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The Mu2e experiment at Fermilab is designed to explore charged lepton flavor violation by searching for muon-to-electron conversion. The magnetic field generated by a system of solenoids is a crucial component of Mu2e and requires accurate characterization to detect any potential flaws and to produce a detailed field map. In order to design and build a precise field mapping system consisting of Hall and NMR probes, tolerances and precision for such a system need to be evaluated. To generate a final magnetic field map of the Mu2e solenoids, a continuous field has to be extracted from a discrete set of measurement points. A design for the Mu2e field mapping hardware, and results from simulations to specify parameters for Hall and NMR probes are presented. A fitting procedure for the analytical treatment of our expected magnetic measurements is introduced.

In preparation for the high luminosity upgrade of the Large Hadron Collider (LHC), the LHC Accelerator Research Program (LARP) is developing a new generation of large aperture high-field quadrupoles based on Nb3Sn technology. One meter long and 120 mm diameter HQ quadrupoles are currently produced as a step toward the eventual aperture of 150 mm. Tests of the first series of HQ coils revealed the necessity for further optimization of the coil design and fabrication process. A new model (HQ02) has been fabricated with several design modifications, including a reduction of the cable size and an improved insulation scheme. Coils in this magnet are made of a cored cable using 0.778 mm diameter Nb3Sn strands of RRP 108/127 subelement design. The HQ02 magnet has been fabricated at LBNL and BNL, and then tested at Fermilab. This paper summarizes the performance of HQ02 at 4.5 K and 1.9 K temperatures.

The first production focusing lens for the HINS beam line at Fermilab has been assembled into a cryostat and tested. A total of 5 devices will be tested before they are installed in the low energy section of the HINS beam line, which uses copper Crossbar-H (CH) style RF cavities. One of the tested CH-section lens assemblies includes a pair of weak orthogonal steering dipoles nested within a strong focusing solenoid, and has six vapor cooled power leads. The other device has only the strong focusing solenoid, and utilizes a single pair of HTS power leads. The production test program is designed to measure the thermal performance of the cryostat, minimum cooling requirements for the HTS leads, quench performance of all superconducting components, and precise determination of the magnetic axis and field angles. Results and future plans for the first production device tests are presented.

Several 90-mm quadrupole coils made of 0.7-mm Nb3Sn strand based on the “Restack Rod Process” (RRP) of 108/127 design, with cored and non-cored cables and different cable insulation, were fabricated and individually tested at Fermi National Accelerator Laboratory (Fermilab) using a test structure designed to provide a quadrupole magnetic field environment. The coils were instrumented with voltage taps and strain gauges to study quench performance and mechanical properties. The Nb3Sn strand and cable parameters, the coil fabrication details, the mirror model assembly procedure and test results at temperatures from 4.5 K to 1.9 K are reported and discussed.

The high energy sections of the Fermilab HINS R&D proton linac will utilize superconducting spoke resonator (SSR) RF cavities. These will be assembled into cryomodules with strong solenoid focusing lenses closely interleaved with the cavities. A design for lenses has been made for the lower (SSR1) and higher (SSR2) energy ranges of the SSR-section. Prototype lenses for both SSR1 and SSR2 sections have been built and the SSR1 has been tested. Shielding is needed to reduce the solenoid fringe field on the cavity wall below the 10 μT level, and a preliminary design was built and tested with the SSR1 prototype lens. We discuss the design requirements and challenges, and the results from quench testing and magnetic measurements of the SSR1 prototype lens.

A compact R&D RF linac is being built at Fermilab to study several key technologies related to accelerating high intensity beams. One of the goals is reduction of beam losses through the use of solenoid lenses in the low energy front end of the linac. A total of 23 compact, high field, superconducting solenoids have been procured by Fermilab for the first (room-temperature RF) section of the linac. In this report we summarize the quench and magnetic performance of the lenses.

The first model of a superconducting quadrupole for use in a Linear Accelerator was designed, built and tested at Fermilab. The quadrupole has a 78 mm aperture, and a cold mass length of 680 mm. A superferric magnet configuration with iron poles and four racetrack coils was chosen based on magnet performance, cost, and reliability considerations. Each coil is wound using enamel insulated, 0.5 mm diameter, NbTi superconductor. The quadrupole package also includes racetrack type dipole steering coils. The results of the quadrupole design, manufacturing and test, are presented. Specific issues related to the quadrupole magnetic center stability, superconductor magnetization and mechanical stability are discussed. The magnet quench performance and results of magnetic measurements will also be briefly discussed.

Fermilab has finished the first phase of Nb3Sn technology scale up by testing 2-m and 4-m long shell-type dipole coils in a dasiamagnetic mirrorpsila configuration. The 2-m long coil, made of Powder-in-Tube (PIT) Nb3Sn strand, reached its short sample limit at a field level of 10 T. The 4-m long coil, made of advanced Nb3Sn strand based on the Restack Rod Process (RRP) of 108/127 design, has been recently fabricated and tested. Coil test results at 4.5 K and 2.2 K are reported and discussed.

A focusing lens R&D program is close to completion and industrial production of magnets has begun. Two types of magnets are being built for use in the room temperature RF section at the front end of a superconducting H-minus linac of a High Intensity Neutrino Source. All of the magnets are designed as a solenoid with bucking coils to cancel the field in the vicinity of adjacent RF cavities, and one type incorporates steering dipole corrector coils. We present a summary of the predicted and measured quench and magnetic properties for both R&D and production device samples that have been tested at Fermilab.

In collaboration between NIMS and Fermilab, we have made copper stabilized Nb3Al Rutherford cables, using Nb-matrixed and Ta-matrixed strands. First these cables were investigated at high current in low self field using a flux pump. Using these Rutherford cables, we built and tested small racetrack magnets. The magnet made with the Nb-matrixed strand showed the flux jump instability in low field. The small racetrack magnet wound with the Ta-matrixed Nb3Al Rutherford cable was very stable at 4.5 K operation without any instability, as well as at 2.2 K operation. With the successful operation of the small racetrack magnet up to its short sample data, the feasibility of the Nb3Al strand and its Rutherford cable for their application to high field magnets is established. The characteristics of Nb3Al Rutherford cable is compared with that of the Nb3Sn Rutherford cable and the advantages of Nb3Al Rutherford cable are discussed.

Fermi National Accelerator Laboratory is involved in the development of a 60 MeV superconducting linac. This linac is part of the High Intensity Neutrino Source (HINS) R&D Program. The initial beam acceleration in the front end section of the linac is achieved using room temperature spoke cavities, each of which is combined with a superconducting focusing solenoid. These solenoid magnets are cooled with liquid helium at 4.5 K, operate at 250 A and have a maximum magnetic field strength of 7.5 T. A prototype solenoid cryostat was built and tested at the Fermilab Magnet Test Facility. This paper discusses the test results of the prototype and compares the measured and estimated performance of the cryostat. We also present the methods and results for measuring and fiducializing the axis of the solenoid lens.

This report summarizes current status of an R&D program to develop a focusing system for the front end of a superconducting RF linac. Superconducting solenoids will be used as focusing lenses in the low energy accelerating sections of the front end. The development of focusing lenses for the first accelerating section is in the production stage, and lens certification activities are in preparation at FNAL. The report contains information about the focusing lens design and performance, including solenoid, dipole corrector, and power leads, and about cryogenic system design and performance. It also describes the lens magnetic axis position measurement technique and discusses scope of an acceptance/certification process.

The design and manufacturing of the first model of an International Linear Collider (ILC) Main Linac superconducting quadrupole is in progress at Fermilab. The quadrupole has a 78 mm aperture, a 36 T integrated gradient, and a cold mass length of 700 mm. A superferric magnet configuration with iron poles and four racetrack coils was chosen based on magnet performance, cost, and reliability considerations. Each coil is wound using enamel insulated, 0.5 mm diameter, NbTi superconductor. The quadrupole package also includes shell type dipole steering coils. The results of the quadrupole design, including magnetic and mechanical analyses, are presented. Specific issues related to the quadrupole magnetic center stability, superconductor magnetization and mechanical stability are discussed and analyzed. The magnet quench protection system, current leads, and mounting the quadrupole inside ILC Main Linac cryomodule will also be briefly discussed.

The International Linear Collider reference design requires over 13000 magnets, of approximately 135 styles, which must operate with very high reliability. The Fermilab Main Injector represents a modern machine with many conventional magnet styles, each of significant quantity, that has now accumulated many hundreds of magnet-years of operation. We review here the performance of the magnets built for this machine, assess their reliability and categorize the failure modes, and discuss implications for reliability of similar magnet styles expected to be used at the ILC.

Two Cu stabilized Nb3Al strands, Fl (Nb matrix) and F3 (Ta matrix), fabricated at NIMS were wound into Rutherford cables at Fermilab in collaboration with NIMS. A small race-track magnet using Fl Rutherford cable, the first Nb3Al dipole magnet in the world, was constructed and tested to full current at Fermilab. This magnet was tested extensively to full short sample data and its quench characteristics were studied and reported. The 3-D magnetic field calculation was done with ANSYS to find the peak field. The quench characteristics of the magnet are explained with the characteristics of the Nb3Al strand and Rutherford cable. The small racetrack magnet built using Ta matrix F3 strand was constructed and will be tested in the near future. The advantages and disadvantages of these Nb3Al cables are briefly discussed.

The international linear collider has about 80 km of beamlines which require over 13,000 magnets for focusing and steering the beams. Approximately 18% are superconducting magnets and the rest "conventional" warm iron-dominated magnets with copper coils, totaling about 135 styles. Superconducting technology is primarily used for the magnets located in the linacs' RF cryomodules, but it is also required for the spin rotation solenoids, damping ring wigglers, positron source undulator and beam delivery octupoles, sextupoles and final doublet quadrupoles. A major criterion for ILC magnet design is to achieve very high availability in spite of the very large number of magnets. The "availability" goal of the ILC is 85% (or better) and the magnets have been budgeted to cause no more than 0.75% down time. Alignment and mechanical stability requirements in many areas are very challenging. In the Beam delivery system, beam positions must be maintained at sub-micron levels to collide the beams at the interaction point. The ILC has 11 styles of kicker, pulsed or septum magnets. Some kickers need rise and fall times of a few ns and will require very powerful pulsers. Strategies for dealing with the major challenges confronting the ILC magnets will be described.

Fermilab, as part of the US-LHC Accelerator Project, is producing superconducting low-beta quadrupole magnets for the large hadron collider (LHC). These 5.5 m long magnets are designed to operate in superfluid helium at 1.9 K with a nominal gradient of 205 T/m in the 70 mm bore. Two quadrupoles separated by a dipole orbit corrector in a single cryogenic assembly comprise the Q2 optical elements of the final focus triplets in the LHC interaction regions. The field quality of the quadrupoles is measured at room temperature during construction of the cold masses as well as during cold testing of the cryogenic assembly. We summarize data from the series measurements of the magnets and discuss various topics of interest.

Production and testing of the high-gradient superconducting quadrupole magnets developed by the US-LHC accelerator project is being completed. The production process included relative alignment of the two MQXB cold masses of the LQXB in a single cryostat, alignment of corrector magnet assemblies supplied by CERN on each of the triplet elements, and final magnet alignment for transfer to cryostat fiducials. Additionally, all LQXB magnets and one each of the LQXA and LQXC have had alignment measurements at Fermilab's magnet test facility (MTF) during cryogenic testing. This paper gives an overview and summary of the available alignment and strength data taken with the single stretched wire (SSW) system for the LQX magnets. Warm-to-cold changes in alignment parameters are also presented.

The design of a focusing solenoid for use in a superconducting RF linac requires resolving a range of problems with conflicting requirements. Providing the required focusing strength contradicts the goal of minimizing the stray field on the surfaces of adjacent superconducting RF cavities. The requirement of a compact solenoid, able to fit into a gap between cavities, contradicts the need of mechanical support necessary to restrain electromagnetic forces that can result in coil motion and subsequent quenching. In this report we will attempt to address these and other issues arising during the development of focusing solenoids. Some relevant test data will also be presented.

A systematic study of the persistent current decay and snapback effect in the fields of Tevatron accelerator dipoles was performed at the Fermilab Magnet Test Facility (MTF). The decay and snapback were measured under a range of conditions including variations of the current ramp parameters and magnet operational history. The study has mostly focused on the dynamic behavior of the normal sextupole component. In addition, the paper presents the persistent current effects observed in the other allowed field harmonics as well. The results provide new information about the previously observed "excess" decay during the first several seconds of the sextupole decay during injection and the correlation between the snapback amplitude and its duration.

Superconducting solenoid magnets suitable for the room temperature front end of the Fermilab high intensity neutrino source (formerly known as proton driver), an 8 GeV superconducting H- linac, have been designed and fabricated at Fermilab, and tested in the Fermilab magnet test facility. We report here results of studies on the first model magnets in this program, including the mechanical properties during fabrication and testing in liquid helium at 4.2 K, quench performance, and magnetic field measurements. We also describe new test facility systems and instrumentation that have been developed to accomplish these tests.

As part of the High Field Magnet program at Fermilab several NbTi and Nb3Sn strands were tested with particular emphasis on the study of voltage spikes and their relationship to superconductor instabilities. The voltage spikes were detected under various experimental conditions using voltage-current (V-I) and voltage-field (V-H) methods. Two types of spikes, designated 'magnetization' and 'transport current' spikes, have been identified. Their origin is most likely related to magnetization flux jump and transport current redistribution, respectively. Many of the signals observed appear to be a combination of these two types of spikes; the combination of these two instability mechanisms should play a dominant role in determining the minimum quench current

In order to study dynamic effects in accelerator magnets, such as the decay of the magnetic field during the dwell at injection and the rapid so-called "snapback" during the first few seconds of the resumption of the energy ramp, a fast continuous harmonics measurement system was required. A new magnetic field measurement system, based on the use of digital signal processors (DSP) and Analog to Digital (A/D) converters, was developed and prototyped at Fermilab. This system uses Pentek 6102 16 bit A/D converters and the Pentek 4288 DSP board with the SHARC ADSP-2106 family digital signal processor. It was designed to acquire multiple channels of data with a wide dynamic range of input signals, which are typically generated by a rotating coil probe. Data acquisition is performed under a RTOS, whereas processing and visualization are performed under a host computer. Firmware code was developed for the DSP to perform fast continuous readout of the A/D FIFO memory and integration over specified intervals, synchronized to the probe's rotation in the magnetic field. C, C++ and Java code was written to control the data acquisition devices and to process a continuous stream of data. The paper summarizes the characteristics of the system and presents the results of initial tests and measurements

As part of the US-LHC collaboration, Fermilab has built and tested seventeen high gradient quadrupole magnets, assembled into nine cryostats, for installation at the Large Hadron Collider Interaction Regions. Most of these magnets have only quarter coil voltage taps for quench characterization, but the magnetic measurement warm bore is instrumented with a quench antenna for localization and characterization. We report on studies using the quench antenna for pre-production prototype (with extensive voltage taps) and 17 production magnets. These include a summary of quench localization and development characteristics, as well as general features of flux changes observed during training ramps

As a part of the USLHC program, Fermilab is building half of the inner triplet quadrupole magnets for the LHC. Two identical quadrupoles (MQXB) with a dipole corrector between them in a single cryogenic unit (LQXB) comprise the Q2 optical element of the final focus triplets in the interaction regions. The 5.5 m long MQXB have a 70 mm aperture and operate in superfluid helium at 1.9 K with a peak field gradient of 215 T/m. Manufacturing of the 18 magnets is in an advanced stage. A program of magnetic field quality measurements of the magnets is performed at room temperature during magnet fabrication as well as at superfluid helium temperature during the cold qualification of each magnet. Results of the measurements are summarized in this paper.

A new 30 kA, 30 V dc Power System was designed, built, and commissioned at Fermilab for testing Superconducting High Field Magnets. This system has been successfully supporting operations at the Fermilab Magnet Test Facility since April 2002. It is based on six commercial 150 kW Power Energy Industries power supply modules and the following in-house modules: six 720 Hz filters, two 15 kA/1 kV dc solid-state dump switch, and a 3 MJ/30 kA/1 kV dc dump resistor. Additional in-house electronic components were designed and built to provide precise current regulation and distribution of current and current rate of change. An industrial-type Programmable Logic Controller system was used to provide equipment interlocks and monitoring. This paper summarizes studies on the influence of characteristics of this new power system-such as ripple current-on the performance of High Field Superconducting magnets.

The US-LHC Accelerator Project is responsible for the production of the Q2 optical elements of the final focus triplets in the LHC interaction regions. As part of this program Fermilab is in the process of manufacturing and testing cryostat assemblies (LQXB) containing two identical quadrupoles (MQXB) with a dipole corrector between them. The 5.5 m long Fermilab designed MQXB have a 70 mm aperture and operate in superfluid helium at 1.9 K with a peak field gradient of 215 T/m. This paper summarizes the test results of several production MQXB quadrupoles with emphasis on quench performance and alignment studies. Quench localization studies using quench antenna signals are also presented.

Two pairs of ASC 6 kA power leads developed for the Tevatron were successfully tested at Fermilab at over-current conditions. Stable operation was achieved while operating at a current of 9.56 kA for five hours and while continuously ramping between 0-9.56 kA at a ramp rate of 200 A/s for one hour. The minimum required liquid nitrogen flow rate was measured to be 1.5 g/s at 10 kA. After ramping up to 10 kA at 200 A/s, it took only 15 minutes to stabilize the upper copper section of the lead with a flow of 1.8 g/s of liquid nitrogen vapor. Testing under extreme operating conditions-270-370 kPa liquid nitrogen vapor pressure and over 0.1 T external magnetic field-demonstrated that the HTS part of the lead can safely operate in the current sharing mode and that this design has large operating margin.

Fermilab is developing and investigating different high-field magnets (HFM) for present and future accelerators. The HFM R&D program focused on the 10-12 T magnets based on Nb/sub 3/Sn superconductor and explored both basic magnet technologies for brittle superconductors-wind-and-react and react-and-wind. Magnet design studies in support of LHC upgrades and VLHC were conducted. A series of 1-m long cos-theta dipole models based on the wind-and-react technique was fabricated and tested. Three 1-m long flat racetracks and the common coil dipole model, based on a single-layer coil and react-and-wind technique, were also fabricated and tested. Extensive theoretical and experimental studies of electro-magnetic instabilities in Nb/sub 3/Sn strands, cables and magnets were performed and led to a successful 10 T dipole model. This paper presents the details of Fermilab's HFM program, reports its status and major results, and formulates the next steps for the program.

As part of the High Field Magnet Program at Fermilab many magnets have been tested which utilize multi strand Rutherford type cable made of state-of-the art Nb/sub 3/Sn strands. During these magnet tests we observed sudden flux changes by monitoring coil voltages and the magnetic field close to the magnets. These flux changes might be linked to magnet instabilities. The voltage spike signals were correlated with quench antenna signals, a strong indication that these are magnet phenomena. With a new high resolution voltage spike detection system, we were able to observe the detailed structure of the spikes. Two fundamentally different signal shapes were distinguished, most likely generated by different mechanisms.

Several different shell type coils were made by using the 'wind-and-react' technique, installed in a mirror magnet configuration and tested at Fermilab. The results revealed that the previously suspect splice technique is adequate and is not responsible for the quench performance limitation. Cable instability is the preferred candidate, however this might be coupled with other effects since all of the experimental results cannot be explained exclusively with cable instability.

As part of the US-LHC Accelerator Project, Fermilab is producing fully cryostated assemblies that will be installed as the Q1, Q2 and Q3 optical elements for the LHC Inner Triplets. The main quadrupole magnets in the Q1 (LQXA) and Q3 (LQXC) assemblies are MQXA elements designed and fabricated by KEK and Toshiba, while those in the Q2 (LQXB) assemblies are MQXB quadrupoles designed and fabricated by Fermilab. The cryostat assemblies for all magnets are designed by Fermilab, and final assembly of the optical elements occurs at Fermilab. This paper describes the production test results for the second LQXB cryostat assembly.

The first one-meter long common coil dipole model (HFDC-01) has been fabricated and tested at Fermilab. This magnet has several innovative features such as: single-layer racetrack coils, a 22-mm wide 60-strand Rutherford-type cable made of 0.7-mm Nb/sub 3/Sn strands, and a stainless steel coil-support structure reinforced by horizontal bridges inserted between coil blocks. The model was instrumented with voltage taps, quench heaters, temperature sensors and strain gauges in order to monitor the quench origin, and to study mechanical and quench protection issues. This paper summarizes the model design parameters, the fabrication procedures and the test results.

The Advanced Hydrotest Facility (AHF), under study by LANL, utilizes large-bore superconducting quadrupole magnets to image protons for radiography of fast events. The lens system uses two types of quadrupoles: a large bore (48-cm beam aperture) for wide field of view imaging and a smaller bore (23 cm aperture) for higher resolution images. The gradients of the magnets are 10.14 T/m and 18.58 T/m with magnetic lengths of 4.3 m and 3.0 m, respectively. The magnets are sufficiently novel to present a design challenge. Evaluation and comparisons were made for various types of magnet design: shell and racetrack coils, cold and warm iron, as well as an active superconducting shield. Nb/sub 3/Sn cable was considered as an alternative to NbTi to avoid quenching under high beam-scattering conditions. Several options are discussed and compared.

A racetrack magnet, using Nb/sub 3/Sn superconducting cable reacted before winding, has been fabricated and tested at Fermilab. It consists of two flat racetrack coils, connected in a common-coil configuration, separated by a 5 mm thick fiberglass plate. Synthetic oil was used to prevent sintering of the strands during the heat treatment. The coils were wound and vacuum impregnated in the mechanical structure. The turn-to-turn insulation, consisting of Kapton/spl reg/ and pre-impregnated fiberglass tapes as wide as the cable, was wound together with the bare cable in order to form a continuous inter-turn spacer. The coils were instrumented with voltage taps, temperature sensors, spot heaters and quench heaters. The maximum current achieved was 12675A which is 78% of the short sample limit at 5.1 K (minimum temperature in the coil during 75 A/s ramp). Measurement of the temperature margin revealed a low degradation in the innermost turns. Quench performances at different temperatures and ramp rate effects have been measured and are presented and discussed.

Production has started for the high-gradient superconducting quadrupole magnets developed by the US LHC Accelerator Project for the Interaction Regions of the Large Hadron Collider. The first full-scale Q2 assembly has recently been measured during fabrication at Fermilab. This paper reports on the mechanical alignment processes used during production of the combined cold-mass assembly and during its installation in the cryostat, and the validation of these processes in meeting accelerator requirements. Also presented are the results of measurements of the field axis and roll angle of the completed magnet assembly. Results are compared to machine performance requirements.

A quench management system has been developed for the Fermilab Magnet Test Facility as part of the overall data acquisition and control system for testing superconducting accelerator magnets. The quench management system accepts a standard set of quench input signals such as magnet voltages and current, safety interlocks, and power supply status, which are multiplexed from several independent test stands. It also issues a standard set of output control signals that are used to activate the dump, the quench protection heater power supplies, and to control the magnet ramp down in the event of a quench. Triggers generated by the quench management system are used to save the logged quench data from both the fast and slow data acquisition instrumentation. The hardware architecture of the quench management system will be discussed along with analog quench detection, digital quench detection, quench logic, and the user interface for configuring and controlling this system.

Two short Nb/sub 3/Sn dipole models based on a single-bore cos-theta coil with a cold iron yoke were fabricated and tested at Fermilab. This paper summarizes the details of magnet design and fabrication procedure, and reports the test results including quench performance and quench heater studies, and the magnetic measurements.

High-gradient quadrupoles (MQXB) are being developed at Fermilab within the framework of the US-LHC Accelerator project for the LHC interaction regions. These 5.5-m-long magnets have a single 70-mm aperture and operate in superfluid helium at a peak gradient of 215 T/m. Magnet quench protection is provided by quench heaters installed on the outer surface of the coil. This paper reports the results of quench protection studies on the first full length MQXB prototype (MQXP01). The measurements from these tests as well as results from the 1.9-m-long model magnet program are combined with computer generated quench simulations to predict the MQXB performance under LHC operating conditions.

Superconducting low-beta quadrupole magnets for the interaction regions of the Large Hadron Collider have been developed by the US-LHC Accelerator Project. These 70 mm bore 5.5 m long quadrupoles are intended to operate in superfluid helium at 1.9 K with a nominal field gradient of 215 T/m. Following a series of 2 m long models, a full scale cryostated cold mass has been fabricated and cold tested at Fermilab. Magnetic field measurements of the prototype, including determination of the field axis using a single stretched wire, have been performed. These measurements and comparisons with results from the model magnets as well as field quality and alignment requirements are reported in this paper.

As part of the US LHC program to provide high gradient superconducting quadrupoles for the LHC interaction regions, a 5.5 meter long prototype magnet has been built and tested horizontally in a production type cryostat at Fermilab. This prototype magnet was used to validate the mechanical and magnetic design, production fabrication and assembly tooling. The first prototype magnet has met the LHC requirements of operating at 215 T/m with excellent magnetic field harmonics. This paper summarizes the test results of this magnet, including quench tests and mechanical behavior over several thermal cycles.

High gradient quadrupoles are being developed by the US-LHC Accelerator project for the LHC interaction region inner triplets. These 5.5 m long magnets have a single 70 mm aperture and operate in superfluid helium at a peak gradient of 215 T/m. Through the construction and test of eight 2 meter long model quadrupoles, strip heaters of various geometries and insulation thicknesses have proven to be effective in protecting the magnets from excessively high coil temperatures and coil voltages to ground. This paper reports on the results of the model program to optimize the heater performance within the context of the LHC inner triplet electrical power and quench detection scheme.

Fermilab, in collaboration with LBNL and BNL, is developing a quadrupole for installation in the interaction region inner triplets of the LHC. This magnet is required to have an operating gradient of 215 T/m across a 70 mm coil bore, and operates in superfluid helium at 1.9 K. A 2 m magnet program addressing mechanical, magnetic, quench protection, and thermal issues associated with the design was completed earlier this year, and production of the first full length, cryostatted prototype magnet is underway. This paper summarizes the conclusions of the 2 m program, and the design and status of the first full-length prototype magnet.

A 43.5 mm aperture dipole magnet with a nominal field of 11 T is being fabricated at Fermilab. The design is based on a two-layer shell-type coil structure made of Rutherford-type Nb/sub 3/Sn cable with wind and react technology. The mechanical support structure consists of vertically split iron yoke locked by two aluminum clamps and a 8 mm thick stainless steel skin. This paper summarizes the fabrication details of the first dipole model and test results from a 2110 mm long mechanical model.

As part of the US LHC program to develop high gradient superconducting quadrupoles for the LHC interaction regions, a series of 2 meter long model magnets has been built and tested at Fermilab. This R&D program was used to refine the mechanical and magnetic design, optimize fabrication and assembly tooling and ensure adequate quench performance. The final design, fabrication, and assembly procedures developed in this program have produced magnets which meet the LHC requirements of operating at 215 T/m with excellent magnetic field harmonics. This paper summarizes the test results of the last five model magnets, including quench tests over several thermal cycles, and excitation current ramp rate and temperature dependence studies.

Fermilab (FNAL) and the Japanese high energy physics lab (KEK) are developing the superconducting quadrupole magnets for the interaction regions (IR) of the Large Hadron Collider (LHC). These magnets have a nominal field gradient of 215 T/m in a 70 mm bore and operate in superfluid helium at 1.9 K. The IR magnets are electrically interconnected with superconducting busbars, which need to be protected in the event of a quench. Experiments to determine the most suitable busbar design for the LHC IR magnets and the analysis of the data are presented. The main purpose of the study was to find a design that allows the inclusion of the superconducting busbars in the magnet quench protection scheme, thus avoiding additional quench protection circuitry. A proposed busbar design that was tested in these experiments consists of a superconducting cable, which is normally used for the inner layer of the Fermilab IR quadrupoles, soldered to similar Rutherford type cables as a stabilizer. A series of prototypes with varying numbers and types of stabilizers (one or two stabilizers, pure copper or Cu/NbTi composite) were tested. These samples were characterized with respect to their quench temperature profile and their quench propagation velocity during normal zone growth. From these tests, a suitable design has been determined.

High-gradient superconducting quadrupole magnets are being developed by the US LHC Accelerator Project for the Interaction Regions of the Large Hadron Collider. Determination of the magnetic axis for alignment of these magnets will be performed using a single stretched wire system. These measurements will be done both at room and cryogenic temperatures with very long wire lengths, up to 20 m. This paper reports on the stretched wire alignment methodology to be employed: and the results of recent room-temperature measurements on a 2 m model magnet with long wire lengths.

Superconducting quadrupole magnets with 70 mm aperture and nominal field gradient of 215 T/m are being developed by the US-LHC Accelerator Project for the Interaction Regions of the Large Hadron Collider. Due to large beam size and orbit displacement in the final focusing triplet, these magnets are subject to stringent field quality requirements. For this reason, a correction scheme based on design calculations, fabrication issues and tests results involving magnetic shims.

The high gradient quadrupole magnets being developed by the US-LHC Accelerator Project for the LHC Interaction Regions have stringent field quality requirements. The field quality of these magnets will be measured using a rotating coil system presently under development. Mechanical vibrations of the coil during field quality measurements are of concern because such vibrations can introduce systematic errors in measurement results. This paper presents calculations of the expected influence of vibrations on field quality measurements and a technique to measure vibrations present in data acquired with standard "tangential-style" probes. Measured vibrations are reported and compared to simulations. Limits on systematic errors in multipole measurements are discussed along with implications for probe and measurement system design.

Measurements of the Fermilab Main Injector dipoles using a partially redundant system of integrated and point measurements were carried out for quality assurance. Additional special measurements studied the hysteretic field strength. Results from these measurements are presented.