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Design and fabrication of solenoids for high magnetic fields

Description: From abstract: "This report consists of papers presented of papers presented at a meeting held in late 1954 to review all the work related to coil design and fabrication."
Date: December 1955
Creator: Coensgen, Frederic H.; Turpen, Oliver S.; Branum, David R.; Meuser, Robert B.; Rhein, Reginald W. & Carlson, Norris W.
Partner: UNT Libraries Government Documents Department

A METHOD FOR PRODUCING A HIGH QUALITY SOLENOIDAL FIELD

Description: A relatively simple and inexpensive device is described which can be used to provide a highly homogeneous solenoidal magnetic field when the solenoid windings are inadequate. Design considerations and experimental measurements are presented. A field straightness of approximately 10{sup -4} radians has been achieved.
Date: January 1, 1981
Creator: Feinberg, B.; Brown, I.G.; Halbach, K. & Kunkel, W.B.
Partner: UNT Libraries Government Documents Department

Effect of various errors on the Spin Tune and Stable Spin Axis

Description: Even though RHIC has two full Siberian snakes in each ring, there are various perturbations to the ideal case including orbit errors at the snakes, experiment solenoids, injection bumps, and interlaced horizontal-vertical bumps at the hydrogen jet polarimeter. These errors can cause depolarization by shifting the spin tune and tilting the stable spin direction away from vertical. Tilting of the stable spin axis can enhance horizontal depolarizing resonances. This paper presents preliminary results for some of these error scenarios, as well as their impact on the stable spin directions at STAR and PHENIX.
Date: October 6, 2008
Creator: MacKay,W.W.
Partner: UNT Libraries Government Documents Department

Effect of Various Errors on the Spin Tune and Stable Spin Axis

Description: Even though RHIC has two full Siberian snakes in each ring, there are various perturbations to the ideal case including orbit errors at the snakes, experiment solenoids, injection bumps, and interlaced horizontal-vertical bumps at the hydrogen jet polarimeter. These errors can cause depolarization by shifting the spin tune and tilting the stable spin direction away from vertical. Tilting of the stable spin axis can enhance horizontal depolarizing resonances. This paper presents preliminary results for some of these error scenarios, as well as their impact on the stable spin directions at STAR and PHENIX.
Date: January 1, 2009
Creator: MacKay,W.W.
Partner: UNT Libraries Government Documents Department

Fabrication, Testing and Modeling of the MICE Superconducting Spectrometer Solenoids

Description: The Muon Ionization Cooling Experiment (MICE), an international collaboration sited at Rutherford Appleton Laboratory in the UK, will demonstrate ionization cooling in a section of realistic cooling channel using a muon beam. A five-coil superconducting spectrometer solenoid magnet will provide a 4 tesla uniform field region at each end of the cooling channel. Scintillating fiber trackers within the 400 mm diameter magnet bore tubes measure the emittance of the beam as it enters and exits the cooling channel. Each of the identical 3-meter long magnets incorporates a three-coil spectrometer magnet section and a two-coil section to match the solenoid uniform field into the other magnets of the MICE cooling channel. The cold mass, radiation shield and leads are currently kept cold by means of three two-stage cryocoolers and one single-stage cryocooler. Liquid helium within the cold mass is maintained by means of a re-condensation technique. After incorporating several design changes to improve the magnet cooling and reliability, the fabrication and acceptance testing of the spectrometer solenoids have proceeded. The key features of the spectrometer solenoid magnets, the development of a thermal model, the results of the recently completed tests, and the current status of the project are presented.
Date: May 16, 2010
Creator: Virostek, S.P.; Green, M.A.; Trillaud, F. & Zisman, M.S.
Partner: UNT Libraries Government Documents Department

ELECTRON CLOUD OBSERVATIONS AND CURES IN RHIC

Description: Since 2001 RHIC has experienced electron cloud effects, which have limited the beam intensity. These include dynamic pressure rises - including pressure instabilities, tune shifts, a reduction of the stability threshold for bunches crossing the transition energy, and possibly incoherent emittance growth. We summarize the main observations in operation and dedicated experiments, as well as countermeasures including baking, NEG coated warm beam pipes, solenoids, bunch patterns, anti-grazing rings, pre-pumped cold beam pipes, scrubbing, and operation with long bunches.
Date: June 25, 2007
Creator: FISCHER,W.; BLASKIEWICZ, M.; HUANG, H.; HSEUH, H.C. & AL., ET
Partner: UNT Libraries Government Documents Department

The Role of Quench-back in the Passive Quench Protection of Uncoupled Solenoids in Series with and without Coil Sub-division

Description: This paper is the final paper in a series of papers that discusses passive quench protection for high inductance solenoid magnets. This report describes how passive quench protection system may be applied to superconducting magnets that are connected in series but not inductively coupled. Previous papers have discussed the role of magnet sub-division and quench back from a conductive mandrel in reducing the hot-spot temperature and the peak coil voltages to ground. When magnets are connected in series, quench-back from a conductive mandrel can cause other magnets in a string to quench even without inductive coupling between magnets. The magnet mandrels must be well coupled to the magnet circuit that is being quenched. When magnet circuit sub-division is employed to reduce the voltages-to-ground within magnets, the resistance across the subdivision becomes the most important factor in the successful quenching of the magnet string.
Date: October 15, 2010
Creator: Guo, Xing Long; Green, Michael A; Wang, Li; Wu, Hong & Pan, Heng
Partner: UNT Libraries Government Documents Department

The Results of Recent MICE Superconducting Spectrometer Solenoid Test

Description: The MICE spectrometer solenoid magnets will be the first magnets to be installed within the MICE cooling channel. The MICE spectrometer solenoids may be the largest magnets that have been cooled using small two stage coolers. During the previous test of this magnet, the cooler first stage temperatures were too high. The causes of some of the extra first stage heat load has been identified and corrected. The rebuilt magnet had a single stage GM cooler in addition to the three pulse tube coolers. The added cooler reduces the temperature of the top of the HTS leads, the shield and of the first stage of the pulse tube coolers.
Date: October 15, 2010
Creator: Green, Michael A.; Virostek, Steve P. & Zisman, Michael S.
Partner: UNT Libraries Government Documents Department

Butt Joint Tool Commissioning

Description: ITER Central Solenoid uses butt joints for connecting the pancakes in the CS module. The principles of the butt joining of the CICC were developed by the JAPT during CSMC project. The difference between the CSMC butt joint and the CS butt joint is that the CS butt joint is an in-line joint, while the CSMC is a double joint through a hairpin jumper. The CS butt joint has to carry the hoop load. The straight length of the joint is only 320 mm, and the vacuum chamber around the joint has to have a split in the clamp shell. These requirements are challenging. Fig.1 presents a CSMC joint, and Fig.2 shows a CS butt joint. The butt joint procedure was verified and demonstrated. The tool is capable of achieving all specified parameters. The vacuum in the end was a little higher than the target, which is not critical and readily correctable. We consider, tentatively that the procedure is established. Unexpectedly, we discover significant temperature nonuniformity in the joint cross section, which is not formally a violation of the specs, but is a point of concern. All testing parameters are recorded for QA purposes. We plan to modify the butt joining tool to improve its convenience of operation and provide all features necessary for production of butt joints by qualified personnel.
Date: December 6, 2007
Creator: Martovetsky, N N
Partner: UNT Libraries Government Documents Department

6D Ionization Cooling Channel with Resonant Dispersion Generation

Description: For muons with preferable for ionization cooling momentum <300MeV/c the longitudinal motion is naturally undamped. In order to provide the longitudinal damping a correlation between muon momentum and transverse position--described in terms of the dispersion function--should be introduced. In the present report we consider the possibility of dispersion generation in a periodic sequence of alternating solenoids (FOFO channel) by choosing the tune in the second passband (i.e. above half-integer per cell) and tilting the solenoids in adjacent cells in the opposite direction. Analytical estimates for equilibrium emittances and cooling rates are presented.
Date: June 1, 2007
Creator: Palmer, R.B.; /Brookhaven; Alexahin, Yuri I.; Yonehara, K. & /Fermilab
Partner: UNT Libraries Government Documents Department

The Effect of Magnetic Field on HTS Leads What Happens when thePower Fails at RAL?

Description: The key to being able to operate the MICE superconducting solenoids on small coolers is the use of high temperature superconducting (HTS) leads between the first stage of the cooler and the magnet, which operates at around 4.2 K. Because MICE magnets are not shielded, all of the MICE magnets have a stray magnetic field in the region where the coolers and the HTS leads are located. The behavior of the HTS leads in a magnetic field depends strongly on the HTS material used for the leads and the temperature of the cooler first stage temperature. The HTS leads can be specified to operate at the maximum current for the magnet. This report shows how the HTS leads can be specified for use the MICE magnets. MICE magnets take from 1.3 hours (the tracker solenoids) to 3.7 hours (the coupling magnet) to charge to the highest projected operating currents. If the power fails, the cooler and the upper ends of the HTS leads warm up. The question is how one can discharge the magnet to protect the HTS leads without quenching the MICE magnets. This report describes a method that one can use to protect the HTS leads in the event of a power failure at the Rutherford Appleton Laboratory (RAL).
Date: February 14, 2007
Creator: Green, Michael A.
Partner: UNT Libraries Government Documents Department

COMMENT ON THE HEALY'S SYMPLECTIFICATION ALGORITHM.

Description: For long-term tracking, it is important to have symplectic maps for the various electromagnetic elements in an accelerator ring. While many standard elements are handled well by modern tracking programs, new magnet configurations (e.g., a helical dipole with a superimposed solenoid [1]) are being used in real accelerators. Transport matrices and higher terms may be calculated by numerical integration through model-generated or measured field maps. The resulting matrices are most likely not quite symplectic due to numerical errors in the integrators as well as the fieldmaps. In his thesis [2], Healy presented a simple algorithm to symplectify a matrix. While the method is quite robust, this paper presents a discussion of its limitations.
Date: June 23, 2006
Creator: MACKAY, W.W.
Partner: UNT Libraries Government Documents Department

HIGH FIELD SOLENOID FOR MUON COOLING.

Description: Magnets made with high-temperature superconducting (HTS) coils operating at low temperatures have the potential to produce extremely high fields for use in accelerators and beam lines. The specific application of interest that we are proposing is to use a very high field (of the order of 50 Tesla) solenoid to provide a very small beta region for the final stages of cooling for a muon collider. With the commercial availability of HTS conductor based on BSCCO technology with high current carrying capacity at 4.2 K, very high field solenoid magnets should be possible. In this paper we will evaluate the technical issues associated with building this magnet. In particular we address how to mitigate the high Lorentz stresses associated with this high field magnet.
Date: June 26, 2006
Creator: KAHN, S.A.; ALSHARO'A, M.; HANLET, P.; JOHNSON, R.P.; KUCHNIR, M.; NEWSHAM, F. et al.
Partner: UNT Libraries Government Documents Department

An ionization cooling channel for muon beams based on alternating solenoids

Description: The muon collider requires intense, cooled muon bunches to reach the required luminosity. Due to the limited life-time of the muon, the cooling process must take place very rapidly. Ionization cooling seems to be our only option, given the large emittances of the muon beam from pion decay. However, this ionization cooling method has been found quite difficult to implement in practice. We describe a scheme based on the use of liquid hydrogen absorbers fol-lowed by r.f. cavities (�pillbox� or �open iris� type), em-bedded in a transport lattice based on high field solenoids. These solenoidal fields are reversed periodically in order to suppress the growth of the canonical angular momentum. This channel has been simulated in detail with independent codes, featuring conventional tracking in e.m. fields and de-tailed simulation of multiple scattering and straggling in the the absorbers and windows. These calculations show that the 15 Tesla lattice cools in 6-Dphase space by a factor {approx} 2 over a distance of 20 m.
Date: April 16, 1999
Creator: al., Juan C. Gallardo et
Partner: UNT Libraries Government Documents Department

OVERVIEW AND STATUS OF THE STAR DETECTOR AT RHIC.

Description: Presented here is the current status of the STAR Detector. STAR is one of the four detectors being constructed at the RHIC collider facility. The STAR detector is scheduled to have its first engineering run with the RHIC beams about six months from the date of this conference. The STAR project is on schedule and expects to recomplete on time.
Date: January 9, 1999
Creator: CHRISTIE,W.B. FOR THE STAR COLLABORATION
Partner: UNT Libraries Government Documents Department

Beam-Based Solenoid Compensation for the PEP-II

Description: Commissioning the compensation system of the solenoid in the BaBar detector presents a challenging problem due to the complexity of the system, which uses twelve normal quadrupoles and twelve skew quadrupoles in each ring. The setting of these skew quadrupoles needs to be readjusted according to the machine optical parameters since the machines always have some unknown errors. In this paper, we will describe a beam based method to match the coupling and optics in the interaction region to compensate for the optical effects due to the solenoid. The method has been successfully used to find the wrong polarities and the wrong scaling factor of the skew quadrupoles in the early stage of the commissioning. It is being refined to set the skew quadrupoles in the machines in order to reduce the beam size at the interaction point and improve the luminosity of PEP-II.
Date: August 26, 1999
Creator: Cai, Yunhai
Partner: UNT Libraries Government Documents Department

Beam-Based Solenoid Compensation for the PEP-II

Description: Commissioning the compensation system of the solenoid in the BaBar detector presents a challenging problem due to the complexity of the system, which uses twelve normal quadrupoles and twelve skew quadrupoles in each ring. The setting of these skew quadrupoles needs to be readjusted according to the machine optical parameters since the machines always have some unknown errors. In this paper, we will describe a beam based method to match the coupling and optics in the interaction region to compensate for the optical effects due to the solenoid. The method has been successfully used to find the wrong polarities and the wrong scaling factor of the skew quadrupoles in the early stage of the commissioning. It is being refined to set the skew quadrupoles in the machines in order to reduce the beam size at the interaction point and improve the luminosity of PEP-II.
Date: August 26, 1999
Creator: Cai, Yunhai
Partner: UNT Libraries Government Documents Department

A Root/10 based software framework for CMS

Description: The implementation of persistency in the Compact Muon Solenoid (CMS) Software Framework uses the core I/O functionality of ROOT. We will discuss the current ROOT/IO implementation, its evolution from the prior Objectivity/DB{trademark} implementation, and the plans and ongoing work for the conversion to ''POOL'', provided by the LHC Computing Grid (LCG) persistency project. The CMS experiment [1] is one of the four approved LHC experiments. Data taking is scheduled to begin in 2007, and will last at least ten years. The CMS software and computing task [2] will be 10-1000 times larger than that of current HEP experiments. Therefore it is essential that software must be modular, flexible, and maintainable as well as providing high performance and quality. One of the technologies utilized has been a C++ based object oriented database management system (ODBMS). Originally, the specific implementation used for object persistency was a commercial product, Objectivity/DB [3]. In 2001, it became apparent that Objectivity was not the optimal long term solution for data persistency, and that it was necessary to abandon Objectivity with a very short time scale. A decision was made to directly use ROOT/IO [4] as a component of an interim persistency implementation. In the very near future, the LHC computing grid persistency project will provide POOL [5] as an implementation for persistency. This paper primarily covers the conversion from Objectivity/DB to ROOT/IO. Also briefly discussed is the ongoing transition to POOL.
Date: August 26, 2004
Creator: Tanenbaum, William
Partner: UNT Libraries Government Documents Department

ANALYSIS OF THE MAGNETIC FIELD MEASURED BY A ROTATING HALL PROBE IN A SOLENOID TO LOCATE ITS MAGNETIC AXIS.

Description: We have analyzed the motion of a Hall probe, which is rotated about an axis that is arbitrarily displaced and oriented with respect to the magnetic axis of a solenoid. We outline how the magnetic field measured by the rotating Hall probe can be calculated. We show how to compare theoretical results with actual measurements, to determine the displacement and orientation of the axis of rotation of the probe from the magnetic axis. If the center of rotation of the probe is known by surveying, the corresponding point on the magnetic axis of the solenoid can be located. This is applied to a solenoid that was built for BNL by Oxford Instruments.
Date: November 6, 2000
Creator: KPONOU,A.; PIKIN,A.; BEEBE,E. & ALESSI,J.
Partner: UNT Libraries Government Documents Department

ELECTRON POLARIZATION IN THE MEDIUM-ENERGY ELECTRON-ION COLLIDER AT JLAB

Description: A key feature of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab is high polarization (over 80%) of the electron beam at all collision points for the particle physics program. The equilibrium electron polarization is arranged to be vertical in the arcs of the figure-8 collider ring of the MEIC and anti-parallel to the arc dipole magnetic fields, in order to take advantage of the preservation of polarization by the Sokolov-Ternov (S-T) effect. Longitudinal polarization is achieved at collision points by utilizing energy-independent universal spin rotators each of which consists of a set of solenoids and dipoles placed at the end of an arc. The equilibrium beam polarization and its lifetime depend on competition between the S-T effect and radiative depolarization. The latter must be suppressed by spin matching. This paper reports on investigations of polarization in the MEIC electron collider ring and a preliminary estimate of beam polarization from calculations using the code SLICK.
Date: July 1, 2012
Creator: Fanglei Lin, Yaroslav Derbenev, Vasiliy Morozov, Yuhong Zhang, Desmond Barber
Partner: UNT Libraries Government Documents Department

Muon Acceleration - RLA and FFAG

Description: Various acceleration schemes for muons are presented. The overall goal of the acceleration systems: large acceptance acceleration to 25 GeV and 'beam shaping' can be accomplished by various fixed field accelerators at different stages. They involve three superconducting linacs: a single pass linear Pre-accelerator followed by a pair of multi-pass Recirculating Linear Accelerators (RLA) and finally a non-scaling FFAG ring. The present baseline acceleration scenario has been optimized to take maximum advantage of appropriate acceleration scheme at a given stage. The solenoid based Pre-accelerator offers very large acceptance and facilitates correction of energy gain across the bunch and significant longitudinal compression trough induced synchrotron motion. However, far off-crest acceleration reduces the effective acceleration gradient and adds complexity through the requirement of individual RF phase control for each cavity. The RLAs offer very efficient usage of high gradient superconducting RF and ability to adjust path-length after each linac pass through individual return arcs with uniformly periodic FODO optics suitable for chromatic compensation of emittance dilution with sextupoles. However, they require spreaders/recombiners switchyards at both linac ends and significant total length of the arcs. The non-scaling Fixed Field Alternating Gradient (FFAG) ring combines compactness with very large chromatic acceptance (twice the injection energy) and it allows for large number of passes through the RF (at least eight, possibly as high as 15).
Date: October 1, 2011
Creator: Bogacz, Alex
Partner: UNT Libraries Government Documents Department