DC Magnet User Program

1. DC Magnet User Program Eric Palm Director, DC User Program Scott Hannahs Director, DC Field Facilities and Instrumentation Magnets People Instrumentation

2. Resistive Split Magnet Installation into Cell 5 Open wall to Optics Cell (3), extend ceiling, 100-300 k$ Cell 5 housing  Cell 2 Cell 5 magnet  Cell 7 Cell 7 magnet  Cell 2 31 T, 50 mm bore in Cell 7 29.5 T, 32 mm bore NMR magnet in Cell 2

3. Resistive Split Magnet • First experiments in June (room temperature) • Need plant upgrade to run in parallel with another magnet (needs more water) • Huge strain on already tapped out optics group (McGill, Smirnov) • Hiring optics technician • Hire New FTIR Scientists soon • Need postdocs to help • Senior Optics faculty member • Buy huge amount of optics to fully outfit cell • List of experiments and priorities for instrumentation purchasing see Steve McGill • Late arrival of NSF money has really hurt the instrumentation effort

4. 28 MW Resistive Magnets • 4 workhorse magnets upgraded to 28 MW • 40-42T w/ 32mm bore, 36-38 T w/ 50mm bore • 2.8 M$ first one, 1.1 M$ each additional, 6.1 M$ total • Why • 20% more efficient • Open up parameter space only available on hybrid • If hybrid outsert degrades – we’re still in comparable phase space • Multi-year project – schedule depends on MS&T personnel transitioning out of other projects

5. Series Connected Hybrid • Series Connected Hybrid completed – 1st quarter 2013 • 14 MW – one power supply – will run in parallel with hybrid! • 36T @ 1ppm homogeneity (40mm bore), 42 T (32mm bore) • Will be used for Chem-Bio NMR – MRI grant for console approved! • Condensed Matter NMR – existing top-loading He-3 cryostat modified to fit. • High field sitters – heat capacity, temperature sweepers. New tail set for Janis dewar • Long range – Condensed Matter NMR faculty member

6. Improvements • FlexTime has provided 30% more magnet time while holding overall energy usage constant via energy budget for user • Improved grounding, shielding, instrumentation has improved user signal to noise. Ground floor in mK lowered with shielding, less RF interference. • Advanced cryogenics has increased user effectiveness. Users spend less time waiting for temperature to stabilize and have less lost time with cryogenic problems. • Power supplies upgraded to 14 MW. Interphase and filter inductors still being optimized. Improved noise and performance.

7. Coming Improvements New easy to use pressure cell for users. Guertin Cells New User Sample Prep Area

8. Hard to know true temperature in field. Hard to control temperature in field. Hard to perform certain experiments. +20% Low Temperature Thermometry 0.03 K@ 0 T 0.71 K@ 0 T 0 -22 % Temperature Deviation -34 % -20% RuO thermometer SCM1 mK (NHMFL) -40% 5 10 15 20 Magnetic Field (Tesla)

9. Zero Field Calibrations Secondary Thermometers • Commercial (e.g. RuO) • Material research • CMN • Commercial sensors • 3He melting curve Field Calibrations • Capacitive thermometers • 3He melting curve • Constant heat method • 3He-4He viscosity User Research • Better thermometers • Calorimeters • many other applications

10. Thermometry Need More Scholar Scientist(s) to provide more support and to free up JH Park to do thermometry Lab space being renovated. Startup / dedicated system for thermometry efforts Thermometry line item in budget Condensed Matter NMR Next Target for Team Noise – goal improve signal to noise so it approaches “home lab levels” Allow systems with few spins to be studied

11. Vision - Magnets • Hybrid Outsert upgraded to 15 T, insert upgraded • total field 48 T • 60 T Hybrid magnet • Very expense (100 M$) – but we you are worth it! Instrumentation / People “Standard” instrumentation (one scientist each) thermodynamic probes (heat capacity, thermopower, etc) dilatometry / magnetostriction TDO / high frequency skin depth “PPMS-like” capability Scanning Probe Microscopy Major research effort Start with SC magnet & build infrastructure

12. Vision Instrumentation / People “Standard” instrumentation (one scientist each) thermodynamic probes (heat capacity, thermopower, etc) dilatometry / magnetostriction TDO / high frequency skin depth “PPMS-like” capability standard puck for resistance, magnetization, etc. plug puck onto probe, load probe, make automated / remote measurement use familiar “PPMS” like interface (QD is interested in helping to develop) measurements could be in 3rd shift or weekends initially use decommissioned 20 MW magnets (31 T, 50 mm bore) technician and scientist to develop technician to run, extra control room personnel (1 or 2), electricity budget Scanning Probe Microscopy Major research effort Start with SC magnet & build infrastructure 1 scientist / 1 postdoc

13. NHMFL Theory Program Initiatives • (V. Dobrosavljevic, director) • Help integrate the in-house science and user programs • Organize “Hot Topic Series” informal discussion seminars (during coffee hour), where users will be invited to present their hottest results to stimulate interaction with in-house people. • Magnet-time allocation letters will invite users to contact theory program people, who will be listed with indicated areas of interest/activity. • Theory Winter Schools for graduate students and postdocs will be organize during the first week of January, every second year, alternating with PPHMF conferences. Most prominent theorists, both form within NHMFL and outside experts, will be selected as speakers. • A Topical Mini-Workshop in the related area will follow the Winter School. This program will facilitate regular visits of most prominent external theorists, who will assist the user program.

14. New Experimental Capabilities • Raman Spectroscopy • Doing with fibers, but limited in sensitivity and geometries • Split Helix gives large angles • Carbon and semiconductor based nanostructures (graphene, quantum wells,…), phase transitions, HTS, quantum spin systems… • THz-Time Domain Spectroscopy • generate low power broadband short pulses • uses FFT to recover both amplitude and phase information from interaction with sample • ac conductivity of superconductors in high fields, cyclotron resonances… • Optical 2D Fourier Transform Spectroscopy and 4-wave Mixing • sensitive interferometery that combines 3 or more beams of light • cutting edge techniques, impossible without the Split-Helix • probes excitonic systems and their dynamics • Improving existing methods: • Photoluminescence • Infrared magneto optics (FTIR…) • EPR/ESR Split magnet enables the ability to do “micro- spectroscopy”, imaging, etc. with many techniques X-ray opportunities FEL opportunities

15. Shopping List • U-shaped non-magnetic optical table around magnet (150 k$) • Optical windows, custom vacuum hardware… (200 k$) • Dewar/cryosystem mounted to optical table (350 k$) • Vibration isolation between dewar and magnet (100 k$) • Narrow band Krypton laser for Raman Spectroscopy (100 k$) • Time correlated photon counter (100 k$) • Micropositioners & rotators, high B/low T (400 k$) • Optics, detectors, etc (400 k$) • New Bruker FTIR spectrometer with microscope (250 k$) • New, small footprint one-box amplifier ultrafast laser system (1 M$) • Custom made ultra low frequency Raman Scattering spectrometer (including custom microscope) (1 M$)