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Cambridge Stereoscan scanning electron microscope, series 1

Made 1965-1966

Scanning electron microscopes (SEM) are a vital scientific tool to obtain an image of the finest details of the surface of a wide range of specimens, determine chemical compositions and gather a wide range of other information. From their first commercial availability in 1965, the use, versatility and importance of SEMs has grown. The Cambridge Instrument Company entered the market with the first production run of five SEMs, followed by a batch of twelve, then another of forty. Sales exceeded on...


The scanning electron microscope (SEM) enables the microscopic details of surfaces to be directly examined and photographed with a minimum of preparation. The nature of the particles making up the surface, the elemental composition, the arrangement of atoms in the specimen and certain electronic characteristics of the specimen can also be examined. The name Stereoscan refers to the three-dimensional appearance of the image of the solid bulk specimens examined (unlike the thin replica specimens required for the transmission electron microscope - first marketed in 1939) and to the scanning action of the electron beam which produces the image.

Electron microscopes are scientific instruments that use a beam of highly energetic electrons to examine objects on a very fine scale. Arrays of electromagnets act as lenses to bend and focus the electron beam onto the sample. In the scanning electron microscope (SEM), an extra set of electromagnets scan the electron beam over the specimen. The electrons which are scattered off the specimen are detected to form an image on a cathode ray tube (CRT) visual display unit in much the same way as in a conventional television (Scanning coils in the CRT of the television sweep the electron beam over the phosphorescent screen of the monitor. The beam moves in synchronisation with the scanning signal originating from the video camera in the studio to form the glowing image. In the SEM, the video signal is synchronised to the scanning motion of the electron beam.).

The Stereoscan SEM can resolves details on the specimen which are as small as 20-50 nanometres with a depth of focus that is at least 300 times greater than that of a light microscope. It has a direct reading magnification system providing a useful range of magnifications from 50 to 50,000 times corresponding to scanned areas of 2mm to 2 micrometres square on the specimen.

Added to the SEM in 1981, the energy dispersive x-ray analyser (or spectrometer - EDS) adds chemical microanalysis ability to the microscope. The instrument detects and analyses x-rays emitted from the sample surface when bombarded by the primary electron beam. The elemental composition of features or phases as small as about 1µm can be analysed.

The EDS x-ray detector measures the number of emitted x-rays versus their energy. The energy of the x-ray is characteristic of the element from which the x-ray was emitted. The EDS computer calculates a spectrum of the energy versus relative counts of the detected x-rays. The operator evaluates this information to determine qualitative and quantitative distributions of the elements present in the sampled volume.

Column: The electron gun is located at the top of a highly evacuated metal column with the specimen chamber at the bottom. A high voltage (up to 20 kV) accelerates the electrons which rapidly move down the column through a series of electromagnetic lenses and a set of scanning coils which focus and move the beam as required. Various knobs on the outside of the column control: the position of the electron filament and an aperture; rotate, tilt and position the specimen; and can isolate various parts of the column from the high vacuum generated by the diffusion pump (second stage of the vacuum system) which is located in the cabinet under the column. An energy dispersive unit, made by Link Systems, System 860, was attached to the specimen level of the column in 1981 - this unit detects the spectral energy of x-rays emitted by the specimen during scanning to determine elemental composition. Many electrical cables are still attached to the base plinth of the column.

Display racks (2): One tall wide grey metal cabinet contains two 'display racks' of electronic systems (each rack has one or more blank panels).
1. The left display rack has modules which are labelled, or referred to in the Operator's Manual as, vacuum control unit; visual display unit (a monitor with long persistence phosphors); "Zenith TV Scan" (This module likely was added after purchase. The original Cambridge scan amplifier module was moved to the right display rack); video amplification; magnification unit; and scan generator.

2. The right display rack contains the video monitor (to monitor the video waveform and for general instrument maintenance - has a circular CRT (cathode ray tube) oscilloscope screen with associated signal controls); EHT control unit (extra high tension - high voltage power to the electron gun, photomultiplier, CRT and electron collector); scan amplifier (diagrams in the Operator's Manual show this module was originally in the left rack next to the visual display unit); record display unit (a higher resolution monitor with short persistence phosphors and with a fitting to attach a Polaroid or 35mm camera); three (3) modules to control the electromagnetic lenses - final condenser lens control unit, condenser lens 2 control unit and condenser lens 1 control unit; differentiator (not shown in Operator's Manual - likely used to control the signal to the record display unit); and hourmeter panel. The rotary pump for the first stage of the vacuum system is within the lower right hand side of the main cabinet. The meter of the gun control unit has a maximum reading of 20 kV which indicates this is a series 1 Stereoscan. According to Alan Agar (see references) Series 2 went up to 25 kV and series 2A went to 30 kV accelerating voltage.

Remote power supply racks (2): One tall grey metal cabinet contains the EHT supplies for the CRT and collector (part of the system to detect electrons coming from the specimen); electron gun, filament and bias supply; gun EHT supply; and EHT mains distribution unit. The second tall grey metal cabinet contains three modules of general voltage stabilised power supplies; two modules for the photomultiplier (part of the electron detector) EHT supply; ventilation fan; remote distribution unit; and lens power supply. Each rack has one or more blank panels.

Counter top: A light grey laminated counter top fits into the front of the electron column and display racks to form a convenient workspace for the SEM operator.

Electrical cables and chain:
--- Cardboard box of assorted cables
--- Assorted (9) single cables and cable bundles with various terminations
--- Length of chain (possibly to suspend a heavy cable)

--- Polaroid camera which attaches to the camera record display unit on the right display rack.
--- Blue-grey metal housing with square flat end which attaches to face of record display monitor and round threaded end to which a 35mm camera would be fitted to photograph the image on the record display screen.
--- Final lens lifting tool (plus other special tools in cardboard box listed in Other associated parts)

Energy dispersive unit components (as previously mentioned the energy dispersive detector is mounted to the electron beam column):
--- Freestanding beige metal cabinet contains the electronic control and computational units for the detector
--- Link System video monitor (connects to System 860 power supply - possibly located in beige control unit)
--- Plastic container of 8 inch floppy disks for System 860 analyser (labelled as spectrum and data discs and dated from 30/1/81 to 26/3/86). Some spare discs.
--- Low wood cabinet contains on the top two sliding shelves:
-- Texas Instruments Silent 700 Electronic Data Terminal which prints out the beam scanning data and other position data;
-- Link System X-Y flat bed chart recorder which produces an ink line of x-ray intensity versus line angle.
(The two lower drawers of the cabinet contained operating manuals and other papers which are listed below in Specimen images, manuals and papers.)

Other associated parts:
--- Electronic box labelled KE (Kneesworth Electronic Developments, Royston, Herts, UK) dynamic focus (with three rotating knobs, high-low switch and a power on indicator light), serial number DF2/76525
--- Electronic box (looks like a custom-made unit) with embossed stick-on label "Frame - Board" and other labels for switches and buttons. Perhaps associated with control of video output or photography.
--- Twin power supply type P2654, Roband Electronics Ltd, England (possibly for use with remote power supply rack)
--- Twin power supply type P2655, Roband Electronics Ltd, England (possibly for use with remote power supply rack)
--- Two blank electronic rack cover plates - possibly for remote power supply racks
--- Cardboard box of assorted spare electronic parts, electrical wire, special tools for the SEM, filament roll and connector box

Manuals, papers and specimen images:
--- Manual: "Stereoscan scanning electron microscope series 1, Operator's Handbook, Cat. No. 96113", (no date observed), in original blue vinyl covered ring binder.

--- Manual: "Stereoscan 96113 spare parts list, No. 17" ("17" is handwritten next to "No." at lower right corner of binder cover), (April 1967 is printed on bottom of 1st page), in original blue vinyl covered ring binder which is printed CONFIDENTIAL in red at top right corner.

--- Manual: "'Stereoscan' S4 scanning electron microscope, Technical Manual, TL 1070-TM-96118, Issue 1", (no date observed), in original black vinyl covered 4-ring binder. Cover is printed with "Cambridge Scientific Instruments Limited, scientific and medical division, GEORGE KENT limited" (George Kent Ltd purchased CIC in 1968 and divested its interest c1975. This manual is for a later design of the Stereoscan - the shape of the top of the beam column as shown in a diagram in the manual is different from the Stereoscan series 1. The S4 microscope was introduced in 1970 and had improved resolution (15 nm) over previous models partly due to a more efficient gun.).

--- Manual: "'Stereoscan' scanning electron microscope, Technical manual, TL 1016-TM-96113, Issue 1", (no date observed), photocopy, non-original tan card covered 3-ring binder.

--- Manual: Photocopy of Stereoscan scanning electron microscope schematic electrical diagrams. The diagrams are labelled TL1016/(followed by a page or diagram number). Two pages of handwritten notes and schematic drawings have been added to the binder. In non-original black covered 3-ring binder.

--- Manual: Photocopy of "Field service Instruction, Electronprobe Stereoscan 2A, FS1/EP/35, Feb 1971", with several pages of handwritten notes and drawings. In non-original black covered 3-ring binder.

--- Manual: Photocopy of "Operating Manual and Spare Parts List of Stereoscan Video Presentation Unit, TL 1044-TM-9611318, Issue 5".

--- Manual: Booklet, "Link Systems, System 860 keyboard operation".

--- Manual: Booklet, "Bryans Southern Instruments Ltd, 30000 Series Systems, X-Y Recorder, Description, Operation and Servicing Instructions".

--- Manual: Booklet, "Texas Instruments, Silent 700, electronic data terminals, International model 743 KSR, Data Terminal Operating Instructions, manual No. 995642-9701, Rev. F, Revised 25 January 1980".

--- Manual: Small manual for automatic bellows for camera.

--- Small notebook, handwritten on cover "Valve equivalents", with handwritten entries and electronic schematic drawings on a few pages.

--- Link Systems sliding scale with standard x-ray data.

--- Clear plastic "Chart overlay for Energy dispersive x-ray analysis system", Link Systems Ltd.

--- Pages (9) and rolls (2) of computer printouts of data and settings.

--- Packing sheet from Anderson Digital Equipment for TI 743.

--- Pad of graph paper for recording information regarding energy dispersive x-ray analysis data, intended to be placed on flat-bed of Link System X-Y recorder, with 7 separate sheets marked with an ink line printout of x-ray intensity versus line angle.

--- Polaroid images of samples (a few).

--- Cards (2) with columns of numbers: small card has 4 columns labelled: "Lens; Range 1 printing; Range 2 printing; Range 5 printing" with rows of 1 or 2 columns of numbers within each separately marked column; large card has 3 columns labelled: "Range 1 scale print neg; Range 2 scale print neg; Range 5 scale print neg", with rows of 3 columns of numbers within each separately marked column.

--- Computer printouts (3) of microscope settings and microanalysis.

--- Photocopies of (11) handwritten sheets of data.

--- Reprint of book or journal article "Chapter 4, The Application of Image Analysis Techniques to Scanning Electron Microscopy and Microanalysis", by DW Gibbard, p. 75-92 (most recent bibliographical reference is dated 1972 so the article is post-1972).


Cambridge Instrument Company (CIC) produced the first commercially available scanning electron microscope (SEM) in 1965. CIC had no idea of market interest in the SEM and at first made five production models, four of which were soon sold. During this early period the company launched a publicity campaign and orders began to roll in. A batch of twelve SEMs was produced, then a further forty. Sales climbed to more than 100 per year in the first three years and other companies quickly started making SEMs. JEOL (Japan Electron Optics Laboratory Co, Ltd) was the second on the world market in 1966, six months after CIC, with its JSM (aka JSM-1). CIC claimed that the Japanese instrument was unable to match the Stereoscan's performance until more than two years after its launch.

By the end of 1966 a total of 30 Stereoscans had been installed and more than 100 by the end of 1967. CIC made only 10 to 20 Stereoscan series 1 SEMs (having a 20 kV gun voltage) before producing the series 2 (25 kV) from mid-1966 and 2A (30 kV) from early 1968. As this SEM is a series 1 it was almost certainly one of the first SEMs made in the world between late 1965 and early 1966. It is unclear why a Series 1 unit (instead of a Series 2) was installed in Australia mid-1967.

The design of the Stereoscan SEM is based on principles developed by Professor C.W. Oatley and his colleagues in the Cambridge University Engineering Laboratories. The name Stereoscan refers to the nature of the solid bulk specimens examined (unlike the thin replica specimens required for the previously developed transmission electron microscope) and to the scanning action of the electron probe.

George Kent Ltd purchased CIC in 1968. Metals Research Ltd took over the Cambridge name in 1975, then Leica in 1990 (formed by the merger of Wild/Leitz and Cambridge), which became LEO in 1995 (when Leica started co-operation with Zeiss). LEO became 100% owned by Carl Zeiss in 2001 and in 2004 the name was changed to Carl Zeiss SMT (Nano Technology Systems Division). Cambridge Scientific Instruments is now part of Zeiss.


Gift of Defence Science and Technology Organisation, 2005
25 October, 2005

Cite this Object

Cambridge Stereoscan scanning electron microscope, series 1 2017, Museum of Applied Arts & Sciences, accessed 22 November 2017, <>
{{cite web |url= |title=Cambridge Stereoscan scanning electron microscope, series 1 |author=Museum of Applied Arts & Sciences |access-date=22 November 2017 |publisher=Museum of Applied Arts & Sciences, Australia}}

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