminum alloy to form a tube with the desired internal shaped and machining the exterior to finish dimensions. The wall thickness of the completed chamber at the beam orbit position is 1 mm. The design utilizes a rigid strongback that limits deflection of the chamber under vacuum despite the thin wall. Chambers with lengths of 2.2m and 5.2 m have been fabricated. Pumping is accomplished by a combination of lumped and distributed non-evaporable getters and ion pumps. An ultimate pressure of 5.1· -11 torr was achieved with the 12-mm vertical aperture prototype. Alignment of the vacuum chamber on its support can be made with a precision of ± 25 μm in the vertical plane, which allows minimum insertion device pole gaps of 14.5 mm, 10.5 mm, and 7.5 mm

  9. Calculation of Wakefields and Higher Order Modes for the New Design of the Vacuum Chamber of the ALICE Experiment for the HL-LHC

    CERN Document Server

    Wanzenberg, Rainer; CERN. Geneva. ATS Department

    2016-01-01

    The High Luminosity Large Hadron Collider (HL-LHC) project was started with the goal to extend the discovery potential of the Large Hadron Collider (LHC). The HL-LHC study implies also an upgraded dimensions of the ALICE beam pipe. The trapped monopole and dipole Higher Order Modes (HOMs) and the short range wakefields for the new design of the ALICE vacuum chamber were calculated with help of the computer codes MAFIA and ECHO2D. The results of the short range wakefields calculations and the HOMs calculations for the ALICE vacuum chamber with new dimensions are presented in this report. The short range wakefields are presented in terms of longitudinal and transverse wake potentials and also in terms of loss and kick parameters. The frequency, the loss parameter, the R/Q and the Qvalues and also power loss parameters are presented as result of the HOMs calculations and can be converted into impedance values.

  10. DC photogun vacuum characterization through photocathode lifetime studies

    International Nuclear Information System (INIS)

    Marcy Stutzman; Joseph Grames; Matt Poelker; Kenneth Surles-Law; Philip Adderley

    2007-01-01

    Excellent vacuum is essential for long photocathode lifetimes in DC high voltage photoelectron guns. Vacuum Research at Thomas Jefferson National Accelerator Facility has focused on characterizing the existing vacuum systems at the CEBAF polarized photoinjector and on quantifying improvements for new systems. Vacuum chamber preprocessing, full activation of NEG pumps and NEG coating the chamber walls should improve the vacuum within the electron gun, however, pressure measurement is difficult at pressures approaching the extreme-high-vacuum (XHV) region and extractor gauge readings are not significantly different between the improved and original systems. The ultimate test of vacuum in a DC high voltage photogun is the photocathode lifetime, which is limited by the ionization and back-bombardment of residual gasses. Discussion will include our new load-locked gun design as well as lifetime measurements in both our operational and new photo-guns, and the correlations between measured vacuum and lifetimes will be investigated

  11. Simulated Field Trials Using an Indoor Aerosol Test Chamber

    National Research Council Canada - National Science Library

    Semler, D. D; Roth, A. P; Semler, K. A; Nolan, P. M

    2004-01-01

    .... In this method, the aerosol chamber control software manipulates circulation fan speeds, chamber vacuum and agent spray times to produce a simulated dynamic cloud within the aerosol test chamber...

  12. Simulated Field Trials Using An Indoor Aerosol Test Chamber

    National Research Council Canada - National Science Library

    Semler, D. D; Roth, A. P; Semler, K. A; Nolan, P. M

    2004-01-01

    .... In this method, the aerosol chamber control software manipulates circulation fan speeds, chamber vacuum and agent spray times to produce a simulated dynamic cloud within the aerosol test chamber...

  13. Vacuum system for the LBL Advanced Light Source (ALS)

    International Nuclear Information System (INIS)

    Kennedy, K.; Henderson, T.; Meneghetti, J.

    1989-03-01

    A 1.5 to 1.9 GeV synchrotron light source is being built at LBL. The vacuum system is designed to permit most synchrotron photons to escape the electron channel and be absorbed in an antechamber. The gas generated by the photons hitting the absorbers in the antechambers will be pumped by titanium sublimation pumps located directly under the absorbers. The electron channel and the antechamber are connected by a 10-mm-high slot that offers good electrodynamic isolation of the two chambers of frequencies affecting the store electron orbit. Twelve 10-meter-long vessels constitute the vacuum chambers for all the lattice magnets. Each chamber will be machined from two thick plates of 5083-H321 aluminum and welded at the perimeter. Machining both the inside and outside of the vacuum chamber permits the use of complex and accurate surfaces. The use of thick plates allows flanges to be machined directly into the wall of each chamber, thus avoiding much welding. 1 ref., 3 figs

  14. Material-controlled dynamic vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1996-10-08

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

  15. Radiation-controlled dynamic vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1995-07-18

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber that includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

  16. ATLAS RPC performance on a dedicated cosmic ray test-stand

    International Nuclear Information System (INIS)

    Liberti, B.; Aielli, G.; Camarri, P.; Cardarelli, R.; Corradi, M.; Di Ciaccio, A.; Di Stante, L.; Palummo, L.; Pastori, E.; Salamon, A.; Santonico, R.; Solfaroli, E.

    2008-01-01

    596 RPC chambers have been assembled in the ATLAS Muon Spectrometer, covering a 7300 m 2 sensitive area with 355.000 read out channels. 1116 RPC Units were produced and tested before integration and installation on the experiment [A. Aloisio et al., 'The trigger chambers of the ATLAS muon spectrometer: production and tests', Nuclear Instruments and Methods A535 (2004) 265-271]. 192 ATLAS RPCs, the Barrel Outer Large (BOL) units were tested in INFN Roma Tor Vergata test stand

  17. Robust Low Cost Liquid Rocket Combustion Chamber by Advanced Vacuum Plasma Process

    Science.gov (United States)

    Holmes, Richard; Elam, Sandra; Ellis, David L.; McKechnie, Timothy; Hickman, Robert; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Next-generation, regeneratively cooled rocket engines will require materials that can withstand high temperatures while retaining high thermal conductivity. Fabrication techniques must be cost efficient so that engine components can be manufactured within the constraints of shrinking budgets. Three technologies have been combined to produce an advanced liquid rocket engine combustion chamber at NASA-Marshall Space Flight Center (MSFC) using relatively low-cost, vacuum-plasma-spray (VPS) techniques. Copper alloy NARloy-Z was replaced with a new high performance Cu-8Cr-4Nb alloy developed by NASA-Glenn Research Center (GRC), which possesses excellent high-temperature strength, creep resistance, and low cycle fatigue behavior combined with exceptional thermal stability. Functional gradient technology, developed building composite cartridges for space furnaces was incorporated to add oxidation resistant and thermal barrier coatings as an integral part of the hot wall of the liner during the VPS process. NiCrAlY, utilized to produce durable protective coating for the space shuttle high pressure fuel turbopump (BPFTP) turbine blades, was used as the functional gradient material coating (FGM). The FGM not only serves as a protection from oxidation or blanching, the main cause of engine failure, but also serves as a thermal barrier because of its lower thermal conductivity, reducing the temperature of the combustion liner 200 F, from 1000 F to 800 F producing longer life. The objective of this program was to develop and demonstrate the technology to fabricate high-performance, robust, inexpensive combustion chambers for advanced propulsion systems (such as Lockheed-Martin's VentureStar and NASA's Reusable Launch Vehicle, RLV) using the low-cost VPS process. VPS formed combustion chamber test articles have been formed with the FGM hot wall built in and hot fire tested, demonstrating for the first time a coating that will remain intact through the hot firing test, and with

  18. Contamination Control Assessment of the World's Largest Space Environment Simulation Chamber

    Science.gov (United States)

    Snyder, Aaron; Henry, Michael W.; Grisnik, Stanley P.; Sinclair, Stephen M.

    2012-01-01

    The Space Power Facility s thermal vacuum test chamber is the largest chamber in the world capable of providing an environment for space simulation. To improve performance and meet stringent requirements of a wide customer base, significant modifications were made to the vacuum chamber. These include major changes to the vacuum system and numerous enhancements to the chamber s unique polar crane, with a goal of providing high cleanliness levels. The significance of these changes and modifications are discussed in this paper. In addition, the composition and arrangement of the pumping system and its impact on molecular back-streaming are discussed in detail. Molecular contamination measurements obtained with a TQCM and witness wafers during two recent integrated system tests of the chamber are presented and discussed. Finally, a concluding remarks section is presented.

  19. Secondary magnetic field harmonics dependence on vacuum beam chamber geometry

    Directory of Open Access Journals (Sweden)

    S. Y. Shim

    2013-08-01

    Full Text Available The harmonic magnetic field properties due to eddy currents have been studied with respect to the geometry of the vacuum beam chamber. We derived a generalized formula enabling the precise prediction of any field harmonics generated by eddy currents in beam tubes with different cross-sectional geometries. Applying our model to study the properties of field harmonics in beam tubes with linear dipole magnetic field ramping clearly proved that the circular cross section tube generates only a dipole field from eddy currents. The elliptic tube showed noticeable magnitudes of sextupole and dipole fields. We demonstrate theoretically that it is feasible to suppress the generation of the sextupole field component by appropriately varying the tube wall thickness as a function of angle around the tube circumference. This result indicates that it is possible to design an elliptical-shaped beam tube that generates a dipole field component with zero magnitude of sextupole. In a rectangular-shaped beam tube, one of the selected harmonic fields can be prevented if an appropriate wall thickness ratio between the horizontal and vertical tube walls is properly chosen. Our generalized formalism can be used for optimization of arbitrarily complex-shaped beam tubes, with respect to suppression of detrimental field harmonics.

  20. Vacuum system design for the PEP-II B Factory High-Energy Ring

    International Nuclear Information System (INIS)

    Perkins, C.; Bostic, D.; Daly, E.

    1994-06-01

    The design of the vacuum system for the PEP-II B Factory High-Energy Ring is reviewed. The thermal design and vacuum requirements are particularly challenging in PEP-II due to high stored beam currents up to 3.0 amps in 1658 bunches. The vacuum chambers for the HER arcs are fabricated by electron beam welding extruded copper sections up to 6 m long. Design of these chambers and the vacuum PumPing configuration is described with results from vacuum and thermal analyses

  1. Vacuum guidelines for ISA insertions

    International Nuclear Information System (INIS)

    Edwards, D. Jr.

    1976-01-01

    Vacuum requirements place design restrictions on the ISA insertions. The vacuum tube diameter, given a distance L between pumps, is determined by the desorption of molecules from the wall under the impact of ions created by the beam, whereas the thickness of the tube must be sufficient to prevent collapse. In addition, the entire vacuum chamber must be able to be baked out at approximately 200 0 C

  2. A First-Level Muon Trigger Based on the ATLAS Muon Drift Tube Chambers With High Momentum Resolution for LHC Phase II

    CERN Document Server

    Richter, R; The ATLAS collaboration; Ott, S; Kortner, O; Fras, M; Gabrielyan, V; Danielyan, V; Fink, D; Nowak, S; Schwegler, P; Abovyan, S

    2014-01-01

    The Level-1 (L1) trigger for muons with high transverse momentum (pT) in ATLAS is based on chambers with excellent time resolution, able to identify muons coming from a particular beam crossing. These trigger chambers also provide a fast pT-measurement of the muons, the accuracy of the measurement being limited by the moderate spatial resolution of the chambers along the deflecting direction of the magnetic field (eta-coordinate). The higher luminosity foreseen for Phase-II puts stringent limits on the L1 trigger rates, and a way to control these rates would be to improve the spatial resolution of the triggering system, drastically sharpening the turn-on curve of the L1 trigger. To do this, the precision tracking chambers (MDT) can be used in the L1 trigger, provided the corresponding trigger latency is increased as foreseen. The trigger rate reduction is accomplished by strongly decreasing the rate of triggers from muons with pT lower than a predefined threshold (typically 20 GeV), which would otherwise trig...

  3. Cosmic ray runs acquired with ATLAS muon stations

    CERN Multimedia

    Cerutti, F.

    Starting in the fall 2005 several cosmic ray runs have been acquired in the ATLAS pit with six muon stations. These were three large outer and three large middle chambers of the feet sector (sector 13) that have been readout in the ATLAS cavern. In the first data taking period the trigger was based on two large scintillators (~300x30 cm2) positioned in sector 13 just below the large chambers. In this first run the precision chambers (the Monitored Drift Tubes) were operated in a close to final configuration. Typical trigger rates with this setup were of the order of 1 Hz. Several data sets of 10k events were acquired with final electronics up to the muon ROD and analysed with ATHENA-based software. These data allowed the first checks of the functionality and efficiency of the MDT stations in the ATLAS pit and the first measurement of the FE electronics noise in the ATLAS environment. A few event were also collected in a combined run with the TILE barrel calorimeter. An event display of a cosmic ray a...

  4. RGA studies on aluminium chambers for transport line-2 of CLIC facility at CERN

    International Nuclear Information System (INIS)

    Kumar, K.V.A.N.P.S.; Yadav, Praveen Kumar; Sindal, B.K.; Tiwari, S.K.; Tripti, B.; Shukla, S.K.

    2009-01-01

    The Aluminium Chambers for Transport Line-2 (TL-2) of CLIC (Compact Linear Collider) facility were developed by RRCAT, Indore under the CERN-DAE collaboration work. The ultimate vacuum required for these chambers is in 10 -10 mbar range. The design and fabrication of the chambers were done at Workshop-A, RRCAT, Indore. Ultra High Vacuum (UHV) Section at RRCAT, Indore was involved in qualifying tests of these chambers for their ultimate vacuum testing and the residual gas spectrum studies as per CERN requirements. The UHV testing part was established and the RGA studies were conducted using Residual Gas Analyser (RGA, 1-100 AMU range, Make: Spectra/MKS, USA). The RGAs were used for vacuum diagnostics like checking for leaks and the vacuum quality in the chambers. Using the RGA, we could also observe out the pumping speed behaviour of a UHV Gauge (Varian UHV-24 type) and the retention-cum-evaluation of captured gases by Sputter Ion Pump was also studied. In this paper, these experiences are reported during ultimate testing of TL-2 chambers for CLIC facility. (author)

  5. H2 Equilibrium Pressure with a Neg-Coated Vacuum Chamber as a Function of Temperature and H2 Concentration

    CERN Document Server

    Rossi, Adriana

    2006-01-01

    Non Evaporable Getter (NEG) coating is used in the Large Hadron Collider (LHC) room-temperature sections to ensure a low residual gas pressure for its properties of distributed pumping, low outgassing and desorption under particle bombardment; and to limit or cure electron cloud build-up due to its low secondary electron emission. In certain regions of the LHC, and in particular close to the beam collimators, the temperature of the vacuum chamber is expected to rise due to energy deposition from particle losses. Hydrogen molecules are pumped by the NEG via dissociation on the surface, sorption at the superficial sites and diffusion into the NEG bulk. In the case of hydrogen, the sorption is thermally reversible, causing the dissociation pressure to increase with NEG temperature and amount of H2 pumped. Measurements were carried out on a stainless steel chamber coated with TiZrV NEG as a function of the H2 concentration and the chamber temperature, to estimate the residual gas pressure in the collimator region...

  6. CERN Open Days 2013, Point 1 - ATLAS: ATLAS Experiment

    CERN Multimedia

    CERN Photolab

    2013-01-01

    Stand description: The ATLAS Experiment at CERN is one of the largest and most complex scientific endeavours ever assembled. The detector, located at collision point 1 of the LHC, is designed to explore the fundamental components of nature and to study the forces that shape our universe. The past year’s discovery of a Higgs boson is one of the most important scientific achievements of our time, yet this is only one of many key goals of ATLAS. During a brief break in their journey, some of the 3000-member ATLAS collaboration will be taking time to share the excitement of this exploration with you. On surface no restricted access  The exhibit at Point 1 will give visitors a chance to meet these modern-day explorers and to learn from them how answers to the most fundamental questions of mankind are being sought. Activities will include a visit to the ATLAS detector, located 80m below ground; watching the prize-winning ATLAS movie in the ATLAS cinema; seeing real particle tracks in a cloud chamber and discussi...

  7. Progress in the construction of the B0 model of the ATLAS Barrel Toroid magnet

    CERN Document Server

    Acerbi, E; Ambrosio, G; Baccaglioni, G; Broggi, F; Rossi, L; Sorbi, M; Volpini, G

    2000-01-01

    The ATLAS Barrel Toroid air-core magnet (BT) will be composed by 8 superconducting coils, each one 25 m long and 5 m wide. In order to validate the technologies and manufacturing processes, a smaller model (9 m long) of one BT coil, named B0, is now under construction. This paper presents a general overview of the B0 project status, with special regard to the components for which the LASA Lab. is responsible: (a) the aluminium-clad NbTi conductor; (b) the double coils winding and impregnation; (c) the components of the cryostat (vacuum chamber, thermal shield and suspension rod). (6 refs).

  8. Results from beam tests of a 2.4 m straw chamber

    International Nuclear Information System (INIS)

    Cizeron, R.; Fournier, D.; Noppe, J.M.; Perdereau, O.; Schaffer, A.C.

    1991-03-01

    Straw chambers have been shown to have good position resolution. By virtue of their cylindrical geometry they are capable of operating in vacuum, which opens the interesting possibility of tracking with a minimum of material. The feasibility of constructing a large surface straw chamber has been studied. A prototype chamber with 2.4 m long straws capable of operating in vacuum has been developed and tested in beams at CERN

  9. Design of a chamber for deposit of thin films by laser ablation

    International Nuclear Information System (INIS)

    Chirino O, S.

    2001-01-01

    The present work has as purpose to design a vacuum chamber, to the one that is denominated chamber of ablation, in which were carried out deposits of thin films using the well-known technique as laser ablation. To fulfill the purpose, the work has been distributed in the following way: in the chapter 1 there are discussed the generalities of the technique of ablation laser for the obtaining of materials in form of thin film, in the chapter 2 the basic concepts of the vacuum technology are mentioned that includes among other things, systems to produce vacuum and vacuum gages and in the chapter 3 the design of the chamber is presented with the accessories and specific systems. (Author)

  10. Large-scale performance studies of the Resistive Plate Chamber fast tracker for the ATLAS 1st-level muon trigger

    CERN Document Server

    Cattani, G; The ATLAS collaboration

    2009-01-01

    In the ATLAS experiment, Resistive Plate Chambers provide the first-level muon trigger and bunch crossing identification over large area of the barrel region, as well as being used as a very fast 2D tracker. To achieve these goals a system of about ~4000 gas gaps operating in avalanche mode was built (resulting in a total readout surface of about 16000 m2 segmented into 350000 strips) and is now fully operational in the ATLAS pit, where its functionality has been widely tested up to now using cosmic rays. Such a large scale system allows to study the performance of RPCs (both from the point of view of gas gaps and readout electronics) with unprecedented sensitivity to rare effects, as well as providing the means to correlate (in a statistically significant way) characteristics at production sites with performance during operation. Calibrating such a system means fine tuning thousands of parameters (involving both front-end electronics and gap voltage), as well as constantly monitoring performance and environm...

  11. Quality Management of CERN Vacuum Controls

    CERN Document Server

    Antoniotti, F; Fortescue-Beck, E; Gama, J; Gomes, P; Le Roux, P; Pereira, H F; Pigny, G

    2014-01-01

    The vacuum controls Section (TE-VSC-ICM) is in charge of the monitoring, maintenance and consolidation of the control systems of all accelerators and detectors in CERN; this represents 6 000 instruments distributed along 128 km of vacuum chambers, often of heterogeneous architectures and of diverse

  12. Vacuum pumping concepts for ETF

    International Nuclear Information System (INIS)

    Homeyer, W.G.

    1980-09-01

    The Engineering Test Facility (ETF) poses unique vacuum pumping requirements due to its large size and long burn characteristics. These requirements include torus vacuum pumping initially and between burns and pumping of neutralized gas from divertor collector chambers. It was found that the requirements could be met by compound cryopumps in which molecular sieve 5A is used as the cryosorbent. The pumps, ducts, and vacuum valves required are large but fit with other ETF components and do not require major advances in vacuum pumping technology. Several additional design, analytical, and experimental studies were identified as needed to optimize designs and provide better design definition for the ETF vacuum pumping systems

  13. Thermal Vacuum Integrated System Test at B-2

    Science.gov (United States)

    Kudlac, Maureen T.; Weaver, Harold F.; Cmar, Mark D.

    2012-01-01

    The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) Plum Brook Station (PBS) Space Propulsion Research Facility, commonly referred to as B-2, is NASA s third largest thermal vacuum facility. It is the largest designed to store and transfer large quantities of liquid hydrogen and liquid oxygen, and is perfectly suited to support developmental testing of chemical propulsion systems as well as fully integrated stages. The facility is also capable of providing thermal-vacuum simulation services to support testing of large lightweight structures, Cryogenic Fluid Management (CFM) systems, electric propulsion test programs, and other In-Space propulsion programs. A recently completed integrated system test demonstrated the refurbished thermal vacuum capabilities of the facility. The test used the modernized data acquisition and control system to monitor the facility during pump down of the vacuum chamber, operation of the liquid nitrogen heat sink (or cold wall) and the infrared lamp array. A vacuum level of 1.3x10(exp -4)Pa (1x10(exp -6)torr) was achieved. The heat sink provided a uniform temperature environment of approximately 77 K (140deg R) along the entire inner surface of the vacuum chamber. The recently rebuilt and modernized infrared lamp array produced a nominal heat flux of 1.4 kW/sq m at a chamber diameter of 6.7 m (22 ft) and along 11 m (36 ft) of the chamber s cylindrical vertical interior. With the lamp array and heat sink operating simultaneously, the thermal systems produced a heat flux pattern simulating radiation to space on one surface and solar exposure on the other surface. The data acquired matched pretest predictions and demonstrated system functionality.

  14. Performance of a First-Level Muon Trigger with High Momentum Resolution Based on the ATLAS MDT Chambers for HL-LHC

    CERN Document Server

    Gadow, P.; Kortner, S.; Kroha, H.; Müller, F.; Richter, R.

    2016-01-01

    Highly selective first-level triggers are essential to exploit the full physics potential of the ATLAS experiment at High-Luminosity LHC (HL-LHC). The concept for a new muon trigger stage using the precision monitored drift tube (MDT) chambers to significantly improve the selectivity of the first-level muon trigger is presented. It is based on fast track reconstruction in all three layers of the existing MDT chambers, made possible by an extension of the first-level trigger latency to six microseconds and a new MDT read-out electronics required for the higher overall trigger rates at the HL-LHC. Data from $pp$-collisions at $\\sqrt{s} = 8\\,\\mathrm{TeV}$ is used to study the minimal muon transverse momentum resolution that can be obtained using the MDT precision chambers, and to estimate the resolution and efficiency of the MDT-based trigger. A resolution of better than $4.1\\%$ is found in all sectors under study. With this resolution, a first-level trigger with a threshold of $18\\,\\mathrm{GeV}$ becomes fully e...

  15. Cosmic ray test system for the ATLAS thin gap chamber modules at KOBE

    CERN Document Server

    Suigmoto, T; Arataki, Y; Bando, T; Homma, Y; Ichimiya, R; Ikeno, M; Ishii, K; Ishino, M; Iwasaki, H; Kurashige, H; Mima, T; Miyazaki, Y; Nakagawa, Y; Nakaune, Y; Nozaki, M; Ohshita, H; Okumura, K; Sasaki, O; Suzuki, R; Takeda, H; Takeshita, T; Tanaka, S; Uda, J; Yokoyama, C

    2004-01-01

    Thin gap chamber modules giving function of forward muon trigger to the ATLAS detector in the LHC experiment have been constructed at High Energy Research Organization (KEK) in Japan and their performances have been checked at Kobe University. A large-scale test system specially designed for measuring uniformity of the detection efficiencies and the timing resolution of 8 TGC modules at the same time was successfully operated. Each TGC module had 72 anode wire channels and 64 cathode strip channels (in total 1088 readout channels for 8 modules). Drift tubes consisted of 12 layers (total 428 tubes), between which the TGC modules are put, determined trajectories of cosmic rays. Hit pattern and timing of all detector signals (Trigger counter. Drift tubes and TGCs) were measured by using VME modules. In regular data acquisition situation, i.e. about effective 19 Hz trigger rate from scintillation counters and 73% tracking efficiency by the drift tubes, the detection efficiency of each layer by 5 mm * 5 mm region ...

  16. External Cylindrical Nozzle with Controlled Vacuum

    Directory of Open Access Journals (Sweden)

    V. N. Pil'gunov

    2015-01-01

    Full Text Available There is a developed design of the external cylindrical nozzle with a vacuum camera. The paper studies the nozzle controllability of flow rate via regulated connection of the evacuated chamber to the atmosphere through an air throttle. Working capacity of the nozzle with inlet round or triangular orifice are researched. The gap is provided in the nozzle design between the external wall of the inlet orifice and the end face of the straight case in the nozzle case. The presented mathematical model of the nozzle with the evacuated chamber allows us to estimate the expected vacuum amount in the compressed section of a stream and maximum permissible absolute pressure at the inlet orifice. The paper gives experimental characteristics of the fluid flow process through the nozzle for different values of internal diameter of a straight case and an extent of its end face remoteness from an external wall of the inlet orifice. It estimates how geometry of nozzle constructive elements influences on the volume flow rate. It is established that the nozzle capacity significantly depends on the shape of inlet orifice. Triangular orifice nozzles steadily work in the mode of completely filled flow area of the straight case at much more amounts of the limit pressure of the flow. Vacuum depth in the evacuated chamber also depends on the shape of inlet orifice: the greatest vacuum is reached in a nozzle with the triangular orifice which 1.5 times exceeds the greatest vacuum with the round orifice. Possibility to control nozzle capacity through the regulated connection of the evacuated chamber to the atmosphere was experimentally estimated, thus depth of flow rate regulation of the nozzle with a triangular orifice was 45% in comparison with 10% regulation depth of the nozzle with a round orifice. Depth of regulation calculated by a mathematical model appeared to be much more. The paper presents experimental dependences of the flow coefficients of nozzle input orifice

  17. Lowering the first ATLAS toroid

    CERN Document Server

    Maximilien Brice

    2004-01-01

    The ATLAS detector on the LHC at CERN will consist of eight toroid magnets, the first of which was lowered into the cavern in these images on 26 October 2004. The coils are supported on platforms where they will be attached to form a giant torus. The platforms will hold about 300 tonnes of ATLAS' muon chambers and will envelop the inner detectors.

  18. Construction and performance of the sTGC and MicroMegas chambers for ATLAS NSW upgrade

    Science.gov (United States)

    Sekhniaidze, G.

    2017-03-01

    The innermost stations of the current ATLAS muon end-cap system, the Small Wheels, must be upgraded in 2019 to retain their good precision tracking and trigger capabilities in the high background environment expected with the upcoming luminosity increase of the LHC. The New Small Wheels (NSW) will employ two chamber technologies: eight layers of MicroMegas (MM) arranged in two quadruplets, sandwiched between two quadruplets of small-strip Thin Gap Chambers (sTGC) for a total of about 2400 m2 of detection planes. All quadruplets have trapezoidal shapes with surface areas between 1 and 3 m2. Both MM and sTGC systems will independently provide trigger and tracking capabilities. The readout boards are industrially produced for both technologies and an accurate quality control is needed. In order to achieve a 15% transverse momentum resolution for 1 TeV muons, in addition to an excellent intrinsic resolution (010 μm), the mechanical precision of each plane of the assembled modules must be as good as 30 μm along the precision coordinate and 80 μm perpendicular to the chamber. In 2016 the milestone to build the first module-0 prototypes for both technologies has been reached. The construction procedure of the module-0 detectors will be reviewed, along with the results of the quality control checks performed during construction. The module-0 have been measured and subjected to a thorough validation. Results obtained with high-energy particle beams, with cosmic rays and with X-rays will be presented.

  19. SPEAKING IN LIGHT - Jupiter radio signals as deflections of light-emitting electron beams in a vacuum chamber

    Science.gov (United States)

    Petrovic, K.

    2015-10-01

    Light emitting electron beam generated in a vacuum chamber is used as a medium for visualizing Jupiter's electromagnetic radiation. Dual dipole array antenna is receiving HF radio signals that are next amplified to radiate a strong electromagnetic field capable of influencing the propagation of electron beam in plasma. Installation aims to provide a platform for observing the characteristics of light emitting beam in 3D, as opposed to the experiments with cathode ray tubes in 2-dimensional television screens. Gas giant 'speaking' to us by radio waves bends the light in the tube, allowing us to see and hear the messages of Jupiter - God of light and sky.

  20. A Python extension to the ATLAS online software for the thin gap chamber trigger system

    CERN Document Server

    Maeno, Tadashi; Komatsu, Satoru; Nakayoshi, Kazuo; Yasu, Yoshiji

    2004-01-01

    A Python extension module for A Toroidal LHC Apparatus (ATLAS) Online Software has been developed for the Thin Gap Chamber (TGC) trigger system. Python is an interactive scripting language including built- in high-level libraries, and provides an easy way to build Web applications. These features are not included in the Online Software, and are important in developing test software for the TGC trigger system. The Python extension module is designed and implemented using a C++ library, "Boost.Python." We have developed a Web application using the extension module and Zope (a Python-based Web application server), which allows one to monitor the TGC trigger system from anywhere in the world. The functionalities of the Python extension module and its application for the TGC trigger system are presented. 7 Refs.

  1. ELETTRA vacuum system

    International Nuclear Information System (INIS)

    Bernardini, M.; Daclon, F.; Giacuzzo, F.; Miertusova, J.; Pradal, F.; Kersevan, R.

    1993-01-01

    Elettra is a third-generation synchrotron light source which is being built especially for the use of high brilliance radiation from insertion devices and bending magnets. The UHV conditions in a storage ring lead to a longer beam lifetime - one of the most important criterion. The Elettra vacuum system presents some pecularities which cannot be found in any already existing machine. The final version of bending magnet vacuum chamber is presented. After chemical and thermal conditioning the specific outgassing rate of about 1.5e-12 Torr. liters sec -1 cm -2 was obtained. A microprocessor-controlled system has been developed to perform bake-out at the uniform temperature. The etched-foil type heaters are glued to the chamber and Microtherm insulation is used. UHV pumps based on standard triode sputter-ion pumps were modified with ST 707 NEG (Non Evaporable Getter) modules. A special installation enables the resistive activation of getters and significantly increases pumping speed for hydrogen and other residual gases (except methane and argon). All these technological innovations improve vacuum conditions in Elettra storage ring and consequently also the other parameters of the light source

  2. Design and fabrication of the vacuum systems for TPS pulsed septum magnets

    Energy Technology Data Exchange (ETDEWEB)

    Chan, C.K.; Chang, C.C.; Chen, C.L.; Yang, C.S.; Chen, C.S.; Lin, F.Y.; Chen, J.R.

    2014-11-01

    Three in-air pulsed septum magnets were developed to inject and extract electron beams for the 3 GeV synchrotron facility, the Taiwan Photon Source (TPS). The vacuum chamber is a novel combined aluminium-stainless steel design, using a bimetallic flange to connect the two material types. To evaluate the vacuum performances of these vacuum chambers, we set up a test bench at which we simultaneously measure the rates of thermal outgassing of the aluminium chamber and the septum tube with a throughput method. The test result indicates that the rate q{sub 72} of thermal outgassing measured after 1 day from baking at 150 °C was 1×10{sup −13} mbar L s{sup −1} cm{sup −2}. The magnetic leakage measurements show the combination of conductor slitting, magnetic shielding and the aluminium vacuum chamber reduce the peak value of the leakage field integral to ∼10 G cm along the trajectory of the stored beam.

  3. Design and fabrication of the vacuum systems for TPS pulsed septum magnets

    Science.gov (United States)

    Chan, C. K.; Chang, C. C.; Chen, C. L.; Yang, C. S.; Chen, C. S.; Lin, F. Y.; Chen, J. R.

    2014-11-01

    Three in-air pulsed septum magnets were developed to inject and extract electron beams for the 3 GeV synchrotron facility, the Taiwan Photon Source (TPS). The vacuum chamber is a novel combined aluminium-stainless steel design, using a bimetallic flange to connect the two material types. To evaluate the vacuum performances of these vacuum chambers, we set up a test bench at which we simultaneously measure the rates of thermal outgassing of the aluminium chamber and the septum tube with a throughput method. The test result indicates that the rate q72 of thermal outgassing measured after 1 day from baking at 150 °C was 1×10-13 mbar L s-1 cm-2. The magnetic leakage measurements show the combination of conductor slitting, magnetic shielding and the aluminium vacuum chamber reduce the peak value of the leakage field integral to ~10 G cm along the trajectory of the stored beam.

  4. Modification of Ultra-High Vacuum Surfaces Using Free Radicals

    CERN Document Server

    Vorlaufer, G

    2002-01-01

    In ultra-high vacuum systems outgassing from vacuum chamber walls and desorption of surface adsorbates are usually the factors which determine pressure and residual gas composition. In particular in beam vacuum systems of accelerators like the LHC, where surfaces are exposed to intense synchrotron radiation and bombardment by energetic ions and electrons, surface properties like the molecular desorption yield or secondary electron yield can strongly influence the performance of the accelerator. Well-established treatment methods like vacuum bake-out or glow-discharge cleaning have been successfully applied in the past to condition ultra-high vacuum surfaces, but these methods are sometimes difficult to carry out, for example if the vacuum chambers are not accessible. In this work, an alternative treatment method is investigated. This method is based on the strong chemical reactivity of free radicals, electrically neutral fragments of molecules. Free radicals (in the case of this work, nitrogen and oxygen radi...

  5. 29th November 2011 - Czech Parliament Members of the Social Committee of the Lower Chamber visiting CERN permanent exhibition Microcosm and ATLAS visitor centre with Senior Czech Physicist and ILO I. Lehraus.

    CERN Multimedia

    Jean-Claude Gadmer

    2011-01-01

    29th November 2011 - Czech Parliament Members of the Social Committee of the Lower Chamber visiting CERN permanent exhibition Microcosm and ATLAS visitor centre with Senior Czech Physicist and ILO I. Lehraus.

  6. Design and Construction of Large Size Micromegas Chambers for the ATLAS Upgrade of the Muon Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-07-01

    Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. A total surface of about 150 m{sup 2} of the forward regions of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each module extends over a surface from 2 to 3 m{sup 2} for a total active area of 1200 m{sup 2}. Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS end-cap muon tracking system in the 2018/19 shutdown. In order to achieve a 15% transverse momentum resolution for 1 TeV muons, in addition to an excellent intrinsic resolution, the mechanical precision of each plane of the assembled module must be as good as 30 μm along the precision coordinate and 80 μm perpendicular to the chamber. In the prototyping towards the final configuration two similar quadruplets with dimensions 1.2 x 0.5 m{sup 2} have been built with the same structure as foreseen for the NSW upgrade. It represents the first example of a Micromegas quadruplet ever built, realized using the resistive-strip technology and decoupling the amplification mesh from the readout structure. All readout planes are segmented into strips with a pitch of 400 μm for a total of 4096 strips. In two of the four planes the strips are inclined by 1.5 deg. and provide a measurement of the second coordinate. The design and construction procedure of the Micromegas modules will be presented, as well as the design for the assembly of modules onto the New Small Wheel. Emphasis will be given on the methods developed to achieve the challenging mechanical precision. Measurements of deformation on chamber prototypes as a function of thermal gradients, gas over-pressure and internal stress (mesh tension and module fixation on supports) will be also shown in comparison to simulation. These tests were essential in the development of the final design in order to minimize the

  7. ATLAS detector records its first curved muon

    CERN Multimedia

    2007-01-01

    The barrel muon spectrometer of the ATLAS detector has acquired its first cosmic event in a magnetic field produced by the barrel toroid magnet. This was an important test of the chambers in their final configurations, and marked the first triggering and measurement of curved cosmic ray muons in ATLAS.

  8. Systems and methods for analyzing liquids under vacuum

    Science.gov (United States)

    Yu, Xiao-Ying; Yang, Li; Cowin, James P.; Iedema, Martin J.; Zhu, Zihua

    2013-10-15

    Systems and methods for supporting a liquid against a vacuum pressure in a chamber can enable analysis of the liquid surface using vacuum-based chemical analysis instruments. No electrical or fluid connections are required to pass through the chamber walls. The systems can include a reservoir, a pump, and a liquid flow path. The reservoir contains a liquid-phase sample. The pump drives flow of the sample from the reservoir, through the liquid flow path, and back to the reservoir. The flow of the sample is not substantially driven by a differential between pressures inside and outside of the liquid flow path. An aperture in the liquid flow path exposes a stable portion of the liquid-phase sample to the vacuum pressure within the chamber. The radius, or size, of the aperture is less than or equal to a critical value required to support a meniscus of the liquid-phase sample by surface tension.

  9. National Ignition Facility Target Chamber

    International Nuclear Information System (INIS)

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

    2000-01-01

    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

  10. Vacuum pipe for e+e- interactions

    International Nuclear Information System (INIS)

    Hoard, C.T.

    1982-10-01

    The design, fabrication and testing of the beryllium vacuum chamber within the Mark II detector at SLAC is described. The Be chamber encloses one interaction point of the PEP circulating ring and is a part of its beam pipe. The Be chamber is captured within the Secondary Vertex Detector (SVD), a drift chamber, which is in turn centered in the Mark II drift chamber. Both ends of the beryllium pipe are brazed to aluminum/stainless transitions for connection to stainless steel bellows. A concentric radiation-screen liner of titanium foil runs the full length of the beryllium pipe

  11. Modelling of the space-to-drift-time relationship of the ATLAS monitored drift-tube chambers in the presence of magnetic fields

    International Nuclear Information System (INIS)

    Dubbert, J.; Horvat, S.; Khartchenko, D.; Kortner, O.; Kotov, S.; Kroha, H.; Manz, A.; Nikolaev, K.; Rauscher, F.; Richter, R.; Staude, A.; Valderanis, Ch.

    2007-01-01

    The ATLAS muon spectrometer uses tracking chambers consisting of up to 5m long drift tubes filled with Ar:CO 2 (93:7) at 3bar. The chambers are run in a average toroidal magnetic field of 0.4T created by 8 air core coils. They provide a track-point accuracy of 40μm if the space-to-drift-time relationship r(t) is known with 20μm accuracy. The magnetic field B influences the electron drift inside the tubes: the maximum drift time t max =700ns increases by ∼70ns/T 2 B 2 . B varies by up to +/-0.4T along the tubes of the chambers mounted near the magnet coils which translates into a variation of t max of up to 45ns. The dependence of r(t) on B must be taken into account. Test-beam measurements show that the electron drift in case of B 0 can be modelled with the required accuracy by a Langevin equation with a friction term which is slightly non-linear in the drift velocity

  12. UHV testing of spare straight section chambers of Indus-2

    International Nuclear Information System (INIS)

    Tiwari, S.K.; Ratnakala, K.C.; Sridhar, R.; Bhange, N.J.; Netram; Shukla, S.K.

    2015-01-01

    The vacuum system of Synchrotron Radiation Source, Indus-2, in RRCAT has been functioning up to the mark, continuously for last 10 years. To continue the same trouble-free functioning, it was planned to procure spares for all critical vacuum components, test for UHV performance and keep ready for installation, in case of requirement. As a part of this planning, fifteen chambers made of Aluminium alloy (6063 T6), procured as spare straight section chambers for Indus-2, and were tested for UHV performance. They were tested in batches of 2 or 3 chambers, depending upon their length, and the similar testing-procedure was followed. This paper narrates the tests carried out, and the results obtained. Ultimate vacuum in the range (2 to 9) x 10 -10 mbar was achieved. (author)

  13. Radial force on the vacuum chamber wall during thermal quench in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Pustovitov, V. D., E-mail: pustovitov-vd@nrcki.ru [National Research Centre Kurchatov Institute (Russian Federation)

    2015-12-15

    The radial force balance during a thermal quench in tokamaks is analyzed. As a rule, the duration τ{sub tp} of such events is much shorter than the resistive time τ{sub w} of the vacuum chamber wall. Therefore, the perturbations of the magnetic field B produced by the evolving plasma cannot penetrate the wall, which makes different the magnetic pressures on its inner and outer sides. The goal of this work is the analytical estimation of the resulting integral radial force on the wall. The plasma is considered axially symmetric; for the description of radial forces on the wall, the results of V.D. Shafranov’s classical work [J. Nucl. Energy C 5, 251 (1963)] are used. Developed for tokamaks, the standard equilibrium theory considers three interacting systems: plasma, poloidal field coils, and toroidal field coils. Here, the wall is additionally incorporated with currents driven by ∂B/∂t≠0 accompanying the fast loss of the plasma thermal energy. It is shown that they essentially affect the force redistribution, thereby leading to large loads on the wall. The estimates prove that these loads have to be accounted for in the disruptive scenarios in large tokamaks.

  14. Design consideration on the synchrotron ultrahigh vacuum system

    International Nuclear Information System (INIS)

    Tsujikawa, H.; Chida, K.; Mizobuchi, A.; Miyahara, A.

    1982-01-01

    Ultrahigh vacuum production for the high-energy heavy-ion accelerator poses special problems concerning beam-gas molecule and beam-wall interactions. In this paper, summary of the TARN ultrahigh vacuum system and design criteria of the synchrotron ultrahigh vacuum system are presented. On-beam pressure of 4 x 10 -11 Torr is achieved in the TARN ultrahigh vacuum system, of which experiences through the construction and the operation are described and discussed. With emphasis on the application of newly developed technique in the fabrication of vacuum chamber and ultrahigh vacuum pump for the synchrotron ultrahigh vacuum system. (author)

  15. TORE SUPRA vacuum vessel and shield manufacturing

    International Nuclear Information System (INIS)

    Blateyron, J.; Lepez, R.

    1984-01-01

    TORE SUPRA vacuum vessel and vacuum chamber shield manufacturing in progress at Jeumont-Schneider consists of three main phases: - Detail engineering and manufacturing fixture construction; - Prototype section manufacturing and process preparation; - Construction of the 6 production modules. The welding techniques adopted, call for three special automatic processes: TIG, MIG and PLASMA welding which guarantee mechanical strength, vacuum tightness and absence of distortion. Production of the modules began July 1984. (author)

  16. Heavy-ion induced desorption of a TiZrV coated vacuum chamber bombarded with 5 MeV/u Ar8+ beam at grazing incidence

    International Nuclear Information System (INIS)

    Hedlund, E.; Malyshev, O. B.; Westerberg, L.; Krasnov, A.; Semenov, A. S.; Leandersson, M.; Zajec, B.; Kollmus, H.; Bellachioma, M. C.; Bender, M.; Kraemer, A.; Reich-Sprenger, H.

    2009-01-01

    TiZrV nonevaporable getter (NEG) coated vacuum chambers is a new vacuum technology which is already used in many particle accelerators worldwide. This coating is also of interest for heavy-ion accelerator vacuum chambers. Heavy-ion desorption yields from an activated as well as a CO saturated NEG coated tube have been measured with 5 MeV/u Ar 8+ beam. The sticking probability of the NEG film was obtained by using the partial pressure ratios on two sides of the NEG coated tube. These ratios were compared to results of modeling of the experimental setup with test particle Monte Carlo and angular coefficient methods. The partial pressures inside the saturated NEG coated tube bombarded with heavy ions were up to 20 times larger than those inside the activated one. However, the partial pressure of methane remained the same. The value of the total desorption yield from the activated NEG coated tube is 2600 molecules/ion. The desorption yields after saturation for CH 4 , H 2 , and CO 2 were found to be very close to the yields measured after the activation, while CO increased by up to a factor of 5. The total desorption yield for the saturated tube is up to 7000 molecules/ion. The large value of the desorption yield of the activated NEG coated tube, an order of magnitude higher than the desorption yield from a stainless steel tube at normal incident angle, could be explained by the grazing incident angle

  17. The design and structure of the ultra-high vacuum system of HIRFL-CSR

    International Nuclear Information System (INIS)

    Yang Xiaotian; Zhang Junhui; Zhang Xinjun; Meng Jun; Zhan Wenlong

    2001-01-01

    To minimize the beam loss due to charge exchange of very heavy ions with the residual gas molecules, ultra-high vacuum of 6x10 -9 Pa is required for the HIRFL-CSR facility, which is the lowest pressure in a large vacuum system in China up to now. The total length of the system is about 450 meters and the total inner surface is about 263 square meters. More than 500 standard vacuum components are needed and more than 400 different chambers have to be manufactured. A lot of researches have been down to try to find out the experiences to obtain the required pressure. In this article the following contents are described: the layout of the system; the structure of main vacuum chambers; the treatment method to reduce the outgassing rate of the chamber wall surfaces; vacuum equipment; pressure distribution and the progress of the system

  18. The Aperture and Layout of the LHC Extraction Septa and TCDS Diluter with an Enlarged MSDC Vacuum Chamber

    CERN Document Server

    Goddard, B

    2003-01-01

    The LHC beam dumping system must safely abort the LHC beams over the whole energy range, under all realistically possible fault conditions. These include normal operation, failure of machine elements and also abnormal performance of subsystems of the beam dumping system itself. To avoid unnecessary irradiation and even equipment damage, the MSD extraction septa must provide sufficient aperture both for the circulating and extracted beams. In order to satisfy this requirement, a modified (enlarged) vacuum chamber design will be used for the limiting MSDC septa. The analysis of the available apertures is presented, with emphasis on the dependence on the local orbit and beam emittance.

  19. Ultra high vacuum systems for accelerators

    International Nuclear Information System (INIS)

    Loefgren, P.

    2001-01-01

    Full text: In order to perform controlled, stable, and reproducible experiments, several research areas today require very low pressures. Maybe the most important example is the research that is performed in storage rings and accelerators where the lifetime and stability of particle beams depends critically on the vacuum conditions. Although the vacuum requirements ultimately depend on the kind of experiments that is performed, the studies of more and more rare and exotic species in storage rings and accelerators today pushes the demands on the vacuum conditions towards lower and lower pressures. The final pressure obtained in the vacuum system can often be the key factor for the outcome of an experiment. Pioneering work in vacuum technology has therefore often been performed at storage rings and accelerator facilities around the world. In order to reach pressures in the low UHV regime and lower (below 10 -11 mbar), several aspects have to be considered which implies choosing the proper materials, pumps and vacuum gauges. In the absence of gases inleaking from the outside, the rate of gas entering a vacuum system is determined by the release of molecules adsorbed on the surfaces and the outgassing from the bulk of the vacuum chamber walls. This means that the choice of material and, equally important, the pre treatment of the material, must be such that these rates are minimised. Today the most widely used material for vacuum applications are stainless steel. Besides its many mechanical advantages, it is resistant to corrosion and oxidation. If treated correctly the major gas source in a stainless steel chamber is hydrogen outgassing from the chamber walls. The hydrogen outgassing can be decreased by vacuum firing at 950 deg. C under vacuum. In addition to choosing the right materials the choice of vacuum pumps is important for the final pressure. Since no vacuum pump is capable of taking care of all kinds of gases found in the rest gas at pressures below 10 -11

  20. Manufacture of the straight section chambers for the SPring-8 storage ring

    International Nuclear Information System (INIS)

    Watanabe, K.; Saeki, H.; Sakaue, H.; Ohkuma, H.; Be, S.H.; Oishi, M.; Tuchiya, M.; Nishidono, T.

    1995-01-01

    To carry out the performance test of the vacuum system, we manufactured three different straight section chambers prior to the manufacture of the 48 cell full scale vacuum systems. One of three straight section chambers contains only downstream end absorber, while the other two contain a downstream end absorber, upstream end bellows and a photon beam extraction duct. In this paper, the manufacture of these chambers and their assemblies are described in detail. (author). 1 ref., 3 figs., 3 tabs

  1. Proposal to negotiate a collaboration agreement for the design and prototyping of a machine for laser treatment of metallic vacuum chamber walls for electron cloud mitigation at the High Luminosity LHC

    CERN Document Server

    2016-01-01

    Proposal to negotiate a collaboration agreement for the design and prototyping of a machine for laser treatment of metallic vacuum chamber walls for electron cloud mitigation at the High Luminosity LHC

  2. Operating status of TARN vacuum system and future tasks

    International Nuclear Information System (INIS)

    Chida, Katsuhisa; Tsujikawa, Hiroshi; Mizobuchi, Akira

    1981-01-01

    TARN (Test Accumulation Ring for Numatron) was constructed for the purpose of obtaining the fundamental data for high energy heavy ion accelerator (Numatron) project, which accelerates heavy ions up to uranium to 1 GeV/nucleon. Its vacuum is required to be 1 x 10 - 10 Torr or less on beam. In February, 1972, only the vacuum system was temporarily assembled, and the vacuum of 2 x 10 - 11 Torr was realized by baking at 300 deg C alone. In July, 1972, the assembling of the vacuum chamber into magnets was completed, and several test experiments were performed using the H 2+ beam from the SF cyclotron. In this report, first, the outline of the vacuum system, and next, its operation are described. For the reason of the purpose of the ring, the vacuum system is required to be atmospheric pressure to attach beam monitors and other measuring instruments just before the machine time. Therefore, it is an important task to make the evacuation time as short as possible. As future tasks, the examination on the material and shape of the chamber, the investigation of pump system (appropriate combination of ion pump, titanium sublimation pump, cryo-pump, molecular pump, etc.), the study on the measuring and control systems (accurate measurement of total pressure and partial pressure and the feedback to the protecting system), the studies of problems on the vacuum wall surface (surface treatment prior to assembling the chamber into the ring and the methods and the effects of baking and electric discharge cleaning) are included. (Wakatsuki, Y.)

  3. Vacuum system of SST-1 Tokamak

    International Nuclear Information System (INIS)

    Khan, Ziauddin; Pathan, Firozkhan; George, Siju; Semwal, Pratibha; Dhanani, Kalpesh; Paravastu, Yuvakiran; Thankey, Prashant; Ramesh, Gattu; Himabindu, Manthena; Pradhan, Subrata

    2013-01-01

    Highlights: ► Air leaks developed during ongoing SST-1 cooldown campaign were detected online using RGA. ► The presence of N 2 and O 2 gases with the ratio of their partial pressures with ∼3.81:1 confirmed the air leaks. ► Baking of SST-1 was done efficiently by flowing hot N 2 gas in C-channels welded on inner surfaces without any problem. ► In-house fabricated demountable bull nose couplers were demonstrated for high temperature and pressure applications. ► Cryopumping effect was observed when liquid helium cooled superconducting magnets reached below 63 K. -- Abstract: Vacuum chambers of Steady State Superconducting (SST-1) Tokamak comprises of the vacuum vessel and the cryostat. The plasma will be confined inside the vacuum vessel while the cryostat houses the superconducting magnet systems (TF and PF coils), LN 2 cooled thermal shields and hydraulics for these circuits. The vacuum vessel is an ultra-high (UHV) vacuum chamber while the cryostat is a high-vacuum (HV) chamber. In order to achieve UHV inside the vacuum vessel, it would be baked at 150 °C for longer duration. For this purpose, U-shaped baking channels are welded inside the vacuum vessel. The baking will be carried out by flowing hot nitrogen gas through these channels at 250 °C at 4.5 bar gauge pressure. During plasma operation, the pressure inside the vacuum vessel will be raised between 1.0 × 10 −4 mbar and 1.0 × 10 −5 mbar using piezoelectric valves and control system. An ultimate pressure of 4.78 × 10 −6 mbar is achieved inside the vacuum vessel after 100 h of pumping. The limitation is due to the development of few leaks of the order of 10 −5 mbar l/s at the critical locations of the vacuum vessel during baking which was confirmed with the presence of nitrogen gas and oxygen gas with the ratio of ∼3.81:1 indicating air leak. Similarly an ultimate vacuum of 2.24 × 10 −5 mbar is achieved inside the cryostat. Baking of the vacuum vessel up to 110 °C with ±10

  4. 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.

  5. Continuous vacuum processing system for quartz crystal resonators

    International Nuclear Information System (INIS)

    Ney, R.J.; Hafner, E.

    1979-01-01

    An ultrahigh vacuum continuous cycle quartz crystal fabrication facility has been developed that assures an essentially contamination-free environment throughout the final manufacturing steps of the crystal unit. The system consists of five essentially tubular vacuum chambers that are interconnected through gate valves. The unplated crystal resonators, mounted in ceramic flatback frames and loaded on carrier trays, enter the vacuum system through an entrance air lock, are UV/ozone cleaned, baked at 300 0 C, plated to frequency, thermocompression sealed, and exit as completed crystal units through an exit air lock, while the bake, plate and seal chambers remain under continuous vacuum permanently. In-line conveyor belts are used, in conjunction with balanced vacuum manipulators, to move the resonator components to the various work stations. Unique high density, highly directional nozzle beam evaporation sources, capable of long term operation without reloading, are used for electroding the resonators simultaneously on both sides. The design goal for the system is a production rate of 200 units per 8 hour day; it is adaptable to automatic operation

  6. Using the Nova target chamber for high-yield targets

    International Nuclear Information System (INIS)

    Pitts, J.H.

    1987-01-01

    The existing 2.2-m-radius Nova aluminum target chamber, coated and lined with boron-seeded carbon shields, is proposed for use with 1000-MJ-yield targets in the next laser facility. The laser beam and diagnostic holes in the target chamber are left open and the desired 10 -2 Torr vacuum is maintained both inside and outside the target chamber; a larger target chamber room is the vacuum barrier to the atmosphere. The hole area available is three times that necessary to maintain a maximum fluence below 12 J/cm 2 on optics placed at a radius of 10 m. Maximum stress in the target chamber wall is 73 MPa, which complies with the intent of the ASME Pressure Vessel Code. However, shock waves passing through the inner carbon shield could cause it to comminute. We propose tests and analyses to ensure that the inner carbon shield survives the environment. 13 refs

  7. Performance Studies of a Micromegas Chamber in the ATLAS Environment

    CERN Document Server

    Kataoka, Y; Ntekas, K

    2014-01-01

    Five small prototype micromegas detectors were positioned in the ATLAS detector during Large Hadron Collider running at $\\sqrt{s} = 7$ and $8\\, \\mathrm{TeV}$. A $9\\times 4.5\\, \\mathrm{cm^2}$ two-gap detector was placed in front of the electromagnetic calorimeter and four $9\\times 10\\, \\mathrm{cm^2}$ detectors on the ATLAS Small Wheel, the first station of the forward muon spectrometer. The one attached to the calorimeter was exposed to interaction rates of about $70\\,\\mathrm{kHz}$ at $\\mathcal{L}=5\\times 10^{33}\\,\\mathrm{cm^{-2}s^{-1}}$ two orders of magnitude higher than the rates in the Small Wheel. We present the results from performance studies carried out using data collected with these detectors and we also compare the currents drawn by the detector installed in front of the electromagnetic calorimeter with the luminosity measurement in ATLAS.

  8. UHV seal studies for the advanced photon source storage ring vacuum system

    International Nuclear Information System (INIS)

    Gonczy, J.D.; Ferry, R.J.; Niemann, R.C.; Roop, B.

    1991-01-01

    The Advanced Photon Source (APS) Storage Ring Vacuum Chambers (SRVC) are constructed of aluminum. The chamber design incorporates aluminum alloy 2219-T87 Conflat flanges welded to an aluminum alloy 6063-T5 extruded chamber body. Vacuum connections to the aluminum Conflat chamber flanges are by means of 304 stainless steel Conflat flanges. To evaluate the Conflat seal assemblies relative to vacuum bake cycles, a Conflat Bake Test Assembly (CBTA) was constructed, and thermal cycling tests were performed between room temperature and 150 degrees C on both stainless steel to aluminum Conflat assemblies and aluminum to aluminum Conflat assemblies. A Helicoflex Bake Test Assembly (HBTA) was similarly constructed to evaluate Helicoflex seals. Both Conflat and Helicoflex seals were studied in a SRVC Sector String Test arrangement of five SRVC sections. The CBTA, HBTA and SRVC tests and their results are reported. 3 refs., 2 figs., 2 tabs

  9. System of multiwire proportional chambers at the separated particle channel for the Mirabelle bubble chamber

    International Nuclear Information System (INIS)

    Bryukhanov, N.S.; Galyaev, N.A.; Kotov, V.I.; Prosin, B.V.; Romanov, Yu.A.; Khodyrev, Yu.S.

    1980-01-01

    A system of multiwire proportional chambers (MPC) operating on-line with a M-6000 computer used during tuning and monitoring of beam parameters in a separated particle channel for the Mirabelle bubble chamber is described. Peculiarities of the construction and main characteristics of two MPC versions are considered. The first version is intended for placing in a vacuum at the edges of high-frequency separator deflector, the second one - for placing outside a vacuum in ionoguide gaps. Power supply of the proportional chambers is carried out from local compact (160x95x50 mm) high-voltage sources remotely controlled from a channel panel by low voltage. A MPC position diagram in the accelerator channel, flowsheet of registering electronics for the MPC system, main circuits of high-voltage power source, analog-to-digital converter of a code and trunk amplifier are given. A graph of amplifier signal amplitude dependence on high voltage of a chamber for a different composition of a gaseous mixture is presented. It is noted that the used elements of the electronic system provide the reliable processing of data and its transmission for a great distance (approximately 400 m). It is underlined that the MPC system operation for a long time has shown its high efficiency and reliability

  10. Application of Molecular Adsorber Coatings in Chamber A for the James Webb Space Telescope

    Science.gov (United States)

    Abraham, Nithin S.

    2017-01-01

    As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground-based space applications, in particular, for vacuum chamber environments. This presentation describes the application of the MAC technology for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap outgassed contaminants, specifically silicone-based diffusion pump oil, from within JSCs cryogenic optical vacuum chamber test facility called Chamber A. This presentation summarizes the background, fabrication, installation, chemical analysis test results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination. As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground-based space applications, in particular, for vacuum chamber environments. This presentation describes the application of the MAC technology for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap outgassed contaminants, specifically silicone-based diffusion pump oil, from within JSCs cryogenic optical vacuum chamber test

  11. Comparison of cold and warm vacuum systems for intersecting storage rings

    International Nuclear Information System (INIS)

    Halama, H.J.; Herrera, J.C.

    1975-01-01

    In storage rings employing superconducting magnets, the use of a cold bore as a cryopump appears, at first glance, as simple and economical. Since the selection of a cold or warm vacuum system has far-reaching implications on the basic design, each system is considered in some detail. The theoretical and practical limitations imposed on the maximum beam current by the gas desorption from the chamber walls are discussed. A realistic design of a cold vacuum chamber is developed and then compared with the proposed warm ISABELLE vacuum system. The comparison shows that the warm approach is preferable. (U.S.)

  12. Assembly of a Vacuum Chamber: A Hands-On Approach to Introduce Mass Spectrometry

    Science.gov (United States)

    Bussie`re, Guillaume; Stoodley, Robin; Yajima, Kano; Bagai, Abhimanyu; Popowich, Aleksandra K.; Matthews, Nicholas E.

    2014-01-01

    Although vacuum technology is essential to many aspects of modern physical and analytical chemistry, vacuum experiments are rarely the focus of undergraduate laboratories. We describe an experiment that introduces students to vacuum science and mass spectrometry. The students first assemble a vacuum system, including a mass spectrometer. While…

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

    International Nuclear Information System (INIS)

    Maya, I.; Schultz, K.R.; Battaglia, J.M.

    1984-09-01

    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 Li 2 O 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 Li 2 O 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 Li 2 O 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

  14. Vacuum system of SST-1 Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Ziauddin, E-mail: ziauddin@ipr.res.in [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382 428 (India); Pathan, Firozkhan; George, Siju; Semwal, Pratibha; Dhanani, Kalpesh; Paravastu, Yuvakiran; Thankey, Prashant; Ramesh, Gattu; Himabindu, Manthena; Pradhan, Subrata [Institute for Plasma Research, Near Indira Bridge, Bhat, Gandhinagar 382 428 (India)

    2013-10-15

    Highlights: ► Air leaks developed during ongoing SST-1 cooldown campaign were detected online using RGA. ► The presence of N{sub 2} and O{sub 2} gases with the ratio of their partial pressures with ∼3.81:1 confirmed the air leaks. ► Baking of SST-1 was done efficiently by flowing hot N{sub 2} gas in C-channels welded on inner surfaces without any problem. ► In-house fabricated demountable bull nose couplers were demonstrated for high temperature and pressure applications. ► Cryopumping effect was observed when liquid helium cooled superconducting magnets reached below 63 K. -- Abstract: Vacuum chambers of Steady State Superconducting (SST-1) Tokamak comprises of the vacuum vessel and the cryostat. The plasma will be confined inside the vacuum vessel while the cryostat houses the superconducting magnet systems (TF and PF coils), LN{sub 2} cooled thermal shields and hydraulics for these circuits. The vacuum vessel is an ultra-high (UHV) vacuum chamber while the cryostat is a high-vacuum (HV) chamber. In order to achieve UHV inside the vacuum vessel, it would be baked at 150 °C for longer duration. For this purpose, U-shaped baking channels are welded inside the vacuum vessel. The baking will be carried out by flowing hot nitrogen gas through these channels at 250 °C at 4.5 bar gauge pressure. During plasma operation, the pressure inside the vacuum vessel will be raised between 1.0 × 10{sup −4} mbar and 1.0 × 10{sup −5} mbar using piezoelectric valves and control system. An ultimate pressure of 4.78 × 10{sup −6} mbar is achieved inside the vacuum vessel after 100 h of pumping. The limitation is due to the development of few leaks of the order of 10{sup −5} mbar l/s at the critical locations of the vacuum vessel during baking which was confirmed with the presence of nitrogen gas and oxygen gas with the ratio of ∼3.81:1 indicating air leak. Similarly an ultimate vacuum of 2.24 × 10{sup −5} mbar is achieved inside the cryostat. Baking of the

  15. LHC vacuum system

    CERN Document Server

    Gröbner, Oswald

    1999-01-01

    The Large Hadron Collider (LHC) project, now in the advanced construction phase at CERN, comprises two proton storage rings with colliding beams of 7-TeV energy. The machine is housed in the existing LEP tunnel with a circumference of 26.7 km and requires a bending magnetic field of 8.4 T with 14-m long superconducting magnets. The beam vacuum chambers comprise the inner 'cold bore' walls of the magnets. These magnets operate at 1.9 K, and thus serve as very good cryo-pumps. In order to reduce the cryogenic power consumption, both the heat load from synchrotron radiation emitted by the proton beams and the resistive power dissipation by the beam image currents have to be absorbed on a 'beam screen', which operates between 5 and 20 K and is inserted inside the vacuum chamber. The design of this beam screen represents a technological challenge in view of the numerous and often conflicting requirements and the very tight mechanical tolerances imposed. The synchrotron radiation produces strong outgassing from the...

  16. Method and apparatus for scientific analysis under low temperature vacuum conditions

    Science.gov (United States)

    Winefordner, James D.; Jones, Bradley T.

    1990-01-01

    A method and apparatus for scientific analysis of a sample under low temperature vacuum conditions uses a vacuum chamber with a conveyor belt disposed therein. One end of the conveyor belt is a cool end in thermal contact with the cold stage of a refrigerator, whereas the other end of the conveyor belt is a warm end spaced from the refrigerator. A septum allows injection of a sample into the vacuum chamber on top of the conveyor belt for spectroscopic or other analysis. The sample freezes on the conveyor belt at the cold end. One or more windows in the vacuum chamber housing allow spectroscopic analysis of the sample. Following the spectroscopic analysis, the conveyor belt may be moved such that the sample moves toward the warm end of the conveyor belt where upon it evaporates, thereby cleaning the conveyor belt. Instead of injecting the sample by way of a septum and use of a syringe and needle, the present device may be used in series with capillary-column gas chromatography or micro-bore high performance liquid chromatography.

  17. Certification and commissioning of barrel stations for the ATLAS muon spectrometer

    CERN Document Server

    Zimmermann, S

    2006-01-01

    The muon spectrometer of the ATLAS experiment, which is scheduled to commence data taking at the Large Hadron Collider, LHC at CERN in 2007, comprises more than a thousand muon stations, which have the double purpose of triggering on high-p/sub t/ muon tracks as well as providing precise trajectory reconstruction. While monitored drift tube chambers are used for track reconstruction in all of the muon spectrometer except for a region close to the beam pipe in forward direction, two different technologies are used for triggering, resistive plate chambers in the barrel region and thin gap chambers in the end-caps. Both have in common that the ATLAS geometry allows only limited accessibility after chambers are installed in the detector. A thorough testing and certification prior to installation is therefore crucial. This paper reviews the test procedure at CERN for barrel chambers of type BO and BM, i.e. of stations for which a drift chamber is coupled with one or two resistive plate chambers. The final certific...

  18. ATLAS Award for Shield Supplier

    CERN Multimedia

    2004-01-01

    ATLAS technical coordinator Dr. Marzio Nessi presents the ATLAS supplier award to Vojtech Novotny, Director General of Skoda Hute.On 3 November, the ATLAS experiment honoured one of its suppliers, Skoda Hute s.r.o., of Plzen, Czech Republic, for their work on the detector's forward shielding elements. These huge and very massive cylinders surround the beampipe at either end of the detector to block stray particles from interfering with the ATLAS's muon chambers. For the shields, Skoda Hute produced 10 cast iron pieces with a total weight of 780 tonnes at a cost of 1.4 million CHF. Although there are many iron foundries in the CERN member states, there are only a limited number that can produce castings of the necessary size: the large pieces range in weight from 59 to 89 tonnes and are up to 1.5 metres thick.The forward shielding was designed by the ATLAS Technical Coordination in close collaboration with the ATLAS groups from the Czech Technical University and Charles University in Prague. The Czech groups a...

  19. Small-Strip Thin Gap Chambers for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    Perez Codina, Estel; The ATLAS collaboration

    2015-01-01

    For the forthcoming Phase-I upgrade to the LHC (2018/19), the first station of the ATLAS muon end-cap system, Small Wheel, needs to be replaced. The New Small Wheel (NSW) will have to operate in a high background radiation region while reconstructing muon tracks with high precision and providing information for the Level-1 trigger. In particular, the precision reconstruction of tracks requires a spatial resolution of about 100 μm, and the Level-1 trigger track segments have to be reconstructed with an angular resolution of approximately 1 mrad. The NSWs consist of eight layers each of Micromegas and small-strip Thin Gap Chambers (sTGC), both providing trigger and tracking capabilities. The single sTGC planes of a quadruplet consists of an anode layer of 50μm gold plated tungsten wire sandwiched between two resistive cathode layers. Behind one of the resistive cathode layers, a PCB with precise machined strips (thus the name sTGC) spaced every 3.2mm allows to achieve a position resolution that ranges from 70...

  20. Chamber transport

    International Nuclear Information System (INIS)

    Olson, Craig L.

    2001-01-01

    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

  1. Design of ITER neutron monitor using micro fission chambers

    International Nuclear Information System (INIS)

    Nishitani, Takeo; Ebisawa, Katsuyuki; Ando, Toshiro; Kasai, Satoshi; Johnson, L.C.; Walker, C.

    1998-08-01

    We are designing micro fission chambers, which are pencil size gas counters with fissile material inside, to be installed in the vacuum vessel as neutron flux monitors for ITER. We found that the 238 U micro fission chambers are not suitable because the detection efficiency will increase up to 50% in the ITER life time by breading 239 Pu. We propose to install 235 U micro fission chambers on the front side of the back plate in the gap between adjacent blanket modules and behind the blankets at 10 poloidal locations. One chamber will be installed in the divertor cassette just under the dome. Employing both pulse counting mode and Campbelling mode in the electronics, we can accomplish the ITER requirement of 10 7 dynamic range with 1 ms temporal resolution, and eliminate the effect of gamma-rays. We demonstrate by neutron Monte Carlo calculation with three-dimensional modeling that we avoid those detection efficiency changes by installing micro fission chambers at several poloidal locations inside the vacuum vessel. (author)

  2. Beam vacuum system of Brookhaven's muon storage ring

    International Nuclear Information System (INIS)

    Hseuth, H.C.; Snydstrup, L.; Mapes, M.

    1995-01-01

    A storage ring with a circumference of 45 m is being built at Brookhaven to measure the g-2 value of the muons to an accuracy of 0.35 ppm.. The beam vacuum system of the storage ring will operate at 10 -7 Torr and has to be completely non-magnetic. It consists of twelve sector chambers. The chambers are constructed of aluminum and are approximately 3.5 m in length with a rectangular cross-section of 16.5 cm high by 45 cm at the widest point. The design features, fabrication techniques and cleaning methods for these chambers are described. The beam vacuum system will be pumped by forty eight non-magnetic distributed ion pumps with a total pumping speed of over 2000 ell/sec. Monte Carlo simulations of the pressure distribution in the muon storage region are presented

  3. The challenge of building large area, high precision small-strip Thin Gap Trigger Chambers for the upgrade of the ATLAS experiment

    CERN Document Server

    Maleev, Victor; The ATLAS collaboration

    2015-01-01

    The current innermost stations of the ATLAS muon endcap system must be upgraded in 2018 and 2019 to retain the good precision tracking and trigger capabilities in the high background environment expected with the upcoming luminosity increase of the LHC. Large area small-strip Thin Gap Chambers (sTGC) up to 2 m2 in size and totaling an active area of 1200 m2 will be employed for fast and precise triggering. The precision reconstruction of tracks requires a spatial resolution of about 100 μm to allow the Level-1 trigger track segments to be reconstructed with an angular resolution of 1mrad. The upgraded detector will consist of eight layers each of Micromegas and sTGC’s detectors together forming the ATLAS New Small Wheels. The position of each strip must be known with an accuracy of 30 µm along the precision coordinate and 80 µm along the beam. On such large area detectors, the mechanical precision is a key point and then must be controlled and monitored all along the process of construction and integrati...

  4. The Challenge of Building Large Area, High Precision Small-Strip Thin Gap Trigger Chambers for the Upgrade of the ATLAS Experiment

    CERN Document Server

    Maleev, Victor; The ATLAS collaboration

    2015-01-01

    The current innermost stations of the ATLAS muon end-cap system must be upgraded in 2018 and 2019 to retain the good precision tracking and trigger capabilities in the high background environment expected with the upcoming luminosity increase of the LHC. Large area small-strip Thin Gap Chambers (sTGC) up to 2 $m^2$ in size and totaling an active area of 1200 $m^2$ will be employed for fast and precise triggering. The precision reconstruction of tracks requires a spatial resolution of about 100 $\\mu m$ while the Level-1 trigger track segments need to be reconstructed with an angular resolution of 1 mrad. The upgraded detector will consist of eight layers each of Micromegas and sTGC’s detectors together forming the ATLAS New Small Wheels. The position of each strip must be known with an accuracy of 40 $\\mu m$ along the precision coordinate and 80 $\\mu m$ along the beam. On such large area detectors, the mechanical precision is a key point and then must be controlled and monitored all along the process of cons...

  5. Vacuum Chamber for the Booster Bending Magnets

    CERN Multimedia

    CERN PhotoLab

    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).

  6. 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.

  7. High vacuum tip-enhanced Raman spectroscope based on a scanning tunneling microscope.

    Science.gov (United States)

    Fang, Yurui; Zhang, Zhenglong; Sun, Mengtao

    2016-03-01

    In this paper, we present the construction of a high-vacuum tip-enhanced Raman spectroscopy (HV-TERS) system that allows in situ sample preparation and measurement. A detailed description of the prototype instrument is presented with experimental validation of its use and novel ex situ experimental results using the HV-TERS system. The HV-TERS system includes three chambers held under a 10(-7) Pa vacuum. The three chambers are an analysis chamber, a sample preparation chamber, and a fast loading chamber. The analysis chamber is the core chamber and contains a scanning tunneling microscope (STM) and a Raman detector coupled with a 50 × 0.5 numerical aperture objective. The sample preparation chamber is used to produce single-crystalline metal and sub-monolayer molecular films by molecular beam epitaxy. The fast loading chamber allows ex situ preparation of samples for HV-TERS analysis. Atomic resolution can be achieved by the STM on highly ordered pyrolytic graphite. We demonstrate the measurement of localized temperature using the Stokes and anti-Stokes TERS signals from a monolayer of 1,2-benzenedithiol on a gold film using a gold tip. Additionally, plasmonic catalysis can be monitored label-free at the nanoscale using our device. Moreover, the HV-TERS experiments show simultaneously activated infrared and Raman vibrational modes, Fermi resonance, and some other non-linear effects that are not observed in atmospheric TERS experiments. The high spatial and spectral resolution and pure environment of high vacuum are beneficial for basic surface studies.

  8. High vacuum tip-enhanced Raman spectroscope based on a scanning tunneling microscope

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yurui [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603-146, Beijing 100190 (China); Bionanophotonics, Department of Applied Physics, Chalmers University of Technology, Göteborg, SE 41296 (Sweden); Zhang, Zhenglong [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603-146, Beijing 100190 (China); School of Physics and Information Technology, Shaanxi Normal University, 710062 Xi’an (China); Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena (Germany); Sun, Mengtao, E-mail: mtsun@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603-146, Beijing 100190 (China)

    2016-03-15

    In this paper, we present the construction of a high-vacuum tip-enhanced Raman spectroscopy (HV-TERS) system that allows in situ sample preparation and measurement. A detailed description of the prototype instrument is presented with experimental validation of its use and novel ex situ experimental results using the HV-TERS system. The HV-TERS system includes three chambers held under a 10{sup −7} Pa vacuum. The three chambers are an analysis chamber, a sample preparation chamber, and a fast loading chamber. The analysis chamber is the core chamber and contains a scanning tunneling microscope (STM) and a Raman detector coupled with a 50 × 0.5 numerical aperture objective. The sample preparation chamber is used to produce single-crystalline metal and sub-monolayer molecular films by molecular beam epitaxy. The fast loading chamber allows ex situ preparation of samples for HV-TERS analysis. Atomic resolution can be achieved by the STM on highly ordered pyrolytic graphite. We demonstrate the measurement of localized temperature using the Stokes and anti-Stokes TERS signals from a monolayer of 1,2-benzenedithiol on a gold film using a gold tip. Additionally, plasmonic catalysis can be monitored label-free at the nanoscale using our device. Moreover, the HV-TERS experiments show simultaneously activated infrared and Raman vibrational modes, Fermi resonance, and some other non-linear effects that are not observed in atmospheric TERS experiments. The high spatial and spectral resolution and pure environment of high vacuum are beneficial for basic surface studies.

  9. Filling the vacuum chamber of a technological system with homogeneous plasma using a stationary glow discharge

    International Nuclear Information System (INIS)

    Metel, A. S.; Grigoriev, S. N.; Melnik, Yu. A.; Panin, V. V.

    2009-01-01

    Experimental study of a glow discharge with electrostatic confinement of electrons is carried out in the vacuum chamber volume V ∼ 0.12 m 3 of a technological system 'Bulat-6' in argon pressure range 0.005-5 Pa. The chamber is used as a hollow cathode of the discharge with the inner surface area S ∼ 1.5 m 2 . It is equipped with two feedthroughs, which make it possible to immerse in the discharge plasma interchangeable anodes with surface area S a ranging from ∼0.001 to ∼0.1 m 2 , as well as floating electrodes isolated from both the chamber and the anode. Dependences of the cathode fall U c = 0.4-3 kV on the pressure p at a constant discharge current in the range I = 0.2-2 A proved that aperture of the electron escape out of the electrostatic trap is equal to the sum S o = S a + S f of the anode surface S a and the floating electrode surface S f . The sum S o defines the lower limit p o of the pressure range, in which U c is independent of p. At p o the cathode fall U c grows up dramatically, when the pressure decreases, and the pressure p tends to the limit p ex , which is in fact the discharge extinction pressure. At p ∼ p ex electrons emitted by the cathode and the first generation of fast electrons produced in the cathode sheath spend almost all their energy up to 3 keV on heating the anode and the floating electrode up to 600-800 o C and higher. In this case the gas in the chamber is being ionized by the next generations of electrons produced in the cathode sheath, their energy being one order of magnitude lower. When S a 1/2 S, where m is the electron mass and M is the ion mass, the anode may be additionally heated by plasma electrons accelerated by the anode fall of potential U a up to 0.5 kV.

  10. An optical sensor for the alignment of the Atlas Muon Spectrometer

    International Nuclear Information System (INIS)

    Barriere, J.-Ch.; Cloue, O.; Duboue, B.; Gautard, V.; Graffin, P.; Guyot, C.; Perrin, P.; Ponsot, P.; Reinert, Y.; Schuller, J.-P.; Schune, Ph.

    2003-01-01

    In the Atlas muon spectrometer (ATLAS Technical Proposal, CERN/LHCC/94-43, 15 December 1994, ATLAS Muon Spectrometer Technical Design Report, CERN/LHCC/97-22, 31 May 1997 and http://atlasinfo.cern.ch:80/Atlas/Welcome.html) the alignment system should control the spatial position of the muon chambers with an accuracy of 30 μm and 200 μrad for a range of ±5 mm and ±10 mrad. The alignment device described in this paper, called Praxial, fulfills these requirements

  11. Vacuum Radiance-Temperature Standard Facility for Infrared Remote Sensing at NIM

    Science.gov (United States)

    Hao, X. P.; Song, J.; Xu, M.; Sun, J. P.; Gong, L. Y.; Yuan, Z. D.; Lu, X. F.

    2018-06-01

    As infrared remote sensors are very important parts of Earth observation satellites, they must be calibrated based on the radiance temperature of a blackbody in a vacuum chamber prior to launch. The uncertainty of such temperature is thus an essential component of the sensors' uncertainty. This paper describes the vacuum radiance-temperature standard facility (VRTSF) at the National Institute of Metrology of China, which will serve to calibrate infrared remote sensors on Chinese meteorological satellites. The VRTSF can be used to calibrate vacuum blackbody radiance temperature, including those used to calibrate infrared remote sensors. The components of the VRTSF are described in this paper, including the VMTBB, the LNBB, the FTIR spectrometer, the reduced-background optical system, the vacuum chamber used to calibrate customers' blackbody, the vacuum-pumping system and the liquid-nitrogen-support system. The experimental methods and results are expounded. The uncertainty of the radiance temperature of VMTBB is 0.026 °C at 30 °C over 10 μm.

  12. Design and construction of vacuum control system on EAST

    International Nuclear Information System (INIS)

    Wang, L.; Zhang, Y.; Hu, Q.S.; Wang, X.M.; Zhang, X.D.; Hu, J.S.; Yang, Y.; Gu, X.M.

    2008-01-01

    The construction of experimental advanced superconducting tokamak (EAST) was finished at the end of 2006 in Hefei, China. Its vacuum system, an important subsystem, has been commissioned in February 2006. The design and construction of this vacuum control system are described in this paper. The requirements for remote automation, distributed control and centralized management, high reliability and expansibility have been taken into account in the design. There are three levels of control in vacuum control system. The bottom level control is performed on the local instruments manually; the medium level control is based on Siemens S7-400 PLC; the top level control is conducted on IPCs with communication through profi b us network. In addition remote handling and centralized monitoring could be realized by a remote control server. The control system could achieve pumping and fueling of the whole vacuum system. Besides that, it also includes the data acquisition of the pressure and temperature. The details are discussed on the monitoring of vacuum system states including cooling water, power and compressed air, etc., safeguards of plasma chamber and cryostat chamber and vacuum equipments, choosing of control modes corresponding to the plasma discharge and wall conditioning. At the end, the parts of EAST device protection system related to vacuum and gas injection system will also be introduced

  13. Technical specification for vacuum systems

    International Nuclear Information System (INIS)

    Khaw, J.

    1987-01-01

    The vacuum systems at the Stanford Linear Accelerator Center (SLAC) are primarily of all-metal construction and operate at pressures from 10 -5 to 10 -11 Torr. The primary gas loads during operation result from thermal desorption and beam-induced desorption from the vacuum chamber walls. These desorption rates can be extremely high in the case of hydrocarbons and other contaminants. These specifications place a major emphasis on eliminating contamination sources. The specifications and procedures have been written to insure the cleanliness and vacuum integrity of all SLAC vacuum systems, and to assist personnel involved with SLAC vacuum systems in choosing and designing components that are compatible with existing systems and meet the quality and reliability of SLAC vacuum standards. The specification includes requirements on design, procurement, fabrication, chemical cleaning, clean room practices, welding and brazing, helium leak testing, residual gas analyzer testing, bakeout, venting, and pumpdown. Also appended are specifications regarding acceptable vendors, isopropyl alcohol, bakeable valve cleaning procedure, mechanical engineering safety inspection, notes on synchrotron radiation, and specifications of numerous individual components

  14. Experimental laser fusion devices and related vacuum problems

    International Nuclear Information System (INIS)

    O'Neal, W.C.; Campbell, D.E.; Glaros, S.S.; Hurley, C.A.; Kobierecki, M.W.; McFann, C.B. Jr.; Monjes, J.A.; Patton, H.G.; Rienecker, F. Jr.

    1977-01-01

    Laser fusion experiments require hard vacuum in the laser-beam spatial filters, target chambers and for target diagnostics instruments. Laser focusing lenses and windows, and target alignment windows must hold vacuum without optical distortion, and must be protected from target debris. The vacuum must be sufficient to prevent residual gas breakdown in focused laser light, avoid arcing at high voltage terminals, minimize contamination and melting of cryogenic targets, and prevent adsorption of the target's microfusion radiation before it reaches the diagnostics instruments

  15. Gas-controlled dynamic vacuum insulation with gas gate

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1994-06-07

    Disclosed is a dynamic vacuum insulation comprising sidewalls enclosing an evacuated chamber and gas control means for releasing hydrogen gas into a chamber to increase gas molecule conduction of heat across the chamber and retrieving hydrogen gas from the chamber. The gas control means includes a metal hydride that absorbs and retains hydrogen gas at cooler temperatures and releases hydrogen gas at hotter temperatures; a hydride heating means for selectively heating the metal hydride to temperatures high enough to release hydrogen gas from the metal hydride; and gate means positioned between the metal hydride and the chamber for selectively allowing hydrogen to flow or not to flow between said metal hydride and said chamber. 25 figs.

  16. Compact vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1993-01-05

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point'' or line'' contacts with the metal wall sheets. In the case of monolithic spacers that form line'' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point'' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

  17. Ion-induced desorption from stainless-steel vacuum chambers has been studied with a view to improving the dynamic pressure in the future LEIR ion accumulator ring for the LHC.

    CERN Multimedia

    Brice Maximilien

    2002-01-01

    This picture shows part of a vacuum chamber fully equipped with St707 non-evaporable getter (NEG) strips which were bombarded in Linac3 with lead ions at 4.2 MeV/u. A change of the surface morphology is visible where the Pb53+ ions impacted under grazing incidence onto the NEG.

  18. Vacuum system design and tritium inventory for the charge exchange diagnostic on the Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    Medley, S.S.

    1986-01-01

    The application of charge exchange analyzers for the measurement of ion temperature in fusion plasma experiments requires a direct connection between the diagnostic and plasma-discharge vacuum chambers. Differential pumping of the gas load from the diagnostic stripping cell operated at > or approx. = 10 -3 Torr is required to maintain the analyzer chamber at a pressure of -6 Torr. The migration of gases between the diagnostic and plasma vacuum chambers must be minimized. In particular, introduction of the analyzer stripping cell gas into the plasma chamber having a base pressure of -8 Torr must be suppressed. The charge exchange diagnostic for the Tokamak Fusion Test Reactor (TFTR) is comprised of two analyzer systems designed to contain a total of 18 independent mass/energy analyzers and one diagnostic neutral beam rated at 80 keV, 15 A. The associated arrays of multiple, interconnected vacuum systems were analyzed using the Vacuum System Transient Simulator (Vsts) computer program which models the transient transport of multigas species through complex networks of ducts, valves, traps, vacuum pumps, and other related vacuum system components. In addition to providing improved design performance at reduced costs, the analysis yields estimates for the exchange of tritium from the torus to the diagnostic components and of the diagnostic working gases to the torus

  19. Development of a cooling system and vacuum chamber for the pion tracker for HADES

    Energy Technology Data Exchange (ETDEWEB)

    Wirth, Joana [Technische Univ. Muenchen, Garching (Germany). Excellence Cluster Universe; Collaboration: HADES-Collaboration

    2013-07-01

    One of the future experiments planned at SIS18 with the HADES spectrometer in GSI Darmstadt envisages the employment of pion beam colliding on LH2 or nuclear target. Due to the fact that secondary pion beam has high momentum spread, since the precise knowledge of pion momentum is mandatory to carry out the planned exclusive measurements, we have to measure the momentum for each individual pion. For this purpose our group is developing a pion beam tracking system, which consists of two silicon detectors. Both detectors are located in the beamline and therefore have to cope the high-intensity secondary beam. Cooling of a silicon detector strongly improves its radiation hardness and performance. It reduces the leakage current and thus the noise, which is important for the detection of MIPs like pions. We have designed and built a complete prototype system of vacuum chamber and detector cooling. With use of the Finite Element Method we simulated the mechanical and thermal properties of the prototype. The proposed poster shows the current status and performance of the cooling system for a test-detector, focusing on the reduction of the leakage current and the noise.

  20. Imploded test-chamber for an ISR intersection

    CERN Multimedia

    CERN PhotoLab

    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.

  1. ATLAS rewards industry

    CERN Multimedia

    2006-01-01

    Showing excellence in mechanics, electronics and cryogenics, three industries are honoured for their contributions to the ATLAS experiment. Representatives of the three award-wining companies after the ceremony. For contributing vital pieces to the ATLAS puzzle, three industries were recognized on Friday 5 May during a supplier awards ceremony. After a welcome and overview of the ATLAS experiment by spokesperson Peter Jenni, CERN Secretary-General Maximilian Metzger stressed the importance of industry to CERN's scientific goals. Close interaction with CERN was a key factor in the selection of each rewarded company, in addition to the high-quality products they delivered to the experiment. Alu Menziken Industrie AG, of Switzerland, was honoured for the production of 380,000 aluminium tubes for the Monitored Drift Tube Chambers (MDT). As Giora Mikenberg, the Muon System Project Leader stressed, the aluminium tubes were delivered on time with an extraordinary quality and precision. Between October 2000 and Jan...

  2. Report of the Synchrotron Radiation Vacuum Workshop

    International Nuclear Information System (INIS)

    Avery, R.T.

    1984-06-01

    The Synchrotron Radiation Vacuum Workshop was held to consider two vacuum-related problems that bear on the design of storage rings and beam lines for synchrotron radiation facilities. These problems are gas desorption from the vacuum chamber walls and carbon deposition on optical components. Participants surveyed existing knowledge on these topics and recommended studies that should be performed as soon as possible to provide more definitive experimental data on these topics. This data will permit optimization of the final design of the Advanced Light Source (ALS) and its associated beam lines. It also should prove useful for other synchrotron radiation facilities as well

  3. Ageing test of the ATLAS RPCs at X5-GIF

    International Nuclear Information System (INIS)

    Aielli, G.; Alviggi, M.; Ammosov, V.

    2004-01-01

    An ageing test of three ATLAS production RPC stations is in course at X5-GIF, the CERN irradiation facility. The chamber efficiencies are monitored using cosmic rays triggered by a scintillator hodoscope. Higher statistics measurements are made when the X5 muon beam is available. We report here the measurements of the efficiency versus operating voltage at different source intensities, up to a maximum counting rate of about 700 Hz/cm 2 . We describe the performance of the chambers during the test up to an overall ageing of 4 ATLAS equivalent years corresponding to an integrated charge of 0.12 C/cm 2 , including a safety factor of 5

  4. Vacuum mechatronic laser alignment system on the Nova laser

    International Nuclear Information System (INIS)

    Holliday, M.; Wong, K.; Shelton, R.

    1991-11-01

    The experiments conducted on NOVA are done to investigate inertially confined laser fusion reactions. To this end, the ten beams of the laser are aligned to within 30mm. The target chamber employs a vacuum mechatronic based reticle/target positioning system to accomplish this. It is a five degree-of-freedom chamber resident system, known as the Alignment Aids Positioner or AAP. The AAP aids in beam and diagnostic alignment by accurately positioning a reticle at target chamber center to with 7mm. The AAP system increases target positioning and alignment flexibility and accuracy through the use of a computer controlled multi degree-of-freedom stage assembly. This device uses microstepping DC stepper motors with encoders to achieve closed loop control in a 10 -6 torr vacuum. The AAP has two positioning regimes to move the alignment reticle and do beam alignment. One is course positioning in the Y-Z plane that moves a high resolution stage assembly to target chamber center. The other regime is high resolution movement in the X,Y,Z and q directions. 5 refs., 9 figs

  5. The first Module0 MicroMegas Chamber for the New Small Wheel Upgrade of the ATLAS Muon Spectrometer: Features and Performances

    CERN Document Server

    Palazzo, Serena; The ATLAS collaboration

    2017-01-01

    After the second long shutdown (LS2) in 2019-2020, the LHC luminosity will be increased up to 2-3$\\cdot$10$^{34}$ cm$^{-2}$ s$^{-1}$ in Phase$-$1 and eventually to 7$\\cdot$10$^{34}$ cm$^{-2}$ s$^{-1}$ in the High Luminosity LHC era. While high luminosity will provide more data, it is essential that the ATLAS detectors are still able to operate in the higher background environment maintaining their performances as good as that at lower luminosities. To obtain this, some of the detectors that are located nearest to the beam pipe have to be replaced. For the upgrade of the ATLAS Muon Spectrometer the present Small Wheel equipped with CSC, MDT and TGC chambers will be replaced the New Small Wheel. This will contain two new detector types: the MicroMegas (MM) and the small-strip TGC (sTGC). The first Module-0 of Micromegas quadruplet has been built by a consortium of several INFN groups in Italy and tested with high energy particles at the H8 SPS Test Beam experimental area at CERN in June 2016. The construction o...

  6. Monitoring the Resistive Plate Chambers in the Muon Spectrometer of ATLAS.

    CERN Document Server

    Al-Qahtani, Shaikha

    2017-01-01

    A software was developed to monitor the resistive plate chambers. The purpose of the program is to detect any weak or dead chambers and locate them for repair. The first use of the program was able to spot several chambers with problems to be investigated.

  7. Argus target chamber

    International Nuclear Information System (INIS)

    Rienecker, F. Jr.; Glaros, S.S.; Kobierecki, M.

    1975-01-01

    A target chamber for application in the laser fusion program must satisfy some very basic requirements. (1) Provide a vacuum on the order of 10 -6 torr. (2) Support a microscopically small target in a fixed point in space and verify its location within 5 micrometers. (3) Contain an adjustable beam focusing system capable of delivering a number of laser beams onto the target simultaneously, both in time and space. (4) Provide access for diagnostics to evaluate the results of target irradiation. (5) Have flexibility to allow changes in targets, focusing optics and number of beams. The ARGUS laser which is now under construction at LLL will have a target chamber which meets these requirements in a simple economic manner. The chamber and auxiliary equipment are described, with reference to two double beam focusing systems; namely, lenses and ellipsoidal mirrors. Provision is made for future operation with four beams, using ellipsoidal mirrors for two-sided illumination and lens systems for tetragonal and tetrahedral irradiation

  8. A review of the use of Al-alloy vacuum components for operation at 10-13 Torr

    Science.gov (United States)

    Ishimaru, Hajime

    1990-02-01

    An extremely high vacuum (XHV) chamber was fabricated and tested. The vacuum chamber was made of special surface finished (EX-process) aluminum alloy in oxygen and argon atmosphere. The chamber was assembled using TIG welding in an argon atmosphere and by electron beam welding. The system was evacuated with a turbo-backed 300 l/s turbomolecular pump separated from the main chamber using a right angle valve. The liquid nitrogen shroud is installed inside the main vacuum chamber. The XHV is maintained by two 300 l/s sputter ion pumps and a titanium sublimation pump with a liquid nitrogen shroud. These pumps are also made of aluminum alloys. An ultimate pressure of 3×10-13 Torr was measured with a point collector gauge with a spherical anode mounted on an Al-flange. Residual gas analysis in the order 10-13 Torr was performed by a newly developed Q-mass filter. To suppress outgassing from the quadrupole electrode, the ion source is mounted on an Al-flange separated from the quadrupole electrode.

  9. Development of a highly selective muon trigger exploiting the high spatial resolution of monitored drift-tube chambers for the ATLAS experiment at the HL-LHC

    CERN Document Server

    Kortner, Oliver; The ATLAS collaboration

    2018-01-01

    The High-Luminosity LHC will provide the unique opportunity to explore the nature of physics beyond the Standard Model. Highly selective first level triggers are essential for the physics programme of the ATLAS experiment at the HL-LHC, where the instantaneous luminosity will exceed the LHC design instantaneous luminosity by almost an order of magnitude. The ATLAS first level muon trigger rate is dominated by low momentum muons, selected due to the moderate momentum resolution of the current system. This first level trigger limitation can be overcome by including data from the precision muon drift tube (MDT) chambers. This requires the fast continuous transfer of the MDT hits to the off-detector trigger logic and a fast track reconstruction algorithm performed in the trigger logic. The feasibility of this approach was studied with LHC collision data and simulated data. Two main options for the hardware implementation will be studied with demonstrators: an FPGA based option with an embedded ARM microprocessor ...

  10. Development of a Highly Selective Muon Trigger Exploiting the High Spatial Resolution of Monitored Drift-Tube Chambers for the ATLAS Experiment at the HL-LHC

    CERN Document Server

    Kortner, Oliver; The ATLAS collaboration

    2018-01-01

    The High-Luminosity LHC will provide the unique opportunity to explore the nature of physics beyond the Standard Model. Highly selective first level triggers are essential for the physics programme of the ATLAS experiment at the HL-LHC, where the instantaneous luminosity will exceed the LHC design instantaneous luminosity by almost an order of magnitude. The ATLAS first level muon trigger rate is dominated by low momentum muons, selected due to the moderate momentum resolution of the current system. This first level trigger limitation can be overcome by including data from the precision muon drift tube (MDT) chambers. This requires the fast continuous transfer of the MDT hits to the off-detector trigger logic and a fast track reconstruction algorithm performed in the trigger logic. The feasibility of this approach was studied with LHC collision data and simulated data. Two main options for the hardware implementation are currently studied with demonstrators, an FPGA based option with an embedded ARM microproc...

  11. Development and fabrication of the vacuum systems for an elliptically polarized undulator at Taiwan Photon Source

    Science.gov (United States)

    Chang, Chin-Chun; Chan, Che-Kai; Wu, Ling-Hui; Shueh, Chin; Shen, I.-Ching; Cheng, Chia-Mu; Yang, I.-Chen

    2017-05-01

    Three sets of a vacuum system were developed and fabricated for elliptically polarized undulators (EPU) of a 3-GeV synchrotron facility. These chambers were shaped with low roughness extrusion and oil-free machining; the design combines aluminium and stainless steel. The use of a bimetallic material to connect the EPU to the vacuum system achieves the vacuum sealing and to resolve the leakage issue due to bake process induced thermal expansion difference. The interior of the EPU chamber consists of a non-evaporable-getter strip pump in a narrow space to absorb photon-stimulated desorption and to provide a RF bridge design to decrease impedance effect in the two ends of EPU chamber. To fabricate these chambers and to evaluate the related performance, we performed a computer simulation to optimize the structure. During the machining and welding, the least deformation was achieved, less than 0.1 mm near 4 m. In the installation, the linear slider can provide a stable and precision moved along parallel the electron beam direction smoothly for the EPU chamber to decrease the twist issue during baking process. The pressure of the EPU chamber attained less than 2×10-8 Pa through baking. These vacuum systems of the EPU magnet have been installed in the electron storage ring of Taiwan Photon Source in 2015 May and have normally operated at 300 mA continuously since, and to keep beam life time achieved over than 12 h.

  12. Development and fabrication of the vacuum systems for an elliptically polarized undulator at Taiwan Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chin-Chun, E-mail: chinchun@nsrrc.org.tw; Chan, Che-Kai; Wu, Ling-Hui; Shueh, Chin; Shen, I.-Ching; Cheng, Chia-Mu; Yang, I.-Chen

    2017-05-01

    Three sets of a vacuum system were developed and fabricated for elliptically polarized undulators (EPU) of a 3-GeV synchrotron facility. These chambers were shaped with low roughness extrusion and oil-free machining; the design combines aluminium and stainless steel. The use of a bimetallic material to connect the EPU to the vacuum system achieves the vacuum sealing and to resolve the leakage issue due to bake process induced thermal expansion difference. The interior of the EPU chamber consists of a non-evaporable-getter strip pump in a narrow space to absorb photon-stimulated desorption and to provide a RF bridge design to decrease impedance effect in the two ends of EPU chamber. To fabricate these chambers and to evaluate the related performance, we performed a computer simulation to optimize the structure. During the machining and welding, the least deformation was achieved, less than 0.1 mm near 4 m. In the installation, the linear slider can provide a stable and precision moved along parallel the electron beam direction smoothly for the EPU chamber to decrease the twist issue during baking process. The pressure of the EPU chamber attained less than 2×10{sup −8} Pa through baking. These vacuum systems of the EPU magnet have been installed in the electron storage ring of Taiwan Photon Source in 2015 May and have normally operated at 300 mA continuously since, and to keep beam life time achieved over than 12 h.

  13. Performance Studies of Micromegas Chambers for the New Small Wheel Upgrade Project

    Directory of Open Access Journals (Sweden)

    Leontsinis S.

    2016-01-01

    Full Text Available The ATLAS collaboration has chosen the Micromegas technology along with the small-strip Thin Gap Chambers for the upgrade of the inner muon station in the high-rapidity region, the so called New Small Wheel upgrade project. It will employ eight layers of Micromegas and eight layers of small-strip Thin Gap Chambers per wheel. The New Small Wheel project requires fully efficient Micromegas chambers, able to cope with the maximum expected rate of 15 kHz/cm2 featuring single plane spatial resolution better than 100 μm. The Micromegas detectors will cover a total active area of ~ 1200 m2 and will be operated in a moderate magnetic field (≤ 0.3 T. Moreover, together with their precise tracking capability the New Small Wheel Micromegas chambers will contribute to the ATLAS Level-1 trigger system. Several studies have been performed on small (10 × 10 cm2 and medium (1 × 0.5 m2 size prototypes using medium (1 − 5 GeV/c and high momentum (120 – 150 GeV/c hadron beams at CERN. A brief overview of the results obtained is presented.

  14. ATLAS Detector Operation 2011 
Muon System

    CERN Document Server

    Iakovidis, G; The ATLAS collaboration

    2012-01-01

    During the 2011 LHC Data taking period the ATLAS Detector recorded 5.22 fb-1 which is 96.5% of the delivered data from proton-proton collisions. The Muon Spectrometer was improved to 100% operational fraction at the Level 1 trigger and more than 98.7% operational fraction of trigger and precision chambers. The recorded data with Muon Spectrometer was at a level of more than 99% good for physics analysis. This illustrates an excellent performance. This poster presents performance of the Muon Spectrometer trigger chambers as well as precision chambers. In addition a combined Muon Spectrometer performance is presented.

  15. Vacuum system operating experience review for fusion applications

    International Nuclear Information System (INIS)

    Cadwallader, L.C.

    1994-03-01

    This report presents a review of vacuum system operating experiences from particle accelerator, fusion experiment, space simulation chamber, and other applications. Safety relevant operating experiences and accident information are discussed. Quantitative order-of-magnitude estimates of vacuum system component failure rates and accident initiating event frequencies are presented for use in risk assessment, reliability, and availability studies. Safety concerns with vacuum systems are discussed, including personnel safety, foreign material intrusion, and factors relevant to vacuum systems being the primary confinement boundary for tritium and activated dusts. This information should be useful to fusion system designers and safety analysts, such as the team working on the Engineering Design Activities for the International Thermonuclear Experimental Reactor

  16. An innovative "ChemicalVia" process for the production of high density interconnect printed circuit boards The ATLAS muon chamber quality control with the X-ray tomograph at CERN

    CERN Document Server

    Da Silva, Vitor; Watts, David; Van der Bij, Erik; Banhidi, Z; Berbiers, Julien; Lampl, W; Marchesotti, M; Rangod, Stephane; Sbrissa, E; Schuh, S; Voss, Rüdiger; Zhuravlov, V

    2004-01-01

    The ChemicalVia process, patented by CERN, provides a new method of making microvias in high-density multilayer printed circuit boards of different types, such as sequential build-up (SBU), high density interconnected (HDI), or laminated multi-chip modules (MCM-L). The process uses chemical etching instead of laser, plasma or other etching techniques and can be implemented in a chain production line. This results in an overall reduced operation and maintenance cost and a much shorter hole production time as compared with other microvia processes. copy Emerald Group Publishing Limited. 4 Refs.4 An essential part of the Muon Spectrometer of the ATLAS experiment is based on the Monitored Drift Tube (MDT) technology. About 1200 muon drift chambers are being built at 13 institutes all over the world. The MDT chambers require an exceptional mechanical construction accuracy of better than 20 mu m. A dedicated X-ray tomograph has been developed at CERN since 1996 to control the mechanical quality of the chambers. The...

  17. Plasma Chamber Design and Fabrication Activities

    Science.gov (United States)

    Parodi, B.; Bianchi, A.; Cucchiaro, A.; Coletti, A.; Frosi, P.; Mazzone, G.; Pizzuto, A.; Ramogida, G.; Coppi, B.

    2006-10-01

    A fabrication procedure for a typical Plasma Chamber (PC) sector has been developed to cover all the manufacturing phases, from the raw materials specification (including metallurgical processes) to the machining operations, acceptance procedures and vacuum tests. Basically, the sector is made of shaped elements (forged or rolled) welded together using special fixtures and then machined to achieve the final dimensional accuracy. An upgraded design of the plasma chamber's vertical support that can withstand the estimated electromagnetic loads (Eddy and Halo current plus horizontal net force resulting from the worst plasma disruption scenario VDE, Vertical Displacement Event) has been completed. The maintenance of the radial support can take place hands-on with a direct access from outside the cryostat. With the present design, vacuum tightness is achieved by welding conducted with automatic welding heads. On the outer surface of the PC a dedicated duct system, filled by helium gas, is included to cool down the PC to room temperature when needed.

  18. Internal motion in high vacuum systems

    Science.gov (United States)

    Frank, J. M.

    Three transfer and positioning mechanisms have been developed for the non-air exposed, multistep processing of components in vacuum chambers. The functions to be performed in all of the systems include ultraviolet/ozone cleaning, vacuum baking, deposition of thin films, and thermocompression sealing of the enclosures. Precise positioning of the components is required during the evaporation and sealing processes. The three methods of transporting and positioning the components were developed to accommodate the design criteria and goals of each individual system. The design philosophy, goals, and operation of the three mechanisms are discussed.

  19. Vacuum system of the Tokamak Novillo

    International Nuclear Information System (INIS)

    Valencia Alvarado, R.; Lopez Callejas, R.; Melendez Lugo, L.; Chavez Alarcon, E.

    1990-01-01

    A toroidal vacuum chamber of 28 access ports was constructed from four stainless steel 316L elbows joined together with dielectric seals to provide voltage break in the toroidal direction. All vacuum seals were viton O-rings. A 500 1/s turbomolecular pump provide a base pressure of 4 x 10 -8 mbar with light backing (∼ 60 deg C). In the regime of cleaning discharge the toroidal chamber is filled with H 2 to a pressure of 0.2 + 0.4 mbar. The ohmic heating coils are pulsed with a AF oscillator (10 kW, 17.5 kHz) for 60-80 msec, at a repetition rate of about 2 Hz. A toroidal magnetic field of roughly 600 G is added to generate the cleaning discharge. According to a residual gas analyzer installed in the system, 80% of the base pressure was given by water; the other components were hydrogen and mon- and dioxides of carbon. (Author)

  20. Performance Studies of Micromegas Chambers for the New Small Wheel Upgrade Project

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00349891; The ATLAS collaboration; Leontsinis, Stefanos

    2015-01-01

    Micromegas, an abbreviation for Micro MEsh Gaseous Structure (MM), is a robust detector with excellent spatial resolution and high rate capability. An $R\\&D$ activity, called Muon ATLAS MicroMegas Activity (MAMMA), was initiated in 2007 in order to explore the potential of the MM technology for use in the ATLAS experiment. After several years of prototyping and testing, the ATLAS collaboration has chosen the MM technology along with the small-strip Thin Gap Chambers (sTGC) for the upgrade of the inner muon station in the high-rapidity region, the so called New Small Wheel (NSW) upgrade project. It will employ eight layers of MM and eight layers of sTGC detectors per wheel. The NSW project requires fully efficient MM chambers, able to cope with the maximum expected rate of $15\\,\\mathrm{kHz/cm^2}$ featuring single plane spatial resolution better than $100\\,\\mu\\mathrm{m}$. The MM detectors will cover a total active area of $\\sim1200\\,\\mathrm{m^2}$ and will be operated in a moderate magnetic field with intens...

  1. Multispecimen dual-beam irradiation damage chamber

    International Nuclear Information System (INIS)

    Packan, N.H.; Buhl, R.A.

    1980-06-01

    An irradiation damage chamber that can be used to rapidly simulate fast neutron damage in fission or fusion materials has been designed and constructed. The chamber operates in conjunction with dual Van de Graaff accelerators at ORNL to simulate a wide range of irradiation conditions, including pulsed irradiation. Up to six experiments, each with up to nine 3-mm disk specimens, can be loaded into the ultrahigh vacuum chamber. Specimen holders are heated with individual electron guns, and the temperature of each specimen can be monitored during bombardment by an infrared pyrometer. Three different dose levels may be obtained during any single bombardment, and the heavy-ion flux on each of the nine specimens can be measured independently with only a brief interruption of the beam. The chamber has been in service for nearly three years, during which time approximately 250 bombardments have been successfully carried out. An appendix contains detailed procedures for operating the chamber

  2. Planetary Atmosphere and Surfaces Chamber (PASC: A Platform to Address Various Challenges in Astrobiology

    Directory of Open Access Journals (Sweden)

    Eva Mateo-Marti

    2014-08-01

    Full Text Available The study of planetary environments of astrobiological interest has become a major challenge. Because of the obvious technical and economical limitations on in situ planetary exploration, laboratory simulations are one of the most feasible research options to make advances both in planetary science and in developing a consistent description of the origin of life. With this objective in mind, we applied vacuum technology to the design of versatile vacuum chambers devoted to the simulation of planetary atmospheres’ conditions. These vacuum chambers are able to simulate atmospheres and surface temperatures representative of the majority of planetary objects, and they are especially appropriate for studying the physical, chemical and biological changes induced in a particular sample by in situ irradiation or physical parameters in a controlled environment. Vacuum chambers are a promising potential tool in several scientific and technological fields, such as engineering, chemistry, geology and biology. They also offer the possibility of discriminating between the effects of individual physical parameters and selected combinations thereof. The implementation of our vacuum chambers in combination with analytical techniques was specifically developed to make feasible the in situ physico-chemical characterization of samples. Many wide-ranging applications in astrobiology are detailed herein to provide an understanding of the potential and flexibility of these experimental systems. Instruments and engineering technology for space applications could take advantage of our environment-simulation chambers for sensor calibration. Our systems also provide the opportunity to gain a greater understanding of the chemical reactivity of molecules on surfaces under different environments, thereby leading to a greater understanding of interface processes in prebiotic chemical reactions and facilitating studies of UV photostability and photochemistry on surfaces

  3. Magnetically Suspended Linear Pulse Motor for Semiconductor Wafer Transfer in Vacuum Chamber

    Science.gov (United States)

    Moriyama, Shin-Ichi; Hiraki, Naoji; Watanabe, Katsuhide; Kanemitsu, Yoichi

    1996-01-01

    This paper describes a magnetically suspended linear pulse motor for a semiconductor wafer transfer robot in a vacuum chamber. The motor can drive a wafer transfer arm horizontally without mechanical contact. In the construction of the magnetic suspension system, four pairs of linear magnetic bearings for the lift control are used for the guidance control as well. This approach allows us to make the whole motor compact in size and light in weight. The tested motor consists of a double-sided stator and a transfer arm with a width of 50 mm and a total length of 700 mm. The arm, like a ladder in shape, is designed as the floating element with a tooth width of 4 mm (a tooth pitch of 8 mm). The mover mass is limited to about 1.6 kg by adopting such an arm structure, and the ratio of thrust to mover mass reaches to 3.2 N/kg under a broad air gap (1 mm) between the stator teeth and the mover teeth. The performance testing was carried out with a transfer distance less than 450 mm and a transfer speed less than 560 mm/s. The attitude of the arm was well controlled by the linear magnetic bearings with a combined use, and consequently the repeatability on the positioning of the arm reached to about 2 micron. In addition, the positioning accuracy was improved up to about 30 micron through a compensation of the 128-step wave current which was used for the micro-step drive with a step increment of 62.5 micron.

  4. Design and performance of main vacuum pumping system of SST-1 Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Ziauddin, E-mail: ziauddin@ipr.res.in; Pathan, Firozkhan; George, Siju; Dhanani, Kalpesh; Paravastu, Yuvakiran; Semwal, Pratibha; Pradhan, Subrata

    2014-01-15

    Highlights: •SST-1 Tokamak was successfully commissioned. •Vacuum vessel and cryostat were pumped down to 6.3 × 10{sup −7} mbar and 1.3 × 10{sup −5} mbar. •Leaks developed during baking were detected in-situ by RGA and confirmed later on. •Cryo-pumping effect was observed when LN2 thermal shields reached below 273 K. •Non-standard aluminum wire-seals have shown leak tightness < 1.0 × 10{sup −9} mbar l/s. -- Abstract: Steady-state Superconducting Tokamak (SST-1) was installed and it is commissioning for overall vacuum integrity, magnet systems functionality in terms of successful cool down to 4.5 K and charging up to 10 kA current was started from August 2012. Plasma operation of 100 kA current for more than 100 ms was also envisaged. It is comprised of vacuum vessel (VV) and cryostat (CST). Vacuum vessel, an ultra-high (UHV) vacuum chamber with net volume of 23 m{sup 3} was maintained at the base pressure of 6.3 × 10{sup −7} mbar for plasma confinement. Cryostat, a high-vacuum (HV) chamber with empty volume 39 m{sup 3} housing superconducting magnet system, bubble thermal shields and hydraulics for these circuits, maintained at 1.3 × 10{sup −5} mbar in order to provide suitable environment for these components. In order to achieve these ultimate vacuums, two numbers of turbo-molecular pumps (TMP) are installed in vacuum vessel while three numbers of turbo-molecular pumps are installed in cryostat. Initial pumping of both the chambers was carried out by using suitable Roots pumps. PXI based real time controlled system is used for remote operation of the complete pumping operation. In order to achieve UHV inside the vacuum vessel, it was baked at 150 °C for longer duration. Aluminum wire-seals were used for all non-circular demountable ports and a leak tightness < 1.0 × 10{sup −9} mbar l/s were achieved.

  5. SU-E-J-129: Atlas Development for Cardiac Automatic Contouring Using Multi-Atlas Segmentation

    International Nuclear Information System (INIS)

    Zhou, R; Yang, J; Pan, T; Milgrom, S; Pinnix, C; Shi, A; Yang, J; Liu, Y; Nguyen, Q; Gomez, D; Dabaja, B; Balter, P; Court, L; Liao, Z

    2015-01-01

    Purpose: To develop a set of atlases for automatic contouring of cardiac structures to determine heart radiation dose and the associated toxicity. Methods: Six thoracic cancer patients with both contrast and non-contrast CT images were acquired for this study. Eight radiation oncologists manually and independently delineated cardiac contours on the non-contrast CT by referring to the fused contrast CT and following the RTOG 1106 atlas contouring guideline. Fifteen regions of interest (ROIs) were delineated, including heart, four chambers, four coronary arteries, pulmonary artery and vein, inferior and superior vena cava, and ascending and descending aorta. Individual expert contours were fused using the simultaneous truth and performance level estimation (STAPLE) algorithm for each ROI and each patient. The fused contours became atlases for an in-house multi-atlas segmentation. Using leave-one-out test, we generated auto-segmented contours for each ROI and each patient. The auto-segmented contours were compared with the fused contours using the Dice similarity coefficient (DSC) and the mean surface distance (MSD). Results: Inter-observer variability was not obvious for heart, chambers, and aorta but was large for other structures that were not clearly distinguishable on CT image. The average DSC between individual expert contours and the fused contours were less than 50% for coronary arteries and pulmonary vein, and the average MSD were greater than 4.0 mm. The largest MSD of expert contours deviating from the fused contours was 2.5 cm. The mean DSC and MSD of auto-segmented contours were within one standard deviation of expert contouring variability except the right coronary artery. The coronary arteries, vena cava, and pulmonary vein had DSC<70% and MSD>3.0 mm. Conclusion: A set of cardiac atlases was created for cardiac automatic contouring, the accuracy of which was comparable to the variability in expert contouring. However, substantial modification may need

  6. UHV testing of vacuum components and diagnostic devices, related to installation of Undulators in Indus-2

    International Nuclear Information System (INIS)

    Ratnakala, K.C.; Tiwari, S.K.; Bhange, N.J.; Yadav, D.P.; Babbar, L.K.; Netram; Sridhar, R.

    2015-01-01

    Two Insertion Devices, both planar Undulators (U1 and U2), have been successfully installed and commissioned in Indus-2, in Raja Ramanna Centre for Advanced Technology, Indore. The radiation from these Undulators are expected to be 2 to 3 orders of magnitude brighter than the radiation from the Bending Magnets. As required for the installation of these Insertion Devices in Indus-2 ring, two vacuum sections (LS 2 and LS 3) were modified. Apart from the main Undulator chambers (which were procured from the Manufacturer), several other components were developed in UHVT Section and Beam Diagnostic Section, for this purpose. The components include Taper chambers, Beam Position Indicators (both Insertion Device BPI-s and Upgraded BPI-s) and RF shielded bellows.Taper chambers were needed for the smooth transition of cross-section of vacuum envelope, from the normal straight section chamber (with dimensions: 36 mm x 86 mm) to the Undulator chamber (with dimensions: 17 mm x 81 mm). These chambers were required at both entry and exit of Undulator chambers. IDBPI-s and Upgraded BPI-s were needed for the precise monitoring of electron beam position, before the entry into the Undulator and after exiting the Undulator, at various critical positions. Bellows were required to be connected at various positions, during the assembly of vacuum chambers, for the mechanical flexibility. RF shielding was mandatory inside these bellows, to provide a smooth contour of the vacuum envelope, inside these bellows. All these components were tested in the UHV Lab, and confirmed for their UHV compatibility, prior to the actual assembly in the ring. Afterwards, these components were successfully installed in Indus-2 ring, by December, 2014. This paper narrates the UHV-tests carried out, including the assembly, leak-testing, baking, pumping etc. and the results. (author)

  7. The vacuum platform

    Science.gov (United States)

    McNab, A.

    2017-10-01

    This paper describes GridPP’s Vacuum Platform for managing virtual machines (VMs), which has been used to run production workloads for WLCG and other HEP experiments. The platform provides a uniform interface between VMs and the sites they run at, whether the site is organised as an Infrastructure-as-a-Service cloud system such as OpenStack, or an Infrastructure-as-a-Client system such as Vac. The paper describes our experience in using this platform, in developing and operating VM lifecycle managers Vac and Vcycle, and in interacting with VMs provided by LHCb, ATLAS, ALICE, CMS, and the GridPP DIRAC service to run production workloads.

  8. Numerical study on the performance of vacuum cooler and evaporation-boiling phenomena during vacuum cooling of cooked meat

    International Nuclear Information System (INIS)

    Jin, T.X.; Xu, L.

    2006-01-01

    The vacuum cooling of cooked meats is described in this paper. Based on the energy and mass balance, a modified mathematical model based on a previous model is developed to analyze the performance of the vacuum cooler and the evaporation-boiling phenomena during vacuum cooling of cooked meat. Validation experimentation is performed in the designed vacuum cooler. Boiling occurs inside the cooked meat. There is a boiling front, and the boiling front moves toward the center of the cooked meat as the vacuum cooling proceeds. The experimental data are compared with the simulation results. It is found that the differences of the temperature between the simulation and the experimentation are within 5 deg. C, and the deviation of weight loss between the simulation and the experimentation is within 4%. The simulation results agree with the experimental data well. The modified model can be used to predict the variation of the vacuum pressure in the chamber, the temperature and pressure distributions and the weight loss profiles of cylindrical cooked meats

  9. Performance Validation of the ATLAS Muon Spectrometer

    CERN Document Server

    Mair, Katharina

    ATLAS (A Toroidal LHC ApparatuS) is a general-purpose experiment for the future Large Hadron Collider (LHC) at CERN, which is scheduled to begin operation in the year 2007, providing experiments with proton-proton collisions. The center-of-mass energy of 14TeV and the design luminosity of 1034 cm−2s−1 will allow to explore many new aspects of fundamental physics. The ATLAS Muon Spectrometer aims at a momentum resolution better than 10% for transverse momentum values ranging from pT = 6 GeV to pT = 1TeV. Precision tracking will be performed by Ar-CO2-gas filled Monitored Drift Tube chambers (MDTs), with a single wire resolution of < 100 μm. In total, about 1 200 chambers, arranged in a large structure, will allow muon track measurements over distances up to 15m in a magnetic field of 0.5 T. Given the large size of the spectrometer it is impossible to keep the shape of the muon chambers and their positions stable within the requested tracking accuracy of 50 μm. Therefore the concept of an optical alig...

  10. Spanish Minister of Science and Technology visits ATLAS

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    H.E. Mr Josep Piqué i Camps, Minister for Science and Technology, Spain, came to CERN in November. He is seen here visiting the ATLAS assembly hall. Photo 01: The Minister (left) is greeted by Peter Jenni, spokesperson for the ATLAS collaboration. In the centre is Matteo Cavalli-Sforza, Spanish scientist at CERN. Photo 02: The Minister (left) in discussion with Peter Jenni. Photo 03: Peter Jenni shows the visitors one of eight vacuum vessels being built by Spanish company Felguera Construcciones Mecanicas SA for the superconducting coils of the air-core ATLAS barrel toroid magnet system: (left to right) Matteo Cavalli-Sforza of CERN; the Minister; M. Aguilar-Benitez, Spanish delegate to CERN Council; G. Léon; and Peter Jenni.

  11. File list: Unc.Adl.50.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Adl.50.AllAg.Egg_chamber dm3 Unclassified Adult Egg chamber SRX914955,SRX914951...,SRX914953 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Unc.Adl.50.AllAg.Egg_chamber.bed ...

  12. Laser Welding Test Results with Gas Atmospheres in Welding Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Chang-Young; Hong, Jin-Tae; Ahn, Sung-Ho; Heo, Sung-Ho; Jang, Seo-Yun; Yang, Tae-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The weld beads of specimens welded under identical conditions in the helium and argon gas were cleaner, more regular, and steadier than those in a vacuum. The penetration depth of the FZ in the vacuum was much deeper than those in the helium and argon gas. To measure the irradiation properties of nuclear fuel in a test reactor, a nuclear fuel test rod instrumented with various sensors must be fabricated with assembly processes. A laser welding system to assemble the nuclear fuel test rod was designed and fabricated to develop various welding technologies of the fuel test rods to joint between a cladding tube and end-caps. It is an air-cooling optical fiber type and its emission modes are a continuous (CW) mode of which the laser generates continuous emission, and pulse (QCW) mode in which the laser internally generates sequences of pulses. We considered the system welding a sample in a chamber that can weld a specimen in a vacuum and inert gas atmosphere, and the chamber was installed on the working plate of the laser welding system. In the chamber, the laser welding process should be conducted to have no defects on the sealing area between a cladding tube and an end-cap.

  13. File list: Unc.Adl.10.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Adl.10.AllAg.Egg_chamber dm3 Unclassified Adult Egg chamber SRX914951,SRX914955...,SRX914953,SRX914957 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Unc.Adl.10.AllAg.Egg_chamber.bed ...

  14. File list: Unc.Adl.05.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Adl.05.AllAg.Egg_chamber dm3 Unclassified Adult Egg chamber SRX914955,SRX914951...,SRX914953,SRX914957 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Unc.Adl.05.AllAg.Egg_chamber.bed ...

  15. File list: Unc.Adl.20.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Adl.20.AllAg.Egg_chamber dm3 Unclassified Adult Egg chamber SRX914951,SRX914955...,SRX914953,SRX914957 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Unc.Adl.20.AllAg.Egg_chamber.bed ...

  16. ATLAS RPC commissioning status and cosmic ray test results

    CERN Document Server

    Bianco, Michele

    2009-01-01

    The muon trigger system of the ATLAS experiment consists of several sub-systems and each of them need to be tested and certified before LHC operation. In the barrel region Resistive Plate Chambers are employed. RPC detector and its level-1 trigger electronics are designed to detect and select high momentum muons with high time resolution and good tracking capability for a total surface of about 4000 m2. The commissioning phase provided an unique opportunity to demonstrate, before LHC start-up, the functionality of the muon trigger components such as detector chambers, level-1 trigger electronics, detector slow control system, data acquisition chain, software and computing. We present the status of ATLAS RPC detector, the problems met during the commissioning and the solutions found and, finally, its performances as obtained by acquiring cosmic rays.

  17. Feasibility study of vacuum technology integrated fused deposition ...

    African Journals Online (AJOL)

    vacuum pump connected will absorb the air inside the chamber until desire pressure while printing object. Mitutoyo SJ-301 portable surface roughness tester and optical microscope used to analyze the quality of surface finish. Result reveal with ...

  18. Compact vacuum insulation embodiments

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1992-04-28

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point' or line' contacts with the metal wall sheets. In the case of monolithic spacers that form line' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included. 26 figs.

  19. File list: Oth.Adl.50.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Adl.50.AllAg.Egg_chamber dm3 TFs and others Adult Egg chamber SRX706815,SRX7068...11,SRX706814,SRX706810 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.Adl.50.AllAg.Egg_chamber.bed ...

  20. File list: Oth.Adl.05.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Adl.05.AllAg.Egg_chamber dm3 TFs and others Adult Egg chamber SRX706810,SRX7068...14,SRX706815,SRX706811 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.Adl.05.AllAg.Egg_chamber.bed ...

  1. File list: Oth.Adl.10.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Adl.10.AllAg.Egg_chamber dm3 TFs and others Adult Egg chamber SRX706814,SRX7068...10,SRX706815,SRX706811 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.Adl.10.AllAg.Egg_chamber.bed ...

  2. File list: Oth.Adl.20.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Adl.20.AllAg.Egg_chamber dm3 TFs and others Adult Egg chamber SRX706814,SRX7068...11,SRX706815,SRX706810 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Oth.Adl.20.AllAg.Egg_chamber.bed ...

  3. Vacuum system for the test accumulation ring for the NUMATRON project (TARN)

    International Nuclear Information System (INIS)

    Mizobuchi, Akira

    1979-01-01

    The vacuum system for the test accumulation ring for the NUMATRON project (TARN) being constructed in the Institute for Nuclear Study, University of Tokyo, for the purpose of accumulating fundamental data on high energy, heavy ion acceleration is presented. The main specifications of TARN are as follows: repetition rate 1 Hz, average radius 5.06 m, the radius of curvature 1.333 m, circumference 31.795 m, the length of a unit cell 3.974 m, the length of a long straight section 1.8 m, the number of unit cells 8, superperiodicity 8, and the structure of a unit cell FODO. The vacuum level of TARN lower than 1 x 10 -10 Torr is necessary. The preliminary test apparatuses, number one and two, for obtaining the basic data on superhigh vacuum were constructed. The characteristics of a molecular vacuum pump and the high temperature baking effect were tested with the number one test apparatus. The glow discharge cleaning effect of the model vacuum chamber for deflecting magnets was tested, utilizing the number two test apparatus. The pressure curve in course of time during pump down, the residual gas components, the residual gas spectrum in vacuum state and the change of residual gas components before and after the glow discharge cleaning are shown as these testing results. The vacuum gauges, which are used for TARN for measuring both the total pressure and the partial pressure of gas, are explained. The vacuum system, the vacuum chamber, the vacuum pumps, the expected exhausting speed and the partial functional test results for the vacuum system are introduced. (Nakai, Y.)

  4. Overall behaviour of PFC integrated SST-1 vacuum system

    Science.gov (United States)

    Khan, Ziauddin; Raval, Dilip C.; Paravasu, Yuvakiran; Semwal, Pratibha; Dhanani, Kalpeshkumar R.; George, Siju; Shoaib, Mohammad; Prakash, Arun; Babu, Gattu R.; Thankey, Prashant; Pathan, Firozkhan S.; Pradhan, Subrata

    2017-04-01

    As a part of phase-I up-gradation of Steady-state Superconducting Tokamak (SST-1), Graphite Plasma Facing Components (PFCs) have been integrated inside SST-1 vacuum vessel as a first wall (FW) during Nov 14 and May 2015. The SST-1 FW has a total surface area of the installed PFCs exposed to plasma is ∼ 40 m2 which is nearly 50% of the total surface area of stainless steel vacuum chamber (∼75 m2). The volume of the vessel within the PFCs is ∼ 16 m3. After the integration of PFCs, the entire vessel as well as the PFC cooling/baking circuits has been qualified with an integrated helium leak tightness of baked at 250 °C for nearly 20 hours employing hot nitrogen gas to remove the absorbed water vapours. Thereafter, Helium glow discharges cleaning were carried out towards the removal of surface impurities. The pump down characteristics of SST-1 vacuum chamber and the changes in the residual gaseous impurities after the installation of the PFCs will be discussed in this paper.

  5. Strategy for allocating the MSD magnets and vacuum chambers

    CERN Document Server

    Gyr, M; Jeanneret, Jean Bernard; Ramberger, S

    2006-01-01

    An analogous strategy as applied for the MSI septum magnets allows an optimisation of the installation of the MSD septa regarding magnet and chamber allocation. Even if the gain in aperture is small, of the order of half a millimetre, it is not negligible and- being essentially for free - should nevertheless be implemented.

  6. Review of vacuum systems for x-ray lithography light sources

    International Nuclear Information System (INIS)

    Schuchman, J.C.

    1990-01-01

    This paper will review and give a status report on vacuum systems for X-Ray lithography light sources. It will include conventional machines and compact machines (machines using superconducting magnets). The vacuum systems will be described and compared with regard to basic machine parameters, pumping systems, types of pumps, chamber design and material, gauging and diagnostics, and machine performane. 23 refs., 8 figs., 1 tab

  7. ANSYS有限元法在测长绝热真空腔二维热分析中的应用%Two-dimentional Thermal Analysis of Adiabatic Vacuum Chamber with ANSYS Finite Element Simulation

    Institute of Scientific and Technical Information of China (English)

    杨丽峰; 罗志勇; 徐爱华

    2012-01-01

    According to the difficulties of measuring temperature distribution in the adiabatic vacuum chamber, the method of combing ANSYS finite element simulation with experimental study is proposed. ANSYS finite element modeling, parameter identification, meshing, applying loads, and the solution process are described. Simulation results show that changes in ambient temperature 1℃ , heat insulation vacuum chamber temperature will change 0. 085 ℃, and verify the simulation results of the experiments. Test results show that use of the simulation can be accurate and reliable analysis of insulation vacuum chamber temperature, and improve test efficiency and reduce experimental costs.%针对测长绝热真空腔内温度场测量困难的特点,提出应用ANSYS有限元仿真与实验研究相结合的方法进行二维热分析.详细介绍了真空腔的ANSYS有限元建模、参数确定、网格划分、施加载荷和求解过程.仿真结果表明外界环境温度变化1℃,绝热真空腔内温度将变化0.085℃.对仿真结果进行了实验验证,实验结果证明利用该仿真技术可准确、可靠地分析绝热真空腔内的温度场,并且提高实验效率的同时降低了实验成本.

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

    International Nuclear Information System (INIS)

    Rose, D.V.; Welch, D.R.; Oliver, B.V.; Clark, R.E.; Sharp, W.M.; Friedman, A.

    2001-01-01

    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

  9. Test and performances of the RPC trigger chambers of the ATLAS experiment at LHC

    CERN Document Server

    Aielli, G; Ammosov, A; Biglietti, M; Brambilla, Elena; Camarri, P; Canale, V; Caprio, M A; Cardarelli, R; Carlino, G; Cataldi, G; Chiodini, G; Di Simone, A; Di Ciaccio, A; Della Volpe, D; De Asmundis, R; Della Pietra, M; Grancagnolo, F; Gorini, E; Iengo, P; Liberti, B; Patricelli, S; Perrino, R; Primavera, M; Santonico, R; Sehkniadze, G; Spagnolo, S; Sviridov, Yu; Zaetz, V G

    2004-01-01

    RPCs will be used as trigger detectors in the barrel region of the Muon Spectrometer of the ATLAS experiment at LHC. The total number of RPC units to be installed is 1088, covering a total surface of about 3500m**2. ATLAS RPCs work in avalanche mode with C//2H//2F //4/C//4H //1//0/SF//6 (94.7%/5%/0.3%) gas mixture. A cosmic ray test stand has been designed and built in Naples laboratories in order to carry out a complete test of the ATLAS RPC units. Since August 2002 about 300 units have been tested. A description of the test stand, test procedure and results are presented.

  10. File list: ALL.Adl.50.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Adl.50.AllAg.Egg_chamber dm3 All antigens Adult Egg chamber SRX914955,SRX914951...16,SRX914954,SRX914966,SRX706813,SRX914963,SRX914959,SRX706814,SRX706810,SRX914953 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Adl.50.AllAg.Egg_chamber.bed ...

  11. Ion-stimulated Gas Desorption Yields of Electropolished, Chemically Etched, and Coated (Au, Ag, Pd, TiZrV) Stainless Steel Vacuum Chambers and St707 Getter Strips Irradiated with 4.2 MeV/u lead ions

    CERN Document Server

    Mahner, E; Küchler, D; Malabaila, M; Taborelli, M

    2005-01-01

    The ion-induced desorption experiment, installed in the CERN Heavy Ion Accelerator LINAC 3, has been used to measure molecular desorption yields for 4.2 MeV/u lead ions impacting under grazing incidence on different accelerator-type vacuum chambers. Desorption yields for H2, CH4, CO, and CO2, which are of fundamental interest for future accelerator applications, are reported for different stainless steel surface treatments. In order to study the effect of the surface oxide layer on the gas desorption, gold-, silver-, palladium-, and getter-coated 316 LN stainless steel chambers and similarly prepared samples were tested for desorption at LINAC 3 and analysed for chemical composition by X-ray Photoemission Spectroscopy (XPS). The large effective desorption yield of 2 x 104 molecules/Pb53+ ion, previously measured for uncoated, vacuum fired stainless steel, was reduced after noble-metal coating by up to 2 orders of magnitude. In addition, pressure rise measurements, the effectiveness of beam scrubbing with le...

  12. Study of the Higgs boson discovery potential in the process pp→H/A→μ+μ-/τ+τ- with the ATLAS detector

    International Nuclear Information System (INIS)

    Dedes, Georgios

    2008-01-01

    In this thesis, the discovery potential of the ATLAS experiment at the Large Hadron Collider (LHC) at CERN for the heavy neutral Higgs bosons H/A of theMinimal Supersymmetric extension of the Standard Model of particle physics (MSSM) in the decay channels H/A→τ + τ - →e/μ+X and H/A→μ + μ - has been studied. The ATLAS detector is designed to study the full spectrum of the physics phenomena occuring in the proton-proton collisions at 14 TeV center-of-mass energy and to provide answers to the question of the origin of particle masses and of electroweak symmetry breaking. For the studies, the ATLAS muon spectrometer plays an important role. The spectrometer allows for a precise muon momentum measurement independently of other ATLAS subdetectors. The performance of the muon spectrometer depends strongly on the performance of the muon tracking detectors, the Monitored Drift Tube Chambers (MDT). Computer programs have been developed in order to test and verify the ATLAS muon spectrometer simulation, an essential ingredient for data analysis. In addition, dedicated programs for the monitoring of the quality of the data collected by the muon spectrometer have been developed and tested with data from cosmic ray muons. High-quality cosmic ray muon data have been used for the calibration of the MDT-chambers. A new calibration method, called analytical autocalibration, has been tested. The proposed method achieved the required accuracy of 20 μm in the determination of the space-to-drift-time relationship of the drift tubes of the MDT chambers with only 2000 muon tracks per chamber. Reliable muon detector simulation and calibration are essential for the study of the MSSM Higgs boson decays H/A→τ + τ - →e/μ+X and H/A→μ + μ - and of the corresponding background processes. The signal selection and background rejection requirements have been optimized for maximum signal significance. The following results have been obtained for different assumptions on the

  13. File list: His.Adl.20.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adl.20.AllAg.Egg_chamber dm3 Histone Adult Egg chamber SRX914961,SRX914956,SRX9...14959,SRX914952,SRX914963,SRX914962,SRX914960,SRX914958,SRX914966,SRX914964,SRX914954 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Adl.20.AllAg.Egg_chamber.bed ...

  14. File list: ALL.Adl.10.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Adl.10.AllAg.Egg_chamber dm3 All antigens Adult Egg chamber SRX914951,SRX914955...58,SRX706813,SRX706815,SRX914957,SRX706816,SRX914964,SRX706811,SRX914966,SRX914954,SRX706812 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Adl.10.AllAg.Egg_chamber.bed ...

  15. File list: ALL.Adl.20.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Adl.20.AllAg.Egg_chamber dm3 All antigens Adult Egg chamber SRX914951,SRX914955...13,SRX914958,SRX914966,SRX914964,SRX706811,SRX914954,SRX706815,SRX706812,SRX706816,SRX706810 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Adl.20.AllAg.Egg_chamber.bed ...

  16. File list: His.Adl.10.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adl.10.AllAg.Egg_chamber dm3 Histone Adult Egg chamber SRX914961,SRX914952,SRX9...14956,SRX914959,SRX914960,SRX914963,SRX914962,SRX914958,SRX914964,SRX914966,SRX914954 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Adl.10.AllAg.Egg_chamber.bed ...

  17. File list: His.Adl.50.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adl.50.AllAg.Egg_chamber dm3 Histone Adult Egg chamber SRX914961,SRX914956,SRX9...14962,SRX914952,SRX914960,SRX914958,SRX914964,SRX914954,SRX914966,SRX914963,SRX914959 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/His.Adl.50.AllAg.Egg_chamber.bed ...

  18. Design of a chamber for deposit of thin films by laser ablation; Diseno de una camara para el deposito de peliculas delgadas por ablacion laser

    Energy Technology Data Exchange (ETDEWEB)

    Chirino O, S

    2001-07-01

    The present work has as purpose to design a vacuum chamber, to the one that is denominated chamber of ablation, in which were carried out deposits of thin films using the well-known technique as laser ablation. To fulfill the purpose, the work has been distributed in the following way: in the chapter 1 there are discussed the generalities of the technique of ablation laser for the obtaining of materials in form of thin film, in the chapter 2 the basic concepts of the vacuum technology are mentioned that includes among other things, systems to produce vacuum and vacuum gages and in the chapter 3 the design of the chamber is presented with the accessories and specific systems. (Author)

  19. The vacuum system of the Karlsruhe magnetic spectrograph 'Little John'

    International Nuclear Information System (INIS)

    Buschmann, J.; Gils, H.J.; Jelitto, H.; Krisch, J.; Ludwig, G.; Manger, D.; Rebel, H.; Seith, W.; Zagromski, S.

    1985-02-01

    The vacuum equipment of the magnetic spectrograph Little John is described. The system is characterized by the following special features: The sliding exit flange of the target chamber can be moved to the desired angle of observation without affecting the high vacuum. The pressure maintained is less by a factor of ten than the pressure in the incoming beam tubing. The vacuum system is divided into several separate pumping sections. Ground loops are strictly avoided. All actual states of relevance are fed back to the control panels. The vacuum installation is protected by hardware interlocking systems as well as by a real time program written in FORTRAN in cooperation with CAMAC interfacing. (orig.) [de

  20. Dynamics of vacuum-sealed, double-leaf partitions

    Science.gov (United States)

    Kavanaugh, Joshua Stephen

    The goal of this research is to investigate the feasibility and potential effectiveness of using vacuum-sealed, double-leaf partitions for applications in noise control. Substantial work has been done previously on double-leaf partitions where the acoustics of the inner chamber and mechanical vibrations of structural supports are passively and actively controlled. The work presented here is unique in that the proposed system aims to eliminate the need for active acoustic control of transmitted acoustic energy by removing all the air between the two panels of the double partition. Therefore, the only remaining energy paths would be along the boundary and at the points where there are intermediate structural supports connecting the two panels. The eventual goal of the research is to develop a high-loss double-leaf partition that simplifies active control by removing the need for control of the air cavity and channeling all the energy into discrete structural paths. The work presented here is a first step towards the goal of designing a high-loss, actively-controlled double-leaf partition with an air-evacuated inner chamber. One experiment is conducted to investigate the effects of various levels of vacuum on the response of a double-leaf partition whose panels are mechanically coupled only at the boundary. Another experiment is conducted which investigates the effect of changing the stiffness of an intermediate support coupling the two panels of a double-leaf partition in which a vacuum has been applied to the inner cavity. The available equipment was able to maintain a 99% vacuum between the panels. Both experiments are accompanied by analytical models used to investigate the importance of various dynamic parameters. Results show that the vacuum-sealed system shows some potential for increased transmission loss, primarily by the changing the natural frequencies of the double-leaf partition.

  1. Aging Analysis of Micromegas Detectors for ATLAS New Small Wheel

    CERN Document Server

    Quinnan, Melissa

    2015-01-01

    In preparation for the coming High Luminosity Large Hadron Collider (HL-LHC) upgrade, the New Small Wheel (NSW) will replace the Small Wheel of the ATLAS Muon Spectrometer as part of the 2018 ATLAS Phase-I upgrade. Micromegas (MM) detectors will serve as one component of the NSW. These gaseous micro-mesh detectors will accommodate the higher luminosity and trigger rate of the future HL-LHC.In order to predict performance of MM after several years in the HL-LHC, radiation aging tests were conducted in the Gamma Irradiation Facility (GIF++) using a Cs 137 source. Two small MM prototype "T" chambers were irradiated and studied over the course of several months to accelerate the aging process and characterize chamber behavior. This report outlines a record of the aging process thus far and demonstrates techniques used to describe aging effects, namely measurements of average current, integrated charge, and gain. These will be used in the ongoing aging analysis of the T chambers and in future aging studies of the ...

  2. The measurement of vacuum at high voltage terminal of the FOTIA facility at BARC

    International Nuclear Information System (INIS)

    Kansara, M.J.; Sapna, P.; Subrahmanyam, N.B.V.; Bhatt, J.P.; Gupta, S.K.; Singh, P.

    2003-01-01

    Full text: In FOTIA, the ion beams accelerated by the low energy tube are injected into the high-energy accelerating tube using the 180 deg folding magnet. In order to have maximum transmission through the magnet chamber the vacuum in this section should be in the range of 10 -8 Torr. The chamber is very narrow (14 mm x 24 mm) and offers low conductance to the vacuum system. For maintaining the required UHV inside this chamber and associated beam lines inside the high voltage terminal at 6 MV, a sputter ion pump (120 litres/sec) is used. However, the control of the ion pump and measurement of the vacuum in the chamber has to be done from the control consol located at ground potential. This has been accomplished through a fibre optic data telemetry system, which offers electrical isolation of 6 MV. This fibre optic system is integrated to the main control system of the FOTIA. For controlling and monitoring the ion pump DOUT and ADC modules of the CAMAC system are used to provide interfacing signals to the fibre optic system. For the measurement of the vacuum, the gauge output provided by the ion pump is converted to a suitable light signal (1 kHz to 10 kHz) and is transmitted to the fibre optic link box (located at ground). At ground level this light signal is converted back to a voltage signal and transmitted to ADC module of the CAMAC system. This voltage signal is calibrated against the vacuum measured in the terminal, which is available in the control room via computer connected to the CAMAC system. In this paper, details of the above system will be presented

  3. Safety and operational aspects in in-situ electrical baking of large vacuum systems of Indus accelerators

    International Nuclear Information System (INIS)

    Bhatnagar, Prateek; Bhange, Nilesh; Joshi, Sujata; Sridhar, R.

    2016-01-01

    In order to achieve pressures in UHV (Ultra High Vacuum) range, the vacuum chambers and associated vacuum components, necessarily made of UHV compatible materials, should be baked sufficiently long enough so as to reduce outgassing rates. The baking period usually ranges from 48 hours to 72 hours for an electrical load of more than 30 kW per sector, in which baking temperatures, a characteristic parameter and specific to material, range from 150°C-180°C for Aluminium alloy and 250°C-300°C for SS (stainless steel). Indus accelerators vacuum installations include more than 300 m long vacuum chamber which are subjected to rigorous, standardized and labour intensive electrical baking procedure involving an intelligent ON-OFF distributed temperature control system with in-built defence of electrical safety and expandability as per the needs. The paper discusses various in built electrical safely features, operational aspects, work practices and challenges involved in accomplishing an interrupt free continuous electrical baking for distributed electrical load of more than 30 kW for a typical vacuum segment of Indus accelerator. (author)

  4. Electromagnetic seal for the impulse feeding of gases into vacuum apparatuses

    International Nuclear Information System (INIS)

    Derevyankin, G.E.; Dudnikov, V.G.; Zhuravlyov, P.A.

    The construction of an electromagnetic seal for the impulse feeding of gases into vacuum systems is described. The seal feeds small bursts of gas into an evacuated chamber at frequencies up to 10 3 Hz. The long lifetime of the seal (more than 10 9 cycles) results from the elimination of stressed metallic components and the use of ''Viton'' for the vacuum gasket under the valve

  5. Performance of ATLAS RPC Level-1 muon trigger during the 2015 data taking

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00001854; The ATLAS collaboration

    2016-01-01

    RPCs are used in the ATLAS experiment at the LHC for muon trigger in the barrel region, which corresponds to |eta|<1.05. The status of the barrel trigger system during the 2015 data taking is presented, including measurements of the RPC detector efficiencies and of the trigger performance. The RPC system has been active in more than 99.9% of the ATLAS data taking, showing very good reliability. The RPC detector efficiencies were close to Run-1 and to design value. The trigger efficiency for the high-pT thresholds used in single-muon triggers has been approximately 4% lower than in Run 1, mostly because of chambers disconnected from HV due to gas leaks. Two minor upgrades have been performed in preparation of Run 2 by adding the so-called feet and elevator chambers to increase the system acceptance. The feet chambers have been commissioned during 2015 and are included in the trigger since the last 2015 runs. Part of the elevator chambers are still in commissioning phase and will probably need a replacement ...

  6. Thermal analysis simulation for a spin-motor used in the advanced main combustion chamber vacuum plasma spray project using the SINDA computer program

    Science.gov (United States)

    Mcdonald, Gary H.

    1990-01-01

    One of the many design challenges of this project is predicting the thermal effects due to the environment inside the vacuum chamber on the turntable and spin motor spindle assembly. The objective of the study is to model the spin motor using the computer program System Improved Numerical Differencing Analyzer (SINDA). By formulating the appropriate input information concerning the motor's geometry, coolant flow path, material composition, and bearing and motor winding characteristics, SINDA should predict temperatures at various predefined nodes. From these temperatures, hopefully, one can predict if the coolant flow rate is sufficient or if certain mechanical elements such as bearings, O ring seals, or motor windings will exceed maximum design temperatures.

  7. Thermal System Upgrade of the Space Environment Simulation Test Chamber

    Science.gov (United States)

    Desai, Ashok B.

    1997-01-01

    The paper deals with the refurbishing and upgrade of the thermal system for the existing thermal vacuum test facility, the Space Environment Simulator, at NASA's Goddard Space Flight Center. The chamber is the largest such facility at the center. This upgrade is the third phase of the long range upgrade of the chamber that has been underway for last few years. The first phase dealt with its vacuum system, the second phase involved the GHe subsystem. The paper describes the considerations of design philosophy options for the thermal system; approaches taken and methodology applied, in the evaluation of the remaining "life" in the chamber shrouds and related equipment by conducting special tests and studies; feasibility and extent of automation, using computer interfaces and Programmable Logic Controllers in the control system and finally, matching the old components to the new ones into an integrated, highly reliable and cost effective thermal system for the facility. This is a multi-year project just started and the paper deals mainly with the plans and approaches to implement the project successfully within schedule and costs.

  8. Performance of the ATLAS muon spectrometer

    International Nuclear Information System (INIS)

    Aleksa, M.

    1999-09-01

    ATLAS is a general-purpose experiment for the future large hadron collider (LHC) at CERN. Its Muon Spectrometer will require ∼5500 m 2 of precision tracking chambers to measure the muon tracks along a spectrometer arm of 5 m to 15 m length, embedded in a magnetic field of ∼0.5 T. 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 LHC physics discovery range indicates the need for a momentum resolution of ∼10 % for muons with a transverse momentum of p T =1 TeV/c. Following a detailed engineering optimisation of the magnetic-field strength versus the chamber resolution, the ATLAS collaboration opted for a drift-chamber system with very high spatial resolution, σ 2 93/7). Measurements performed in a high-background environment - similar to the ATLAS operational environment - gave us a complete understanding of the individual effects which deteriorate the spatial resolution at high rates. Four effects responsible for a resolution deterioration have been identified: two electronics effects which depend on the count rate of a tube (baseline shift and baseline fluctuations), and two space-charge effects that depend on the local count rate (gain drop and field fluctuations). The understanding of these effects had a major impact on the choice of the drift gas and the front-end electronics. The strong dependence of the drift velocity on the drift field is one major disadvantage of the baseline gas. In this work the full set of effects which lead to systematic errors to the track-position measurement in one tube (e.g. variations of the background rate) was investigated and quantified for realistic LHC operating conditions. For the biggest effects analytical corrections are presented. Finally, the muon-system performance was investigated and a calibration method for the absolute mass scale developed. By means of simulation it was shown that the energy

  9. Spanish Minister of Science and Technology visits ATLAS

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    H.E. Mr Josep Piqué i Camps, Minister for Science and Technology, Spain, pictured in front of a barrel toroid cryostat vessel in the ATLAS assembly hall. The air-core ATLAS barrel toroid magnet system will consist of eight large superconducting coils, each in its own vacuum vessel, built by Spanish company Felguera Construcciones Mecanicas SA under the responsibility of IFAE (Institute for High Energy Physics), Barcelona. Photo 01: The Minister in front of the cryostat vessel. Photo 02: The Minister (right) with H.E. Mr Joaquin Pérez-Villanueva y Tovar, Spanish Ambassador to the United Nations in Geneva. Photo 03: (left to right) Manuel Delfino, leader of the Information Technology division at CERN; Matteo Cavalli-Sforza of CERN; Juan Antonio Rubio, leader of the Education and Technology Transfer division at CERN; The Minister; and Peter Jenni, ATLAS spokesperson.

  10. File list: InP.Adl.20.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Adl.20.AllAg.Egg_chamber dm3 Input control Adult Egg chamber SRX706813,SRX70681...2,SRX706816 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Adl.20.AllAg.Egg_chamber.bed ...

  11. File list: InP.Adl.50.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Adl.50.AllAg.Egg_chamber dm3 Input control Adult Egg chamber SRX706812,SRX70681...6,SRX706813 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Adl.50.AllAg.Egg_chamber.bed ...

  12. File list: InP.Adl.05.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Adl.05.AllAg.Egg_chamber dm3 Input control Adult Egg chamber SRX706813,SRX70681...2,SRX706816 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Adl.05.AllAg.Egg_chamber.bed ...

  13. File list: InP.Adl.10.AllAg.Egg_chamber [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Adl.10.AllAg.Egg_chamber dm3 Input control Adult Egg chamber SRX706813,SRX70681...6,SRX706812 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/InP.Adl.10.AllAg.Egg_chamber.bed ...

  14. Neutronics and activation of the preliminary reaction chamber of HiPER reactor based in a SCLL blanket

    Energy Technology Data Exchange (ETDEWEB)

    Juárez, Rafael, E-mail: rafael.juarez@upm.es [Instituto de Fusión Nuclear, UPM, Madrid (Spain); Escuela Técnica Superior de Ingenieros Industriales, UNED, Madrid (Spain); Sanz, Javier; Lopez-Revelles, A.J. [Escuela Técnica Superior de Ingenieros Industriales, UNED, Madrid (Spain); Perlado, José Manuel [Instituto de Fusión Nuclear, UPM, Madrid (Spain)

    2013-10-15

    Highlights: • Neutronic study of a proposal of a reaction chamber for HiPER reactor. • Two options for the blanket size, thin and thick, are studied and compared. • The thin blanket performs better than the thick blanket. • The proposed Vacuum Vessel is unviable as lifetime component in both cases. • Likely solutions for the Vacuum Vessel lifetime extension are explored. -- Abstract: The HiPER reactor design is exploring different reaction chambers. In this study, we tackle the neutronics and activation studies of a preliminary reaction chamber based in the following technologies: unprotected dry wall for the First Wall, self-cooled lead lithium blanket, and independent low activation steel Vacuum Vessel. The most critical free parameter in this stage is the blanket thickness, as a function of the {sup 6}Li enrichment. After a parametric study, we select for study both a “thin” and “thick” blanket, with “high” and “low” {sup 6}Li enrichment respectively, to reach a TBR = 1.1. To help to make a choice, we compute, for both blanket options, in addition to the TBR, the energy amplification factor, the tritium partial pressure, the {sup 203}Hg and {sup 210}Po total activity in the LiPb loop, and the Vacuum Vessel thickness required to guarantee the reweldability during its lifetime. The thin blanket shows a superior performance in the safety related issues and structural viability, but it operates at higher {sup 6}Li enrichment. It is selected for further improvements. The Vacuum Vessel shows to be unviable in both cases, with the thickness varying between 39 and 52 cm. Further chamber modifications, such as the introduction of a neutron reflector, are required to exploit the benefits of the thin blanket with a reasonable Vacuum Vessel.

  15. Rotating target wheel system for super-heavy element production at ATLAS

    CERN Document Server

    Greene, J P; Falout, J; Janssens, R V F

    2004-01-01

    A new scattering chamber housing a large diameter rotating target wheel has been designed and constructed in front of the Fragment Mass Analyzer (FMA) for the production of very heavy nuclei (Z greater than 100) using beams from the Argonne Tandem Linear Accelerator System (ATLAS). In addition to the target and drive system, the chamber is extensively instrumented in order to monitor target performance and deterioration. Capabilities also exist to install rotating entrance and exit windows for gas cooling of the target within the scattering chamber. The design and initial tests are described.

  16. Gases vacuum dedusting and cooling

    Directory of Open Access Journals (Sweden)

    Alexey А. Burov

    2015-03-01

    Full Text Available Represented are the results of operating the ladle degassing vacuum plant (productivity: 120 tons of liquid steel with various dust collectors. The process gases’ cooling and dedusting, obtained in the closed loop buran study, provides opportunity to install a bag filter after that closed loop and its efficient use. Proven is the effectiveness of the cylindrical cyclone replacement with a multichannel (buran dust collector, based on a system of closed-loop (return coupling serially connected curved ducts, where the dusty gas flow rotation axis is vertically positioned. The system of closed-loop serially connected curvilinear channels creates preconditions for the emergence of a negative feedback at the curvilinear gas flow containing transit and circulating flows. These conditions are embodied with circulating flows connecting the in- and outputs of the whole system each channel. The transit flow multiple continuous filtration through the circulating dust layers leads to the formation and accumulation of particles aggregates in the collection chamber. The validity of such a dusty flow control mechanism is confirmed by experimental data obtained in a vacuum chamber. Therefore, replacing one of the two buran’s forevacuum pumps assemblies with the necessary number of curved channels (closed loop is estimated in a promising method.

  17. Development and Testing of an ISRU Soil Mechanics Vacuum Test Facility

    Science.gov (United States)

    Kleinhenz, Julie E.; Wilkinson, R. Allen

    2014-01-01

    For extraterrestrial missions, earth based testing in relevant environments is key to successful hardware development. This is true for both early component level development and system level integration. For In-Situ Resource Utilization (ISRU) on the moon, hardware must interface with the surface material, or regolith, in a vacuum environment. A relevant test environment will therefore involve a vacuum chamber with a controlled, properly conditioned bed of lunar regolith simulant. However, in earth-based granular media, such as lunar regolith simulant, gases trapped within the material pore structures and water adsorbed to all particle surfaces will release when exposed to vacuum. Early vacuum testing has shown that this gas release can occur violently, which loosens and weakens the simulant, altering the consolidation state. A mid-size chamber (3.66 m tall, 1.5 m inner diameter) at the NASA Glenn Research Center has been modified to create a soil mechanics test facility. A 0.64 m deep by 0.914 m square metric ton bed of lunar simulant was placed under vacuum using a variety of pumping techniques. Both GRC-3 and LHT-3M simulant types were used. Data obtained from an electric cone penetrometer can be used to determine strength properties at vacuum including: cohesion, friction angle, bulk density and shear modulus. Simulant disruptions, caused by off-gassing, affected the strength properties, but could be mitigated by reducing pump rate. No disruptions were observed at pressures below 2.5 Torr, regardless of the pump rate. The slow off-gassing of the soil at low pressure lead to long test times; a full week to reach 10(exp -5) Torr. Robotic soil manipulation would enable multiple ISRU hardware test within the same vacuum cycle. The feasibility of a robotically controlled auger and tamper was explored at vacuum conditions.

  18. The vacuum interlock system for the CELSIUS ring

    International Nuclear Information System (INIS)

    Gajewski, K.

    1990-01-01

    A vacuum interlock system has been designed and built for the CELSIUS storage ring. The ultrahigh-vacuum system of CELSIUS has a design pressure of 10 -11 mbar. This is achieved by using vacuum-fired stainless-steel chambers, baking the whole ring to 300degC and running some 50 sputter ion and titanium sublimation pumps. The turbopumps, combined with roughing pumps, are used during the pump-down and the bake-out. The pressure is monitored by Penning vacuum gauges. There is a number of programmable pressure thresholds set to trigger various events (like closing the sector valves, disabling the bake-out, etc.). The interlock system is based on the Mitsubishi programmable logic controller (PLC). An IBM PC is used as an operator's console. The operation and performance of the system is described. On the basis of present experience an upgrading of the system is suggested. (orig.)

  19. Construction and Test of Muon Drift Tube Chambers for High Counting Rates

    CERN Document Server

    Schwegler, Philipp; Dubbert, Jörg

    2010-01-01

    Since the start of operation of the Large Hadron Collider (LHC) at CERN on 20 November 2009, the instantaneous luminosity is steadily increasing. The muon spectrometer of the ATLAS detector at the LHC is instrumented with trigger and precision tracking chambers in a toroidal magnetic field. Monitored Drift-Tube (MDT) chambers are employed as precision tracking chambers, complemented by Cathode Strip Chambers (CSC) in the very forward region where the background counting rate due to neutrons and γ's produced in shielding material and detector components is too high for the MDT chambers. After several upgrades of the CERN accelerator system over the coming decade, the instantaneous luminosity is expected to be raised to about five times the LHC design luminosity. This necessitates replacement of the muon chambers in the regions with the highest background radiation rates in the so-called Small Wheels, which constitute the innermost layers of the muon spectrometer end-caps, by new detectors with higher rate cap...

  20. ATLAS : magnet industrial production Conference MT17

    CERN Multimedia

    2001-01-01

    With overall dimensions of 26 meters in length and 20 meters in diameter, the ATLAS magnet system is the largest integrated superconducting magnet ever built. The system is made up of four super-conducting magnets, a power supply, cryogenics, vacuum, control, and safety systems. The coils are built with Aluminum stabilized NbTi/Cu superconductor indirectly cooled at 4.5 K by liquid Helium forced flow.

  1. Quality Management of CERN Vacuum Controls

    CERN Document Server

    Antoniotti, F; Fortescue-Beck, E; Gama, J; Gomes, P; Le Roux, P; Pereira, H; Pigny, G

    2014-01-01

    The vacuum controls Section (TE-VSC-ICM) is in charge of the monitoring, maintenance and consolidation of the control systems of all accelerators and detectors in CERN; this represents 6 000 instruments distributed along 128 km of vacuum chambers, often of heterogeneous architectures and of diverse technical generations. In order to improve the efficiency of the services provided by ICM, to vacuum experts and to accelerator operators, a Quality Management Plan is being put into place. The first step was the standardization of the naming convention across different accelerators. The traceability of problems, requests, repairs, and other actions, has also been put into place (VTL). This was combined with the effort to identify each individual device by a coded label, and register it in a central database (MTF). Occurring in parallel, was the gathering of old documents and the centralization of information concerning architectures, procedures, equipment and settings (EDMS). To describe the topology of control c...

  2. ATLAS gets its own luminosity detector

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    During the winter shutdown, the ATLAS collaboration has completed the installation of ALFA, the detector system that aims at the LHC absolute luminosity at Point 1 analysing the elastic scattering of protons at small angles.   Upper and lower ALFA Roman Pots as installed in sector 8-1 of the LHC tunnel, 240 metres from the ATLAS Interaction Point. The detectors of the ALFA system are installed at ± 240 meters from the interaction point 1, on either side of the ATLAS detector. The whole system consists of four stations, two on each side of the interaction point. Each station is equipped with two Roman Pots; each pot – that is separated from the vacuum of the accelerator by a thin window but is connected with bellows to the beam-pipe – can be moved very close to the beam. “The Roman Pot technique has been used successfully in the past for the measurement of elastic scattering very close to the circulating beam,” says Patrick Fassn...

  3. First ATLAS Barrel Toroid coil casing arrives at CERN

    CERN Multimedia

    2002-01-01

    The first of eight 25-metre long coil casings for the ATLAS experiment's barrel toroid magnet system arrived at CERN on Saturday 2 March by road from Heidelberg. This structure will be part of the largest superconducting toroid magnet ever made.   The first coil casing for the toroidal magnets of Atlas arrives at Building 180. This is the start of an enormous three-dimensional jigsaw puzzle. Each of the eight sets of double pancake coils will be housed inside aluminium coil casings, which in turn will be held inside a stainless steel vacuum vessel. A huge construction, the casing that arrived at CERN measures 25 metres in length and 5 metres in width. It weighs 20 tones. And this is just the beginning of the toroid jigsaw: by early April a batch of four double pancake coils, which altogether weighs 65 tones, will arrive from Ansaldo in Italy. The first vacuum vessel will also be arriving from Felguera in Spain this month. It will take about two years for all these 25 m long structures of casings, coils a...

  4. Vacuum System and Modeling for the Materials Plasma Exposure Experiment

    International Nuclear Information System (INIS)

    Lumsdaine, Arnold; Meitner, Steve; Graves, Van; Bradley, Craig; Stone, Chris

    2017-01-01

    Understanding the science of plasma-material interactions (PMI) is essential for the future development of fusion facilities. The design of divertors and first walls for the next generation of long-pulse fusion facilities, such as a Fusion Nuclear Science Facility (FNSF) or a DEMO, requires significant PMI research and development. In order to meet this need, a new linear plasma facility, the Materials Plasma Exposure Experiment (MPEX) is proposed, which will produce divertor relevant plasma conditions for these next generation facilities. The device will be capable of handling low activation irradiated samples and be able to remove and replace samples without breaking vacuum. A Target Exchange Chamber (TEC) which can be disconnected from the high field environment in order to perform in-situ diagnostics is planned for the facility as well. The vacuum system for MPEX must be carefully designed in order to meet the requirements of the different heating systems, and to provide conditions at the target similar to those expected in a divertor. An automated coupling-decoupling (“autocoupler”) system is designed to create a high vacuum seal, and will allow the TEC to be disconnected without breaking vacuum in either the TEC or the primary plasma materials interaction chamber. This autocoupler, which can be actuated remotely in the presence of the high magnetic fields, has been designed and prototyped, and shows robustness in a variety of conditions. The vacuum system has been modeled using a simplified finite element analysis, and indicates that the design goals for the pressures in key regions of the facility are achievable.

  5. Estimates of Two-Phase Flow Parameters in the Cyclone Chamber

    Directory of Open Access Journals (Sweden)

    Razva Aleksandr

    2016-01-01

    Full Text Available It provides analysis of methods for assessing circumferential speeds distribution of pressure in the cyclone chamber. It is shown that for cylindrical chambers of less than two diameters and the inlet section of at least 0.1 square cross section the maximum peripheral speed and rate distributions circumferential speeds along the current line is not changed. Analysis of the distribution shows that the concentration of small particles that are typical for gas dedusting systems have a significant impact on the distribution of pressure, vacuum and on the axis of the absolute value decreases toward dust of output section unlike the swirl chambers fuel combustion.

  6. Vacuum system for the Stanford-LBL storage ring (PEP)

    International Nuclear Information System (INIS)

    Bostic, D.; Cummings, U.; Dean, N.; Jeong, B.; Jurow, J.

    1975-03-01

    The vacuum system for PEP will be similar in design, construction and operation to the system currently in operation at SPEAR. There will, of course, be quantitative differences since the closed path of PEP will be 10 times longer than the SPEAR path. Some qualitative differences will also arise since the radiated synchrotron power for PEP will be about 13 times greater than for SPEAR giving rise to an increased linear power density incident on the chamber wall. Other differences arise from the higher energy spectrum of the synchrotron radiation. The SPEAR vacuum system has been in operation since April 1972 and has proven satisfactory in design, construction and operation. The chamber has been subject to synchrotron radiation for approximately 300 ampere-hours and beam lifetimes are now more than several hours. The details of the PEP design and the SPEAR operating experience will be further discussed in this paper. 1 ref., 4 figs

  7. ISRU Soil Mechanics Vacuum Facility: Soil Bin Preparation and Simulant Strength Characterization

    Science.gov (United States)

    Kleinhenz, Julie; Wilkinson, Allen

    2012-01-01

    Testing in relevant environments is key to exploration mission hardware development. This is true on both the component level (in early development) and system level (in late development stages). During ISRU missions the hardware will interface with the soil (digging, roving, etc) in a vacuum environment. A relevant test environment will therefore involve a vacuum chamber with a controlled, conditioned simulant bed. However, in earth-based granular media, such as lunar soil simulant, gases trapped within the material pore structures and water adsorbed to all particle surfaces will release when exposed to vacuum. Early vacuum testing has shown that this gas release can occur violently, which loosens and weakens the simulant, altering the consolidation state. The Vacuum Facility #13, a mid-size chamber (3.66m tall, 1.5m inner diameter) at the NASA Glenn Research Center has been modified to create a soil mechanics test facility. A 0.64m deep by 0.914m square metric ton bed of lunar simulant was placed under vacuum using a variety of pumping techniques. Both GRC-3 and LHT-3M simulant types have been used. An electric cone penetrometer was used to measure simulant strength properties at vacuum including: cohesion, friction angle, bulk density and shear modulus. Simulant disruptions, caused by off gassing, affected the strength properties, but could be mitigated by reducing pump rate. No disruptions were observed at pressures below 2.5Torr, regardless of the pump rate. However, slow off gassing of the soil lead to long test times, a full week, to reach 10-5Torr. This work highlights the need for robotic machine-simulant hardware and operations in vacuum to expeditiously perform (sub-)systems tests.

  8. Miniature pulsed vacuum arc plasma gun and apparatus for thin-film fabrication

    Science.gov (United States)

    Brown, Ian G.; MacGill, Robert A.; Galvin, James E.; Ogletree, David F.; Salmeron, Miquel

    1998-01-01

    A miniature (dime-size in cross-section) vapor vacuum arc plasma gun is described for use in an apparatus to produce thin films. Any conductive material can be layered as a film on virtually any substrate. Because the entire apparatus can easily be contained in a small vacuum chamber, multiple dissimilar layers can be applied without risk of additional contamination. The invention has special applications in semiconductor manufacturing.

  9. Vacuum design for a superconducting mini-collider

    International Nuclear Information System (INIS)

    Barletta, W.A.; Monteiro, S.

    1991-01-01

    The phi factory (Superconducting Mini-Collider or SMC) proposed for construction at UCLA is a single storage ring with circulating currents of 2 A each of electrons and positrons. The small circumference exacerbates the difficulties of handling the gas load due to photodesorption from the chamber walls. The authors analyze the vacuum system for the phi factory to specify design choices

  10. Aging studies of resistive bulk Micromegas chambers for the ATLAS muon spectrometer upgrade

    CERN Document Server

    Spencer, Katie Louise

    2017-01-01

    A long-term operation study is presented as a probe of the aging properties of two bulk-resistive Micromegas chambers installed at the GIF$^{++}$ Gamma Irradiation Facility at CERN. Trends in the instantaneous chamber current, recorded over $\\approx$ 500 days of sustained exposure to the GIF$^{++}$ high intensity photon source, are analysed as a function of time in order to identify any signs of detector aging. As part of the study, additional variations in the current due to the changing external conditions of the chambers must be corrected for in order to isolate any aging effects. These include the changing chamber positions with respect to the photon source and the temperature and pressure fluctuations of the detector gas medium. Due to a number of subsets of the total irradiation period in which the exact detector positions are unknown, the aging study at the present time remains inconclusive. As a result, an alternative long-term aging study utilising the instantaneous chamber dark currents is suggested...

  11. The high-precision x-ray tomograph for quality control of the ATLAS MDT muon spectrometer

    CERN Document Server

    Drakoulakos, D G; Maugain, J M; Rohrbach, F; Sedykh, Yu

    1997-01-01

    For the Large Hadron Collider (LHC) of the next millennium, a large general-purpose high-energy physics experiment, the ATLAS project, is being designed by a world-wide collaboration. One of its detectors, the ATLAS muon tracking detector, the MDT project, is on the scale of a very large industrial project: the design, the construction and assembly of twelve hundred large muon drift chambers are aimed at producing an exceptional quality in terms of accuracy, material reliability, assembly, and monitoring. This detector, based on the concept of very high mechanical precision required by the physics goals, will use tomography as a quality control platform. An X-ray tomograph prototype, monitored by a set of interferometers, has been developed at CERN to provide high-quality control of the MDT chambers which will be built in the collaborating institutes of the ATLAS project. First results have been obtained on MDT prototypes showing the validity of the X-ray tomograph approach for mechanical control of the detec...

  12. Performance of Large Area Micromegas Detectors for the ATLAS Muon Spectrometer Upgrade Project

    CERN Document Server

    Losel, Philipp Jonathan; The ATLAS collaboration; Hertenberger, Ralf; Mueller, Ralph Soeren Peter; Bortfeldt, Jonathan; Flierl, Bernhard Matthias; Zibell, Andre

    2016-01-01

    Four German institutes are building the 32 high-rate capable SM2 Micromegas quadruplets, for the upgrade of the Small Wheels of the ATLAS muon spectrometer. The cathodes and strip-anodes of the m$^2$ in size quadruplets consist of stable honeycomb sandwiches with a requested planarity better than 80 $\\mu$m. The qualification of a full-size SM2 quadruplet, foreseen by ATLAS time schedule for August 2015, will be performed in the Munich Cosmic Ray Measurement Facility (CRMF). Two fully working 4 m$\\times$ 2.2 m ATLAS drift-tube chambers provide muon tracking, a RD51 SRS based data acquisition system provides readout of all 12288 electronic channels using 96 APV25 frontend boards. We report on homogeneity of pulse-height and efficiency and will present measurements of the planarity of the sandwich planes and the positions of the readout-strips. This has been pioneered by studying a $102 \\times 92$ cm$^2$ Micromegas chamber with similar readout pitch in the CRMF using the TPC-like analysis method. At trigger rate...

  13. Studies of ageing effects of Small-Strip Thin Gap Chambers for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00425540; The ATLAS collaboration

    2016-01-01

    The instantaneous luminosity of the Large Hadron Collider at CERN will be increased by up to seven times its design value by undergoing an extensive upgrade program over the coming decade. The largest upgrade project for the ATLAS Muon System is the replacement of the present first station in the forward regions with the so-called New Small Wheels (NSWs), to be installed during the LHC long shutdown in 2019-2020. Small-Strip Thin Gap Chambers (sTGC) detectors are one chosen technology to provide fast trigger and high precision muon tracking under the high luminosity LHC conditions. The basic sTGC structure consists of a grid of gold-plated tungsten wires sandwiched between two resistive cathode planes at a small distance from the wire plane. We study ageing effects of sTGC detectors with a gas mixture of 55\\% of CO$_{2}$ and 45\\% of n-pentane. A sTGC detector was irradiated with beta-rays from a 10~mCi~$^{90}$Sr source. Three different gas flow rates were tested. We observed no deterioration on pulse height o...

  14. Studies of ageing effects of Small-Strip Thin Gap Chambers for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    Gignac, Matthew; The ATLAS collaboration

    2016-01-01

    The instantaneous luminosity of the Large Hadron Collider at CERN will be increased up to a factor of five with respect to the design value by undergoing an extensive upgrade program over the coming decade. The largest upgrade project for the ATLAS Muon System is the replacement of the present first station in the forward regions with the so-called New Small Wheels (NSWs), to be installed during the LHC long shutdown in 2019/20. Small-Strip Thin Gap Chambers (sTGC) detectors are one chosen technology to provide fast trigger and high precision muon tracking under the high luminosity LHC conditions. The basic sTGC structure consists of a grid of gold-plated tungsten wires sandwiched between two resistive cathode planes at a small distance from the wire plane. We study ageing effects of sTGC detectors with a gas mixture of 55% of CO_2 and 45% of n-pentane. A sTGC detector was irradiated with beta-rays from a Sr-90 source. Three different gas flow rates were tested. We observed no deterioration on pulse height of...

  15. Performance of a Full-Size Small-Strip Thin Gap Chamber Prototype for the ATLAS New Small Wheel Muon Upgrade

    CERN Document Server

    Abusleme, Angel; Bellerive, A.; Benhammou, Y.; Botte, J.; Cohen, H.; Davies, M.; Du, Y.; Gauthier, L.; Koffas, T.; Kuleshov, S.; Lefebvre, B.; Li, C.; Lupu, N.; Mikenberg, G.; Mori, D.; Ochoa-Ricoux, J.P.; Perez Codina, E.; Rettie, S.; Robichaud-Véronneau, A.; Rojas, R.; Shoa, M.; Smakhtin, V.; Stelzer, B.; Stelzer-Chilton, O.; Toro, A.; Torres, H.; Ulloa, P.; Vachon, B.; Vasquez, G.; Vdovin, A.; Viel, S.; Walker, P.; Weber, S.; Zhu, C.

    2016-01-01

    The instantaneous luminosity of the Large Hadron Collider at CERN will be increased up to a factor of five with respect to the present design value by undergoing an extensive upgrade program over the coming decade. The most important upgrade project for the ATLAS Muon System is the replacement of the present first station in the forward regions with the so-called New Small Wheels (NSWs). The NSWs will be installed during the LHC long shutdown in 2018/19. Small-Strip Thin Gap Chamber (sTGC) detectors are designed to provide fast trigger and high precision muon tracking under the high luminosity LHC conditions. To validate the design, a full-size prototype sTGC detector of approximately 1.2 $\\times$ $1.0\\, \\mathrm{m}^2$ consisting of four gaps has been constructed. Each gap provides pad, strip and wire readouts. The sTGC intrinsic spatial resolution has been measured in a $32\\, \\mathrm{GeV}$ pion beam test at Fermilab. At perpendicular incidence angle, single gap position resolutions of about $50\\,\\mathrm{\\mu m...

  16. Making MUSIC: A multiple sampling ionization chamber

    International Nuclear Information System (INIS)

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

    2007-01-01

    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. 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

  17. 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.

  18. 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.

  19. Large vacuum system for experiences in magnetic confined plasmas

    International Nuclear Information System (INIS)

    Honda, R.Y.; Kayama, M.E.; Boeckelmann, H.K.; Aihara, S.

    1984-01-01

    It is presented the operation method of a theta-pinch system capable of generating and confine plasmas with high densities and temperatures. Some characteristics of Tupa theta-pinch, which is operating at UNICAMP, emphasizing the cleaning mode of the vacuum chamber, are also presented. (M.C.K.) [pt

  20. Vacuum system of the high energy ring of an asymmetric B-factory based on PEP

    International Nuclear Information System (INIS)

    Barletta, W.A.; Calderon, M.O.; Wong, R.; Jenkins, T.M.

    1991-01-01

    The multi-ampere currents required for high luminosity operation of an asymmetric B factory leads to extremely stressing requirements on a vacuum system suitable for maintaining long beam-gas lifetimes and acceptable background levels in the detector. We present the design for a Cu alloy vacuum chamber and its associated pumping system for the 9 GeV electron storage ring of the proposed B factory based on PEP. The excellent thermal and photo-desorption properties of Cu allows handling the high proton flux in a conventional, single chamber design with distributed ion pumps. The x-ray opacity of the Cu is sufficiently high that no additional lead shielding is necessary to protect the dipoles from the intense synchrotron radiation generated by the beam. The design allows chamber commissioning in <500 hr of operation. 5 refs., 3 figs., 2 tabs

  1. LHC vacuum upgrade during LS1

    International Nuclear Information System (INIS)

    Jimenez, J.M.; Baglin, V.; Chiggiato, P.; Cruikshank, P.; Gallilee, M.; Garion, C.; Gomes, P.

    2012-01-01

    The last two years of LHC operation have highlighted concerns on the levels of the dynamic vacuum in the long straight sections in presence of high intensity beams. The analysis of the existing data has shown relationship between pressures spikes and beam screen temperature oscillations or micro-sparking in the RF fingers of the bellows on one side and coincidence of pressure bumps with stimulated desorption by electron cloud, beam losses and/or thermal out gassing stimulated by higher order modes (HOM) losses. The electron cloud mitigation solutions will be adapted to the different configurations: cold/warm transitions, non-coated surfaces in direct view of beams, photoelectrons, etc. All scenarios will be presented together with their efficiencies. Additional pumping and re-engineering of components will reduce the sensitivity of the vacuum system to beam losses or HOM inducing out gassing. The expected margin at nominal intensity and energy resulting from these consolidations will be summarized. Finally, the challenges of the Experimental areas will be addressed, more specifically the status of the new Beryllium pipes (ATLAS and CMS) which are in the critical path and the consolidation of vacuum instrumentation, pumping and electron cloud mitigation. The risk corresponding to the proposed consolidations will be shown and the margins with respect to the schedule analysed. (authors)

  2. Tracking and Level-1 triggering in the forward region of the ATLAS Muon Spectrometer at sLHC

    International Nuclear Information System (INIS)

    Bittner, B; Dubbert, J; Kroha, H; Richter, R; Schwegler, P

    2012-01-01

    In the endcap region of the ATLAS Muon Spectrometer (η > 1) precision tracking and Level-1 triggering are performed by different types of chambers. Monitored Drift Tube chambers (MDT) and Cathode Strip Chambers (CSC) are used for precision tracking, while Thin Gap Chambers (TGC) form the Level-1 muon trigger, selecting muons with high transverse momentum (p T ). When by 2018 the LHC peak luminosity of 10 34 cm −2 s −1 will be increased by a factor of ∼ 2 and by another factor of ∼ 2–2.5 in about a decade from now (''SLHC''), an improvement of both systems, precision tracking and Level-1 triggering, will become mandatory in order to cope with the high rate of uncorrelated background hits (''cavern background'') and to stay below the maximum trigger rate for the muon system, which is in the range of 10–20 % of the 100 kHz rate, allowed for ATLAS. For the Level-1 trigger of the ATLAS Muon Spectrometer this means a stronger suppression of sub-threshold muons in the high-p T trigger as well as a better rejection of tracks not coming from the primary interaction point. Both requirements, however, can only be fulfilled if spatial resolution and angular pointing accuracy of the trigger chambers, in particular of those in the Inner Station of the endcap, are improved by a large factor. This calls for a complete replacement of the currrently used TGC chambers by a new type of trigger chambers with better performance. In parallel, the precision tracking chambers must be replaced by chambers with higher rate capability to be able to cope with the intense cavern background. In this article we present concepts to decisively improve the Level-1 trigger with newly developed trigger chambers, being characterized by excellent spatial resolution, good time resolution and sufficiently short latency. We also present new types of precision chambers, designed to maintain excellent tracking efficiency and spatial resolution in the presence of high levels of uncorrelated

  3. Study of the Higgs boson discovery potential in the process pp{yields}H/A{yields}{mu}{sup +}{mu}{sup -}/{tau}{sup +}{tau}{sup -} with the ATLAS detector

    Energy Technology Data Exchange (ETDEWEB)

    Dedes, Georgios

    2008-04-22

    In this thesis, the discovery potential of the ATLAS experiment at the Large Hadron Collider (LHC) at CERN for the heavy neutral Higgs bosons H/A of theMinimal Supersymmetric extension of the Standard Model of particle physics (MSSM) in the decay channels H/A{yields}{tau}{sup +}{tau}{sup -}{yields}e/{mu}+X and H/A{yields}{mu}{sup +}{mu}{sup -} has been studied. The ATLAS detector is designed to study the full spectrum of the physics phenomena occuring in the proton-proton collisions at 14 TeV center-of-mass energy and to provide answers to the question of the origin of particle masses and of electroweak symmetry breaking. For the studies, the ATLAS muon spectrometer plays an important role. The spectrometer allows for a precise muon momentum measurement independently of other ATLAS subdetectors. The performance of the muon spectrometer depends strongly on the performance of the muon tracking detectors, the Monitored Drift Tube Chambers (MDT). Computer programs have been developed in order to test and verify the ATLAS muon spectrometer simulation, an essential ingredient for data analysis. In addition, dedicated programs for the monitoring of the quality of the data collected by the muon spectrometer have been developed and tested with data from cosmic ray muons. High-quality cosmic ray muon data have been used for the calibration of the MDT-chambers. A new calibration method, called analytical autocalibration, has been tested. The proposed method achieved the required accuracy of 20 {mu}m in the determination of the space-to-drift-time relationship of the drift tubes of the MDT chambers with only 2000 muon tracks per chamber. Reliable muon detector simulation and calibration are essential for the study of the MSSM Higgs boson decays H/A{yields}{tau}{sup +}{tau}{sup -}{yields}e/{mu}+X and H/A{yields}{mu}{sup +}{mu}{sup -} and of the corresponding background processes. The signal selection and background rejection requirements have been optimized for maximum signal

  4. The vacuum system for the PEP II high energy ring straight sections

    International Nuclear Information System (INIS)

    Wienands, U.; Daly, E.; Heifets, S.A.; Kulikov, A.; Kurita, N.; Nordby, M.; Perkins, C.; Reuter, E.; Seeman, J.T.; Belser, F.C.; Berg, J.; Holdener, F.R.; Kerns, J.A.; McDaniel, M.R.; Stoeffl, W.

    1995-01-01

    The six straight sections of the PEP II High Energy Ring (HER) serve various functions: lattice tuning, beam injection and abort, providing space for rf cavities, longitudinal and transverse feedback, beam diagnostics and the interaction point. A stainless steel vacuum system has been designed; prototypes are currently being built. Cooling is required due to radiation coming from the last arc dipole and resistive losses in the vacuum chamber. Although the nominal beam current of the HER is 1 A the vacuum system is designed for 3 A to provide margin and an upgrade path. 5 refs., 7 figs

  5. Vacuum-integrated electrospray deposition for highly reliable polymer thin film.

    Science.gov (United States)

    Park, Soohyung; Lee, Younjoo; Yi, Yeonjin

    2012-10-01

    Vacuum electrospray deposition (ESD) equipment was designed to prepare polymer thin films. The polymer solution can be injected directly into vacuum system through multi-stage pumping line, so that the solvent residues and ambient contaminants are highly reduced. To test the performance of ESD system, we fabricated organic photovoltaic cells (OPVCs) by injecting polymer solution directly onto the substrate inside a high vacuum chamber. The OPVC fabricated has the structure of Al∕P3HT:PCBM∕PEDOT:PSS∕ITO and was optimized by varying the speed of solution injection and concentration of the solution. The power conversion efficiency (PCE) of the optimized OPVC is 3.14% under AM 1.5G irradiation without any buffer layer at the cathode side. To test the advantages of the vacuum ESD, we exposed the device to atmosphere between the deposition steps of the active layer and cathode. This showed that the PCE of the vacuum processed device is 24% higher than that of the air exposed device and confirms the advantages of the vacuum prepared polymer film for high performance devices.

  6. Performance test of micro-fission chambers for in-vessel neutron monitoring of ITER

    International Nuclear Information System (INIS)

    Yamauchi, Michinori; Nishitani, Takeo; Ochiai, Kentaro; Morimoto, Yuichi; Hori, Jun-ichi; Ebisawa, Katsuyuki; Kasai, Satoshi

    2002-03-01

    A micro-fission chamber with 12 mg UO 2 and a dummy chamber without uranium were fabricated and the performance was tested. They are designed to be installed inside the vacuum vessel of the compact ITER (ITER-FEAT) for neutron monitoring. The vacuum leak rate of the dummy chamber with MI cable, resistances of chambers between central conductor and outer sheath, and mechanical strength up to 50G acceleration were confirmed to meet the design criteria. The gamma-ray sensitivity was measured for the dummy chamber with the 60 Co gamma-ray irradiation facility at JAERI Takasaki. The output signals for gamma-rays in Campbelling mode were estimated to be less than 0.1% of those by neutrons at the location behind the blanket module in ITER-FEAT. The detector response for 14 MeV neutrons was investigated with the FNS facility. Excellent linearity between count rates, square of Campbelling voltage and neutron fluxes was confirmed in the temperature range from 20degC (room) to 250degC. However, a positive dependence of 14 MeV neutron count rates on temperature was observed, which might be caused by the increase in the pulse height with temperature rise. Effects of a change of surrounding materials were evaluated by the sensitivity measurements of the micro-fission chamber inserted into the shielding blanket mock-up. The sensitivity was enhanced by slow-downed neutrons, which agreed with the calculation result by MCNP-4C code. As a result, it was concluded that the developed micro-fission chamber is applicable for ITER-FEAT. (author)

  7. Phacoemulsification tip vacuum pressure: Comparison of 4 devices.

    Science.gov (United States)

    Payne, Marielle; Georgescu, Dan; Waite, Aaron N; Olson, Randall J

    2006-08-01

    To determine the vacuum pressure generated by 4 phacoemulsification devices measured at the phacoemulsification tip. University ophthalmology department. The effective vacuum pressures generated by the Sovereign (AMO), Millennium (Bausch & Lomb), Legacy AdvanTec (Alcon Laboratories), and Infiniti (Alcon Laboratories) phacoemulsification machines were measured with a device that isolated the phacoemulsification tip in a chamber connected to a pressure gauge. The 4 machines were tested at multiple vacuum limit settings, and the values were recorded after the foot pedal was fully depressed and the pressure had stabilized. The AdvanTec and Infiniti machines were tested with and without occlusion of the Aspiration Bypass System (ABS) side port (Alcon Laboratories). The Millennium machine was tested using venturi and peristaltic pumps. The machines generated pressures close to the expected at maximum vacuum settings between 100 mm Hg and 500 mm Hg with few intermachine variations. There was no significant difference between pressures generated using 19- or 20-gauge tips (Millennium and Sovereign). The addition of an ABS side port decreased vacuum by a mean of 12.1% (P < .0001). Although there were some variations in vacuum pressures among phacoemulsification machines, particularly when an aspiration bypass tip was used, these discrepancies are probably not clinically significant.

  8. Evaluation of supercapacitors for space applications under thermal vacuum conditions

    Science.gov (United States)

    Chin, Keith C.; Green, Nelson W.; Brandon, Erik J.

    2018-03-01

    Commercially available supercapacitor cells from three separate vendors were evaluated for use in a space environment using thermal vacuum (Tvac) testing. Standard commercial cells are not hermetically sealed, but feature crimp or double seam seals between the header and the can, which may not maintain an adequate seal under vacuum. Cells were placed in a small vacuum chamber, and cycled between three separate temperature set points. Charging and discharging of cells was executed following each temperature soak, to confirm there was no significant impact on performance. A final electrical performance check, visual inspection and mass check following testing were also performed, to confirm the integrity of the cells had not been compromised during exposure to thermal cycling under vacuum. All cells tested were found to survive this testing protocol and exhibited no significant impact on electrical performance.

  9. A vacuum disengager for tritium removal from HYLIFE-II Reactor Flibe

    International Nuclear Information System (INIS)

    Dolan, T.J.; Longhurst, G.R.; Garcia-Otero, E.

    1992-01-01

    We have designed a vacuum disengager system to remove tritium from the Flibe (Li 2 BeF 4 ) molten salt coolant of the HYLIFE-II fusion reactor. There is a two-stage vacuum disengager in each of three intermediate heat exchanger (IHX) loops. Each stage consists of a vacuum chamber 4 m in diameter and 7 m tall. As 0.2 mm diameter molten salt droplets fall vertically downward into the vacuum, most of the tritium diffuses out of the droplets and is pumped away. A fraction Φ ∼10 -5 of the 8.6 MCi/day tritium source (from breeding in the Flibe and from unburned fuel) remains in the Flibe as it leaves the vacuum disengagers, and about 21% of that permeates into the intermediate coolant loop, so about 20 Ci/day leak into the steam system. With Flibe primary coolant and a vacuum disengager, it appears that an intermediate coolant loop is not needed to prevent tritium from leaking into the steam system. An experiment is needed to demonstrate Flibe vacuum disengager operation

  10. Consolidation of cloud computing in ATLAS

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00224309; The ATLAS collaboration; Cordeiro, Cristovao; Hover, John; Kouba, Tomas; Love, Peter; Mcnab, Andrew; Schovancova, Jaroslava; Sobie, Randall; Giordano, Domenico

    2017-01-01

    Throughout the first half of LHC Run 2, ATLAS cloud computing has undergone a period of consolidation, characterized by building upon previously established systems, with the aim of reducing operational effort, improving robustness, and reaching higher scale. This paper describes the current state of ATLAS cloud computing. Cloud activities are converging on a common contextualization approach for virtual machines, and cloud resources are sharing monitoring and service discovery components. We describe the integration of Vacuum resources, streamlined usage of the Simulation at Point 1 cloud for offline processing, extreme scaling on Amazon compute resources, and procurement of commercial cloud capacity in Europe. Finally, building on the previously established monitoring infrastructure, we have deployed a real-time monitoring and alerting platform which coalesces data from multiple sources, provides flexible visualization via customizable dashboards, and issues alerts and carries out corrective actions in resp...

  11. Precision Muon Tracking at Future Hadron Colliders with sMDT Chambers

    CERN Document Server

    Kortner, Oliver; Müller, Felix; Nowak, Sebastian; Richter, Robert

    2016-01-01

    Small-diameter muon drift tube (sMDT) chambers are a cost-effective technology for high-precision muon tracking. The rate capability of the sMDT chambers has been extensively tested at the Gamma Irradiation Facility at CERN in view of expected rates at future high-energy hadron colliders. Results show that it fulfills the requirements over most of the acceptance of muon detectors. The optimization of the read-out electronics to further increase the rate capability of the detectors is discussed. Chambers of this type are under construction for upgrades of the muon spectrometer of the ATLAS detector at high LHC luminosities. Design and construction procedures have been optimized for mass production while providing a precision of better than 10 micrometers in the sense wire positions and the mechanical stability required to cover large areas.

  12. Design and fabrication of a chamber for the deposit of thin films by laser ablation

    International Nuclear Information System (INIS)

    Chirino O, S.; Escobar A, I.; Camps C, E.; Garcia E, J.I.

    2000-01-01

    The laser ablation technique is an alternative for the obtention of thin films which is less expensive, more reliable, efficient and with some advantages with respect to conventional processes. On of the most important components which forms a laser ablation system is the vacuum chamber, that has as general purposes the following: a) To carry out studies about plasma such as optical emission spectroscopy and measurements by deflectometry. b) To carry out an In situ monitoring about the film growth through the reflectivity measurements of the combination substrate-film. c) To deposit thin films of different materials such as oxides, carbon, metals, etc. In this work it is showed how the vacuum chamber was designed and made to perform the store of thin films by laser ablation and for characterising the formed plasma as a result of the ablation process. The chamber design was enough versatile that will allow to add it more accessory just making it simple modifications. Its cost was very cheap more or less one twentieth of a commercial chamber. (Author)

  13. Development of a compact freeze vacuum drying for jelly fish (Schypomedusae)

    Science.gov (United States)

    Alhamid, M. Idrus; Yulianto, M.; Nasruddin

    2012-06-01

    A new design of a freeze vacuum drying with internal cooling and heater from condenser's heat loss was built and tested. The dryer was used to dry jelly fish (schypomedusae), to study the effect of drying parameters such as the temperature within the drying chamber on mass losses (evaporation) during the freezing stage and the moisture ratio at the end of the drying process. The midili thin layer mathematical drying model was used to estimate and predict the moisture ratio curve based on different drying chamber temperatures. This experiment shows that decreasing the drying chamber temperature with constant pressure results in less mass loss during the freezing stage Drying time was reduced with an increase in drying temperature. Decreasing the drying chamber temperature results in lower pressure saturation of the material has no effect of drying chamber pressure on mass transfer.

  14. Helium Leak Test for the PLS Storage Ring Chamber

    International Nuclear Information System (INIS)

    Choi, M. H.; Kim, H. J.; Choi, W. C.

    1993-01-01

    The storage ring vacuum system for the Pohang Light Source (PLS) has been designed to maintain the vacuum pressure of 10 1 0 Torr which requires UHV welding to have helium leak rate less than 1x10 1 0 Torr·L/sec. In order to develop new technique (PLS) welding technique), a prototype vacuum chamber has been welded by using Tungsten Inert Gas welding method and all the welded joints have been tested with a non-destructive method, so called helium leak detection, to investigate the vacuum tightness of the weld joints. The test was performed with a detection limit of 1x10 1 0 Torr·L/sec for helium and no detectable leaks were found for all the welded joints. Thus the performance of welding technique is proven to meet the criteria of helium leak rate required in the PLS Storage Ring. Both the principle and the procedure for the helium leak detection are also discussed

  15. Upgrade of the ATLAS Muon System for the HL-LHC

    CERN Document Server

    Amelung, Christoph; The ATLAS collaboration

    2018-01-01

    The muon spectrometer of the ATLAS detector will be significantly upgraded during the Phase-II upgrade in Long Shutdown 3 in order to cope with the operational conditions at the High-Luminosity LHC in Run 4 and beyond. Most of the electronics for the Resistive Plate Chambers (RPC), Thin Gap Chambers (TGC), and Monitored Drift Tube (MDT) chambers will be replaced to make them compatible with the higher trigger rates and longer latencies necessary for the new level-0 trigger. The MDT chambers will be integrated into the level-0 trigger in order to sharpen the momentum threshold. Additional RPC chambers will be installed in the inner barrel layer to increase the acceptance and robustness of the trigger. Some of the MDT chambers in the inner barrel layer will be replaced with new small-diameter MDTs. New TGC triplet chambers in the barrel-endcap transition region will replace the current TGC doublets to suppress the high trigger rate from random coincidences in this region. The power system for the RPC, TGC, and ...

  16. Alignment of the ATLAS central muon spectrometer

    CERN Document Server

    Chevallier, F

    2008-01-01

    The muon spectrometer of the ATLAS experiment is one of the largest detectors ever built. At the LHC, new physics signs could appear through high momenta muons (1 TeV). Identification and precise momentum measurement of such muons are two of the main challenges of the ATLAS muon spectrometer. In order to get a good resolution for high energy muons (i.e. 10% at 1 TeV), the accuracy on the alignment of precision chambers must be of the order of 50 microns. Several procedures have been developed to reach such a precision. This document describes complementary techniques used to align the muon sub-detectors, and their results : the optical system, the muon cosmic rays and the straight tracks coming from collisions.

  17. Vacuum properties of TiZrV non-evaporable getter films [for LHC vacuum system

    CERN Document Server

    Benvenuti, Cristoforo; Costa-Pinto, P; Escudeiro-Santana, A; Hedley, T; Mongelluzzo, A; Ruzinov, V; Wevers, I

    2001-01-01

    Sputter-deposited thin films of TiZrV are fully activated after 24 h "in situ" heating at 180 degrees C. This activation temperature is the lowest of some 18 different getter coatings studied so far, and it allows the use of the getter thin film technology with aluminium alloy vacuum chambers, which cannot be baked at temperatures higher than 200 degrees C. An updated review is given of the most recent results obtained on TiZrV coatings, covering the following topics: influence of the elemental composition and crystal structure on activation temperature, discharge gas trapping and degassing, dependence of pumping speed and surface saturation capacity on film morphology, ageing consequent to activation-air-venting cycles and ultimate pressures. Furthermore, the results obtained when exposing a coated particle beam chamber to synchrotron radiation in a real accelerator environment (ESRF Grenoble) are presented and discussed. (13 refs).

  18. Simulation of the ATLAS New Small Wheel (NSW) System

    CERN Document Server

    Maekawa, Koki; The ATLAS collaboration

    2017-01-01

    The instantaneous luminosity of the Large Hadron Collider (LHC) at CERN will be increased up to a factor of five with respect to the present design value by undergoing an extensive upgrade program over the coming decade. In order to benefit from the expected high luminosity performance that will be provided by the Phase-1 upgraded LHC, the first station of the ATLAS muon end-cap Small Wheel system will need to be replaced by a New Small Wheel (NSW) detector. The NSW is going to be installed in the ATLAS detector in the forward region of 1.3 < |η| < 2.7 during the second long LHC shutdown. The NSW will have to operate in a high background radiation region, while reconstructing muon tracks with high precision as well as furnishing information for the Level-1 trigger. A detailed study of the final design and validation of the readout electronics for a set of precision tracking (Micromegas) and trigger chambers (small-strip Thin Gap Chambers or sTGC) that are able to work at high rates with excellent real-...

  19. Vacuum performance of a carbon fibre cryosorber for the LHC LSS beam screen

    CERN Document Server

    Anashin, V V; Dostovalov, R V; Korotaeva, Z A; Krasnov, A A; Malyshev, O B; Poluboyarov, V A

    2004-01-01

    A new carbon fibre material was developed at the Institute of Solid State Chemistry and Mechanochemistry at the Siberian Branch of the Russian Academy of Science (SB RAS) to meet the large hadron collider (LHC) vacuum chamber. The material must have a large sorbing capacity, a certain pumping speed, a working temperature range between 5 and 20K, a low activation temperature (below room temperature), a certain size in order to fit into the limited space available and it should be easy to mount. The vacuum parameters of the LHC vacuum chamber prototype with a carbon fibre cryosorber mounted onto the beam screen were studied in the beam screen temperature range from 14 to 25K at the Budker Institute of Nuclear Physics SB RAS. This carbon fibre material has shown sufficient sorption capacity for hydrogen at operational temperatures of the beam screen in the LHC long straight sections. It is also very important that this material does not crumble and makes a convenient fixation onto the beam screen in comparison t...

  20. Application of local vacuum slide sealing electron beam welding procedure

    International Nuclear Information System (INIS)

    Sato, Shozo; Takano, Genta; Minami, Masaharu; Enami, Koji; Uchikawa, Takashi; Kuri, Shuhei

    1982-01-01

    Electron beam welding process is efficient and is superior in workmanship and its application to the welding of large plate structures is eagerly awaited. However, since electron beam welding is generally performed with the object of welding entirely put in a vacuum chamber, high welding cost becomes a problem. In response to this demand, two kinds of local vacuum slide sealing type electron beam welding machines have been developed. These welding machines are designed to perform welding with only the neighborhood of the weld line put in vacuum, one of which is for longitudinal joints and the other for circumferential joints. The welding machine for circumferential joints has been put to practical use for the welding of nucear fusion reactor vacuum vessels (outside diameter 3.5 m, inside diameter 1.7 m), showing that it is applicable to the welding of large structures. (author)

  1. Portable mini-chamber for temperature dependent studies using small angle and wide angle x-ray scattering

    Science.gov (United States)

    Dev, Arun Singh; Kumar, Dileep; Potdar, Satish; Pandit, Pallavi; Roth, Stephan V.; Gupta, Ajay

    2018-04-01

    The present work describes the design and performance of a vacuum compatible portable mini chamber for temperature dependent GISAXS and GIWAXS studies of thin films and multilayer structures. The water cooled body of the chamber allows sample annealing up to 900 K using ultra high vacuum compatible (UHV) pyrolytic boron nitride heater, thus making it possible to study the temperature dependent evolution of structure and morphology of two-dimensional nanostructured materials. Due to its light weight and small size, the chamber is portable and can be accommodated at synchrotron facilities worldwide. A systematic illustration of the versatility of the chamber has been demonstrated at beamline P03, PETRA-III, DESY, Hamburg, Germany. Temperature dependent grazing incidence small angle x-ray scattering (GISAXS) and grazing incidence wide angle x-ray scattering (GIWAXS) measurements were performed on oblique angle deposited Co/Ag multilayer structure, which jointly revealed that the surface diffusion in Co columns in Co/Ag multilayer enhances by increasing temperature from RT to ˜573 K. This results in a morphology change from columnar tilted structure to densely packed morphological isotropic multilayer.

  2. Molecular beam sampling from a rocket-motor combustion chamber

    International Nuclear Information System (INIS)

    Houseman, John; Young, W.S.

    1974-01-01

    A molecular-beam mass-spectrometer sampling apparatus has been developed to study the reactive species concentrations as a function of position in a rocket-motor combustion chamber. Unique design features of the sampling system include (a) the use of a multiple-nozzle end plate for preserving the nonuniform properties of the flow field inside the combustion chamber, (b) the use of a water-injection heat shield, and (c) the use of a 300 CFM mechanical pump for the first vacuum stage (eliminating the use of a huge conventional oil booster pump). Preliminary rocket-motor tests have been performed using the highly reactive propellants nitrogen tetroxide/hydrazine (N 2 O 4 /N 2 H 4 ) at an oxidizer/fuel ratio of 1.2 by weight. The combustion-chamber pressure is approximately 60psig. Qualitative results on unreacted oxidizer/fuel ratio, relative abundance of oxidizer and fuel fragments, and HN 3 distribution across the chamber are presented

  3. The design of high vacuum system for baby electron beam machine (baby ebm): a comparison between theoretical and experimental

    International Nuclear Information System (INIS)

    Mohd Rizal Mamat; Rosli Darmawan; Lee Chee Huei; Mohd Rizal Md Chulan; Leo Kwee Wah; Muhamad Zahidee Taat; Fadzlie Nordin; Abu Bakar Mhd Ghazali

    2005-01-01

    Baby ebm which was developed to study the engineering and physics of electrons requires the use of high vacuum system in order to prevent electron loss and ionization of air molecules. In selecting the high vacuum system for baby ebm two main factors were considered: the ultimate pressure and the pump down time. The ultimate pressure required for the operation of the baby ebm is in 10-7 torr range. The pump down time was estimated from calculations, taking into account the vacuum pump and chamber size. The turbomolecular pump system (tmp), which is capable of achieving the required vacuum level was selected as the high vacuum system and installed to baby ebm. The tmp is currently fully operational. It was found that the vacuum pumping performance of the tmp differs considerably from what the calculations indicate. Compared to the calculations, it takes a much longer time to achieve the required operating pressure of baby ebm. This could be due to the fact that the formula used for the calculations was a very simplified formula that takes into account the main factors only which are the vacuum pump and chamber size. This paper attempts to present the comparison of the tmp performance between the theoretical and experimental. (Author)

  4. Local tracking in the ATLAS muon spectrometer

    CERN Document Server

    Primor, David; Mikenberg, Giora

    2007-01-01

    The LHC, the largest hadron collider accelerator ever built, presents new challenges for scientists and engineers. With the anticipated luminosity of the LHC, it is expected to have as many as one billion total collisions per second, of which at most 10 to 100 per second might be of potential scientific interest. One of the two major, general-purpose experiments at LHC is called ATLAS. Since muons are one of the important signs of new physics, the need of their detection has lead to the construction of a stand- alone Muon Spectrometer. This system is located in a high radiation background environment (mostly neutrons and photons) which makes the muon tracking a very challenging task. The Muon Spectrometer consists of two types of precision chambers, the Monitor Drift Tube (MDT) chambers, and the Cathode Strip Chambers (CSC). In order to detect the muon and estimate its track parameters, it is very important to detect and precisely estimate its local tracks within the CSC and MDT chambers. Using advanced signa...

  5. Consolidation of cloud computing in ATLAS

    Science.gov (United States)

    Taylor, Ryan P.; Domingues Cordeiro, Cristovao Jose; Giordano, Domenico; Hover, John; Kouba, Tomas; Love, Peter; McNab, Andrew; Schovancova, Jaroslava; Sobie, Randall; ATLAS Collaboration

    2017-10-01

    Throughout the first half of LHC Run 2, ATLAS cloud computing has undergone a period of consolidation, characterized by building upon previously established systems, with the aim of reducing operational effort, improving robustness, and reaching higher scale. This paper describes the current state of ATLAS cloud computing. Cloud activities are converging on a common contextualization approach for virtual machines, and cloud resources are sharing monitoring and service discovery components. We describe the integration of Vacuum resources, streamlined usage of the Simulation at Point 1 cloud for offline processing, extreme scaling on Amazon compute resources, and procurement of commercial cloud capacity in Europe. Finally, building on the previously established monitoring infrastructure, we have deployed a real-time monitoring and alerting platform which coalesces data from multiple sources, provides flexible visualization via customizable dashboards, and issues alerts and carries out corrective actions in response to problems.

  6. Nova target chamber decontamination study

    International Nuclear Information System (INIS)

    1979-05-01

    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

  7. Note: A single-chamber tool for plasma activation and surface functionalization in microfabrication

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, Adam J.; Scherrer, Joseph R.; Reiserer, Ronald S., E-mail: ron.reiserer@vanderbilt.edu [Vanderbilt Institute for Integrative Biosystems Research and Education and Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States)

    2015-06-15

    We present a simple apparatus for improved surface modification of polydimethylsiloxane (PDMS) microfluidic devices. A single treatment chamber for plasma activation and chemical/physical vapor deposition steps minimizes the time-dependent degradation of surface activation that is inherent in multi-chamber techniques. Contamination and deposition irregularities are also minimized by conducting plasma activation and treatment phases in the same vacuum environment. An inductively coupled plasma driver allows for interchangeable treatment chambers. Atomic force microscopy confirms that silane deposition on PDMS gives much better surface quality than standard deposition methods, which yield a higher local roughness and pronounced irregularities in the surface.

  8. Vacuum die attach for integrated circuits

    Science.gov (United States)

    Schmitt, E.H.; Tuckerman, D.B.

    1991-09-10

    A thin film eutectic bond for attaching an integrated circuit die to a circuit substrate is formed by coating at least one bonding surface on the die and substrate with an alloying metal, assembling the die and substrate under compression loading, and heating the assembly to an alloying temperature in a vacuum. A very thin bond, 10 microns or less, which is substantially void free, is produced. These bonds have high reliability, good heat and electrical conduction, and high temperature tolerance. The bonds are formed in a vacuum chamber, using a positioning and loading fixture to compression load the die, and an IR lamp or other heat source. For bonding a silicon die to a silicon substrate, a gold silicon alloy bond is used. Multiple dies can be bonded simultaneously. No scrubbing is required. 1 figure.

  9. Effects of ambient temperature and water vapor on chamber pressure and oxygen level during low atmospheric pressure stunning of poultry.

    Science.gov (United States)

    Holloway, Paul H; Pritchard, David G

    2017-08-01

    The characteristics of the vacuum used in a low atmospheric pressure stunning system to stun (render unconscious) poultry prior to slaughter are described. A vacuum chamber is pumped by a wet screw compressor. The vacuum pressure is reduced from ambient atmospheric pressure to an absolute vacuum pressure of ∼250 Torr (∼33 kPa) in ∼67 sec with the vacuum gate valve fully open. At ∼250 Torr, the sliding gate valve is partially closed to reduce effective pumping speed, resulting in a slower rate of decreasing pressure. Ambient temperature affects air density and water vapor pressure and thereby oxygen levels and the time at the minimum total pressure of ∼160 Torr (∼21 kPa) is varied from ∼120 to ∼220 sec to ensure an effective stun within the 280 seconds of each cycle. The reduction in total pressure results in a gradual reduction of oxygen partial pressure that was measured by a solid-state electrochemical oxygen sensor. The reduced oxygen pressure leads to hypoxia, which is recognized as a humane method of stunning poultry. The system maintains an oxygen concentration of air always reduces the oxygen concentrations to a value lower than in dry air. The partial pressure of water and oxygen were found to depend on the pump down parameters due to the formation of fog in the chamber and desorption of water from the birds and the walls of the vacuum chamber. © The Author 2017. Published by Oxford University Press on behalf of Poultry Science Association.

  10. New design of a variable-temperature ultrahigh vacuum scanning tunneling microscope

    NARCIS (Netherlands)

    Mugele, Friedrich Gunther; Rettenberger, A.; Boneberg, J.; Leiderer, P.

    1998-01-01

    We present the design of a variable-temperature ultrahigh vacuum (UHV) scanning tunneling microscope which can be operated between 20 and 400 K. The microscope is mounted directly onto the heat exchanger of a He continuous flow cryostat without vibration isolation inside the UHV chamber. The coarse

  11. Upgrade of the ATLAS Muon Barrel Trigger for HL-LHC

    CERN Document Server

    Romano, Marino; The ATLAS collaboration

    2015-01-01

    The present ATLAS muon trigger in the barrel region (|eta|<1.05) is based on three layers of RPC chambers. It was designed to run for 10 years at the LHC luminosity of 10^{34} cm^{-2}s^{-1} and operated successfully and with high selectivity during the first run of the LHC. In order to ensure a stable performance of the RPCs until 2035 at the higher rates and at luminosities of 5-7x10^{34} cm^{-2}s^{-1} provided by HL-LHC, the chambers will have to be operated with reduced gas gain to respect the original design limits on currents and integrated charge. The ATLAS muon collaboration proposes an upgrade of the system by installing an inner layer of new generation RPCs during the LHC shutdown expected for the year 2023. This new layer will increase the system redundancy and therefore allow operation with high efficiency and high selectivity during the HL-LHC phase. The insertion of this new layer will also increase the geometrical acceptance in the barrel region from 75% to 95%. Moreover, the additional measu...

  12. Upgrade of the ATLAS Muon Barrel Trigger for HL-LHC.

    CERN Document Server

    Biondi, Silvia; The ATLAS collaboration

    2015-01-01

    The present ATLAS muon trigger in the barrel region (|η | < 1.05) is based on three layers of RPC chambers. It was designed to run for 10 years at the LHC luminosity of 1034cm−2s−1 and operated successfully and with high selectivity during the first run of the LHC. In order to ensure a stable performance of the RPCs until 2035 at the higher rates and at luminosities of 5−7x1034cm−2s−1 provided by HL-LHC, the chambers will have to be operated with reduced gas gain to respect the original design limits on currents and integrated charge. The ATLAS muon collaboration proposes an upgrade of the system by installing an inner layer of new generation RPCs during the LHC shutdown expected for the year 2023. This new layer will increase the system redundancy and therefore allow operation with high efficiency and high selectivity during the HL-LHC phase. The insertion of this new layer will also increase the geometrical acceptance in the barrel region from 75% to 95%. Moreover, the additional measurements ...

  13. Additive manufacturing of magnetic shielding and ultra-high vacuum flange for cold atom sensors.

    Science.gov (United States)

    Vovrosh, Jamie; Voulazeris, Georgios; Petrov, Plamen G; Zou, Ji; Gaber, Youssef; Benn, Laura; Woolger, David; Attallah, Moataz M; Boyer, Vincent; Bongs, Kai; Holynski, Michael

    2018-01-31

    Recent advances in the understanding and control of quantum technologies, such as those based on cold atoms, have resulted in devices with extraordinary metrological performance. To realise this potential outside of a lab environment the size, weight and power consumption need to be reduced. Here we demonstrate the use of laser powder bed fusion, an additive manufacturing technique, as a production technique relevant to the manufacture of quantum sensors. As a demonstration we have constructed two key components using additive manufacturing, namely magnetic shielding and vacuum chambers. The initial prototypes for magnetic shields show shielding factors within a factor of 3 of conventional approaches. The vacuum demonstrator device shows that 3D-printed titanium structures are suitable for use as vacuum chambers, with the test system reaching base pressures of 5 ± 0.5 × 10 -10 mbar. These demonstrations show considerable promise for the use of additive manufacturing for cold atom based quantum technologies, in future enabling improved integrated structures, allowing for the reduction in size, weight and assembly complexity.

  14. High power spectrometer for the characterization of photovoltaic cells in a controlled atmosphere or vacuum

    DEFF Research Database (Denmark)

    Krebs, Frederik C; Jørgensen, M.

    2003-01-01

    single monochromator grating. The photovoltaic sample under test is placed in a stainless-steel vacuum chamber allowing for operating pressures down to 10(-6) mbar equipped with a quartz window and electrical connections. The entire vacuum chamber was placed on a moving arm allowing for positioning...... in a selected part of the diffracted beam of the monochromator. The typical spectral resolution was 12 nm cm(-1) which gave bandwidths of 25 nm with a 2 cm sample width. The electrical characteristics of the photovoltaic device under test was measured using a source meter giving an experimental current...... sensitivity of 10 pA. We finally demonstrate the application of the instrumental setup for the characterization of a polymer based photovoltaic. (C) 2003 American Institute of Physics....

  15. The accuracy of the ATLAS muon X-ray tomograph

    Science.gov (United States)

    Avramidou, R.; Berbiers, J.; Boudineau, C.; Dechelette, C.; Drakoulakos, D.; Fabjan, C.; Grau, S.; Gschwendtner, E.; Maugain, J.-M.; Rieder, H.; Rangod, S.; Rohrbach, F.; Sbrissa, E.; Sedykh, E.; Sedykh, I.; Smirnov, Y.; Vertogradov, L.; Vichou, I.

    2003-01-01

    A gigantic detector, the ATLAS project, is under construction at CERN for particle physics research at the Large Hadron Collider which is to be ready by 2006. An X-ray tomograph has been developed, designed and constructed at CERN in order to control the mechanical quality of the ATLAS muon chambers. We reached a measurement accuracy of 2 μm systematic and 2 μm statistical uncertainties in the horizontal and vertical directions in the working area 220 cm (horizontal)×60 cm (vertical). Here we describe in detail the fundamental approach of the basic principle chosen to achieve such good accuracy. In order to crosscheck our precision, key results of measurements are presented.

  16. The accuracy of the ATLAS muon X-ray tomograph

    International Nuclear Information System (INIS)

    Avramidou, R.; Berbiers, J.; Boudineau, C.; Dechelette, C.; Drakoulakos, D.; Fabjan, C.; Grau, S.; Gschwendtner, E.; Maugain, J.-M.; Rieder, H.; Rangod, S.; Rohrbach, F.; Sbrissa, E.; Sedykh, E.; Sedykh, I.; Smirnov, Y.; Vertogradov, L.; Vichou, I.

    2003-01-01

    A gigantic detector, the ATLAS project, is under construction at CERN for particle physics research at the Large Hadron Collider which is to be ready by 2006. An X-ray tomograph has been developed, designed and constructed at CERN in order to control the mechanical quality of the ATLAS muon chambers. We reached a measurement accuracy of 2 μm systematic and 2 μm statistical uncertainties in the horizontal and vertical directions in the working area 220 cm (horizontal)x60 cm (vertical). Here we describe in detail the fundamental approach of the basic principle chosen to achieve such good accuracy. In order to crosscheck our precision, key results of measurements are presented

  17. Cryogenic vacuum pumping at the LBL 88-inch cyclotron

    International Nuclear Information System (INIS)

    Elo, D.; Morris, D.; Clark, D.J.; Gough, R.A.

    1978-09-01

    A cryogenic vacuum pumping panel has been in operation at the 88-inch cyclotron since 1974. The nude pumping panel is located in the acceleration chamber. The pumping surface consists of tubing cooled to 20 0 K by a closed loop helium refrigeration system. The pumping surfaces are shielded from radiation heat loads and water vapors by liquid nitrogen cooled baffles. The panel was designed for an average pumping speed of 14,000 liters/sec. for air. This approximately tripled the total effective pumping on the acceleration chamber from the existing diffusion pumped system, significantly reducing charge exchange losses of heavy ions during acceleration. Design, installation and performance characteristics are described

  18. Development of large size Micromegas detectors for the upgrade of the ATLAS experiments

    CERN Document Server

    Bianco, Michele

    2014-01-01

    The luminosity upgrade of the Large Hadron Collider at CERN f oresees a luminosity increase by a factor 3 compared to the LHC luminosity design value. To c ope with the corresponding rate increase, the Muon System of the ATLAS experiment at CER N needs to be upgraded. In the first station of the high rapidity region, micromegas det ectors have been chosen as the main tracking chambers but will, at the same time, also contribut e to the trigger. We describe the R&D; efforts that led to the construction of the first (1 × 2.4 m 2 ) large micromegas detectors at CERN and outline the next steps towards the construction of the 12 00 m 2 of micromegas detectors for the ATLAS upgrade. The technical solutions, adopted in the c onstruction of the chamber as well as results on the detector performance with cosmic rays are s hown.

  19. Vacuum variable-angle far-infrared ellipsometer

    Science.gov (United States)

    Friš, Pavel; Dubroka, Adam

    2017-11-01

    We present the design and performance of a vacuum far-infrared (∼50-680 cm-1) ellipsometer with a rotating analyser. The system is based on a Fourier transform spectrometer, an in-house built ellipsometer chamber and a closed-cycle bolometer. The ellipsometer chamber is equipped with a computer controlled θ-2θ goniometer for automated measurements at various angles of incidence. We compare our measurements on SrTiO3 crystal with the results acquired above 300 cm-1 with a commercially available ellipsometer system. After the calibration of the angle of incidence and after taking into account the finite reflectivity of mirrors in the detector part we obtain a very good agreement between the data from the two instruments. The system can be supplemented with a closed-cycle He cryostat for measurements between 5 and 400 K.

  20. ATLAS's superconducting solenoid takes up position

    CERN Multimedia

    2004-01-01

    The ATLAS superconducting solenoid was moved to its final destination on 16 January. It has taken up position opposite the ATLAS liquid argon barrel cryostat, which will house the electromagnetic calorimeter. All that remains to do now is to slide it into the insulation vacuum, this will be done in the next few weeks. Built by Toshiba, under responsibility of KEK in Japan, the central solenoid is 2.4 metres in diameter, 5.3 metres long and weighs 5.5 tonnes. "It will provide an axial magnetic field of 2 Tesla that will deflect particles inside the inner detector," as Roger Ruber, on-site project coordinator, explains. The inner detector, which consists of three sub-detectors, will be installed inside the solenoid later. The solenoid during one of the transport operations. Securely attached to the overhead travelling crane, the solenoid is situated in front of the opening to the liquid argon calorimeter, it will be inserted soon.

  1. Assessment of differences between products obtained in conventional and vacuum spray dryer

    Directory of Open Access Journals (Sweden)

    Fernanda de Melo RAMOS

    Full Text Available Abstract In this work, an experimental unit of a vacuum spray dryer was built. This prototype attempted to combine the advantages of freeze-drying (drying at low temperatures due to vacuum and spray drying (increase of surface area aiming the improvement of heat transfer efficiency. Maltodextrin solutions were dried in the vacuum operated equipment and in conventional spray dryer. The vacuum spray dryer system allowed obtaining powder at low temperatures due to the lowering of pressure conditions (2-5 kPa inside the drying chamber. The products obtained in the two systems were characterized and compared for particle size distribution, moisture content, water activity, bulk density and solubility in water. The processes yields were also evaluated and compared. The vacuum spray dryer system allowed the production of larger, more soluble and less dense particles than those obtained in the conventional configuration of the equipment, resulting in drier and, therefore, with lower water activity particles. Thus, the use of the vacuum spray dryer as a drying technique may be an alternative for the production of powder rich in thermosensitive compounds.

  2. Dynamic Low-Vacuum Scanning Electron Microscope Freeze Drying Observation for Fresh Water Algae

    International Nuclear Information System (INIS)

    Mohsen, H.T.; Ghaly, W.A.; Zahran, N.F.; Helal, A.I.

    2010-01-01

    A new perpetration method for serving in dynamic examinations of the fresh water algae is developed in connection with the Low-Vacuum Scanning Electron Microscope (LV-SEM) freeze drying technique. Specimens are collected from fresh water of Ismailia channel then transferred directly to freeze by liquid nitrogen and dried in the chamber of the scanning electron microscope in the low vacuum mode. Scanning electron micrographs revealed that the drying method presented the microstructure of algae. Dehydration in a graded ethanol series is not necessary in the new method. Dried algae specimen is observed in SEM high vacuum mode after conductive coating at higher resolution. Low-vacuum SEM freeze drying technique is a simple, time-saving and reproducible method for scanning electron microscopy that is applicable to various aquatic microorganisms covered with soft tissues.

  3. Scattering chamber for the Holifield Heavy Ion Research Facility

    International Nuclear Information System (INIS)

    Goodman, C.D.; Corum, J.E.

    1977-09-01

    A conceptual design is presented for a 62-in.-diam. general purpose scattering chamber to be used for nuclear research with heavy ions. The detector rotation mechanism is based on large diameter (approx. 58 in.) peripherally driven rings. This leaves the central region open for detectors and other apparatus and permits the use of a perpendicular ring for rotating a detector out of the reaction plane. A precision target slide with provisions for removing the entire slide under vacuum is part of the design. Access and viewing ports on the dished top and in the reaction plane will be provided. Cryogenic pumping will be used to keep the vacuum free from hydrocarbon vapors, water vapor, and oxygen

  4. Study of weak vacuum polarization in $Z \\to 2l \\gamma$

    CERN Document Server

    Zhabin, Viktor

    2017-01-01

    The goal of the work was to perform a search of weak vacuum polarization in the channel $Z \\to 2l \\gamma$ using $20 \\text{ fb}^{-1}$ of $pp$ collision data collected by the ATLAS experiment in 2012 at 8 TeV. The ratio of the distribution of an invariant mass of $l\\gamma$ obtained from experimental data to the MC distribution from the experimental data was used for the search of the effect. Total significance of weak vacuum polarization signal in the invariant mass distribution of $l \\gamma$ in only one of four channels has some significance. First studies indicate that an evidence of about $3.5 \\sigma$ can be reached. The parameters, amplitude and phase, determined from the fit are different in each channel and thus inconclusive.

  5. The vacuum vessel for the FTU device: design constraints and stress analysis

    International Nuclear Information System (INIS)

    Andreani, R.; Cecchini, A.; Gasparotto, M.; Lovisetto, L.; Migliori, S.; Pizzuto, A.

    1984-01-01

    The FTU vacuum vessel must withstand large electromagnetic loads due to the interactions between the eddy currents in the vessel and high magnetic fields of the machine, the atmospheric pressure and the severe thermal loads due to plasma losses and RF power not coupled to the plasma. In order to minimise the stresses on the vacuum chamber, an optimization of the wall thickness has been performed and, in order to assess the feasibility of the vessel, an extensive three dimensional finite element stress analysis has been developed. The main results obtained are illustrated. (author)

  6. Lifetime and shelf life of sealed tritium-filled plasma focus chambers with gas generator

    Directory of Open Access Journals (Sweden)

    B.D. Lemeshko

    2017-11-01

    Full Text Available The paper describes the operation features of plasma focus chambers using deuterium–tritium mixture. Handling tritium requires the use of sealed, vacuum-tight plasma focus chambers. In these chambers, there is an accumulation of the impurity gases released from the inside surfaces of the electrodes and the insulator while moving plasma current sheath inside chambers interacting with β-electrons generated due to the decay of tritium. Decay of tritium is also accompanied by the accumulation of helium. Impurities lead to a decreased yield of neutron emission from plasma focus chambers, especially for long term operation. The paper presents an option of absorption type gas generator in the chamber based on porous titanium, which allows to significantly increase the lifetime and shelf life of tritium chambers. It also shows the results of experiments on the comparison of the operation of sealed plasma focus chambers with and without the gas generator. Keywords: Plasma focus, Neutron yield, Tritium-filled plasma focus chambers, PACS Codes: 29.25.-v, 52.58.Lq

  7. United State Collaboration working in the Atlas hall experiment (B180).

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    It's a small world; at least you might think so after a visit to Building 180. Inside, about 30 engineers and physicists weld, measure and hammer away. They hail from Pakistan, Israel, Japan, China, Russia and the United States and they work toward one common goal: the completion of the ATLAS muon chamber endcaps

  8. United State Collaboration working in the ATLAS hall experiment (B180).

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    It's a small world; at least you might think so after a visit to Building 180. Inside, about 30 engineers and physicists weld, measure and hammer away. They hail from Pakistan, Israel, Japan, China, Russia and the United States and they work toward one common goal: the completion of the ATLAS muon chamber endcaps.

  9. Technical Design Report for the Phase-II Upgrade of the ATLAS Muon Spectrometer

    CERN Document Server

    Collaboration, ATLAS

    2017-01-01

    The muon spectrometer of the ATLAS detector will be significantly upgraded during the Phase-II upgrade in LS3 in order to cope with the operational conditions at the HL-LHC in Run 4 and beyond. A large fraction of the frontend and on- and off-detector readout and trigger electronics for the Resistive Plate Chambers (RPC), Thin Gap Chambers (TGC), and Monitored Drift Tube (MDT) chambers will be replaced to make them compatible with the higher trigger rates and longer latencies necessary for the new level-0 trigger. The MDT chambers will be integrated into the level-0 trigger in order to sharpen the momentum threshold. Additional RPC chambers will be installed in the inner barrel layer to increase the acceptance and robustness of the trigger, and some chambers in high-rate regions will be refurbished. Some of the MDT chambers in the inner barrel layer will be replaced with new small-diameter MDTs. New TGC triplet chambers in the barrel-endcap transition region will replace the current TGC doublets to suppress t...

  10. LAr calorimeter for SCC with a common vacuum bulkhead---a concept to improve hermeticity

    International Nuclear Information System (INIS)

    Pope, W.L.; Watt, R.D.

    1989-11-01

    A new concept for a Barrel/Endcap LAr Calorimeter (LAC) is described in which the Barrel and Endcaps are in separate vacuum enclosures but share a common vacuum bulkhead (CVB). We explore 2 possible bulkhead construction types; welded plate sandwich panels, and brazed sandwich panels in which the core is an isotropic cellular solid--foamed aluminum. Gas lines and electric cables from he innermost Drift Chamber pass through radial holes in the core of the sandwich bulkhead. The CVB concept offers the potential to obtain a more hermetic calorimeter with significantly reduced dead material and/or space in the interface region common to conventional design LAr detectors for the SSC with Endcap features. To utilize a common additional steps to remove the Drift Chamber, a large increase in Endcap standby heat leak, and perhaps, new cryogenic safety issues. We find that significant amount of dead mass can be removed from critical regions of the vacuum shells when compared to a promising SSC LAC reference design. It is also shown that the increased standby heat leak of this concept can be easily removed by existing cooling capacity in another large LAr calorimeter. It is further shown that shut-downs need not be appreciably longer. Finally, it is argued that cryogen spill hazards can be avoided if the Endcap's LAr is removed during Drift chamber maintenance shutdowns, and that cryogenic safety is not compromised

  11. Micromegas Detectors for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00211509

    2016-01-01

    Large area Micromegas (MM) detectors will be employed for the Muon Spectrometer upgrade of the ATLAS experiment at the LHC. A total surface of about $150m^2$ of the forward regions of the Muon Spectrometer will be equipped with 8 layers of MM modules. Each module covers a surface area of approximately 2 to $3 m^2$ for a total active area of $1200 m^2$. Together with the small- strips Thin Gap Chambers, they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS Endcap Muon tracking system in the planned 2018/19 shutdown. This upgrade will mantain a low pt threshold for single muons and provides excellent tracking capabilities for the HL-LHC phase. The NSW project requires fully efficient MM chambers with spatial resolution down to $100 \\mu m$, at rate capability up to about $15kHz/cm^2$ and operation in a moderate (highly inhomogeneous) magnetic field up to B=0.3 T. The required tracking capability is provided by the intrinsic spatial resolution combined with a challengi...

  12. Micromegas Detectors for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    Iodice, M; The ATLAS collaboration

    2014-01-01

    The Micromegas (MICRO MEsh GAseous Structure) chambers have been proven along the years to be reliable detectors with excellent space resolution and high rate capability. Large area Micromegas will be employed for the first time in high-energy physics for the Muon Spectrometer upgrade of the ATLAS experiment at CERN LHC. A total surface of about 150 m2 of the forward regions of the Muon Spectrometer will be equipped with 8 layers of Micromegas modules. Each module covers a surface from 2 to 3 m2 for a total active area of 1200 m2. Together with the small-strips Thin Gap Chambers, they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS Endcap Muon tracking system in the 2018/19 shutdown. The principles of operation and recent developments of this type of Micro Pattern Gas Detector will be reviewed, along with our plans towards the construction of the modules, which will take place in several production sites. An overview of the detector performances obtained in the re...

  13. Micromegas Detectors for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    Bianco, Michele; The ATLAS collaboration

    2015-01-01

    Large area Micromegas (MM) detectors will be employed for the Muon Spectrometer upgrade of the ATLAS experiment at the LHC. A total surface of about 150 m2 of the forward regions of the Muon Spectrometer will be equipped with 8 layers of MM modules. Each module covers a surface area of approximately 2 to 3 m$^{2}$ for a total active area of 1200 m$^{2}$. Together with the small-strips Thin Gap Chambers, they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS Endcap Muon tracking system in the planned 2018/19 shutdown. This upgrade will maintain a low pt threshold for single muons and provides excellent tracking capabilities for the HL- LHC phase. The NSW project requires fully efficient MM chambers with spatial resolution down to 100 $ \\mu m$, a rate capability up to about 15 kHz/cm$^{2}$ and operation in a moderate (highly inhomogeneous) magnetic field up to B=0.3 T. The required tracking capability is provided by the intrinsic spatial resolution combined with a cha...

  14. Baking controller for synchrotron beamline vacuum systems

    International Nuclear Information System (INIS)

    Garg, C.K.; Kane, S.R.; Dhamgaye, V.P.

    2003-01-01

    The 2.5 GeV electron storage ring Indus-2 is a hard X-ray Synchrotron Radiation (SR) Source. Nearly 27 beamlines will be installed on Indus-2 and they will cater to different experiments and applications. Most of the beamlines will be in Ultra High Vacuum (UHV) the only exception being hard X-rays beamlines. However the front ends of all the beamlines will be in UHV. Practicing UHV requires efforts and patience. Evacuating any chamber, volume gases can be removed easily. However, outgassing phenomena like desorption, diffusion and permeation restricts the system to attain UHV. All processes except the volume gas removal are temperature dependent. At ambient temperature, gas pressure decreases so slowly that outgassing limit (i.e. 10 -10 1/s/cm 2 ) can hardly be achieved on a practical time scale. Also there are three orders of magnitude difference in outgassing between baked and unbaked systems. Depending on the vacuum chamber and the components inside it, the thermal outgassing (baking) of system is required and can be done at various temperatures between 150 degC to 450 deg C. For whole baking cycle, constant monitoring and controlling of the systems is required which takes tens of hours. This paper describes the automation for such baking system, which will be used for SR beamlines

  15. Vacuum system for LHC

    International Nuclear Information System (INIS)

    Groebner, O.

    1995-01-01

    The Large Hadron Collider (LHC) which is planned at CERN will be housed in the tunnel of the Large Electron Positron collider (LEP) and will store two counter-rotating proton beams with energies of up to 7 TeV in a 27 km accelerator/storage ring with superconducting magnets. The vacuum system for the LHC will be at cryogenic temperatures (between 1.9 and 20 K) and will be exposed to synchrotron radiation emitted by the protons. A stringent limitation on the vacuum is given by the energy deposition in the superconducting coils of the magnets due to nuclear scattering of the protons on residual gas molecules because this may provoke a quench. This effect imposes an upper limit to a local region of increased gas density (e.g. a leak), while considerations of beam lifetime (100 h) will determine more stringent requirements on the average gas density. The proton beam creates ions from the residual gas which may strike the vacuum chamber with sufficient energy to lead to a pressure 'run-away' when the net ion induced desorption yield exceeds a stable limit. These dynamic pressure effects will be limited to an acceptable level by installing a perforated 'beam screen' which shields the cryopumped gas molecules at 1.9 K from synchrotron radiation and which also absorbs the synchrotron radiation power at a higher and, therefore, thermodynamically more efficient temperature. (author)

  16. Prototype development or multi-cavity ion chamber for depth dose measurement

    International Nuclear Information System (INIS)

    Nayak, M.K.; Sahu, T.K.; Haridas, G.; Bandyopadhyay, Tapas; Tripathi, R.M.; Nandedkar, R.V.

    2016-01-01

    In high energy electron accelerators, when the electrons interact with vacuum chamber or surrounding structural material, Bremsstrahlung x-rays are produced. It is having a broad spectrum extending up to the electron energies. Dose measured as a function of depth due to electromagnetic cascade will give rise to depth dose curve. To measure the online depth dose profile in an absorber medium, when high energy electron or Bremsstrahlung is incident, a prototype Multi-Cavity Ion Chamber (MCIC) detector is developed. The paper describes the design and development of the MCIC for measurement of depth dose profile

  17. Study on alumina-alumina brazing for application in vacuum chambers of proton synchrotron

    International Nuclear Information System (INIS)

    Yadav, D.P.; Kaul, R.; Ganesh, P.; Shiroman, Ram; Tiwari, Pragya; Sridhar, R.; Kukreja, L.M.

    2013-01-01

    The paper describes an experimental study to standardize vacuum brazing process to obtain satisfactory high purity alumina brazed joints for application in rapid cycle proton synchrotron machine. Two different brazing routes, adopted for making alumina-alumina brazed joints, included (i) multi-step Mo-Mn metallization and brazing with BVAg-8 alloy and (ii) advanced single-step active brazing with CuSil-ABA alloy. Brazed alumina specimens, prepared by both the routes, yielded ultra high vacuum compatible, helium leak tight and bakeable joints. Active-brazed specimens exhibited satisfactory strength values in tensile and four-point bend tests. Metallized-brazed specimens, although exhibited relatively lower tensile strength than the targeted value, displayed satisfactory flexural strength in four-point bend test. The results of the study demonstrated that active brazing is the simple and cost effective alternative to conventional metallization route for producing satisfactory brazed joints for application in rapid cycle proton synchrotron machine. (author)

  18. Members of the Science and Technology Commission, Spanish Senate visit ATLAS

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    Photo 01: Members of the Science and Technology Commission, Spanish Senate, in front of a barrel toroid cryostat vessel in the ATLAS assembly hall. The air-core ATLAS barrel toroid magnet system will consist of eight large superconducting coils, each in its own vacuum vessel, built by Spanish company Felguera Construcciones Mecanicas SA under the responsibility of IFAE (Institute for High Energy Physics), Barcelona. Standing (left to right): Dr Peter Jenni, ATLAS spokesperson; Dr Manuel Aguilar-Benitez, delegate for Spain to CERN Council; Mrs Mercedes Senen, Lawyer of the Commission; Mr Alonso Arroyo, President of the Commission; Mr Ramon Antonio Socias, Second Vice-President of the Commission; Mr Francisco Xabier Albistur, Senator; H.E. Mr Joaquin Pérez-Villaneuva Y Tovar, Ambassador, Permanent Representative of Spain to the Office of the United Nations in Geneva and other international organisations in Switzerland, Spanish delegate to CERN Council; and Miguel Gomez. Seated (left to right): Mr Adolfo Abejon...

  19. A gas monitoring facility with a quadrupole mass spectrometer for the ZEUS transition-radiation chambers

    International Nuclear Information System (INIS)

    Kapp, U.

    1988-07-01

    A gas analysis facility for the ZEUS transition-radiation chambers based on a quadrupole mass spectrometer is described. After a description of the spectrometer, the vacuum system, and the software, some test results are presented. (HSI)

  20. The ATLAS Level-1 Trigger System with 13TeV nominal LHC collisions

    CERN Document Server

    Helary, Louis; The ATLAS collaboration

    2017-01-01

    The Level-1 (L1) Trigger system of the ATLAS experiment at CERN's Large Hadron Collider (LHC) plays a key role in the ATLAS detector data-taking. It is a hardware system that selects in real time events containing physics-motivated signatures. Selection is purely based on calorimetry energy depositions and hits in the muon chambers consistent with muon candidates. The L1 Trigger system has been upgraded to cope with the more challenging run-II LHC beam conditions, including increased centre-of-mass energy, increased instantaneous luminosity and higher levels of pileup. This talk summarises the improvements, commissioning and performance of the L1 ATLAS Trigger for the LHC run-II data period. The acceptance of muon triggers has been improved by increasing the hermiticity of the muon spectrometer. New strategies to obtain a better muon trigger signal purity were designed for certain geometrically difficult transition regions by using the ATLAS hadronic calorimeter. Algorithms to reduce noise spikes in muon trig...

  1. The radiation environment in the ATLAS inner detector

    CERN Document Server

    Dawson, I

    2000-01-01

    The radiation environment in the inner detector has been simulated using the particle transport program FLUKA with a recent description of the ATLAS experiment. Given in this paper are particle fluences and doses at positions relevant to the three inner detector subsystems; the Pixel, SCT and TRT detectors. In addition, studies are reported on in which (1) information concerning the optimization of the inner detector neutron-moderators is obtained and (2) the impact of including additional vacuum-equipment material is assessed. (19 refs).

  2. Reduction of the suction pressure of a liquid ring vacuum pump with a supersonic gas ejector

    Directory of Open Access Journals (Sweden)

    Olšiak Róbert

    2018-01-01

    Full Text Available A supersonic gas ejector in conjunction with a liquid ring vacuum pump is used for creating and maintaining vacuum in a chamber for technological purposes. In this paper the authors submit an overview about the problematics of suction pressure reduction with a supersonic gas ejector used as a pre-stage of a liquid ring vacuum pump. This system has also the function of a cavitation protection due to the higher pressure present at the suction throat of the vacuum pump. A part of this paper is devoted to the governing equations used at the definition of the flow through an ejector. The experimental studies are then carried out in or own laboratory for verification purposes.

  3. CMS and ATLAS honour their suppliers

    CERN Multimedia

    2001-01-01

    In order to motivate the hundreds of companies building their detectors, the CMS and ATLAS collaborations have recently been handing out awards of excellence to their top suppliers. At its second ceremony of this kind, CMS honoured four of its suppliers, while ATLAS for the first time paid tribute to two of its contractors. The atmosphere in the Council Chamber was festive rather than formal at the start of CMS week on Monday 5 March. Before embarking upon a long series of seminars and presentations, the Collaboration held its second awards ceremony to honour its top suppliers. By paying tribute to the exceptional efforts of certain suppliers, the Collaboration's aim is to motivate all the firms, some 500 in total, taking part in the experiment's construction. The CMS Awards panel thus singles out contractors who have not only provided full satisfaction in terms of compliance with specifications, quality and deadlines, but have in addition provided original solutions to delicate problems. Four firms came away...

  4. Wafer-Level Vacuum Packaging of Smart Sensors.

    Science.gov (United States)

    Hilton, Allan; Temple, Dorota S

    2016-10-31

    The reach and impact of the Internet of Things will depend on the availability of low-cost, smart sensors-"low cost" for ubiquitous presence, and "smart" for connectivity and autonomy. By using wafer-level processes not only for the smart sensor fabrication and integration, but also for packaging, we can further greatly reduce the cost of sensor components and systems as well as further decrease their size and weight. This paper reviews the state-of-the-art in the wafer-level vacuum packaging technology of smart sensors. We describe the processes needed to create the wafer-scale vacuum microchambers, focusing on approaches that involve metal seals and that are compatible with the thermal budget of complementary metal-oxide semiconductor (CMOS) integrated circuits. We review choices of seal materials and structures that are available to a device designer, and present techniques used for the fabrication of metal seals on device and window wafers. We also analyze the deposition and activation of thin film getters needed to maintain vacuum in the ultra-small chambers, and the wafer-to-wafer bonding processes that form the hermetic seal. We discuss inherent trade-offs and challenges of each seal material set and the corresponding bonding processes. Finally, we identify areas for further research that could help broaden implementations of the wafer-level vacuum packaging technology.

  5. Wafer-Level Vacuum Packaging of Smart Sensors

    Directory of Open Access Journals (Sweden)

    Allan Hilton

    2016-10-01

    Full Text Available The reach and impact of the Internet of Things will depend on the availability of low-cost, smart sensors—“low cost” for ubiquitous presence, and “smart” for connectivity and autonomy. By using wafer-level processes not only for the smart sensor fabrication and integration, but also for packaging, we can further greatly reduce the cost of sensor components and systems as well as further decrease their size and weight. This paper reviews the state-of-the-art in the wafer-level vacuum packaging technology of smart sensors. We describe the processes needed to create the wafer-scale vacuum microchambers, focusing on approaches that involve metal seals and that are compatible with the thermal budget of complementary metal-oxide semiconductor (CMOS integrated circuits. We review choices of seal materials and structures that are available to a device designer, and present techniques used for the fabrication of metal seals on device and window wafers. We also analyze the deposition and activation of thin film getters needed to maintain vacuum in the ultra-small chambers, and the wafer-to-wafer bonding processes that form the hermetic seal. We discuss inherent trade-offs and challenges of each seal material set and the corresponding bonding processes. Finally, we identify areas for further research that could help broaden implementations of the wafer-level vacuum packaging technology.

  6. Development of Glassy Carbon Blade for LHC Fast Vacuum Valve

    CERN Document Server

    Coly, P

    2012-01-01

    An unexpected gas inrush in a vacuum chamber leads to the development of a fast pressure wave. It carries small particles that can compromise functionality of sensitive machine systems such as the RF cavities or kickers. In the LHC machine, it has been proposed to protect this sensitive equipment by the installation of fast vacuum valves. The main requirements for the fast valves and in particular for the blade are: fast closure in the 20 ms range, high transparency and melting temperature in case of closure with beam in, dust free material to not contaminate sensitive adjacent elements, and last but not least vacuum compatibility and adequate leak tightness across the blade. In this paper, different designs based on a vitreous carbon blade are presented and a solution is proposed. The main reasons for this material choice are given. The mechanical study of the blade behaviour under dynamic forces is shown.

  7. High voltage pulse system for the streamer chamber supply of the GIBS spectrometer

    International Nuclear Information System (INIS)

    Aksinenko, V.D.; Glagoleva, N.S.; Dement'ev, E.A.; Kaminskij, N.I.; Matyushin, A.T.; Matyushin, V.T.; Rozhnyatovskaya, S.A.; Ryakhovskij, V.N.; Nurgozhin, N.N.; Khusainov, E.K.

    1987-01-01

    Results of development and testing of high voltage pulse system HVPS for the streamer chamber supply of the GIBS spectrometer are presented. HVPS consists of the following basic blocks: nanosecond pulse high voltage generator, high voltage charging supply, trigger generator, chamber parameter control devices, gas-oil vacuuming supply systems, auxiliary and fire-prevention devices. The system blocks are described. Experimental results of HVPC testing are presented. HVPC provides a reliable (10 5 operations) of streamer chamber supply with high voltage pulse parameters: amplitude - 500 kV, amplitude instability (0.5-1.5)%, pulse duration - 12 ns, delay time - 500 ns, delay instability (2.5-5)%, mean frequency of output a signals - 0.1 Hz

  8. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: A modular vacuum ultraviolet source

    International Nuclear Information System (INIS)

    Sloan Roberts, F.; Anderson, Scott L.

    2013-01-01

    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a “soft” photoionization source for gas-phase mass spectrometry

  9. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: A modular vacuum ultraviolet source

    Energy Technology Data Exchange (ETDEWEB)

    Sloan Roberts, F.; Anderson, Scott L. [Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, Utah 84112 (United States)

    2013-12-15

    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a “soft” photoionization source for gas-phase mass spectrometry.

  10. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: a modular vacuum ultraviolet source.

    Science.gov (United States)

    Roberts, F Sloan; Anderson, Scott L

    2013-12-01

    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a "soft" photoionization source for gas-phase mass spectrometry.

  11. Coupling impedance of an in-vacuum undulator: Measurement, simulation, and analytical estimation

    Science.gov (United States)

    Smaluk, Victor; Fielder, Richard; Blednykh, Alexei; Rehm, Guenther; Bartolini, Riccardo

    2014-07-01

    One of the important issues of the in-vacuum undulator design is the coupling impedance of the vacuum chamber, which includes tapered transitions with variable gap size. To get complete and reliable information on the impedance, analytical estimate, numerical simulations and beam-based measurements have been performed at Diamond Light Source, a forthcoming upgrade of which includes introducing additional insertion device (ID) straights. The impedance of an already existing ID vessel geometrically similar to the new one has been measured using the orbit bump method. The measurement results in comparison with analytical estimations and numerical simulations are discussed in this paper.

  12. Monitored Drift Tube (MDT) chambers for precise measurement of muon trajectories in the ATLAS muon spectrometer.

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    The basic detection component of the chamber is the cylindrical, aluminium, gas-filled MDT with its central tungsten rhenium wire. Each chamber is an assembly of two parallel multilayers of MDTs separated by a spacer frame. The chambers are pictured here in building 887 on the Prévessin site where they are being tested.

  13. Twin-tubes: 3D tracking based on the ATLAS muon drift tubes

    International Nuclear Information System (INIS)

    Woudstra, M.; Bobbink, G.J.; Eldik, N. van; Graaf, H. van der; Kluit, P.; Koutsman, A.; Limper, M.; Linde, F.; Massaro, G.; Snuverink, J.; Vreeswijk, M.; Groenstege, H.; Koopstra, J.; Mos, S.; Rewiersma, P.; Timmermans, C.; Dijkema, J.

    2006-01-01

    The Monitored Drift Tubes (MDTs) of the ATLAS Muon Spectrometer have been paired to form so-called twin-tubes to measure the coordinate which runs along the wire direction. This modification endows the MDTs with full 3D track reconstruction using specially designed electronic boards. The performance of the twin-tubes has been measured for an equipped MDT chamber at the ATLAS Muon Cosmic Ray Test Stand at NIKHEF. The efficiency of a twin-tube has been determined to be 99.8%, and the measured resolution 17 cm per hit. By equipping one multilayer consisting of three layers and combining the measurements a resolution of 10 cm has been obtained

  14. MMS Observatory Thermal Vacuum Results Contamination Summary

    Science.gov (United States)

    Rosecrans, Glenn P.; Errigo, Therese; Brieda, Lubos

    2014-01-01

    The MMS mission is a constellation of 4 observatories designed to investigate the fundamental plasma physics of reconnection in the Earths magnetosphere. Each spacecraft has undergone extensive environmental testing to prepare it for its minimum 2 year mission. The various instrument suites measure electric and magnetic fields, energetic particles, and plasma composition. Thermal vacuum testing was conducted at the Naval Research Laboratory (NRL) in their Big Blue vacuum chamber. The individual spacecraft were tested and enclosed in a cryopanel enclosure called a Hamster cage. Specific contamination control validations were actively monitored by several QCMs, a facility RGA, and at times, with 16 Ion Gauges. Each spacecraft underwent a bakeout phase, followed by 4 thermal cycles. Unique aspects of the TV environment included slow pump downs with represses, thruster firings, Helium identification, and monitoring pressure spikes with Ion gauges. Various data from these TV tests will be shown along with lessons learned.

  15. Helium pressures in RHIC vacuum cryostats and relief valve requirements from magnet cooling line failure

    Energy Technology Data Exchange (ETDEWEB)

    Liaw, C.J.; Than, Y.; Tuozzolo, J.

    2011-03-28

    A catastrophic failure of the RHIC magnet cooling lines, similar to the LHC superconducting bus failure incident, would pressurize the insulating vacuum in the magnet and transfer line cryostats. Insufficient relief valves on the cryostats could cause a structural failure. A SINDA/FLUINT{reg_sign} model, which simulated the 4.5K/4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the vacuum cryostat and discharging via the reliefs into the RHIC tunnel, had been developed to calculate the helium pressure inside the cryostat. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces were included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Existing relief valve sizes were reviewed to make sure that the maximum stresses, caused by the calculated maximum pressures inside the cryostats, did not exceed the allowable stresses, based on the ASME Code B31.3 and ANSYS results. The conclusions are as follows: (1) The S/F simulation results show that the highest internal pressure in the cryostats, due to the magnet line failure, is {approx}37 psig (255115 Pa); (2) Based on the simulation, the temperature on the cryostat chamber, INJ Q8-Q9, could drop to 228 K, which is lower than the material minimum design temperature allowed by the Code; (3) Based on the ASME Code and ANSYS results, the reliefs on all the cryostats inside the RHIC tunnel are adequate to protect the vacuum chambers when the magnet cooling lines fail; and (4) In addition to the pressure loading, the thermal deformations, due to the temperature decrease on the cryostat chambers, could also cause a high stress on the chamber, if not properly supported.

  16. Helium pressures in RHIC vacuum cryostats and relief valve requirements from magnet cooling line failure

    International Nuclear Information System (INIS)

    Liaw, C.J.; Than, Y.; Tuozzolo, J.

    2011-01-01

    A catastrophic failure of the RHIC magnet cooling lines, similar to the LHC superconducting bus failure incident, would pressurize the insulating vacuum in the magnet and transfer line cryostats. Insufficient relief valves on the cryostats could cause a structural failure. A SINDA/FLUINT(reg s ign) model, which simulated the 4.5K/4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the vacuum cryostat and discharging via the reliefs into the RHIC tunnel, had been developed to calculate the helium pressure inside the cryostat. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces were included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Existing relief valve sizes were reviewed to make sure that the maximum stresses, caused by the calculated maximum pressures inside the cryostats, did not exceed the allowable stresses, based on the ASME Code B31.3 and ANSYS results. The conclusions are as follows: (1) The S/F simulation results show that the highest internal pressure in the cryostats, due to the magnet line failure, is ∼37 psig (255115 Pa); (2) Based on the simulation, the temperature on the cryostat chamber, INJ Q8-Q9, could drop to 228 K, which is lower than the material minimum design temperature allowed by the Code; (3) Based on the ASME Code and ANSYS results, the reliefs on all the cryostats inside the RHIC tunnel are adequate to protect the vacuum chambers when the magnet cooling lines fail; and (4) In addition to the pressure loading, the thermal deformations, due to the temperature decrease on the cryostat chambers, could also cause a high stress on the chamber, if not properly supported.

  17. Vacuum system design and performance for the Daresbury HBL

    International Nuclear Information System (INIS)

    Reid, R.J.

    1988-01-01

    This paper reports on the vacuum performance of an electron storage ring dedicated to the production of synchrotron radiation which is characterized in terms of the single parameter electron beam lifetime at the working current of the machine. The Daresbury SRS had performed satisfactorily in this respect over much of its working life, with lifetimes in excess of 10 hours at 300 mA stored current at a beam energy of 2 GeV. When the decision was taken to upgrade the performance of the machine by increasing the source brilliance, it was important that this performance should continue. However, it was clear that apertures - and hence gas flow conductances - in some of the new vacuum chambers were very restricted. Thus it was by no means obvious that the requisite vacuum levels (approx. 10 -7 Pascal) could be obtained given the engineering constraints on the possible location and physical size of suitable vacuum pumps. Extensive and detailed calculations were therefore carried out using a finite-element type of analysis to compute pressure profiles in the proposed machine, with the vacuum pumps being treated as semi-free parameters. A suitable scheme was evolved, and has proved satisfactory, with beam lifetimes of 24 hours at 200 mA stored beam at 2 GeV being regularly achieved. These lifetimes are in excess of the anticipated values, and this is discussed

  18. Small-sized pump for the target chamber of the E-SUVI accelerator

    International Nuclear Information System (INIS)

    Borts, B.V.; Kravchenko, S.F.; Pisarev, G.V.; Rubashko, V.G.; Khorenko, V.K.

    1980-01-01

    The target chamber of the accelerator ESUVI is located at the high voltage end of the accelerating tube under the electrostatic generator conductor. The pumping out from the target chamber region has been performed through the accelerating tube its rate constituting 1.5 l/s which resulted in oxidation and contamination of the surface of irradiated targets in the course of the irradiation of chemically active materials. For obtaining high vacuum in a target chamber a small-size gettering-ionic pump of the ORBITRON type has been developed which operates in the autonomous mode. The pump pumping out rate in the pressure range 10 -5 -10 -7 mm Hg constitutes for air and nitrogen 20-25 l/s, ffor oxygen 30-40 l/s, for hydrogen 100-120 l/s. The pump weight without supply units is 2 kg. The pumps permits performing pressure indicator in the target chamber. Using the developed pump makes possible to decrease the target chamber pressure to 1x10 -6 mm Hg for active gases to 10 -8 -10 -9 mm Hg

  19. Simulation of the High Performance Time to Digital Converter for the ATLAS Muon Spectrometer trigger upgrade

    International Nuclear Information System (INIS)

    Meng, X.T.; Levin, D.S.; Chapman, J.W.; Zhou, B.

    2016-01-01

    The ATLAS Muon Spectrometer endcap thin-Resistive Plate Chamber trigger project compliments the New Small Wheel endcap Phase-1 upgrade for higher luminosity LHC operation. These new trigger chambers, located in a high rate region of ATLAS, will improve overall trigger acceptance and reduce the fake muon trigger incidence. These chambers must generate a low level muon trigger to be delivered to a remote high level processor within a stringent latency requirement of 43 bunch crossings (1075 ns). To help meet this requirement the High Performance Time to Digital Converter (HPTDC), a multi-channel ASIC designed by CERN Microelectronics group, has been proposed for the digitization of the fast front end detector signals. This paper investigates the HPTDC performance in the context of the overall muon trigger latency, employing detailed behavioral Verilog simulations in which the latency in triggerless mode is measured for a range of configurations and under realistic hit rate conditions. The simulation results show that various HPTDC operational configurations, including leading edge and pair measurement modes can provide high efficiency (>98%) to capture and digitize hits within a time interval satisfying the Phase-1 latency tolerance.

  20. Ultra-high vacuum photoelectron linear accelerator

    Science.gov (United States)

    Yu, David U.L.; Luo, Yan

    2013-07-16

    An rf linear accelerator for producing an electron beam. The outer wall of the rf cavity of said linear accelerator being perforated to allow gas inside said rf cavity to flow to a pressure chamber surrounding said rf cavity and having means of ultra high vacuum pumping of the cathode of said rf linear accelerator. Said rf linear accelerator is used to accelerate polarized or unpolarized electrons produced by a photocathode, or to accelerate thermally heated electrons produced by a thermionic cathode, or to accelerate rf heated field emission electrons produced by a field emission cathode.