 |
|
 |
Executive Summary
This progress has been achieved under some budgetary constraint and pressures resulting from a natural evolution of the laboratory from a phase with heavy emphasis on construction to a phase with more emphasis on user programs and in-house research programs. These pressures have resulted in some difficult decisions to delay or defer projects; among them are advanced phases of the high resolution NMR magnet construction (the 900 MHz magnet project) and development of an NMR users program. Support funds for equipment purchases in other user programs may also be critically short.
The moves toward better staffing for user support and the development of an in-house research program have, nevertheless, been sound, and efforts to secure other sources of funding for some of the deferred activities have been outstanding. The Review Committee in general concurs with the goals and priorities outlined for the coming year, especially those involving continuance of the hybrid 45T project, both the 60T and 100T pulsed magnet projects, and initiation of the construction phase of the 900 MHz NMR magnet project. Efforts to retain world class capabilities in resistive magnet technology as some core projects are completed, by pacing construction and involving staff in projects outside the core is applauded. However, caution must be exercised to avoid unnecessary delays in reaching primary goals.
The Review Committee would urge continued vigilance in maintaining an adequate level of user access and user support. This must be given a high priority. Budgetary pressures from increased power consumption should not be addressed by simply curtailing access time. Due consideration should be given to other options. Close involvement of users and external advisors in decisions in this area is important. Monitoring the success of the newly initiated in-house research program in terms of quality of research and involvement of a broad spectrum of faculty and staff of the founding institutions are important over the next year.
The Review Committee also urges exploration of an untapped potential for bringing unique capabilities of the laboratory to bear on application of nuclear magnetic resonance to structural biology. This will require careful reassessment of long-term goals for the 900 MHz project and opportunities for multi-agency support.
INTRODUCTION
RESPONSE TO RENEWAL REVIEW
1) The possibility for broadening the base of financial support was among the issues explicitly raised. A number of significant new initiatives along this line have been taken: Keck Foundation support for construction of a 25T resistive magnet for magnetic resonance research, SBIR support for development of a higher field superconducting inner coils, DOE support for the 100T pulsed magnet, DOD support for MRI, and additional NSF-Chemistry and state support for ICR are good examples. The investigators are to be congratulated on these efforts. However, some important options remain to be explored; among them, multi-agency support for a high field NMR program.
2) Institution of a more formal procedure for review of allocations of magnet time was also recommended. A very sensible procedure involving a second stage review of written proposals by a proposal review committee has been proposed. This is a good start.
3) Increased user support, particularly at the pulsed magnet facility was encouraged. This has been met with additional staff allocations and the support level seems much improved.
4) A shift in management structure to match the move of the lab from a construction phase to a phase with more emphasis on user and in- house research was suggested. The management does appear very receptive to addressing this issue and is responding positively to user input. This trend is expected to continue.
5) The development of a science program to stimulate design and provide intellectual leadership was deemed essential. The investigators have committed funds and established a very well designed procedure for supporting in-house research. Reviewing of the first batch of in-house research proposals has begun. It is too early to gauge the outcome of the first round of review, but there is every indication that the procedures can lead to selection of high quality projects.
6) Complete transfer of management of the Hybrid 45T project to NHMFL was recommended. This transfer is now complete, and while an additional burden has been placed on NHMFL resources, the project appears to be moving smoothly ahead.
7) The importance of reaching out to the chemistry and biology communities using construction of as many as two 900 MHz class superconducting NMR magnets was recommended. Response to this particular issue has been slow, in part due to budgetary constraints and lack of a clear long term connection with a user community. At this point priorities and options for an expanded funding base for this important area should be reconsidered. The Director had requested that faculty in this area draw up a self study document (White Paper on Magnetic Resonance) to address the needs and opportunities in this area. This is a good first step.
USERS' PROGRAMS
In response to the Users' Committee's recommendation, the Tallahassee lab has added a 10-300 MHz dual frequency spectrometer for NMR experiments in the resistive magnets. In addition, a high-field (15/17 Tesla) superconducting magnet with 1 ppm resolution has been purchased for medium resolution NMR experiments. The added capability for magneto-optics and microwave impedance measurements in resistive magnets is also noteworthy. The decision to seek advice of the Users' Committee in prioritizing future equipment purchases should be complimented.
In terms of technical support to the users, the Tallahassee lab plans to add two Ph.D. level scientists in the areas of optics and low- temperature physics. This decision is a timely response to the increasing needs for users' support and to lowering the burden on the overloaded existing technical support staff. This move will certainly further enhance the quality of users' support.
[2] Pulsed-Field Magnets and Facilities:
The NHMFL should be congratulated on their continuing efforts in the
development of various state-of-the-art pulsed-field magnets and their
increasing users' support in both the facilities and staff at the LANL.
The near completion of a quasi-continuous 60-Tesla magnet which produces a
constant 60-Tesla field for 100 ms, as well as the ongoing efforts of
building a non-destructive 100-Tesla pulsed magnet, are both at the cutting
edge of the magnet technology. Once completed, new science will
undoubtedly emerge from these unique facilities. The recent addition of a
40-Tesla capacitor magnet with a long pulse length of 500 ms, as well as
new facilities such as gas handling systems, pumping stations, and a 94 GHz
microwave spectrometer for complex conductivity measurements of materials,
are also excellent support for the users' programs.
In a timely response to the increasing demand, the LANL has added a new Ph.D. level staff scientist with expertise in low-temperature physics to assist users' technical support, and is planning to add one more Ph.D. level support staff in the area of optics.
[3] Ultra-High B/T Facilities
The progress of the ultra-high B/T project in Gainesville has been
satisfactory except for the delay in the delivery of a 20-Tesla magnet by
Cryomagnetics. Once completed, this facility will be able to provide users
with the highest possible ratio of B/T in the world. Interesting new
science can be expected in this unique regime.
II. Concerns and Recommendations
Despite all the fine achievements and efforts by the NHMFL, the following
issues do raise concern and should be addressed.
[1] Magnet Time Available to Users
The rapid increase of users has unexpectedly run up the electricity power
cost. The immediate impact on the users' program could be two months down
time (August and December of 1996) for the DC resistive magnets. It is very
important for the NHMFL to actively pursue creative means in reducing the
cost, minimizing the magnet down time, and optimizing the efficient use of
magnet time. Among suggestions that came up in the course of discussion
are: negotiating new rates with the power company, changing the magnet
run-time to 24 hours a day for a few months, followed by one month down
time, etc.
It is also necessary to improve reviewing of proposals by users so that scarse resources can be directed to the best research. The reviewing procedure presented was a good one and should be implemented. The key content of the procedure is summarized as follows: A short proposal by a first-time user will be screened by the NHMFL staff and the Director for the quality and feasibility. A regular proposal will be requested if more than 1% of the total available magnet time is needed. The regular proposals are subject to peer reviews by three external referees in the proposer's field, and will be ranked by a study panel, called the Proposal Review Committee (PRC) , according to both the scientific merits and availability of resources. The NHMFL support staff will then schedule the magnet time according to the ranking of proposals and the optimization of resources and magnet time.
[2] Users' Equipment Support
Currently support for users' instrumentation is entirely funded by the
state of Florida. The one-time $11M fund for this purpose is down to $3M,
which is only sufficient for about two years. This is an issue which will
have severe impact on the users needs. It is therefore very important to
plan ahead before the remaining $3M in support funds are exhausted.
Various potential sources of support, such as federal funding agencies,
industry, private foundations, and additional state support, should be
actively explored.
[3] Support Staff
The increasing popularity of the NHMFL facilities among users as well as
the increasing degrees of sophistication of various new magnets place more
demand on technical support to the users. It is foreseeable that with the
completion of the 45-Tesla hybrid magnet in Tallahassee, as well as the
60-Tesla quasi-continuous magnet and 100-Tesla non- destructive magnet in
LANL, new scientists and technicians will be needed to assist users. The
recent addition of new hires should be commended. However, further increase
of staff in the near future, either through new hires or through transfer
of personnel from other areas (such as the Magnet Science and Technology )
of the Users' Program, could be necessary. It is also important that staff
not be over- burdened so that they can maintain a proper level of their own
research and keep up with the rapidly evolving technology associated with
scientific research.
IN-HOUSE RESEARCH PROGRAM
A process has been created and implemented which is managed by a Director
of In-House Research. This position will rotate amongst the NHMFL
institutions. A call for proposals was issued on May 6, 1996, with Letters
of Intent due June 15, 1996, and full proposals due on August 16, 1996.
Proposals are reviewed in a two-step peer review process. At present,
first round proposals have been received and reviewed by the internal
Science Program Committee and surviving proposals are out for review by
members of an external review panel. Based upon these reviews, the Director
of the In-House Research Programs, in consultation with the Science Program
Committee, will make funding recommendations to the NHMFL Chief Scientist
who will make the final funding decisions. This process will be repeated
annually and should yield high quality programs which will further the
mission of the laboratory. The Review Committee believes that the program
should encompass several aspects which are essential and appropriate for an
in- house research program at a national center. It should provide: i)
small, seeded collaborations between in-house and external investigators
that utilize their separate expertise, ii) bold but risky efforts to
dramatically extend the range of measurements, and improve design, iii)
start-up support for new faculty with that support targeted to magnet
laboratory enhancements.
One of the hallmarks of a successful in-house research program will be the
full involvement of the faculty of the NHMFL institutions in the scientific
life of the laboratory. At the next meeting of the External Review
Committee the role of the faculty should be discussed.
EDUCATION AND OUTREACH
In addition, the FSU labortory offered, lectures which reached 1700 students last year, tours of the Laboratory (1500 students and the general public), and an annual open house. The director has also made a lecture tour of local civic organizations.
Finally NHMFL has developed the first ever magnetism display for a science museum; first shown in MOSI it will tour the country for two years.
Beyond these educational outreach programs the NHMFL is actively involved in internal graduate programs. For example, research on topics related to the 900 MHz magnet system have led to an M.S. and Ph.D. degree for one student and M.S. degrees for four other graduate students.
Industrial, International, and other Collaborations.
Education is not the only way in which the NHMFL has an impact on the long
term vitality of science and technology. Outreach in the form of
partnership with the private sector and furtherance of US competitiveness
was implicit in the charge to establish a magnet science and technology
program. Interactions on a broader scope have also become important in
leveraging limited funding and fully utilizing unique capabilities of the
laboratory. Initially the NHMFL encountered some opposition in Florida to
technological interactions because of the belief that growing education and
state activities were sufficient to fuel development. As these latter
activities have slowed, NHMFL efforts at technological interactions and
development are gaining greater interest from agencies such as the Gulf
Coast Alliance for Technology Transfer and the Tallahassee Regional
Development Council. However, to date, principal successes have been with
companies with a national prospective. The NHMFL has done an excellent job
of fostering these, as well as, international, and other collaborative
efforts on magnet projects and facilities. A summary of these follows:
Industrial Collaboration: Industrial partnerships with IGC on the 45 T
hybrid magnet (including a $ 0.7 M contribution) and on the 900 Mhz NMR
magnet ($ 1.0 M contribution for wire) were a part of the major start-up
construction projects for NHMFL. In addition, the NHMFL has arranged a
donation from Oxford/Varian of a 720 MHz FT-NMR magnet and spectrometer.
Industrial collaboration is in progress on high temperature superconductors
for a HTC coil insert for the 900 Mhz NMR magnet. Funds ($600K) have been
allocated for this activity via an SBIR supported by the National Institute
of Health. The NHMFL is collaborating with Oxford Superconductor, IGC, and
American Superconductor in this area. An agreement with Varian and
Conductus has been reached for NHMFL to be a Beta test site for HTC NMR
probes. Finally, the NHMFL has also entered into a 3 yr Cooperative
Research and Development Agreement (CRADA) with EURUS Technologies for a
total of $ 815 K.
Partnerships: The NHMFL has fostered partnerships with the department of the Navy for Superconducting Magnetic Energy Storage (SMES) in Tallahassee. In addition, $5M has been received from the DOD for a 12 T, 40 cm bore superconducting magnet at the University of Florida Brain Institute for MRI, and a grant ($600K) has been received from the Keck Foundation for the construction of a > 25 T, 52 mm bore, < 1 ppm resistive magnet for NMR. Agreements now exist for smaller scale projects to build magnets for NASA ($89K) and for LANL ($47K); the latter is for a 30 T capacitor driven magnet for neutron scattering experiments. International Collaboration: The NHMFL has entered into a cooperative agreement with Grenoble to build for NHMFL a 20 T, 20 cm bore resistive magnet that will consume < 20 MW. A similar magnet will be built for Grenoble and will share much of the same technology. The NHMFL has also contracted with the National Research Institute for Metals (NRIM) in Japan to build a resistive magnet for $657K. The latter project is a "work for others" type activity, but is attractive to the lab since it helps maintain its skilled labor force against budget pressures that would otherwise result in staff reductions.
Conclusion: : The NHMFL has done a very good job of forming partnerships and collaborations and in attracting funds for NHMFL magnet projects. We encourage them to continue to pursue these activities in future years. The Review Committee does have one concern with respect to doing work for others. While such work is useful in maintaining high quality magnet design and construction personnel, the concern is the potential conflict of interest that might occur between such projects and the timely support for completing NSF funded projects.
MAGNET SCIENCE AND TECHNOLOGY
Resistive Magnets
The NHMFL is a world leader in resistive magnet design and has produced
record fields in the past year. The Review Committee applauds these
accomplishments. The user community has also expressed clear wishes for
continued production of specialty magnets of this class. Retaining the
collected expertise in this important area is a valid goal. To this end,
the work load for the magnet science and technology group has been spread
over the 5 year period, and additional sources for funding has been found
in magnet construction for other institutions. The Review Committee agrees
with this basic philosophy, however, continued sensitivity to a balance
with other NHMFL goals must be maintained.
An additional concern is the future availability of improved materials, both superconductors and conventional conductors for Bitter- type and pulsed field magnets. Since these materials are not expected to be provided by the commercial sector, a significant research effort will be needed. The Review Committee recognizes that the NHMFL is not in a position to fund all such research programs, and it recommends that active steps be taken to seek out collaborations, both on the national and international level. Exceptionally strong metallurgy and materials expertise exists at LANL at FU, and a focused effort is encouraged to tap into those sources.
Pulsed Magnets and Facilities
The NHMFL leadership, together with the staff affiliated with the pulsed
magnet development and users' support, should be congratulated on their
outstanding accomplishments and endeavor for the state-of-the-art magnet
technology. An on-site visit to the pulsed field facilities gave the
Review Committee an opportunity to observe first-hand some of these
accomplishments. Institutional commitment as affirmed by the LANL director
is clearly evident.
The major accomplishments and the significant progress in the pulsed magnet
facilities include:
[1] Ongoing construction of the worlds first 60-Tesla quasi-continuous
magnet with a constant 60-Tesla field for 100 ms in a cold bore of 34 mm,
expected to be completed in October 1997. This system can be upgraded to 70
Tesla, and will serve as a unique facility to enhance magnetism related
science research.
[2] Ongoing efforts at building the worlds highest non-destructive
pulsed magnet, a 100-Tesla magnet with field duration of about 15 ms in a
cold bore of 24 mm. The completion of this project will certainly enhance
frontier and unique science research in areas of condensed matter physics,
materials science and engineering, as well as chemistry.
[3] The flux compression capability of the ``Dirac series'', with
pulsed fields up to 1000 Tesla.
[4] The addition of a new wide-bore 40-Tesla pulsed capacitor-driven
magnet, in response to users' requests.
[5] The ongoing development of a new 70-Tesla capacitor-driven pulsed
magnet.
[6] The increase of operating fields for the standard 50 and 60-Tesla
pulsed magnets to 55 and 65-Tesla.
[7] The addition of various measurement capabilities for users'
experiments such as transport, optics, and 94 GHz microwave impedance.
[8] The addition of new staff scientists for supporting users.
The overall direction of the pulsed magnet programs is visionary, and the accomplishments impressive. In order to fully explore the potential of the new pulsed magnets and the existing facilities, it will be helpful to consider adding new experimental capabilities such as measurements of broader-band microwave impedance. Finally, on the development of future pulsed magnets, it will be desirable to continuously upgrade the present magnets and the achievable pulsed field range. An active in-house materials effort under, or in collaboration with, the Magnet Science and Technology program will certainly help further progress of pulsed magnet technology.
45-T Hybrid Project
The 45T hybrid magnet has the potential to be the centerpiece of the NHMFL.
This is an ambitious project which is in mid-stride at this time. A
progress report on the project was presented. The outer coils A-C are all
still under construction. The heat treatment and vacuum impregnation
techniques have been tested and qualified. Heat treatment of coils A and B
are scheduled this fall and both coils should be completed by February
1997. The NHMFL is receiving the last pancakes for coil C from FBNML at
the time of this review. Shipment of these pancakes ends the management
responsibilities of FBNML and fully vests the management for the project
with NHMFL. The NHMFL has picked up many manufacturing tasks formally
assigned to FBNML for coil C and for the resistive insert. The net effect
of NHMFL picking up these tasks is an increase in the cost-to-complete of
the project by $1.7 M, bringing the overall cost of the hybrid to about
$16M.
No new major technical problems have been encountered since the last review, however, several potential problems were mentioned in the presentation. The number of unblemished coil C pancakes available from FBNML is just adequate to complete the coil, and an insulating vacuum leak in the cryostat, believed to be responsible for a higher than expected heat leak to the 1.8 K chamber is suspected. These are not insurmountable difficulties, and the project is scheduled to be completed by the end of 1997.
Concern was expressed regarding the additional demands on NHMFL labor force as a result of the additional tasks assumed from FBNML, and the Review Committee notes that no contingency remains to cover technical problems encountered in the final assembly and testing of the magnet. This project is a complicated one that pushes the state-of-the- art, and as such, success on the first try is not guaranteed. Many possible failure modes or difficulties might be encountered. Any such difficulty that requires access to or replacement of a coil element inside the cryostat would be expensive, perhaps of order $1M. The management should be aware that such possibilities exist and plan accordingly. During the course of the discussion it was also pointed out that at least one additional technician would be required when the magnet came into operation. Finally, the Review Committee views as attractive the possibility of adding a high uniformity resistive insert to the hybrid to explore the potential benefits for NMR at these very high fields. The Review Committee encourages the lab to pursue this possibility as a long term goal.
900 MHz Wide Bore NMR Magnet.
This project was intended to be the first stage in an effort to push
continuous field superconducting magnets to their high field limits, and
make the resulting magnets available for exploration of new NMR
applications. The Review Committee heard a presentation on the current
target, a 900 MHz wide bore (110 mm warm bore) magnet to be operated at 1.8
K. This project is a collaboration between the NHMFL and Intermagnetics
General Corporation (IGC). NHMFL is responsible for technology
development, engineering design, fabrication of the Nb3Sn coils, magnet
assembly, and system components (cryostat and electronics). IGC is
responsible for the detailed manufacturing design for the magnet and
fabrication of the NbTi coils. The completed system is to be installed in
the NMR research facility of the NHMFL.
The current status of the project is that the completed Engineering Design Report has been sent to IGC for review. Conductor specifications have been finalized and purchase of conductor is being negotiated. The critical currents of the Nb3Sn conductors at 4.2 K were found to be lower than the benchmark design. This has necessitated redesign of the magnet to incorporate more wire. An initial small test coil of Nb3Sn has been fabricated and tested. Results from an analysis of quench-initiated stress stimulated a design change from stainless steel to copper stainless steel as the sheath for the copper-cladded conductor. A detailed work chart was presented showing the schedules for subsequent work to be performed; this calls for completion of the magnet at the end of 1998.
The two previous reviews have stressed the importance of this project as the first step in a two-stage project that can lead to higher field magnets of great importance to the NMR community. This Review Committee reiterates this message and strongly advises NHMFL to give this project a priority second only to the 45 T hybrid magnet, at least among projects underway at FSU. Further slippage of this project will close the window of opportunity. Ideally, one would have constructed two wide bore magnets 900 MHz (21T) magnets, putting one into service while using the second as a stage to push to 1.1 GHz (25T). The current level of funding unfortunately does not allow for the construction of a second wide-bore 900 MHz magnet. For this reason and because the NMR user program is being put on hold, the magnet currently under development should be devoted primarily to testing the inserts developed with NIH SBIR funding and for developing successors to these designs that will lead to the target 1.1 GHz field.
PRIORITIES
Within the budget plan for magnet science & technology the highest priorities were assigned to completion of ongoing programs (45T hybrid, 900 MHz NMR magnet, maintenance of resistive magnets) and development of the 100T pulsed magnet (with joint funding by DOE). Another priority set was retention of the unique expertise in magnet technology that has made the NHMFL a world leader. This is what led to the decision to spread magnet building efforts more uniformly over the next five years and also to get involved in work not funded by the NSF core grant (Resistive MR magnet-Keck Foundation plus FL, ICR systems-NSF Chem plus FL). Some delays in new magnet deliveries will result from this decision, but the additional projects fit into a general strategic plan to expand the technical expertise and enhance magnet availability. While the Review Committee applauds the efforts of the Director to leverage the resources of the NSF grant by seeking external funding and contracts, it cautions that this needs to be done in a way that does not delay delivery on the chief research and development goals of the laboratory. The Director appears to be aware of this potential conflict.
One of the major priority decisions was that the magnetic resonance activities not be funded on a significant level out of the NSF core grant in the first budgeting cycle. In part this decison was based on a lack of a clear mission statement for the NHMFL in the field of magnetic resonance. The director presented to the Review Committee a plan for formulating a clear statement in the next half year and asked the Review Committee for their input on this matter. This point is addressed further in the Future Vision section of this report.
BUDGET
As a result of budgetary constraints only the in-house research program for 1996 was funded on a similar level (115%) as anticipated in the 1995 renewal proposal, while all other programs received 66 to 77% of the requested level. In the management & facilities category the transfer of personnel to the state payroll freed up approx. $1M/year to cover some of the short-fall.
By the end of FY 97 the budget will have obtained its planned
distribution.
Users program: 49%
In house research program: 12%
Magnet science and technology: 26%
Management and administration: 13%
The in-house research program is just beginning, with the first round
proposals still in the review stage. The Review Committee believes that
the current proposed budget is adequate for the initiation of this program.
In the next two NSF reviews of the NHMFL the funded proposals must be
reviewed for their innovativeness and range so that proper levels of
funding can be evaluated.
Inside the users program, the costs are distributed as follows:
staff support to users: 30%
electricity costs: 27%
misc. 17%
overhead costs: 26%
The recent escalation of power consumption and the associated cost increase has put strain on the budget, and the Director has presented various possibilities to deal with this cost factor (some of the options appear in the User's program section of the report). The Review Committee urges the laboratory management to seek and consider user input on this important matter. This question should be revisited at next year's review after consideration of options by the director.
The users program also does not contain funds for new instrumentation. For that the NHMFL is dependent on the remaining $3 M from the original $11 M awarded by the State of Florida for this purpose. This money will be exhausted before the end of the NSF contract and presents a future problem for the budget.
While it might seem the needs of the users program could be met by further reducing the magnet program, the NHMFL management is appropriately concerned with maintaining its leadership in resistive magnet construction and with the development of its reputation for hybrids and pulsed magnets. Moreover, there are serious materials problems for which the lab needs both to develop an in-house research effort and to foster international collaborations with other magnet laboratories. The tactic of building magnets for others using existing strengths offers a partial solution. It enhances the skills of the in-house staff, and the income (from fully loaded salaries and materials costs) frees up core funds for other uses.
Finally we note the magnetic resonance users program is currently supported by Florida State funds. Since these funds could be used to support the hard-pressed NSF users program, it is essential that the magnetic resonance develop an internationally unique program. This requires a much more focused magnet building program, a suitable in-house leader and the additional outside funding (i.e., from the NIH).
In summary, funding and appropriately allocating sufficient funds for the four primary missions of the NHMFL -- users, new magnets, innovative high field science, and education -- pose a severe test of the NHMFL FUTURE VISION - NMR PROGRAM
The NHMFL management has recognized the difficult issues surrounding optimization of the long term impact of the 900 MHz project and funding of a user program in conjunction with the broad magnetic resonance program represented by the Center for Interdisciplinary Magnetic Resonance (CIMAR). A white paper (self-study) had been commissioned and was made available to the Review Committee. Additional input from the Review Committee was requested. The White Paper outlines an ambitious plan for an integrated program in NMR, EMR, MRI/S and ICR. This paper demonstrates existing strengths in ICR and MRI and growing strength in EMR. It shows, however, some lack of leadership and vision in NMR spectroscopy, which this Review Committee considers to be the area of magnetic resonance in which NHMFL could make its most important contribution.
The most promising new area of applications for NMR is the interface of chemistry, physics, and biology, which is generally described as structural biology. NMR has already made key contributions to structural biology, and improved resolution at higher fields will leverage these contributions. However, completely new types of applications also await higher magnetic fields:
Biological macromolecules in solution (DNA, RNA, proteins) are oriented in high fields, and this gives rise to orientation-dependent couplings that reveal structure. Observation is marginal at fields of current commercial magnets, but effects rise with field squared, becoming a readily accessible new source of structural information at fields accessible by the NHMFL. Most orientation dependent measurements need to be made at several field strengths, and a facility with spectrometers operating to 1.1 GHz would be in great demand for such studies.
Intact cells and viral particles in mixed phase aggregates also are oriented in high magnetic fields. The resulting systems give rise to high resolution rare-spin spectra, without mechanical spinning which is often difficult or impossible for such fragile materials. Homogeneity of these oriented phases increases with field. The higher the field, the better the resolution.
Proteins uniformly labeled with 13C will at high field give rise to 13C NMR spectra in which signals from different types of carbons (carbonyls, aromatics, `-carbons, aliphatic carbons) will behave as though they arise from different types of nuclei. The isotropic chemical shift difference will be so large that homonuclear couplings will behave as heteronuclear couplings. This means that complete structural analysis of proteins in the solid state will eventually be possible. While needs for enrichment in low abundance stable isotopes such as 13C may eventually decrease as experiments with protons become possible, judicious enrichment will initially be essential. The NHMFL is in a particularly good position to support this aspect through involvement of the Stable Isotope Facility at LANL.
Magic-angle spinning experiments on 17O-labeled biological molecules in the solid state will be greatly simplified at high magnetic field because the field-dependent Zeeman interaction will exceed the field-independent quadrupolar interaction. The net result will be simple spectra easily interpreted for an atom central to biochemistry.
In all these examples, the absolutely key ingredient is the high magnetic field. The Review Committee believes that an NMR program (scientists, staff, spectrometers and probes, built around magnets delivering high fields not attainable elsewhere in the world will attract an international community of structural biologists committed to NMR. The enthusiasm for a program in NMR targeted at structural biology and use of very high fields could be tested by a 2-day workshop at the NHMFL with invited speakers highlighting a variety of applications in these areas. Assuming such a workshop confirms our belief, the Review Committee recommends that the primary long-range goals of the NHMFL for NMR should be:
Access to a 45-T hybrid magnet with 1-ppm homogeneity. Use will be aimed at solids NMR applications. The initial hybrid may use a resistive magnet core that is later replaced by a driven high-Tc superconducting core. Strategies of magnet design are best left to the NHMFL, which has the finest magnet-design engineers in the world. the goal is the highest field practical with solids-NMR resolution and economic operation.
A 25-T persistent or driven, superconducting magnet with 0.1-ppm resolution(without shims) and 0.01-ppm resolution (with shims). The magnet will be based on the 900-MHz wide-bore magnet, currently funded for development, and will use inserts to reach first 1.1 GHz and eventually 1.5 GHz. The wide bore of the 900-MHz design is unique and should be exploited.
The recruitment of a vigorous, young, proven scientist (Associate or Full Professor) committed to both structural biology and NMR applications would ensure the sustained focus for the program and provide a de facto program leader. The Review Committee is pleased that Florida State University and the University of Florida have added junior faculty in the biological NMR area who are associated with the Magnet Lab, the Review Committee, however, does not believe that junior faculty members should be put in the position of having to direct user facilities at a time when they are getting their research programs underway.
These goals tap existing programs and make use of magnet technology available nowhere else in the world. If the resulting magnets are coupled to spectrometers designed for structural biology, the combination will be unmatched in the world. The Review Committee realizes that achieving these goals may require reallocation of funds that may delay other NHMFL programs. But with proper direction, new sources of funding can be attracted because of the importance of high-field NMR to structural biology and because of the expected demand for use of the unique tools present in the NHMFL for solving problems in this area.
NSF ANNUAL PROGRESS REVIEW
NATIONAL HIGH MAGNETIC FIELD LABORATORY
SEPTEMBER 16-18, 1996
REVIEW COMMITTEE MEMBERS:
Dr. Bertram Batlogg
Department Head
Bell Laboratories
Lucent Technologies
Dr. Robert D. Kephart
Physicist, Research Division
Fermilab
Prof. John L. Markley
Biochemistry Department
University of Wisconsin
Prof. James H. Prestegard
(chair)
Department of Chemistry
Yale University
Prof. Jacob Schaefer
Department of Chemistry
Washington University
Dr. Kenneth C. Stanfield
Deputy Director
Fermi National Accelerator Lab
Prof. John W. Wilkins
Department of Physics
Ohio State University
Prof. Nai-Chang Yeh
Department of Physics
California Inst. of Technology
Return to NHMFL Home Page
Return to NHMFL Operations Home Page
 |
 |
 |
 |