Optimization of pion and muon production/collection for neutrino factories and muon colliders is described along with recent developments of the MARS15 code event generators and effects influencing the choice of the optimal beam energy.

One of the straightforward ways towards the higher luminosity in the LHC is a replacement of the present 70-mm NbTi quadrupoles with Nb3Sn quadrupoles which would provide the same field gradient but in a larger aperture. Conceptual designs of such magnets with 90 mm aperture have been developed and studied. This paper discusses the possibilities and limitations of further increasing the aperture of Nb3Sn low-beta quadrupoles, and shows that an aperture up to 110 mm is possible.

Interaction region inner triplets are among the systems which may limit the LHC performance. An option for a new higher luminosity IR is a double-bore inner triplet with separation dipoles placed in front of the first quadrupole. The radiation load on the first dipole, resulting from pp-interactions, is a key parameter to determine the feasibility of this approach. Detailed energy deposition calculations were performed with the MARS14 code for two Nb3Sn dipole designs with no superconductor on the mid-plane. Comparison of peak power densities with those in the baseline LHC IR suggests that it may be possible to develop workable magnets for luminosities up to 10(35) CM-2 S-1.

Conceptual designs of 90-mm aperture high-gradient quadrupoles based on the Nb/sub 3/Sn superconductor, are being developed at Fermilab for possible 2nd generation IRs with the similar optics as in the current low-beta insertions. Magnet designs and results of magnetic, mechanical, thermal and quench protection analysis for these magnets are presented and discussed.

Beam-induced energy deposition in the LHC high luminosity interaction region (IR) com- ponents due to both ppcollisions and beam loss in the IR vicinity is a significant challenge for the design of the high luminosity insertions. It was shown in our previous studies that a set of collimators in the machine and absorbers within the low-beta quadrupoles would reduce both the peak power density and total heat load to tolerable levels with a reasonable safety margin. In this paper the results of further optimization and comprehensive MARS calculations are sum- marized for the updated IP1 and IP5 layouts and a baseline pp-collision source term. Power density, power dissipation, particle fluxes and spectra, accumulated dose and residual dose rates are studied in the components of the inner triplets including their TAS absorbers, the TAN neutral beam absorbers, separation dipoles, and quadrupoles of the outer triplets and possible collimators there. It is shown that the optimized absorbers would provide adequate protection of all the critical components. Results are given for the nominal luminosity of 10 34 cm−2s−1. Consideration is limited to luminosity-driven energy deposition effects in the inner and outer triplets. Impact of beam loss of circulating and misbehaved beams on the machine and detector components is considered elsewhere.

Fermilab and LBNL are in the midst of a model magnet program to develop and prove the design of quadrupoles for use in the LHC Interaction Region inner triplets. These magnets have a nominal gradient of 205 T/m in a 70 mm bore, and operate in superfluid helium at 1.9 K. The R&D program addresses magnetic, mechanical, thermal design and quench protection issues. This paper describes design, fabrication experience and test results from the first 2 m models.

As part of the LHC magnet development program, CERN in collaboration with Oxford Instruments has designed, built and tested a one metre model of a 70 mm aperture low-beta quadrupole. The magnet features a four layer coil, and is designed for 250 T/m at 1.9 K. We review the results of the magnet training and quench propagation studies performed at 4.3 K and 1.9 K, and report on the magnetic field measurements.

The high gradient quadrupole (HGQ) being developed for the LHC interaction regions by the collaboration of FNAC/LBNL/BNL, relies on the use of quench protection heaters. As part of the HGQ R&D program at Fermilab, Tevatron low-/spl beta/ quadrupoles installed with quench protection heaters were tested in normal and superfluid helium. This paper focuses on heater operation time delay and quench propagation velocity measurements since these are important input parameters for designing the quench protection system of the HGQ.

Future high energy accelerators such as the Large Hadron Collider require accelerator magnets with the highest possible fields. For NbTi conductor magnets, this means operating at superfluid helium temperatures in the range of 1.8-1.9K. As part of Fermilab’s superconducting magnet R&D program, we have built a facility to test magnets in a vertical dewar of superfluid liquid helium. The dewar is designed for magnets up to 4 m length and 620 mm diameter, with a temperature range of 1.8 K to 4.4 K and 1 atmosphere helium. The power system consists of 10 kA and 8.8 kA power supplies operating in parallel, with bus work and an extraction circuit that can accommodate up a 18kA excitation current. A description of the facility as well as operational experience from the first magnet tests are presented.

Fermilab, Lawrence Berkeley National Laboratory and Brookhaven National Laboratory have formed a consortium to provide components for the Large Hadron Collider (LHC) to be built at CERN. The U.S. contribution includes half of the high gradient quadrupoles (HGQ) for the inner focusing triplets. In this paper a description of the HGQ magnetic design is given, including short sample limit for field gradient, sources and expected values of systematic and random field errors, and possible strategies for field quality correction

The overall machine and detector performances at the LHC are strongly dependent on the interaction region (IR) scheme and details. Beam-induced energy deposition in the components of the complex due to both p-p collisions and beam loss in the IR vicinity is a significant challenge for the design of the high luminosity insertions. It was shown in our previous studies that a set of collimators in the machine and absorbers within the low-beta quadrupoles would reduce both the peak power density and total heat load to tolerable levels with a reasonable safety margin. New optical configurations for the IRs developed in the past year may require changes in the absorber dimensions. In this paper we present studies of the radial and azimuthal distributions of the deposited power density and the dependence of peak power density on absorber thickness. These can be used to guide further studies of the optics and absorber systems.

Future high energy accelerators such as the Large Hadron Collider require accelerator magnets with the highest possible fields. For NbTi conductor magnets, this means operating at superfluid helium temperatures in the range of 1.8-1.9 K. As part of Fermilab's superconducting magnet R&D program, we have built a facility to test magnets in a vertical dewar of superfluid liquid helium. The dewar is designed for magnets up to 4 m length and 620 mm diameter, with a temperature range of 1.8 K to 4.4 K and 1 atmosphere helium. The power system consists of 10 kA and 8.8 kA power supplies operating in parallel, with a bus work and an extraction circuit that can accommodate up a 18 kA excitation current. A description of the facility as well as operational experience from the first magnet tests are presented

Full length and short model SSC 50 mm bore dipoles are being built and tested at Fermilab. Mechanical design of these magnets has been determined from experience involved in the construction of previous superconducting magnets. Construction experience includes coil fabrication, ground insulation, instrumentation, collaring and yoke assembly. Fabrication techniques are explained. Construction problems and their solutions are reviewed. Relationship of short to long model construction is discussed.

Several short model SSC 50mm bore dipoles are being built and tested at Fermilab. Mechanical design of these magnets has been determined from experience involved in the construction and testing of 40mm dipoles. Construction experience includes coil winding, curing and measuring, coil end part design and fabrication, ground insulation, instrumentation, collaring and yoke assembly. Fabrication techniques are explained and construction problems are discussed. Similarities and differences from the 40mm dipole tooling and magnet components are outlined. Test results from the first models are presented.

We have experimentally simulated the wedge regions of the winding of the Superconducting Super Collider dipole and studied the propagation of quenches in them. This study is relevant for proper selection and design of the quench protection scheme. The windings of these 16.6 m long dipoles incorporate copper wedges in order to achieve the required magnetic field uniformity, and the delay that they impose on the transverse spreading of normal zones is one of the needed data that we present here. Quenches under constant currents were triggered with spot heaters, and their development recorded from voltage taps strategically located. Currents as high as 6 kA were used. Under zero magnetic field conditions the delays are too long for self-protecting schemes.

of the magnets. A means is needed to accurately determine the ac electrical characteristics of the superconducting magnets. The ac characteristics of magnets will be used to predict the ripple distribution of the long string of superconducting magnets. Magnet ac characteristics can also provide necessary information for the regulation loop design. This paper presents a method for measuring the ac characteristics of superconducting magnets. Two collider dipole magnets, one superconducting and one at room temperature, were tested at Brookhaven National Lab.

The 1 st generation of low-beta quadrupoles for the LHC interaction region (IR) was designed to achieve the nominal LHC luminosity of 10 34 cm -2 s -1 . Given that the lifetime of the 1 st generation IR quadrupoles is limited by ionizing radiation to 6-7 years, the 2 nd generation of IR quadrupoles has to be developed with the goal to achieve the ultimate luminosity up to 10 35 cm -2 s -1 . The IR quadrupole parameters such as nominal gradient, dynamic aperture and physical aperture, operation margins are the main factors limiting the machine performance. Conceptual designs of 90-mm aperture high-gradient quadrupoles, suitable for use in 2 nd generation high- luminosity LHC IRs with the similar optics, are presented. The issues related to the field gradient, field quality and operation margins are discussed.