University of Minnesota Duluth
Department of Geology at the University of Minnesota Duluth
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Microscopy Lab

We installed a new microscopy lab in 2006 to replace our traditional lab layout with benches of 30-yr-old Zeiss monocular petrographic microscopes. It was a very successful project and the lab is used more than ever for classes and student research. Optical microscopy is not dead! Since then, we’ve had a lot of interest in finding out about the lab structure, both in terms of physical layout and equipment, so here are some notes on what we did. For further information, please feel free to contact John Goodge.

Most of the funds for our lab overhaul were provided by donations from alumni, emeritus faculty and friends of the department. We are very grateful to these individuals. Among other donations, we received individual gifts of $5,000 to $20,000 that went directly toward the purchase of new student microscopes. We also received support from the College of Science and Engineering, and the University for lab renovation and furnishings.

Lab layout. Petrology labs get lots of different uses (rocks, minerals, thin sections, experiments, etc.) and not many departments can afford to have a separate microscopy lab. A common layout for this kind of multi-purpose lab is rows of lab benches. The main problem with this is lack of flexibility and a hindrance to students working with each other. We decided to structure the lab around three microscopy hubs, each constructed as hexagonal tables, with free space at the back of the room for lab benches suitable for hand specimens and other wet or dirty lab exercises. The room layout shows the overall arrangement.

The hexagonal tables were custom built by a local cabinetmaker. The tables are equipped with power outlets for 6 microscopes and have a central open pillar (the “rabbit hole”) that provides access for video cabling and power conduit through the floor. The tables are smaller than ideal for working comfort, but because of the room dimensions we had to stay within code for handicap access. Still, they work great and the clustering of students is fantastic from a teaching standpoint -- students talk to each other a lot more than if strung out along long tables. By being across from one another, they interact more, helping each other to learn. Also, an instructor can wander through the tables much more easily. In the back of the room we have several large tables for laying out rock samples and where we can do "wet" things, so we can keep the scope half as clean as possible.

Video equipment.  Each student microscope is fitted with an analog-type CCD video camera. There is no image capture with these cameras, but rather they port live video feed to an overhead LCD projector. We have two overhead projectors — on the right are feeds from all the video cameras (cabling under the floor and up in the demonstration bench to a 16-channel "multiplexer" with a row of buttons on the front panel so you can easily select the view from any scope); on the left, you can feed in from a laptop, the lab computer, digital camera on the instructor scope, or video camera on the instructor scope. The room layout shows how things are routed. So, there is lots of flexibility to show a combination of live images and presentations. In addition, each microscope hub has a laser pointer so that students can become the instructor right from their microscope position! This is a great advantage in teaching.

Student microscopes. Each microscope has a solid-state CCD video camera mounted on the photo tube. These provide live, analog video-out, and no image capture capability. We decided to stay away from "consumer" style digital cameras because they have too many options for students to mess with, and we were concerned about long-term wear and tear, and being able to keep the same models on the scopes. Digital cameras from vendors are usually very expensive. The Hitachi cameras we bought are very good — the are high resolution and have auto focus, auto white balance, auto contrast, etc. There are some options you can adjust, but basically they are simple to operate. No moving parts! They are also not very big so don't obscure the view to the front. In short, the live analog video provides the best resolution possible with rapid refresh rate and the ability to switch instantly from the view of one scope to another.

Instructor microscope.  In addition to the student scopes, we bought a research-grade microscope for instructor use, and for students to use on classroom or thesis research projects. It has the same CCD video camera as the other scopes and is tied to the mixer for live projection. It also has a separate digital camera for high-resolution image capture to an attached computer, plus some image processing software. This gives instructors and students access to traditional digital image capture as needed. From this microscope there are several projection options – (a) live images from the CCD camera, (b) live images from the digital camera capture window, or (c) presentations from the computer.

SEM Lab Manager