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Title: High Performance PrFeB Permanent Magnets through Novel Pulse Alignment and Compaction Method for Cryogenic Permanent Magnet Undulators (CPMU)

Authors:
 [1]
  1. IAP Research Inc., Dayton, OH (United States)
Publication Date:
Research Org.:
IAP Research Inc., Dayton, OH (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC); Arnold Magnetic Technologies, Rochester, NY (United States); Moog Inc., East Aurora, NY (United States)
OSTI Identifier:
1346858
Report Number(s):
DOE-IAP-07656
DOE Contract Number:
SC0007656
Type / Phase:
SBIR
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 36 MATERIALS SCIENCE; magnetic alignment; anisotropic powder; bonded magnet; net shape rotor

Citation Formats

Chelluri, Bhanumathi. High Performance PrFeB Permanent Magnets through Novel Pulse Alignment and Compaction Method for Cryogenic Permanent Magnet Undulators (CPMU). United States: N. p., 2017. Web.
Chelluri, Bhanumathi. High Performance PrFeB Permanent Magnets through Novel Pulse Alignment and Compaction Method for Cryogenic Permanent Magnet Undulators (CPMU). United States.
Chelluri, Bhanumathi. Wed . "High Performance PrFeB Permanent Magnets through Novel Pulse Alignment and Compaction Method for Cryogenic Permanent Magnet Undulators (CPMU)". United States. doi:.
@article{osti_1346858,
title = {High Performance PrFeB Permanent Magnets through Novel Pulse Alignment and Compaction Method for Cryogenic Permanent Magnet Undulators (CPMU)},
author = {Chelluri, Bhanumathi},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Mar 15 00:00:00 EDT 2017},
month = {Wed Mar 15 00:00:00 EDT 2017}
}

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  • The Phase I feasibility results of processing PrFeB magnets have shown highly promising magnetic property results with the potential to equal or exceed the best PrFeB properties reported. These findings will be advanced in Phase II through composition tuning, optimization of powder alignment from 95% to > 98%, sintering and heat treat adjustments. The objectives of Phase I were successfully achieved during Phase I work. These were to produce PrFeB magnets and test to establish a baseline process including material chemistry, alloy milling to 3 microns, compaction with domain alignment, and liquid Phase sintering and annealing – under both thermalmore » and vacuum cycles. Success of proper chemistry and processing is determined by the finished magnet density and magnetic performance. A density of 7.45 +/-0.03 g/cm3 has been established as demonstrating full density.« less
  • Magnetic modeling was performed to estimate achievable magnetic field strengths of superconducting undulators (SCUs) and to compare them with those of cryogenically cooled permanent magnet undulators (CPMUs). Starting with vacuum (beam stay-clear) gaps of 4.0 and 6.0 mm, realistic allowances for beam chambers (in the SCU case) and beam liners (in the CPMU case) were added. (A 6.0-mm vacuum gap is planned for the upgraded APS). The CPMU magnetic models consider both CPMUs that use NdFeB magnets at ~150 K and PrFeB magnets at 77 K. Parameters of the magnetic models are presented along with fitted coefficients of a Halbach-typemore » expression for the field dependence on the gap-to-period ratio. Field strengths for SCUs are estimated using a scaling law for planar SCUs; an equation for that is given. The SCUs provide higher magnetic fields than the highest-field CPMUs – those using PrFeB at 77 K – for period lengths longer than ~14 mm for NbTi-based SCUs and ~10 mm for Nb3Sn-based SCUs. To show that the model calculations and scaling law results are realistic, they are compared to CPMUs that have been built and NbTi-based SCUs that have been built. Brightness tuning curves of CPMUs (PrFeB) and SCUs (NbTi) for the upgraded APS lattice are also provided for realistic period lengths.« less
  • Short period high field undulators are of interest for X-ray brilliance enhancement in synchrotron radiation applications and for compact Free Electron Lasers. Cryogenic in-vacuum undulators [1] are one of the possible solutions. At SOLEIL, PrFeB magnets were directly chosen, even if still under development at that time. Indeed, they enable to avoid the spin transition reorientation phenomenon which occurs with NdFeB magnets [2] and the magnets can be cooled down directly at 77 K. The first selected grade CR53 from Hitachi presents a remanence of 1.35 T at 293 K and 1.57 T at 77 K, with a coercivity ofmore » 1355 kA/m at 293 K and 6000 kA/m at 77 K. A 2 m long cryogenic undulator of period 18 mm was first built in-house, with a specific Hall probe bench directly installed in the final vacuum chamber. This first cryogenic undulator has been in operation on the storage ring for 4 years [3]. A second U18 cryo-ready undulator using a slightly different magnet grade with a higher coercivity and modules with magnets surrounded by two half poles for easier magnetic optimization is under construction. A third 3 m long cryo-ready undulator U15 with a period of 15 mm is under development. It will be first used for the LUNEX5 FEL [4, 5] project (COXINEL demonstration of FEL amplification with a laser wakefield acceleration [6]). The measurement bench will include a correction of the Hall probe position and angle, the field integrals will be measured with a stretched wire.« less
  • The effect of temperatures up to 600 d C and the combined effect of temperature and vibration on the magnetic performance of Alnico V and Alnico VI magnet were investigated. (auth)