The History and Structure of the Electron Microbeam Analysis Laboratory at Michigan
Essene†, Geological Sciences
John Mansfield, North Campus EMAL & Materials Science and Engineering
To be updated in 2013, John Mansfield May 2nd 2013.
In the mid-60’s Professor Bigelow of the then Department of Materials and Metallurgical Engineering approached the Vice President of the University with a plan to assemble a University-funded electron microbeam laboratory with a transmission electron microscope (TEM), scanning electron microscope (SEM) and electron microprobe. Support included salary lines committed to the laboratory, purchase of equipment, and renovations. An ARL-EMX electron microprobe was purchased for $100,000 with University funds and placed into this facility in 1968. Electron microprobes provide chemical analysis of solid materials down to a scale of a few μm and is critical to research in geology and materials science. The facility, which was housed in the East Engineering Bldg., also contained two scanning electron microscopes (SEMs) and a transmission electron microscope (TEM). All these machines use an electron beam as the basis of their operation and may collectively be described as electron microbeam analytical equipment, the source of the name eventually chosen for the new laboratory. The SEM allows one to view small objects, down to a few tens of nanometers in scale and up to a few mm or so. The TEM allows microstructural and microchemical study thin foils materials. Imaging in the TEM is possible in either diffraction or phase contrast modes. In diffraction contrast the direct imaging of dislocations, twinning, exsolution, antiphase domains, and other submicroscopic features is possible. Phase contrast images contain the “so-called” atomic contrast that is formed by the recombination of the amplitudes and phases of the diffracted electron beam after transit through the sample and these images allow direct imaging of the atomic structure of grain boundaries, dislocations and other defects. Electron diffraction in the TEM allows the determination of the crystal structure, lattice parameters and point and space groups of phases. Additional attachments to the TEM, such as X-ray energy dispersive spectrometers (XEDS) and electron energy loss spectrometers (EELS), allow the energy analysis of scattered electrons or emitted X-rays to measure the chemical composition of the sample and also the electronic structure of phases within the sample.
The facility was run by Professor Bigelow and was supported financially by the Vice President for Research and the Deans of several Colleges. Improvements were made to the electron microbeam instruments over the next dozen years, An XEDS system, which is critical to rapid identification of both standards and unknowns, was added to the electron microprobe and SEM in the mid-70's. On the electron microprobe, implementation of mainframe computer reduction of analytical data and tape deck readouts to eliminate the use of computer cards, kept it current and functioning. New spectrometer crystals improved greatly the capability for analysis of the light elements Na, Mg, Al and Si, and Michigan become the one of the first microbeam laboratories to undertake routine analysis for the ultralight element F. This capability was made possible by Professor Bigelow’s careful maintenance of the vacuum system of the. ARL electron microprobe. His skill also allowed him to maintain the SEM and TEMs in excellent working order. His mastery of vacuum systems, so critical to the effective operation of these early machines, led to Prof. Bigelow writing and publishing a book on vacuum technology that is widely respected and cited today.
By 1980 it was clear that wholly new equipment was needed in the microbeam laboratory. Funds were gathered for a new electron microprobe with improved EDS and back-scattered electron (BSE) imaging capabilities, and automated spectrometers by Professors Essene, Bigelow, and Dr. Allard through Earth Sciences NSF in 1983A new SEM with automatic focus and both EDS and BSE attachments was also funded with the help of Dr. Peter Kaufmann in Botany. Soon thereafter the Engineering College was moved to North Campus, and Professor Bigelow's facility was split into two. The new SEM, electron microprobe and one of the older SEMs was placed in the C.C. Little location, with major renovations provided by LSA, while the relatively new JEOL 100CX STEM (essentially a TEM with additional scanning coils and a electron detector similar to those of an SEM) moved to North Campus. The two locations continued to be operated as a single entity, although the day to day management and finances were now handled through the departments where the instruments were housed. The Department of Geological Science is the home of the Central Campus EMAL and the Department of Materials Science and Engineering is the home of the North Campus branch. Each branch operates on a budget that is kept separate from that of its home department.. At the same time that the two branches of the lab were formed, Professor Ronald Gibala, the recently arrived chair of Materials Science and Engineering, approached the College of Engineering (COE) with a request to help support two new TEMs for the North Campus branch. The COE funded the purchase of two advanced TEMs. One instrument was strictly for analytical studies, a JEOL 2000FX with a scanning transmission system (STEM), XEDS system and an EELS system. The second instrument was for high resolution work, a JEOL 4000EX, and had a TV camera system attached. In addition at this time, a PHI/Perkin Elmer 5400 X-ray Photoelectron spectrometer (XPS) was purchased with funds from the COE and placed in the North Campus facility.
In August of 1987 Dr. John Mansfield, a Research Scientist, was hired as the manager of the North Campus branch of the laboratory and under his tutelage the North Campus facility has been highly successful in obtaining new equipment. When Mansfield arrived, the facility contained the three TEMs and the XPS system. The laboratory current contains three TEMs, four SEMs (two of which are also focused ion beam workstations), a new XPS system, a scanning probe microscope and a Nanoindenter system In fact, both branches of EMAL strive to replace their equipment as it becomes obsolete, usually through NSF grants obtained with substantial matching funds from the Office of Vice-President for Research (OVPR) as well as support from the Colleges of Engineering and of LSA and individual matching from users and their departments. In 1986 a new Philips CM-12 STEM was purchased through the efforts of Prof. Donald R. Peacor, Prof. Bigelow, and others and placed in the Central Campus facility. This was a Philips CM12, an analytical instrument with an XEDS detector and a STEM system. In 1989, Professor Kim Ford-Hayes, a new professor of Civil and Environmental Engineering, obtained funds to purchase a Digital Instruments Scanning Probe Microscope. Professor David Martin of Materials Science and Engineering also contributed funds to this purchase and the instrument was located in the North Campus EMAL. In 1990 the Amoco Foundation donated funds to the College of Engineering that were directed towards the purchase of an ElectroScan E3 Environmental SEM, an instrument that is capable of imaging samples in their natural state and even wet materials. In 1995 the Department of Materials Science and Engineering invested in a scanning electron microscope for teaching, this instrument, a Philips XL30, was initially installed in EMAL while a suitable location for it was prepared in the MSE department. When the XL30 moved to the Dow Building eighteen months later it was replaced by a field emission version of the same instrument, the funding for which came from a number of engineering faculty. In 1997, the Central Campus SEM was replaced by a new, fully digital, Hitachi variable-pressure S3200 SEM with BSE and EDS capabilities. Also in 1997, GTE-Valenite donated a PHI/Perkin Elmer 600 Scanning Auger Microprobe to the North Campus facility, this instrument was subsequently upgraded to a model 660 with a donation from Dow Corning. In 1998 the Digital Instruments Scanning Probe was updated by Professors Martin and Gibala and a second microscope installed to house a Triboscope™ mechanical indenting system. Also in 1997, Professor David Martin, with co-PIs Dr. Mansfield and Professors Gary Was, Johannes Schwank and Xiaoqing Pan, secured funding from NSF, via a Major Research Instrumentation proposal, for a Gatan Imaging Filter which was installed on EMAL’s JEOL 4000EX in the North Campus EMAL.
In 1998, Dr. Mansfield with co-PIs Professors Pan, Peacor, Ewing and Dr. Wang (the latter two from Nuclear Engineering and Radiological Sciences) submitted a successful proposal to NSF (DMR 98-71177) for a field emission gun analytical electron microscope, a JEOL 2010F. This instrument was delivered in February of 2000 and is still in use in the North Campus facility. It is a scanning transmission electron microscope with XEDS, conventional bright and dark field imaging and high angle annular dark field (HAADF) imaging. The Gatan Image Filter from the 4000EX was relocated and attached to this new instrument. The 2010F replaced the JEOL 2000FX.
In the Central Campus EMAL, the CAMECA MBX electron microprobe has remained operational to the present day. It has been updated with digitized imaging, new pseudocrystals, and new software written and installed by Carl Henderson, the Central Campus EMAL manager. By 1990 it became clear that four spectrometers were needed in order to be able to analyze REE-rich minerals and other phases with 15-20 elements, such as allanite, xenotime, monazite, effectively. In 1992, Professor Essene raised $42,000 from the Office of Vice-President for Research matched by the Central Campus EMAL to purchase a second three-spectrometer MBX electron microprobe from MIT. Its two vertical spectrometers were added to the first MBX and the extra horizontal spectrometer was placed on the MIT MBX machine, which also received Mr. Henderson’s updated software system. Both machines were maintained by Carl Henderson until Professor Essene submitted a successful proposal to NSF in 1999 for a new fully automated electron microprobe. At that time a Cameca SX100 probe was installed and the old MIT MBX instrument was mothballed and was kept for its parts. Probe work in EMAL is principally performed on the SX100, with the original MBX instrument as a backup.
In 2003, a successful Materials Research Instrumentation program proposal, written Dr. Mansfield and Prof. Ewing, with Prof. Ewing as PI and Mansfield and Professors Clarke, Pavlidis and Pollock as Co-PIs, funded the acquisition of two dual column focused ion beam workstations (FIBs). The dual column FIB is an instrument that combines an electron-optical column with an ion-optical column to allow the modification and analysis of materials on the submicron basis. Two instruments from FEI were purchased, an FEI Nova NanoLab with a field emission electron gun and an FEI Quanta 3D with a tungsten electron gun and environmental scanning electron microscope capability.
In the same year, John Mansfield wrote a proposal for a new high resolution TEM to the Instrumentation for Materials Research program in the Division of Materials Research at NSF with co-PIs Eric Essene, David Martin and Lumin Wang. The resulting funding was used to replace the aging JEOL 4000EX which was over 17 years old.In 2004, Joerg Lahann, a new professor in Chemical Engineering lead a proposal with Co-PIs Schwank, Martin, Mansfield and Takayama, to secure funds for a new X-ray Photoelectron Spectrometer to replace the original Perkin Elmer/PHI 5400. The new instrument, a Kratos Analytical Axis-Ultra with imaging and high resolution spectroscopic capabilities was installed in 2005.
In 2007, Xiaoqing Pan with Co-PIs Clarke, Mansfield, Ewing and Wang wrote another successful MRI proposal for an aberration corrected ultra high resolution transmission electron microscope. In the Fall of 2008, after a lengthy evaluation procedure, a JEOL 3011 R05 was ordered. This instrument, a cold field emission gun, dual Cs-Corrected scanning transmission/transmission electron microscope with XEDS, imaging filter and HAADF detectors will be installed in August of 2011.
In 2011, two proposals were submitted to NSF from EMAL users. EMAL Associate Director Youxue Zhang, a professor in Geological Sciences, led a group of principally Central Campus users in an effort to secure funding to replace the Hitachi S3200SEM with a modern field emission gun instrument with cathodoluminescence and XEDS systems. New Assistant Professor Emmanuelle Marquis, of Materials Science and Engineering, together with Co-PIs Alan Hunt, Cagliyan Kurdak, John Mansfield and Lumin Wang, submitted a proposal for a further dual column FIB with XEDS, electron backscattered diffraction and cathodoluminescence systems. As of February 2011, these proposals are still under review.
The EMAL Management Structure
EMAL has a well-organized structure and management that allows it to run effectively and efficiently, the details of which are outlined below.
EMAL Executive Committee
The EMAL Executive Committee guides the long-term strategy and development of the laboratory. The EMAL structure was established by the OVPR so that all University users and many visitors would have access to the equipment therein. The only restriction that might be placed on potential users is the appropriateness of the equipment to the problem at hand, which is addressed in initial discussions with the EMAL Staff and, if necessary, the executive committee.. Prof. Bigelow initially was placed in charge of the EMAL laboratories until his retirement from the lab directorship in 1987. Prof. Donald Peacor took over from Bigelow as Lab Director and a formal Executive Committee was formed, it consisted of two members from the Central campus Lab, Don Peacor, the director and Prof. Eric Essene of Geological Sciences and Profs Johannes Schwank of Chemical Engineering and Gary Was of Nuclear Engineering and Radiological Sciences. Dr. John Mansfield, as the North Campus Manager, was also included on the committee for most meetings. Shortly after Don Peacor retired in 2000, Professor Ron Gibala was appointed as director for a period of two and a half years. At that time Gary Was had become Associate Dean for Research in the College of Engineering and so he stepped down from the executive committee and Johannes Schwank retired from the committee. Profs Xiaoqing Pan, Lumin Wang and Megan Aronson became members of the Executive Committee. Pan and Wang represented North Campus interests and Aronson, together with long standing member Essene, represented Central Campus. When Ron Gibala stepped down and Megan Aronson left the university, Lumin Wang became director and Prof. Adam Matzger of Chemistry was elected to be the new Central Campus representative and Dr. John Mansfield the North Campus manager became the second North Campus representative. When Lumin Wang completed his tenure as director in 2009, Xiaoqing Pan became director and Lumin continued as North Campus representative. After the sad passing of the the long serving Eric Essene, Prof. Youxue Zhang of Geological Sciences became the new representative for Central Campus.The EMALs are currently directed by Professor Xiaoqing Pan, and there are now two Associate Directors, Dr. John Mansfield (EMAL and MSE) and Professor Youxue Zhang (GS), and two committee members, Professor Adam Matzger and Professor Lumin Wang. Staff Carl Henderson, a senior research laboratory specialist is responsible for managing the Central Campus laboratory. He earned his bachelor’s degree from Dartmouth College in 1981. He joined the University of Michigan in 1984 and is an expert in electron microprobe analysis. He is a frequent collaborator on a wide array of electron microprobe based publications. Henderson is supported by Dr. Anja Schleicher, a Visiting Assistant Research Scientist in Geological Sciences and she provides assistance on the Central Campus TEM and XRD systems. John Mansfield, an associate research scientist, manages the North Campus EMAL. Mansfield has over 30 years experience in the field of electron microscopy and related microanalysis. Mansfield earned his PhD at the University of Bristol in the UK in 1983 under the supervision of John Steeds. His post-doctoral studies took him to Argonne National Laboratory and the Microelectronics Center of North Carolina. Mansfield has managed the North Campus EMAL for over twenty years. Mansfield is assisted by 2 full-time PhD-level scientists. The first, Kai Sun, an assistant research scientist, earned his PhD from Dalian University of Technology, Dalian, China in 1998. The second, Haiping Sun, a research electron microscopist, earned his PhD from the University of Michigan, Ann Arbor, Michigan in 2005. Both have extensive research experience of materials characterization by electron microscopy. All three full-time staff actively collaborate with EMAL users, designing experiments, acquiring and analyzing data. They also, when time permits, have their own research efforts. Instrument Recharge Rates & Maintenance The expenses incurred in maintaining EMAL are offset by recharges to the individual investigator’s research grants. Currently the instruments are recharged at a rate of $39 per hour. The charges are calculated to cover the operation and maintenance of the laboratory and do not cover the salaries of the staff of the facility. The charges are reviewed and set annually by the U of M Financial Operations (following the guidelines set by the Federal sponsors of the research grants that use the facility). Some of the equipment in EMAL is not maintained on a service contract; the experience and abilities of Henderson, Mansfield, K. Sun and H. Sun are sufficient to maintain the instruments in top working order. However, the JEOL, Cameca and FEI instruments are especially heavily used and it is imperative that they are available for use virtually continuously. This equipment is maintained on manufacturers’ service contracts. User Training The staff of EMAL is responsible for the training of users and advising potential users of the most suitable equipment for their needs. There are two courses, one in Geological Sciences (Mineralogical Techniques of Analysis) and one in MSE (Introduction to Electron Microscopy and Microanalysis), which provide extensive background in the theory and operation of the EMAL equipment. The Geological Sciences course, currently taught by Professor Udo Becker or Professor Rod Ewing, includes sections on TEM, STEM, SEM, electron microprobe analysis, XPS and SPM. Xiaoqing Pan currently teaches the MSE course. The course focuses on TEM, STEM, SEM, electron diffraction, and introduces HRTEM, CBED, EDS, EELS, SPM and XPS. Both courses feature extensive laboratory components and the students all have hands-on experience on the EMAL instruments. Since EMAL has in excess of 600 users each year, there are frequent periods, between the formal courses, during which the laboratory staff trains users either on a one-to-one basis or in small groups. The laboratory staff monitors the users’ abilities and determines when a user can use the equipment independently without oversight. Staff also aid in specimen preparation, data analysis and interpretation.