27 results on '"Reiner Denz"'
Search Results
2. Performance of the Large Hadron Collider's Cryogenic Bypass Diodes Over the First Two Physics Runs, Future Projects, and Perspectives
- Author
-
Andrzej Siemko, Arjan Verweij, Z. Charifoulline, Krzysztof Stachon, F. Rodriguez-Mateos, Daniel Wollmann, Arnaud Monteuuis, Andreas Will, Reiner Denz, Mathieu Favre, D. Hagedorn, and G. D'Angelo
- Subjects
Physics ,Cryostat ,Luminosity (scattering theory) ,Large Hadron Collider ,Physics::Instrumentation and Detectors ,Superconducting magnet ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Nuclear physics ,Magnet ,Physics::Accelerator Physics ,Electrical and Electronic Engineering ,Quadrupole magnet ,Superfluid helium-4 ,Diode - Abstract
Cryogenic bypass diodes have been installed in all superconducting dipole magnets (1232) and quadrupole magnets (392) of the Large Hadron Collider (LHC) at CERN, and operated during the physics runs since 2009. The bypass diodes are a fundamental ingredient of the quench protection system for those main dipoles and quadrupoles magnets. The diodes are located inside the magnet cryostats, operating in superfluid helium and exposed to ionizing radiation. The connection between the superconducting magnet and the bypass diode is made through a mechanical clamping system and copper bus bars. Since their first installation, all LHC diodes have undergone at least two full thermal cycles (from 1.9 K to room temperature and back to superfluid helium temperature). The evolution of electrical parameters as well as improvements and modifications made over a period of 10 years are reviewed in this paper. With CERN preparing for LHC's High Luminosity era, the long-term strategy for cold diodes is presented, based on the overall results and experience gathered so far, including the studies related to the tolerance with respect to the radiation doses and neutron fluences expected.
- Published
- 2020
3. Application of the New Generic Quench Detection System for LHC's 11 T Dipole Magnet
- Author
-
Severin Haas, Ernesto De Matteis, Andrzej Siemko, Surbhi Mundra, Reiner Denz, Jens Steckert, Tomasz Podzorny, Jelena Spasic, and Daniel Blasco Serrano
- Subjects
Large Hadron Collider ,Physics::Instrumentation and Detectors ,Computer science ,Firmware ,business.industry ,Electrical engineering ,Superconducting magnet ,Modular design ,Condensed Matter Physics ,computer.software_genre ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Magnetic circuit ,Dipole magnet ,Magnet ,0103 physical sciences ,Electrical and Electronic Engineering ,010306 general physics ,Field-programmable gate array ,business ,computer - Abstract
The high luminosity upgrade of large hadron collider (LHC) introduces a large number of new superconducting elements of various technologies. In order to ensure protection of these elements, a modular, versatile quench detection system had been developed. Designed to be flexible enough to detect quenches in superconducting bus-bars as well as in magnets, one generic base system is applied to various detection tasks. The fully customized system is based on a field programmable gate array that is connected to 16 galvanically insulated front-end channels. Due to the presence of radiation in some of the dedicated installation areas, the system is designed to be radiation tolerant up to 1 Gy/y. The first application of this system is the 11 T dipole magnet in Nb3Sn technology, which is foreseen to be installed during LHC's long shutdown 2. To gain experience with magnets made with this superconductor, which had not been used in LHC so far, the development of the detection system follows the tests of the magnet prototypes. Especially, the mitigation of flux jumps to avoid false triggers is a challenge for the system. A description of the hardware and firmware is given. Measurements from the recent magnet prototype and mitigation techniques against electrical oscillations are presented.
- Published
- 2019
4. New Quench Detection System to Enhance Protection of the Individually Powered Magnets in the Large Hadron Collider
- Author
-
Reiner Denz, Jens Steckert, Andrzej Siemko, Severin Haas, and Jelena Spasic
- Subjects
Large Hadron Collider ,Analog signal ,business.industry ,Computer science ,Magnet ,Electrical engineering ,Electronic board ,business ,Accelerators and Storage Rings ,Closed loop ,Signal ,Signal acquisition ,Acquisition rate - Abstract
To further improve the existing Quench Detection System (QDS) of individually powered magnets installed in the Large Hadron Collider (LHC), a new radiation tolerant electronic board was developed. The board provides three signal acquisition channels. It is able to acquire with different and configurable signal resolution and acquisition rate the analog signals of different properties. These enhancements enable the application of different quench detection algorithms depending on the protected magnet. Additionally, the board can be used with newly developed current derivative sensors for reliable detection of symmetric quenches. The new system supports both open and closed loop current sensors.
- Published
- 2020
5. Characterization of the radiation tolerance of cryogenic diodes for the High Luminosity LHC inner triplet circuit
- Author
-
Arjan Verweij, A.-S. Mueller, Axel Bernhard, Andrzej Siemko, Krzysztof Stachon, Reiner Denz, Emmanuele Ravaioli, F. Rodriguez Mateos, Daniel Wollmann, D. Hagedorn, G. D'Angelo, Arnaud Monteuuis, and Andreas Will
- Subjects
Cryostat ,Nuclear and High Energy Physics ,Technology ,Large Hadron Collider ,Materials science ,Physics and Astronomy (miscellaneous) ,010308 nuclear & particles physics ,Physics::Instrumentation and Detectors ,High Luminosity Large Hadron Collider ,Surfaces and Interfaces ,01 natural sciences ,Accelerators and Storage Rings ,0103 physical sciences ,Neutron ,Irradiation ,Atomic physics ,010306 general physics ,ddc:600 ,Superfluid helium-4 ,Diode ,Electronic circuit - Abstract
Cryogenic bypass diodes are part of the baseline powering layout for the circuits of the new ${\mathrm{Nb}}_{3}\mathrm{Sn}$ based final focus magnets of the high luminosity Large Hadron Collider. They will protect the magnets against excessive transient voltages during a nonuniform quenching process. The diodes are located inside an extension to the magnet cryostat, operated in superfluid helium and exposed to ionizing radiation. Therefore, the radiation tolerance of different types of diodes has been tested at cryogenic temperatures in CERN's CHARM irradiation test facility during its 2018 run. The forward bias characteristics, the turn-on voltage and the reverse blocking voltage of each diode were measured weekly at 4.2 K and 77 K, as a function of the accumulated radiation dose. The diodes were submitted to a total dose close to 12 kGy and a 1 MeV neutron equivalent fluence of $2.2\ifmmode\times\else\texttimes\fi{}{10}^{14}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}2}$. After the end of the irradiation program the annealing behavior of the diodes was tested by increasing the temperature slowly to 293 K. This paper describes the experimental setup, the measurement procedure and the analysis of the measurements performed during the irradiation program as well as the results of the annealing study.
- Published
- 2020
6. Fast Failures in the LHC and the future High Luminosity LHC*
- Author
-
Reiner Denz, Lorenzo Bortot, Bjorn Lindstrom, Christoph Wiesner, Markus Zerlauth, Ruediger Schmidt, Emmanuele Ravaioli, F. Rodriguez Mateos, Matthias Mentink, Matthieu Valette, Philippe Belanger, Arjan Verweij, Jan Uythoven, and Daniel Wollmann
- Subjects
Physics ,Accelerator Physics (physics.acc-ph) ,Nuclear and High Energy Physics ,Large Hadron Collider ,Luminosity (scattering theory) ,Physics and Astronomy (miscellaneous) ,Proton ,Physics::Instrumentation and Detectors ,High Energy Physics::Phenomenology ,FOS: Physical sciences ,Acceleratorfysik och instrumentering ,Surfaces and Interfaces ,Accelerator Physics and Instrumentation ,Accelerators and Storage Rings ,Nuclear physics ,lcsh:QC770-798 ,Physics::Accelerator Physics ,lcsh:Nuclear and particle physics. Atomic energy. Radioactivity ,Physics - Accelerator Physics ,Beam (structure) ,physics.acc-ph - Abstract
An energy of $362\:\text{MJ}$ is stored in each of the two LHC proton beams for nominal beam parameters. This will be further increased to about $700\:\text{MJ}$ in the future High Luminosity LHC (HL-LHC) and uncontrolled beam losses represent a significant hazard for the integrity and safe operation of the machine. In this paper, a number of failure mechanisms that can lead to a fast increase of beam losses are analyzed. Most critical are failures in the magnet protection system, namely the quench heaters and a novel protection system called Coupling-Loss Induced Quench (CLIQ). An important outcome is that magnet protection has to be evaluated for its impact on the beam and designed accordingly. In particular, CLIQ, which is to protect the new HL-LHC triplet magnets, constitutes the fastest known failure in the LHC if triggered spuriously. A schematic change of CLIQ to mitigate the hazard is presented. A loss of the Beam-Beam Kick due to the extraction of one beam is another source of beam losses with a fast onset. A significantly stronger impact is expected in the upcoming LHC Run III and HL-LHC as compared to the current LHC, mainly due to the increased bunch intensity. Its criticality and mitigation methods are discussed. It is shown that symmetric quenches in the superconducting magnets for the final focusing triplet can have a significant impact on the beam on short timescales. The impact on the beam due to failures of the Beam-Beam Compensating Wires as well as coherent excitations by the transverse beam damper are also discussed., Comment: 28 pages, 23 figures. To be published in Physical Review Accelerators and Beams
- Published
- 2020
- Full Text
- View/download PDF
7. Development of a Digital Quench Detection System for Nb3Sn Magnets and First Measurements on Prototype Magnets
- Author
-
Reiner Denz, Josef Steckert, Hugues Bajas, Spyridon Georgakakis, Jelena Spasic, Josef Kopal, Ernesto De Matteis, and Andrzej Siemko
- Subjects
010302 applied physics ,Large Hadron Collider ,Physics::Instrumentation and Detectors ,business.industry ,Firmware ,Computer science ,Electrical engineering ,Superconducting magnet ,Isolation amplifier ,Condensed Matter Physics ,computer.software_genre ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Magnetic circuit ,chemistry.chemical_compound ,chemistry ,Magnet ,0103 physical sciences ,Electrical and Electronic Engineering ,Niobium-tin ,010306 general physics ,business ,computer ,Digital signal processing - Abstract
The High Luminosity upgrade for the Large Hadron Collider LHC (HL-LHC) requires new Nb3Sn superconducting magnets and it triggers a development of novel hardware for the quench detection system (QDS) based on a field programmable gate array (FPGA) digital platform and a number of individually isolated analogue front-ends. Galvanic insulation has been implemented downstream the analogue to digital convertors to eliminate a usage of analogue isolation amplifiers. This concept was already successfully implemented in the current LHC QDS system, however the mitigation of new phenomena inside Nb3Sn materials required development of a new generation of QDS. The newly developed universal QDS offers flexibility of firmware defined architecture. Adopted prototype driven strategy includes thorough characterization of the analogue front-ends in the laboratory and prototype unit measurements performed on HL-LHC magnet prototypes at CERN's superconducting magnet test facility SM18. The tests also reveal the characteristics of the magnets as well as the measurement electronics at an early stage. The test results are used to optimize the analogue input stages as well as the digital signal processing within the FPGA. The preliminary test results are presented and focus is given to the measurement and studies of the so-called “flux jumps” to mitigate the effects of these voltage perturbations in the QDS.
- Published
- 2018
8. Resistance of Splices in the LHC Main Superconducting Magnet Circuits at 1.9 K
- Author
-
Andrzej Siemko, M. Bednarek, Markus Zerlauth, Christian Scheuerlein, Arjan Verweij, Z. Charifoulline, Sandrine Le Naour, J. P. Tock, Reiner Denz, and Jens Steckert
- Subjects
Superconductivity ,Large Hadron Collider ,Materials science ,Thermal runaway ,Busbar ,Nuclear engineering ,Superconducting magnet ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Magnetic circuit ,Magnet ,0103 physical sciences ,Electrical and Electronic Engineering ,010306 general physics ,Electronic circuit - Abstract
The electrical interconnections between the LHC main magnets are made of soldered joints (splices) of two superconducting Rutherford cables, stabilized by a copper busbar. In 2009, a number of splices was found not properly stabilized and could have suffered a thermal runaway in case of quench at high current. The LHC was, therefore, operated at reduced energy and all joints were continuously monitored by a newly installed layer of the quench protection system. During the first long shutdown (LS1) in 2013/14, the high-current busbar joints were consolidated to allow us a safe operation of the LHC at its design energy, i.e., 14-TeV center-of-mass. The superconducting magnets and circuits consolidation project has coordinated the consolidation of the 10306 13-kA busbar splices. Since 2015, the LHC is successfully operated at an energy of 13-TeV center-of-mass. This paper will briefly describe the applied analysis method and will present the results and comparisons of the Rutherford-cable splice resistance measurements at 1.9 K before and after LS1, based on an unprecedented amount of information gathered during long-term operation of superconducting high-current joints. A few outliers that are still present after the splice consolidation will also be shortly discussed.
- Published
- 2018
9. New Method for Magnet Protection Systems Based on a Direct Current Derivative Sensor
- Author
-
Reiner Denz, Andrzej Siemko, Daniel Calcoen, Jens Steckert, E. De Matteis, and M. B. Storkensen
- Subjects
Physics ,010308 nuclear & particles physics ,Direct current ,Superconducting magnet ,Condensed Matter Physics ,Topology ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,law.invention ,Magnetic circuit ,Electromagnetic coil ,law ,Magnet ,0103 physical sciences ,Quadrupole ,Electrical and Electronic Engineering ,010306 general physics ,Transformer ,Electronic circuit - Abstract
A new method of the quench detection systems (QDS) designed for the LHC ${600 \;\mathrm{A}}$ corrector magnet circuits and ${6 \;\mathrm{kA}}$ individual powered quadrupole (IPQ) magnet circuits is presented. In order to improve the dependability of QDS, a direct measurement of the current derivative is proposed. The quench detection scheme for the ${600 \;\mathrm{A}}$ corrector magnet circuits uses the current derivative numerically evaluated from a direct current measurement. In order to make the calculation stable, the current derivative is heavily filtered, thus introducing a significant phase shift, which restricts the operational range of circuit parameters such as the acceleration. For the ${6{\text{-}}\mathrm{kA}}$ IPQ magnet circuits the main quench detection is based on a classical bridge configuration. The introduction of an additional detection channel for the direct measurement of the current derivative helps to overcome the lack of sensitivity to fully aperture symmetric quenches of the bridge configuration. Transformer-based current derivative sensors are currently under development, using cut cores for easy prototyping, performance control, and installation. Prototypes for the ${\pm 600 \;\mathrm{A}}$ current range and ramp rates between 0.1 and ${5 \;\mathrm{A/s}}$ were built using different core materials (electrical steel and nanocrystalline cores) and pickup coils with 10 000 and 20 000 windings. In order to characterize the prototypes, the performance was defined in terms of mean sensitivity of the sensor response in [V/A/s] and the performance quality factor (PQF), defined as a percentage of nonlinearity of the response. An optimization procedure was implemented for finding the best configuration of the sensors, i.e., the air gap in the cut core in order to maximize the mean sensitivity and to minimize the PQF. The tests were carried out at different working points (current ranges and ramp rates) showing promising results (PQF ${ with a sensitivity of ${5.5 \;\mathrm{{mV/A/s}}}$ ).
- Published
- 2018
10. A New Cryogenic Test Facility for Large and Heavy Superconducting Magnets
- Author
-
Daniel Calcoen, G. J. Coelingh, Michel Arnaud, S. Russenschuck, Luigi Serio, David A. Hay, Hans Mueller, Eun Jung Cho, Piotr Szwangruber, Stefano Moccia, Y. Muttoni, Reiner Denz, Caterina Bertone, Jens Steckert, Felix Wamers, Vasilis Velonas, E. Blanco, H. Thiesen, Gerard Willering, Dominique Missiaen, Vitaliano Inglese, Giancarlo Golluccio, V. Mertens, A. Perin, Ina Pschorn, Andre Henriques, Rene Necca, K. Dahlerup-Petersen, Pierre Schnizer, M. Charrondiere, Yu Xiang, J. Hendrie Derking, Antoine Kosmicki, and Fahim Dhalla
- Subjects
Physics ,Measurement method ,Test facility ,Superconducting electric machine ,Liquid helium ,Nuclear engineering ,Superconducting magnet ,Cryogenics ,Superconducting magnetic energy storage ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,law.invention ,Nuclear magnetic resonance ,law ,Electrical and Electronic Engineering - Published
- 2017
11. Next Generation of Quench Detection Systems for the High-Luminosity Upgrade of the LHC
- Author
-
Ernesto De Matteis, Andrzej Siemko, Reiner Denz, and Jens Steckert
- Subjects
Physics ,Large Hadron Collider ,Physics::Instrumentation and Detectors ,010308 nuclear & particles physics ,Nuclear engineering ,Niobium-titanium ,Superconducting magnet ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Nuclear physics ,chemistry.chemical_compound ,Upgrade ,chemistry ,Magnet ,0103 physical sciences ,Physics::Accelerator Physics ,Electrical and Electronic Engineering ,Niobium-tin ,010306 general physics ,Quadrupole magnet ,Compact Muon Solenoid - Abstract
The foreseen upgrade of the large hadron collider (LHC) for high-luminosity operation will incorporate a new generation of high field superconducting magnets. In particular, the current inner triplet magnets in LHC experiments A Toroidal LHC Apparatus (ATLAS) and Compact Muon Solenoid (CMS) in points 1 and 5 will be replaced by novel large aperture Nb 3 Sn quadrupole magnets. In addition, there will be a variety of new magnets based on NbTi conductors. For the magnet powering, the novel MgB 2 based superconducting links will be used, thus allowing the installation of sensitive equipment such as power converters in radiation-free areas of the LHC. The protection of the superconducting elements will be ensured by various elements such as quench heaters and the recently developed coupling-loss induced quench system, which are triggered by a dedicated set of quench detection systems. These custom-made systems are the result of a complete new development and adapted to the specific features of the newly installed superconducting elements. This concerns in particular the Nb 3 Sn based magnets, requiring an effective rejection of voltage spikes resulting from flux jumps and a dynamic setting of detection parameters when energizing the magnet. The new detection systems will be complemented by data acquisition systems, offering significantly higher sampling rates and resolution than previously installed systems.
- Published
- 2017
12. Overview of the Performance of Quench Heaters for High-Current LHC Superconducting Magnets
- Author
-
Arjan Verweij, Gerard Willering, Reiner Denz, Andrzej Siemko, Felix Rodriguez Mateos, Lorenzo Bortot, Jens Steckert, and Z. Charifoulline
- Subjects
Physics ,Resistive touchscreen ,Large Hadron Collider ,Physics::Instrumentation and Detectors ,Nuclear engineering ,Physics::Medical Physics ,Superconducting magnet ,Power factor ,Condensed Matter Physics ,01 natural sciences ,Computer Science::Other ,Electronic, Optical and Magnetic Materials ,Physics::Fluid Dynamics ,Nuclear magnetic resonance ,Dipole magnet ,Magnet ,0103 physical sciences ,Electrical and Electronic Engineering ,010306 general physics ,Quadrupole magnet ,Overheating (electricity) - Abstract
Quench heaters are an essential part of the protection of all high-current large hadron collider (LHC) superconducting circuits. About 2000 dipole and quadrupole magnets are equipped with quench heaters in order to protect them against development of excessive voltage and overheating after a resistive transition. The quench heaters are made of stainless steel foil partially plated with copper and connected to 900 V capacitor bank discharge power supplies. During Hardware Commissioning campaigns and machine operation every quench heater discharge event is carefully analysed to detect a possible failure or a precursor of a failure, which could lead to damage of the heater or to the superconducting coils in subsequent discharges. This paper will briefly describe two different ways of quench heater data analysis and will present the heaters performance during the years 2008-2015. A summary of the quench heater fatigue test performed on a spare LHC main dipole magnet will also be given.
- Published
- 2017
13. Radiation Testing of an SAR ADC for Use in Quench Detection Systems for the HiLumi LHC
- Author
-
Jelena Spasic, Reiner Denz, Jens Steckert, and Josef Kopal
- Subjects
010302 applied physics ,Materials science ,Large Hadron Collider ,Physics::Instrumentation and Detectors ,Nuclear engineering ,Successive approximation ADC ,Superconducting magnet ,Radiation ,01 natural sciences ,Radiation testing ,0103 physical sciences ,Irradiation ,010306 general physics ,Beam (structure) ,Electronic circuit - Abstract
This work presents a radiation assessment of a successive-approximation-register (SAR) analog-to-digital converter (ADC) for purposes of a new generation of quench detection systems (QDS) that will be used in the radiation environment of High-Luminosity Large Hadron Collider (HLLHC). The assessment has been performed by conducting an irradiation testing campaign using a proton beam with radiation doses up to 1 kGy. The test results render the selected ADC highly robust for use in future applications of quench protection in the LHC superconducting magnet circuits.
- Published
- 2017
14. Single event effects in high-energy accelerators
- Author
-
Joao Pedro De Carvalho Saraiva, Francesco Cerutti, Salvatore Danzeca, Slawosz Uznanski, Lionel L Foro, R. Secondo, Alfredo Ferrari, Ruben Garcia Alia, Reiner Denz, Yves Thurel, Jens Steckert, Ketil Røed, Markus Brugger, Iacocpo Toccafondo, and Paul Peronnard
- Subjects
Physics ,Range (particle radiation) ,Photon ,Interaction point ,010308 nuclear & particles physics ,Electron ,Radiation ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Nuclear physics ,0103 physical sciences ,Electromagnetic shielding ,Materials Chemistry ,Physics::Accelerator Physics ,Electrical and Electronic Engineering ,010306 general physics ,Event (particle physics) ,Beam (structure) - Abstract
The radiation environment encountered at high-energy hadron accelerators strongly differs from the environment relevant for space applications. The mixed-field expected at modern accelerators is composed of charged and neutral hadrons (protons, pions, kaons and neutrons), photons, electrons, positrons and muons, ranging from very low (thermal) energies up to the TeV range. This complex field, which is extensively simulated by Monte Carlo codes (e.g. FLUKA) is due to beam losses in the experimental areas, distributed along the machine (e.g. collimation points) and deriving from the interaction with the residual gas inside the beam pipe. The resulting intensity, energy distribution and proportion of the different particles largely depends on the distance and angle with respect to the interaction point as well as the amount of installed shielding material. Electronics operating in the vicinity of the accelerator will therefore be subject to both cumulative damage from radiation (total ionizing dose, displacement damage) as well as single event effects which can seriously compromise the operation of the machine. This, combined with the extensive use of commercial-off-the-shelf components due to budget, performance and availability reasons, results in the need to carefully characterize the response of the devices and systems to representative radiation conditions.
- Published
- 2017
15. Development of radiation tolerant components for the Quench Protection System at CERN
- Author
-
O. Bitterling, Reiner Denz, Jens Steckert, and Slawosz Uznanski
- Subjects
Physics ,Large Hadron Collider ,010308 nuclear & particles physics ,business.industry ,Physics::Instrumentation and Detectors ,Nuclear engineering ,Electrical engineering ,Analog-to-digital converter ,Radiation ,01 natural sciences ,Accelerators and Storage Rings ,law.invention ,Data acquisition ,law ,0103 physical sciences ,Electronics ,Irradiation ,Radiation protection ,010306 general physics ,business ,Instrumentation ,Mathematical Physics ,Beam (structure) - Abstract
This paper describes the results of irradiation campaigns with the high resolution Analog to Digital Converter (ADC) ADS1281. This ADC will be used as part of a revised quench detection circuit for the 600 A corrector magnets at the CERN Large Hadron Collider (LHC) . To verify the radiation tolerance of the ADC an irradiation campaign using a proton beam, applying doses up to 3,4 kGy was conducted. The resulting data and an analysis of the found failure modes is discussed in this paper. Several mitigation measures are described that allow to reduce the error rate to levels acceptable for operation as part of the LHC QPS.
- Published
- 2016
16. Consolidation of the 13 kA Interconnects in the LHC for Operation at 7 TeV
- Author
-
F. Bertinelli, Reiner Denz, Michael Koratzinos, J.-P Tock, S. Mathot, Jens Steckert, Stefano Sgobba, Herman H.J. ten Kate, Cedric Garion, Arjan Verweij, Nuria Catalán Lasheras, Gerard Willering, Christian Scheuerlein, Paolo Fessia, A. Perin, and Z. Charifoulline
- Subjects
Interconnection ,Materials science ,Large Hadron Collider ,Busbar ,Mechanical engineering ,Superconducting magnet ,Integrated circuit ,XX ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,law.invention ,law ,Magnet ,Soldering ,Electrical and Electronic Engineering ,Electronic circuit - Abstract
The accident in the LHC in September 2008 occurred in an interconnection between two magnets of the 13 kA dipole circuit. Successive measurements of the resistance of other interconnects revealed other defective joints, even though the SC cables were properly connected. These defective joints are characterized by a poor bonding between the SC cable and the copper stabilizer in combination with an electrical discontinuity in the copper stabilizer. A quench at the 7-13 kA level in such a joint can lead to a fast and unprotected thermal run-away and hence opening of the circuit. It has therefore been decided to operate the LHC at a reduced and safe current of 6 kA corresponding to 3.5 TeV beam energy until all defective joints are repaired. A task force is reviewing the status of all electrical joints in the magnet circuits and preparing for the necessary repairs. The principle solution is to resolder the worst defective joints and, in addition, to apply an electrical shunt made of copper across all joints with sufficient cross-section to guarantee safe 12-13 kA operation at 7-7.5 TeV. In this paper the various actions that have lead to this solution are presented.
- Published
- 2011
17. Commissioning of the Low-$\beta$ Triplets of the Large Hadron Collider
- Author
-
R. Ostojic, H. Thiesen, A. Perin, F. Gicquel, T. Page, K.-i. Sasaki, Sandor Feher, J. C. Perez, T.J. Peterson, Reiner Denz, C. Darve, Cedric Garion, P.J. Limon, J. Kerby, Thomas H. Nicol, Roger Rabehl, H. Prin, and S. Mathot
- Subjects
Physics ,Particle physics ,Luminosity (scattering theory) ,Large Hadron Collider ,Physics::Instrumentation and Detectors ,Aperture ,Superconducting magnet ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Nuclear physics ,Dipole ,Beta (plasma physics) ,Quadrupole ,Physics::Accelerator Physics ,Electrical and Electronic Engineering ,Beam (structure) - Abstract
The low-beta triplets of the Large Hadron Collider were designed and constructed by a world-wide collaboration officially formed in 1998. Over the course of the following years the collaboration worked to produce the triplet components, including four 215 T/m, 70 mm aperture quadrupoles, a DFBX distribution feedbox, and at the low luminosity interaction points a cold D1 beam separation dipole. In 2005 the first triplet was installed in the LHC tunnel, and at the end of 2007 hardware commissioning of the first triplets started. As of August 2008 five triplets have been successfully powered. This paper documents the processes and experience gained during the commissioning phase of the LHC.
- Published
- 2009
18. The Quench Protection System for the LHC Test String 2
- Author
-
F. Rodriguez-Mateos, F. Tegenfeldt, D. Milani, K. Dahlerup-Petersen, and Reiner Denz
- Subjects
Large Hadron Collider ,Physics::Instrumentation and Detectors ,Computer science ,Busbar ,String (computer science) ,Principal (computer security) ,Superconducting magnet ,Condensed Matter Physics ,System monitoring ,Accelerators and Storage Rings ,Electronic, Optical and Magnetic Materials ,Reliability engineering ,Power electronics ,Electrical and Electronic Engineering ,Interlock - Abstract
The large hadron collider (LHC) string program has focused over the years the efforts of many teams that have tested and validated their systems under operating conditions close to the final ones in the LHC machine tunnel and underground areas. During the various phases while commissioning or performing dedicated experiments, the quench protection system (QPS) has been tested and improved. A large variety of designs of the QPS equipment have been validated. The experience gained, especially concerning both the commissioning and the interaction with systems working within close interfaces (interlocks, powering, controls), is a valuable expertise to undertake the LHC challenge. In the LHC, the QPS will be the only system monitoring and protecting the superconducting elements: the integrity of all the superconducting magnets, bus bars and high-T/sub c/ superconducting current leads will depend on its reliable operation. A description of the system installed in String 2 will be given together with the principal similarities and differences with respect to the equipment planned for installation in the LHC. The key experimental results will be explained.
- Published
- 2004
19. First powering of the LHC Test String 2
- Author
-
A. Rijllart, F. Bordry, R. Saban, B. Puccio, F. Rodriguez-Mateos, Reiner Denz, K. Dahlerup-Petersen, D. Bozzini, H. Thiesen, Luigi Serio, and R. Schmidt
- Subjects
Physics ,Particle physics ,Large Hadron Collider ,Physics::Instrumentation and Detectors ,Project commissioning ,String (computer science) ,Mechanical engineering ,Superconducting magnet ,Test string ,Condensed Matter Physics ,Accelerators and Storage Rings ,Electronic, Optical and Magnetic Materials ,Dipole ,Magnet ,Physics::Accelerator Physics ,Electrical and Electronic Engineering ,Quadrupole magnet - Abstract
String 2 is a full-size model of a regular cell in an LHC arc. In the first phase, three dipole magnets and two quadrupole magnets have been assembled in String 2 and commissioning started in April 2001. By the beginning of 2002 three pre-series dipole magnets will be added to complete the cell. As for its predecessor String 1, the facility was built to individually validate the LHC systems and to investigate their collective behaviour for normal operation with the magnets at a temperature of 1.9 K, during transients as well as during exceptional conditions. String 2 is a precious milestone before installation and commissioning of the first LHC sector (1/8 of the machine) in 2004, with respect to infrastructure, installation, tooling and assembly procedures, testing and commissioning of individual systems, as well as the global commissioning of the technical systems. This paper describes the commissioning, and retraces the first powering history.
- Published
- 2002
20. The commissioning of the LHC technical systems
- Author
-
Stefano Redaelli, Amalia Ballarino, F. Bordry, Glyn Kirby, Verena Kain, G. J. Coelingh, B. Bellesia, F. Rodriguez-Mateos, Reyes Alemany-Fernández, R. Lauckner, V. Baggiolini, Luigi Serio, R. Flora, Andrzej Siemko, Reiner Denz, Antonio Vergara-Fernandez, S. Claudet, V. Chareyre, A. Rijllart, B. Perea-Solano, Maria-Paz Casas-Lino, R. Rabehl, R. Saban, Arjan Verweij, David Nisbet, D. Bozzini, V. Montabonnet, F. Millet, E. Barbero-Soto, S. Le Naour, Markus Zerlauth, Matteo Solfaroli-Camillocci, Mirko Pojer, K H Mess, M. Gruwe, S. Feher, H. Thiesen, R. Schmidt, Michael Koratzinos, K. Dahlerup-Petersen, Rosario Principe, and W. Venturini
- Subjects
Physics ,Large Hadron Collider ,Project commissioning ,Technical systems ,Systems engineering ,Architecture ,Field (computer science) - Abstract
The LHC is an accelerator with unprecedented complexity where the energy stored in magnets and the beams exceeds other accelerators by one-to-two orders of magnitude. To ensure a safe and efficient machine start-up without being plagued by technical problems, a phase of "hardware commissioning" was introduced: a thorough commissioning of technical systems without beam. This activity started in June 2005 with the commissioning of individual systems, followed by operating a full sector, one eighth of the machine; the commissioning is expected to last until spring 2008 when commissioning with beam will start. The LHC architecture allows the commissioning of each of the eight sectors independently from the others, before the installation of other sectors is complete. An important effort went into the definition of the programme and the organization of the coordination in the field, as well as in the preparation of the tools to record and analyze test results. This paper discusses the experience with this approach, presents results from the commissioning of the first LHC sector and gives an outlook for future activities.
- Published
- 2007
21. LHC machine protection
- Author
-
R. Schmidt, Jan Uythoven, Jorg Wenninger, E. Carlier, Reiner Denz, Markus Zerlauth, R W Assmann, B. Puccio, Verena Kain, Eva Barbara Holzer, Benjamin Todd, B Goddard, and Bernd Dehning
- Subjects
Proton (rocket family) ,Physics ,Nuclear physics ,Large Hadron Collider ,Magnet ,Nuclear engineering ,Stored energy ,Physics::Accelerator Physics ,Beam instrumentation ,Protection system ,Interlock ,Accelerators and Storage Rings ,Beam (structure) - Abstract
For nominal beam parameters at 7 TeV/c each of the two LHC proton beams has a stored energy of 362 MJ threatening to damage accelerator equipment in case of uncontrolled beam loss. The energy stored in the magnet system at 7 TeV/c will exceed 10 GJ. In order to avoid damage of accelerator equipment, complex machine protection systems are required. Magnet protection and powering interlock systems must be operational already before commissioning the magnet powering system. Beam operation, throughout the operational cycle from injection to colliding beams, requires fully operational protection systems, including beam interlock systems, beam dumping system, beam instrumentation (mainly beam loss monitors) as well as collimators and beam absorbers. Details of LHC machine protection have been presented on several occasions and the systems involved in protection are well documented [1]. This paper gives an overview of LHC machine protection, discusses the progress with the implementation and presents first results from the commissioning of some systems.
- Published
- 2007
22. Electronic Systems for the Protection of Superconducting Elements in the LHC
- Author
-
Reiner Denz
- Subjects
Physics ,Superconductivity ,Large Hadron Collider ,Busbar ,Physics::Instrumentation and Detectors ,Superconducting magnet ,Condensed Matter Physics ,Engineering physics ,Accelerators and Storage Rings ,Electronic, Optical and Magnetic Materials ,Nuclear magnetic resonance ,Nuclear electronics ,visual_art ,Electronic component ,visual_art.visual_art_medium ,High Energy Physics::Experiment ,Electronics ,Electrical and Electronic Engineering ,Electrical conductor - Abstract
The Large Hadron Collider LHC, currently under construction at CERN, will incorporate an unprecedented number of superconducting magnets, busbars and current leads. As most of these elements depend on active protection in case of a transition from the superconducting to the resistive state, the so-called quench, a protection system based on modern, state of the art electronics has been developed.
- Published
- 2006
23. Protection of the CERN Large Hadron Collider
- Author
-
Jorg Wenninger, Benjamin Todd, B Goddard, Eva Barbara Holzer, M Zerlauth, Bernd Dehning, Reiner Denz, B. Puccio, Verena Kain, Jan Uythoven, R. Schmidt, Ralph Assmann, and E. Carlier
- Subjects
Physics ,Large Hadron Collider ,Nuclear engineering ,General Physics and Astronomy ,Superconducting magnet ,Accelerators and Storage Rings ,law.invention ,Nuclear physics ,Safe operation ,law ,Magnet ,Stored energy ,Physics::Accelerator Physics ,Beam dump ,Interlock ,Beam (structure) - Abstract
TheLargeHadronCollider(LHC)atCERNwillcollidetwocounter- rotating proton beams, each with an energy of 7TeV. The energy stored in the superconducting magnet system will exceed 10GJ, and each beam has a stored energy of 362MJ which could cause major damage to accelerator equipment in the case of uncontrolled beam loss. Safe operation of the LHC will therefore rely on a complex system for equipment protection. The systems for protection of the superconducting magnets in case of quench must be fully operational before powering the magnets. For safe injection of the 450GeV beam into the LHC, beam absorbers must be in their correct positions and specific procedures must be applied. Requirements for safe operation throughout the cycle necessitate early detection of failures within the equipment, and active monitoring of the beam with fast and reliable beam instrumentation, mainly beam loss monitors (BLM). When operating with circulating beams, the time constant for beam loss after a failureextendsfrom ≈mstoafewminutes—failuresmustbedetectedsufficiently early and transmitted to the beam interlock system that triggers a beam dump. It is essential that the beams are properly extracted on to the dump blocks at the end of a fill and in case of emergency, since the beam dump blocks are the only elements of the LHC that can withstand the impact of the full beam.
- Published
- 2006
24. The LHC test string: results from run 2
- Author
-
B. Puccio, Reiner Denz, R. Herzog, Luca Bottura, V. Granata, D. Milani, F. Tegenfeldt, H. Thiesen, Luigi Serio, Etienne Carlier, R. van Weelderen, F. Rodriguez-Mateos, E. Blanco-Vinuela, F. Bordry, R. Saban, C. Calzas-Rodriguez, Q. King, R. Schmidt, and D. Bozzini
- Subjects
Physics ,Cryostat ,Large Hadron Collider ,business.industry ,Instrumentation ,Nuclear engineering ,Electrical engineering ,Cryogenics ,Superconducting magnet ,Converters ,business ,Cryogenic processor ,Electronic circuit - Abstract
After the commissioning and the first powering of the main circuits in autumn 2001 in its shorter version, the facility was completed to a full cell of LHC in the regular part of an arc and commissioned in July 2002. During this second run, which accumulated more than 4000 hours below 2 K, a very dense experimental program was carried-out to validate the final versions of the technical systems and design choices such as the bus-bar cables running along the magnet cold masses inside the cryostats. The program included the investigation of thermo-hydraulics of quenches, quench propagation, power converter controls and tracking between power converters. The cryogenic process dynamics were studied in length; predictive control techniques were tested and their performance assessed. During a short shutdown starting in December 2002, the facility was stripped of all instrumentation contributing to increased heat loads and heat load measurements will be performed in a last run during the first half of 2003. The paper describes the facility and details the results obtained during the experimental program.
- Published
- 2004
25. The commissioning of the LHC test string 2
- Author
-
J. Casas-Cubillos, F. Rodriguez-Mateos, R. Schmidt, F. Bordry, Luigi Serio, K. Dahlerup-Petersen, Reiner Denz, R. Herzog, R. Saban, B. Puccio, P. Cruikshank, and D. Bozzini
- Subjects
Physics ,Large Hadron Collider ,Physics::Instrumentation and Detectors ,Project commissioning ,business.industry ,Technical systems ,Astrophysics::Instrumentation and Methods for Astrophysics ,Electrical engineering ,Mechanical engineering ,Cryogenics ,Superconducting magnet ,Test string ,Accelerators and Storage Rings ,Magnet ,Stepping stone ,Physics::Accelerator Physics ,business - Abstract
String 2 [1,2] is a full-size model of an LHC cell of the regular part of the arc. It is composed of six dipole magnets with their correctors, two short straight sections with their orbit and lattice corrector magnets, and a cryogenic distribution line running alongside the magnets. The commissioning of String 2 Phase 1, with one half-cell and the following quadrupole, has started in April 2001. As for String 1 [3], the facility was built to individually validate the LHC systems and to investigate their collective behaviour during normal operation (pump-down, cool-down and powering) as well as during exceptional conditions such as quenches. String 2 is a stepping stone towards the commissioning of the first sector (one eight of LHC) planned for 2004. It is expected to yield precious information on the infrastructures, the installation, the tooling and the procedures for the assembly, the testing and the commissioning of the individual systems, as well as the global commissioning of the technical systems. This paper describes the procedures followed for the commissioning and details the preparation for the first cool-down and for the powering.
- Published
- 2002
26. The Protection System for the Superconducting Elements of the Large Hadron Collider at CERN
- Author
-
K. Dahlerup-Petersen, Reiner Denz, F. Sonnemann, R. Schmidt, P. Proudlock, D. Hagedorn, F. Rodrinuez-Mateos, and J.L. Gomez-Costa
- Subjects
Superconductivity ,Physics ,Large Hadron Collider ,Physics::Instrumentation and Detectors ,Detector ,Superconducting magnet ,Accelerators and Storage Rings ,law.invention ,Overcurrent ,Nuclear physics ,law ,Redundancy (engineering) ,High Energy Physics::Experiment ,Resistor ,Diode - Abstract
The protection system for the superconducting elements of the Large Hadron Collider (LHC) [1] at the European Laboratory for Particle Physics (CERN), and its associated equipment are presented: quench detectors, cold diodes, quench heaters and related power supplies, extraction resistors and associated current breakers. Features such as radiation resistance, redundancy and required reliability are discussed.
- Published
- 1999
27. Single event effects in high-energy accelerators.
- Author
-
Rubén García Alía, Markus Brugger, Salvatore Danzeca, Francesco Cerutti, Joao Pedro de Carvalho Saraiva, Reiner Denz, Alfredo Ferrari, Lionel L Foro, Paul Peronnard, Ketil Røed, Raffaello Secondo, Jens Steckert, Yves Thurel, Iacocpo Toccafondo, and Slawosz Uznanski
- Subjects
HADRONS ,PARTICLE accelerators ,FORCE & energy ,RADIATION ,MUONS ,PARTICLES (Nuclear physics) - Abstract
The radiation environment encountered at high-energy hadron accelerators strongly differs from the environment relevant for space applications. The mixed-field expected at modern accelerators is composed of charged and neutral hadrons (protons, pions, kaons and neutrons), photons, electrons, positrons and muons, ranging from very low (thermal) energies up to the TeV range. This complex field, which is extensively simulated by Monte Carlo codes (e.g. FLUKA) is due to beam losses in the experimental areas, distributed along the machine (e.g. collimation points) and deriving from the interaction with the residual gas inside the beam pipe. The resulting intensity, energy distribution and proportion of the different particles largely depends on the distance and angle with respect to the interaction point as well as the amount of installed shielding material. Electronics operating in the vicinity of the accelerator will therefore be subject to both cumulative damage from radiation (total ionizing dose, displacement damage) as well as single event effects which can seriously compromise the operation of the machine. This, combined with the extensive use of commercial-off-the-shelf components due to budget, performance and availability reasons, results in the need to carefully characterize the response of the devices and systems to representative radiation conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.