The International Axion Observatory (IAXO) will be a forth generation axion helioscope. As its primary physics goal, IAXO will look for axions or axion-like particles (ALPs) originating in the Sun via the Primakoff conversion of the solar plasma photons. In terms of signalto-noise ratio, IAXO will be about 4-5 orders of magnitude more sensitive than CAST, currently the most powerful axion helioscope, reaching sensitivity to axion-photon couplings down to a few ×10 −12 GeV −1 and thus probing a large fraction of the currently unexplored axion and ALP parameter space. IAXO will also be sensitive to solar axions produced by mechanisms mediated by the axion-electron coupling g ae with sensitivity −for the first time− to values of g ae not previously excluded by astrophysics. With several other possible physics cases, IAXO has the potential to serve as a multi-purpose facility for generic axion and ALP research in the next decade. In this paper we present the conceptual design of IAXO, which follows the layout of an enhanced axion helioscope, based on a purpose-built 20m-long 8-coils toroidal superconducting magnet. All the eight 60cm-diameter magnet bores are equipped with focusing x-ray optics, able to focus the signal photons into ∼ 0.2 cm 2 spots that are imaged by ultra-low-background Micromegas x-ray detectors. The magnet is built into a structure with elevation and azimuth drives that will allow for solar tracking for ∼12 h each day.

We study the feasibility of a new generation axion helioscope, the most ambitious and promising detector of solar axions to date. We show that large improvements in magnetic field volume, x-ray focusing optics and detector backgrounds are possible beyond those achieved in the CERN Axion Solar Telescope (CAST). For hadronic models, a sensitivity to the axion-photon coupling of g aγ few × 10 −12 GeV −1 is conceivable, 1-1.5 orders of magnitude beyond the CAST sensitivity. If axions also couple to electrons, the Sun produces a larger flux for the same value of the Peccei-Quinn scale, allowing one to probe a broader class of models. Except for the axion dark matter searches, this experiment will be the most sensitive axion search ever, reaching or surpassing the stringent bounds from SN1987A and possibly testing the axion interpretation of anomalous white-dwarf cooling that predicts m a of a few meV. Beyond axions, this new instrument will probe entirely unexplored ranges of parameters for a large variety of axion-like particles (ALPs) and other novel excitations at the low-energy frontier of elementary particle physics. 6 Detectors 25 7 Conclusions 28

The status of the research on muon colliders is discussed and plans are outlined for future theoretical and experimental studies. Besides work on the parameters of a 3-4 and 0.5 TeV center-of-mass (COM) energy collider, many studies are now concentrating on a machine near 0.1 TeV (COM) that could be a factory for the s-channel production of Higgs particles. We discuss the research on the various components in such muon colliders, starting from the proton accelerator needed to generate pions from 1098-4402͞99͞2(8)͞081001(73)$15.00 © 1999 The American Physical Society 081001-1 PRST-AB 2 CHARLES M. ANKENBRANDT et al. 081001 (1999) a heavy-Z target and proceeding through the phase rotation and decay (p ! m n m ) channel, muon cooling, acceleration, storage in a collider ring, and the collider detector. We also present theoretical and experimental R&D plans for the next several years that should lead to a better understanding of the design and feasibility issues for all of the components. This report is an update of the progress on the research and development since the feasibility study of muon colliders presented at the Snowmass '96

Abstracl-LBNL is using pressurized bladders in its high field snperconducting magnet program. Magnet RD3j a 14 Trace track dipole; has been assembled and pre-stressed using such a system. The bladder, placed between the coil pack and the iron yoke, can provide 70 MPa of pressure while compressing the coil pack and tensioning a 40 mm thick structural Aluminum shell. Interference keys replace the bladder's functionality as they are deflated and removed leaving the shell in 140 MPa of tension. During cool down, stress in the shell increases to 250 MPa as a result of the difrerencc in thermal expansion between the Aluminum shell and the inner iron yoke. A number of strain gauges mounted onto the shell were used to monitor its strain during assembly, cool·down and testing. This technique ensures that the final and ma'"(imum stress in the shell is reached before the magnet is ever energized.The use of a structural shell and pressurized bladders has simplified magnet assembly considerably. In this paper we describe the bladder system and its usc in the assembly of a 14T Nb3Sn magnet.

There have been active efforts in the U.S., Europe, and Japan on the design of a neutrino factory. This type of facility produces intense beams of neutrinos from the decay of muons in a high-energy storage ring. In the U.S., a second detailed feasibility study (FS2) for a neutrino factory was completed in 2001. Since that report was published, new ideas in bunching, cooling, and acceleration of muon beams have been developed. We have incorporated these ideas into a new facility design, which we designate as study 2B (ST2B), that should lead to significant cost savings over the FS2 design.

REBCO coated conductors maintain high engineering current density above 16 T at 4.2 K. That fact will significantly impact markets of various magnet applications including high-field magnets for high-energy physics and fusion reactors. One of the main challenges for the high-field accelerator magnet is the use of multitape REBCO cables with high engineering current density in magnet development. Several approaches developing high-field accelerator magnets using REBCO cables are demonstrated. In this paper, we introduce an alternative concept based on the canted cos θ (CCT) magnet design using Conductor on Round Core (CORC R) wires that are wound from multiple REBCO tapes with a Cu core. We report the development and test of double-layer three-turn CCT dipole magnets using CORC R wires at 77 K and 4.2 K. The scalability of the CCT design allowed us to effectively develop and demonstrate important magnet technology features such as coil design, winding, joints and testing with minimum conductor lengths. The test results showed that the CCT dipole magnet using CORC R wires was a viable option in developing REBCO accelerator magnet. One of the critical development needs is to increase the engineering current density of the 3.7 mm diameter CORC R wire to 540 A mm −2 at 21 T, 4.2 K and to reduce the bending radius to 15 mm. This would enable a compact REBCO dipole insert magnet to generate a 5 T field in a background field of 16 T at 4.2 K.

Future high-energy accelerators will need very high magnetic fields in the range of 20 T. The EuCARD-2 work-package-10 is a collaborative push to take HTS materials into an accelerator quality demonstrator magnet. The demonstrator will produce 5 T standalone and between 17 T and 20 T, when inserted into the 100 mm aperture of Fresca-2 high field out-sert magnet. The HTS magnet will demonstrate the field strength and field quality that can be achieved. An effective quench detection and protection system will have to be developed to operate with the HTS superconducting materials. This paper presents a ReBCO magnet design using multi strand Roebel cable that develops a stand-alone field of 5 T in a 40 mm clear aperture and discusses the challenges associated with good field quality using this type of material. A selection of magnet designs is presented as result of a first phase of development.Presented at: ASC 2014, 10-15 August, Charlotte, USA Geneva, Switzerland February 2015 Abstract -Future high-energy accelerators will need very high magnetic fields in the range of 20 T. The EuCARD-2 workpackage-10 is a collaborative push to take HTS materials into an accelerator quality demonstrator magnet. The demonstrator will produce 5 T standalone and between 17 T and 20 T, when inserted into the 100 mm aperture of Fresca-2 high field out-sert magnet.The HTS magnet will demonstrate the field strength and field quality that can be achieved. An effective quench detection and protection system will have to be developed to operate with the HTS superconducting materials. This paper presents a ReBCO magnet design using multi strand Roebel cable that develops a stand-alone field of 5 T in a 40 mm clear aperture and discusses the challenges associated with good field quality using this type of material. A selection of magnet designs is presented as result of a first phase of development. IndexTerms-Accelerator magnet, EuCARD-2, Superconducting Magnets, HTS magnet design, quench protection, YBCO Roebel cable, ReBCO.

DOI: will be assignedThe International Axion Observatory (IAXO) is a new generation axion helioscope aiming at a sensitivity to the axion-photon coupling of gaγ few × 10 −12 GeV −1 , i.e. 1-1.5 orders of magnitude beyond the one currently achieved by CAST. The project relies on improvements in magnetic field volume together with extensive use of x-ray focusing optics and low background detectors, innovations already successfully tested in CAST. Additional physics cases of IAXO could include the detection of electron-coupled axions invoked to explain the white dwarf cooling, relic axions, and a large variety of more generic axionlike particles (ALPs) and other novel excitations at the low-energy frontier of elementary particle physics. This contribution is a summary of our recent paper [1].