| 1. |
- Abele, H., et al.
(författare)
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Particle physics at the European Spallation Source
- 2023
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Ingår i: Physics reports. - : Elsevier. - 0370-1573 .- 1873-6270. ; 1023, s. 1-84
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Forskningsöversikt (refereegranskat)abstract
- Presently under construction in Lund, Sweden, the European Spallation Source (ESS) will be the world’s brightest neutron source. As such, it has the potential for a particle physics program with a unique reach and which is complementary to that available at other facilities. This paper describes proposed particle physics activities for the ESS. These encompass the exploitation of both the neutrons and neutrinos produced at the ESS for high precision (sensitivity) measurements (searches).
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| 2. |
- Bagni, Tommaso, et al.
(författare)
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Modeling Results of the Quench Behavior of a Nb-Ti Canted-Cosine-Theta Corrector Magnet for LHC
- 2024
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Ingår i: IEEE transactions on applied superconductivity (Print). - : Institute of Electrical and Electronics Engineers (IEEE). - 1051-8223 .- 1558-2515. ; 34:5, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- A newly designed superconducting magnet of the Canted-Cosine-Theta (CCT) type was developed as a result of a collaboration between Swedish universities (Uppsala and Linneaus) and Swedish industries. This magnet was designed to function as a replacement of the present LHC orbit corrector magnets, which are approaching their end of life due to the radiation load. As a result, the new CCT magnet was developed to be more radiation tolerant and to constitute a one-to-one replacement to the currently installed version, which is a 1 m long 70 mm double aperture dipole magnet. The final magnet, which is currently under construction, will be tested at FREIA laboratory at Uppsala University and generate a magnetic field of 3.3 T and an integrated field of 2.8 Tm at about 85 A. To examine the magnet quench behavior and to identify a suitable quench protection system, the 3D electro-magnetic and thermal behavior of the coil was modeled using the RAT-Raccoon software. Based on the simulation results, a Metrosil varistor was selected to protect the magnet during the test. In this article, we report the results of the numerical analysis. The magnet model is equipped with a spot heater to initialize the quench and the temperature and voltages are monitored during the avalanche effect. The simulated current decay and the hot-spot temperature are analyzed with a focus on the impact of quench-back on the magnet protection.
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| 3. |
- Barna, D., et al.
(författare)
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Test Results of the First Wax-Impregnated Nb-Ti Canted Cosine Theta Septum Magnet “SuShi”
- 2024
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Ingår i: IEEE transactions on applied superconductivity (Print). - : Institute of Electrical and Electronics Engineers (IEEE). - 1051-8223 .- 1558-2515. ; 34:5, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- In the framework of the future circular collider study, a new septum magnet concept (“SuShi”) has been developed, and a prototype was built at Wigner RCP, and tested at the FREIA facility of Uppsala University. The concept uses a canted cosine theta (CCT)-like superconducting magnet and a passive superconducting shield to create a zero-field and high-field region within its aperture. SuShi is the first CCT magnet with both of its winding layers simultaneously impregnated with wax. Details of the construction will be presented, with special emphasis on the wax impregnation procedure which deals with the ∼ 15% contraction of wax upon solidification. The empty magnet (no shield in its aperture) was powered without training to 450 A with a peak field of 3.64 T, corresponding to 80% of the short sample limit of the conductor along the load line. No quench or other anomaly was observed during the entire testing period. A clear onset of quench-back was observed above about 200 A.
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| 4. |
- Barna, D., et al.
(författare)
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Training-free performance of the wax-impregnated SuShi septum magnet
- 2024
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Ingår i: Superconductors Science and Technology. - : Institute of Physics (IOP). - 0953-2048 .- 1361-6668. ; 37:4
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Tidskriftsartikel (refereegranskat)abstract
- In the framework of the Future Circular Collider Study a new septum magnet concept, nicknamed 'SuShi' has been developed, and a prototype was built at Wigner Research Center for Physics, and tested at the FREIA facility of Uppsala University in April 2023. The concept uses a canted cosine theta (CCT)-like superconducting magnet and a passive superconducting shield to create a zero-field and high-field region within its aperture. SuShi is the first CCT magnet with both of its winding layers simultaneously impregnated with wax. This paper describes the first powering test of the empty magnet at 4.2 K, without the shield being inserted in its aperture. The performance of the magnet, including the observation of quench-back, estimation of hot-spot temperatures and the fraction of energy dissipated in the magnet are presented, and most interestingly the absence of any quench during the entire testing period is reported. Sushi reached its nominal +5% peak field of 3.64 T at 450 A, which corresponds to 80% of the calculated short sample limit along the load line, without training.
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| 5. |
- Burgman, A., et al.
(författare)
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The ESSnuSB Design Study: Overview and Future Prospects
- 2023
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Ingår i: Universe. - : MDPI. - 2218-1997. ; 9:8
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Forskningsöversikt (refereegranskat)abstract
- ESSnuSB is a design study for an experiment to measure the CP violation in the leptonic sector at the second neutrino oscillation maximum using a neutrino beam driven by the uniquely powerful ESS linear accelerator. The reduced impact of systematic errors on sensitivity at the second maximum allows for a very precise measurement of the CP violating parameter. This review describes the fundamental advantages of measurement at the second maximum, the necessary upgrades to the ESS linac in order to produce a neutrino beam, the near and far detector complexes, and the expected physics reach of the proposed ESSnuSB experiment, concluding with the near future developments aimed at the project realization.
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| 6. |
- Burgman, A., et al.
(författare)
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The European Spallation Source neutrino super-beam conceptual design report
- 2022
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Ingår i: The European Physical Journal Special Topics. - : Springer Nature. - 1951-6355 .- 1951-6401. ; 231:21, s. 3779-3955
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Forskningsöversikt (refereegranskat)abstract
- A design study, named ESSνSB for European Spallation Source neutrino Super Beam, has been carried out during the years 2018–2022 of how the 5 MW proton linear accelerator of the European Spallation Source under construction in Lund, Sweden, can be used to produce the world’s most intense long-baseline neutrino beam. The high beam intensity will allow for measuring the neutrino oscillations near the second oscillation maximum at which the CP violation signal is close to three times higher than at the first maximum, where other experiments measure. This will enable CP violation discovery in the leptonic sector for a wider range of values of the CP violating phase δCPδCP and, in particular, a higher precision measurement of δCPδCP. The present Conceptual Design Report describes the results of the design study of the required upgrade of the ESS linac, of the accumulator ring used to compress the linac pulses from 2.86 ms to 1.2 μs, and of the target station, where the 5 MW proton beam is used to produce the intense neutrino beam. It also presents the design of the near detector, which is used to monitor the neutrino beam as well as to measure neutrino cross sections, and of the large underground far detector located 360 km from ESS, where the magnitude of the oscillation appearance of νe from νμ is measured. The physics performance of the ESSνSB research facility has been evaluated demonstrating that after 10 years of data-taking, leptonic CP violation can be detected with more than 5 standard deviation significance over 70% of the range of values that the CP violation phase angle δCPδCP can take and that δCPδCP can be measured with a standard error less than 8° irrespective of the measured value of δCPδCP. These results demonstrate the uniquely high physics performance of the proposed ESSνSBESSνSB research facility.
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| 7. |
- Burgman, A., et al.
(författare)
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Updated physics performance of the ESSnuSB experiment
- 2021
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Ingår i: European Physical Journal C. - : Springer Nature. - 1434-6044 .- 1434-6052. ; 81:12
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present the physics performance of the ESSnuSB experiment in the standard three flavor scenario using the updated neutrino flux calculated specifically for the ESSnuSB configuration and updated migration matrices for the far detector. Taking conservative systematic uncertainties corresponding to a normalization error of 5% for signal and 10% for background, we find that there is 10 sigma (13 sigma) CP violation discovery sensitivity for the baseline option of 540 km (360 km) at delta(CP) = +/- 90 degrees. The corresponding fraction of delta(CP )for which CP violation can be discovered at more than 5 sigma is 70%. Regarding CP precision measurements, the 1 sigma error associated with delta(CP )= 0 degrees is around 5 degrees and with delta(CP )= -90 degrees is around 14 degrees (7 degrees) for the baseline option of 540 km (360 km). For hierarchy sensitivity, one can have 3 sigma sensitivity for 540 km baseline except delta(CP) = +/- 90 degrees and 5 sigma sensitivity for 360 km baseline for all values of delta(CP). The octant of theta(23) can be determined at 30 for the values of: theta(23) > 51 degrees (theta(23) < 42 degrees and theta(23) > 49 degrees) for baseline of 540 km (360 km). Regarding measurement precision of the atmospheric mixing parameters, the allowed values at 3 sigma are: 40 degrees < theta(23) < 52 degrees (42 degrees < theta(23) < 51.5 degrees) and 2.485 x 10(-3) eV(2) < Delta(2)(m31) < 2.545 x 10(-3) eV(2) (2.49x 10(-3 ) eV(2) < Delta(2)(m31) < 2.54 x 10(-3) eV(2)) for the baseline of 540 km (360 km).
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| 8. |
- Cederkall, Joakim, et al.
(författare)
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The ESSνSB project
- 2020
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Ingår i: European Physical Society Conference on High Energy Physics, EPS-HEP2019. - Trieste, Italy : Sissa Medialab srl. ; EPS-HEP2019
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Konferensbidrag (refereegranskat)abstract
- The ESS nu SB project aims to produce a neutrino beam of unique intensity for a long-baseline oscillation measurement of CP-violation in the leptonic sector. The project, supported within the H2020 framework programme of the European Union, is currently in a conceptual design study phase, and work is ongoing within the project to develop viable solutions for the upgrade of the linear accelerator of the European Spallation Source (ESS), for the associated ring accumulator and the high-power target stations, as well as to establish solutions for the near and far detectors. The unique strength of the project lies in the capability to produce a neutrino beam that is intense enough to place the far detector at the second oscillation maximum. Such a placement will reduce the sensitivity of the experiment to systematic errors, which, due to the recently established value of the neutrino mixing angle theta(13), is now known to limit the measurement precision at the first oscillation maximum. In this paper we outline the basic components of the project and discuss the status of the ongoing conceptual design study.
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| 9. |
- Lindström, Björn
(författare)
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Criticality of fast failures in the High Luminosity Large Hadron Collider
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Each of the two Large Hadron Collider (LHC) beams contain 362 MJ of energy. This will be further increased to 678 MJ in the upcoming upgrade to the High Luminosity LHC (HL-LHC). In the event of an uncontrolled beam loss, a significant hazard occurs, that can damage the machine components. This thesis is focused on failures that can lead to a fast increase of beam losses, with a focus on the new optics and equipment in the HL-LHC. The criticality for a number of failure scenarios is studied, under different optics configurations of the machine. Mitigation strategies, involving dedicated interlocking and a reduction of the impact that the failures have on the beam are proposed for the most critical scenarios. For a number of less critical failures it is determined that current interlock strategies are sufficient.Failures involving the magnet protection and the crab cavities constitute the most severe hazards. The former consists of quench heaters and a new system known as coupling loss induced quench (CLIQ). A new connection scheme is proposed for these, in order to limit their effect on the beam. Dedicated interlocks for detecting spurious discharges of these systems are also found to be necessary. The perturbation of the beam orbit caused by the extraction of only one beam is another source of uncontrolled beam losses. A fast hardware linking of the two beams to limit the delay between extracting the two beams of maximum one LHC turn (89 µs) is found to be necessary.Beam-dust interactions have detrimental effects on the machine performance and availability. Advances are made on the understanding of their dynamics through dedicated experiments combined with theoretical work and simulations. Superconducting magnet quenches are shown capable of causing fast orbit perturbations. The effects of beam-beam compensating wires as well as coherent excitations by the transverse beam damper are also discussed. Finally, realistic combinations of multiple failures is also discussed.
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| 10. |
- Olvegård, Maja, 1981-
(författare)
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Emittance and Energy Diagnostics for Electron Beams with Large Momentum Spread
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Following the discovery of the Higgs-like boson at the Large Hadron Collider, there is demand for precision measurements on recent findings. The Compact Linear Collider, CLIC, is a candidate for a future linear electron-positron collider for such precision measurements. In CLIC, the beams will be brought to collisions in the multi-TeV regime through high gradient acceleration with high frequency RF power. A high intensity electron beam, the so-called drive beam, will serve as the power source for the main beam, as the drive beam is decelerated in special structures, from which power is extracted and transfered to the main beam. When the drive beam is decelerated the beam quality deteriorates and the momentum spread increases, which makes the beam transport challenging. Dedicated diagnostics to monitor the momentum profile along each bunch train and transverse profile diagnostics will be needed to guarantee the reliability of the decelerator and consequently the power source of the main beam acceleration.A test facility, CTF3, has been constructed at CERN to validate key technical aspects of the CLIC concept. The beam quality in the decelerator will be investigated in the test beam line, TBL, where several power extraction structures reduce the drive beam energy by up to 55%. At the same time, the single-bunch rms energy spread grows from the initial value of 1% to almost 6%. To monitor the parameters of such a beam is challenging but crucial for the optimization of the beamline. In this thesis we report on progress made on adapting generally used methods for beam profile measurements to the demanding conditions of a wide momentum profile. Two detector technologies are used for measuring transverse profile and momentum profile and we discuss the performance of these instruments, in the view of the large momentum spread and with the outlook towards equivalent beam profile monitors in the CLIC decelerator.
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| 11. |
- Pepitone, Kevin, Dr, 1988-, et al.
(författare)
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Design and Fabrication of a Canted-Cosine-Theta Double Aperture Orbit Corrector Dipole for the LHC
- 2023
-
Ingår i: IEEE transactions on applied superconductivity (Print). - : IEEE. - 1051-8223 .- 1558-2515. ; 33:5
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Tidskriftsartikel (refereegranskat)abstract
- A prototype CCT dipole magnet developed by a collaboration between Swedish universities, Swedish industry and CERN will be tested at Uppsala University. This 1 m long double-aperture magnet can provide a field strength of 3.3 T at 85 A in a 70 mm aperture with an integrated field of 2.8 Tm. It is intended to replace the current LHC orbit corrector magnets which are reaching the end of their expected life due to the radiation load. The new magnet is designed to handle the radiation dose of the upgrade to the high-luminosity LHC, which will deliver about ten times the current radiation dose. It must therefore be more resistant to radiation and meet strict requirements in terms of electrical insulation while matching the original field quality and self-protective capability, mechanical volume, and maximum excitation current. This paper will present the latest of the design and manufacturing work, including the results of simulations of the mechanical field and the mechanical stress. Details of the various tests performed before machining the parts are also presented.
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| 12. |
- Pepitone, Kevin, Dr, 1988-, et al.
(författare)
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Design of a Canted-Cosine-Theta Orbit Corrector for the High Luminosity LHC
- 2022
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Ingår i: IEEE transactions on applied superconductivity (Print). - : IEEE. - 1051-8223 .- 1558-2515. ; 32:6
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Tidskriftsartikel (refereegranskat)abstract
- The High Luminosity LHC requires dipole orbit correctors grouped in double aperture magnet assemblies. They provide a field of 3.1 T at 100 A in an aperture of 70 mm. The current standard design is a classical cosine-theta layout made with ribbon cable. However, the electric insulation of this cable is not radiation-resistant enough to withstand the radiation load expected in the coming years of LHC operation. A new design, based on a cable with polyimide insulator, that can replace the existing orbit correctors, is needed. The challenge is to design a magnet that fits directly into the existing positions and that can operate with the same busbars, passive quench protection, and power supplies. The new orbit corrector design meets high requirements on the field quality while keeping within the same mechanical volume and maximum excitation current. A collaboration of Swedish universities and Swedish industry has been formed for the development and production of a prototype magnet following a concurrent engineering methodology to reduce the time needed to produce a CCT magnet. The magnet has a 1 m long CCT dipole layout consisting of two coils. The superconductor is a commercially available 0.33 mm wire with polyimide insulation in a 6-around-1 cable. The channels in the coil formers, that determine the CCT layout, allow for 2 x 5 cable layers. A total of 70 windings makes that the coil current can be kept below 100 A. We will present the detailed design and preliminary quench simulations.
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| 13. |
- Ruber, Roger, et al.
(författare)
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Accelerator development at the FREIA Laboratory
- 2021
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Ingår i: Journal of Instrumentation. - : Institute of Physics Publishing (IOPP). - 1748-0221. ; 16:7
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Tidskriftsartikel (refereegranskat)abstract
- The FREIA Laboratory at Uppsala University focuses on superconducting technology and accelerator development. It actively supports the development of the European Spallation Source, CERN, and MAX IV, among others. FREIA has developed test facilities for superconducting accelerator technology such as a double-cavity horizontal test cryostat, a vertical cryostat with a novel magnetic field compensation scheme, and a test stand for short cryomodules. Accelerating cavities have been tested in the horizontal cryostat, crab-cavities cavities in the vertical cryostat, and cryomodules for ESS on the cryomodule test stand. High power radio-frequency amplifier prototypes based on vacuum tube technology were developed for driving spoke cavities. Solid-state amplifiers and power combiners are under development for future projects. We present the status of the FREIA Laboratory complemented with results of recent projects and future prospects.
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