NHMFL Users Committee Report
Meeting of November 14-15, 1997 at LANL
January 7, 1998

The Users Committee met at Los Alamos November 14-15, 1997.

Members present: M. Aronson, B. Boebbinger, C. Agosta, W.G. Clark, C.H. Perry, J. Furdyna, R.ÝGoodrich, M. Naughton, E. Zuiderweg.

Members absent: P.M. Chaikin, L. Kevan, R.R. Vold.

The agenda and discussion covered a very broad spectrum of issues. Our comments and recommendations resulting from these discussions are covered in this report.

GENERAL

Much of our discussion centered upon issues of balance between new magnet facilities, new instrumentation, magnet operations, and support for external users. This is a difficult issue that requires constant attention and for which there is no simple answer. Several of our detailed comments and recommendations are covered later in this report. We have, however, two general recommendations to transmit: (1) The level of external user support should be increased further and (2) new resistive/hybrid magnet designs with relatively low power requirements that optimize the number of experiments that can run simultaneously should be favored over those whose power consumption reduces significantly the number of concurrent measurements.

In regard to the second point, we recognize that there are instances where it is important to obtain a peak level of performance at the facility, even when it is at the expense of reducing or excluding concurrent measurements. Our view on this point is that when this kind of exclusion is an issue, the threshold for creating and using such a magnet system should be substantially higher than it is for ones whose exclusion effect is less serious.

The Committee recommends exploring a new option for increased user support. It is for the Lab to sponsor partial (1/3 to 1/2) postdoc funding towards sharing a postdoc with one of more research teams from universities. The participating university group(s) would provide the rest of the postdoctoral salary, presumably from an extramurally funded grant. This activity would bring into the lab new Ph.D's with new ideas, insight and expertise, at something like 1/3 to 1/2 the cost to the lab.

While the PFF will require additional positions as its user base grows, the recent additions of postdocs specializing in susceptibility and magnetotransport, plus one technician line, have clearly made a difference in internal and external productivity.

THANKS

We thank and commend Larry Campbell for the leadership and service he has provided as Director of the Pulsed Field Facility at LANL.

We also acknowledge the excellent work of Dr. Chuck Mielke, who has left his postdoc position at the PFF for a permanent staff position at LANL. We recommend that the Laboratory use Dr. Mielke as a model for the skill level, commitment, attitude and enthusiasm desired by the user community in these positions. Thanks and good Luck, Chuck.

USERS COMMITTEE ISSUES

We recommend that the NHMFL develop a strategy to include on the Users Committee a broader active representation that includes both industry and chemical/biological magnetic resonance.

For future meetings, we would like the presentations at User Committee Meetings to have a balance between scientific and technological achievements.

In order to use meeting time more effectively, we request that summaries of new capabilities and personnel, magnet usage statistics for ALL THREE SITES, and the list of scientific highlights be provided to each member of the Users Committee at least one week prior to the meeting. The format (or an equivalent one) of magnet usage used by the Tallahassee lab should be used by the other two in presenting their statistics of use to the Committee.

MEETINGS, PUBLIC RELATIONS, ETC.

Based upon the success of its information booth, we recommend that the NHMFL discontinue its open meeting at the March Meeting of the American Physical Society.

In regard to advertising the strengths of the Laboratory, we suggest that there be a notable display at the PPHMF-3 conference flaunting the scientific and technical accomplishments of the lab.

Moreover, we suggest holding a brainstorm session (or sessions) during the conference involving the Executive, Users and External Advisors Committees, as well as other interested parties, on critical issues of the lab, in preparation for the renewal proposal. The users' committee wishes to be involved in and contribute to this renewal proposal; the lab should feel free to call on its members for input.

PROPOSAL REVIEW

We view the described proposal review process very positively, as it has the potential for making magnet access equitable and timely, while improving the overall quality of experiments. We also have two recommendations for proposal and scheduling policy:

(1) The Proposal Review Committee should limit the user queues for each magnet at each of the three sites to no more than three months. At the end of each period, the pending proposals for magnet time of all users, including those not receiving magnet time during the current period, would be considered for the following period. (This approach has worked well at other large facilities).

(2) While some flexibility should still be given to the Pulsed Field Facility, we would like to see a constantly increasing use of serious external review of proposals. Experiments which require the joint scheduling of the 20 T superconducting magnet with one of the pulsed field magnets should receive priority over those which use the 20 T magnet exclusively. We also request that all NHMFL users receive a request for proposals for experiments at all three sites via email as soon as possible. The solicitation should include references to the NHMFL web page, for more information about the latest experimental capabilities and to obtain proposal submission forms.

POSTDOCTORAL PERSONNEL ISSUE AT LANL

One of the responses of the Laboratories to the need for additional external user support has been to expand the number of postdoctoral researchers who are available to assist external users. We are very favorably impressed with the commitment of the current scientist and postdoc staff to users. Their addition has provided a big boost to the operation of the laboratory.

There are, however, some problems with the current system at Los Alamos in regard to career development on the part of the postdocs. If someone is hired as a postdoc, he or she should be guaranteed a certain percentage of time for research, as opposed to providing full-time service to external users. Here, we discuss that problem and suggest a mode of operation that could mitigate it.

We see that the postdocs are being worked so hard in support of users that many of them have insufficient time or energy remaining to carry out their own research programs. We also perceive that there are other technical staff who have been involved in laboratory development whose duties could be redirected to user support. For this reason, we support the policy, originally proposed by Alex Lacerda, that a set of postdoc/technician teams be developed. In this scenario, the user in a particular measurement area would have available a postdoc who knows the science involved and the measurement technique to set up the data taking run. In addition there would be available a knowledgeable technician to assist with carrying out of the measurements. Such an arrangement would provide the postdocs with additional time to pursue their own research (instead of, for example, spending many hours of simply being there to fire shots on a pulsed magnet). It would also provide the user with knowledgeable technical support.

We realize that the implementation of this plan must be a minimal cost situation. Therefore, we propose that part of the staff of the current machine shop be redirected to postdoc/technician teams. Work that is produced in this shop can be contracted out to other LANL machine shops and this increased outside cost offset by a reduction in the total number of technical staff support from four to three. Since a scientist staff position is now devoted to magnetization measurement, theareas of greatest need this postdoc/technician team support are optics, far infrared, and transport.

DEVELOPMENT PROJECTS

1. 900 MHz HIGH RESOLUTION NMR SYSTEM - Cognizant of the emphasis placed upon biological NMR in the NSF site visit report, the committee endorses the NHMFL plans to go forward with the construction of the 900 MHz high homogeneity NMR superconducting magnet. The wide-bore design of this magnet will distinguish it from commercial magnets of approximately the same field strength that might become available in the near future. This design will allow the construction of specialty probes, such as those containing high Tc superconducting transmitter/receiver coils. In addition, the committee recognizes that 900 MHz / 1 GHz NMR magnets will demand a price of 8-10 million dollars per system, so that it is unlikely that individual researchers/universities will be able to afford such systems. Therefore, such systems will become available only as regional facilities, of which Tallahassee will be one. The Committee also applauds the NHMFL's initiative to plan a comprehensive facility plan (collaboratorium).

2. SPECIALTY MAGNET - The Users' Committee reiterates its view that the user community strongly desires a 30-T-class "specialty" magnet which allows for inserts which can provide substantial field modulation and field gradients, with some user input into the insert parameters. Over the years, it seems that this magnet keeps getting put on a back burner, due either to manpower shortages or lack of resolve. While we recognize that the specialty magnet will set no maximum field records, it will significantly enhance the scientific output of the laboratory. We are pleased to see that it is on track for late 1998 operation.

3. SERIES-CONNECTED (SCH) HYBRID MAGNETS - The prospects for a new generation of power-efficient SCH magnets appears very promising. They have the potential for operation at very high magnetic fields at moderate power levels that do not exclude other uses from concurrent operation at Tallahassee. It appears that in comparison with purely resistive magnets, their most obvious risk is the three-to-six years expected for their much larger capital cost to be balanced by their substantially lower operating cost. Once this crossover is achieved, their low operating costs should reap dividends for many additional years. Because of the great promise of this concept, we recommend that the Laboratory proceed expeditiously with their design and locating the capital resources needed for their construction.

We also recommend that the user community be invited to participate in a meaningful way in the deliberations that determine which SCH design parameters are given the highest priority.

PULSED FIELD FACILITY ISSUES

We are very enthusiastic about the prospects for doing experiments using the new 60 T quasi- continuous magnet at Los Alamos and congratulate the design team for a job well done. We also look forward he the 100 T magnet that will be growing out of this project. In this section we discuss issues that should be addressed to obtain the maximal productivity from this unique facility.

There are still a few bugs in the 60 T system, which is understandable given the complexity of the project. The highest priority should be given to fix the current monitoring system.

The second problem that must be addressed is the field oscillations that occur when the magnet is being run by the power supply. (The oscillations go away when the magnet is crow barred.) We strongly endorse a solution to the oscillation problem, which we understand can be solved by installing and driving a set of compensation coils to stabilize the field. Although this solution is expensive, the experiments the users have planned for the 60 T magnet require that the problem be solved. As a side benefit, these compensation coils also could be used to modulate the field in a controlled fashion, which is a need for a number of users.

We are cautiously optimistic about the possibility of developing a100 T single turn magnet system. Our concern is where the resources will be found for developing and operating this project. We urge that it obtain very strong scientific justification before substantial funds are expended on it. Perhaps the LANL DX Division can provide support for its development given its use as a staging magnet for the explosive field generation runs.

The Users Committee applauds the success of the Dirac and other explosive magnetic field generator experiments. We urge the Laboratory to carefully select the last experiments of the Dirac series to maximize their scientific return.

As user demand for the pulsed magnetic field laboratory increases, better facilities for staging and testing user experiments are needed. We suggest priority be given for use of the 20 T superconducting magnet to the users of the pulsed field facilities when it will help to make the pulsed field experiments operate more effectively.

That there are major, but as yet untapped opportunities for the 50T and 60T pulsed magnets in the area of far-infrared (FIR) magnetospectroscopy. Excellent CO2-pumped lasers operating at wavelengths between 50 and 2000 micrometers are commercially available. Acquisition of such a source would open the way to experiments in the area of cyclotron resonance, magnetoplasma resonance, and a host of high-field magnetic resonances (paramagnetic, ferromagnetic,and antiferromagnetic). One example is cyclotron resonance in inorganic semiconductors, which is simply not possible to observe at "ordinary" fields because of the large masses and large resonance linewidths characteristic. There are many other examples, including the effect of the magnetic field on the effective mass and polaronic effects and using the field to modify exchange interaction effects. Facilities for carrying out such experiments already exist in Japan. Although the U.S. has impressive strengths in pulsed magnetic fields, it is conspicuously lacking in having a presence in this important field.
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