The materials used are the best available at the time of purchase
Material is obtained from a wide variety of sources from all over the world and is dependent on
customers requirements and available price. It is only obtained from bona-fide chemical and (SRM) standards material suppliers. Where possible certificates of analysis and Safety Data Sheets are obtained.
All information regarding source of material, analysis & Safety Data Information is logged and kept on file
indefinitely. Data of receipt and date of usage is recorded.
Minerals are obtained from a variety of sources and suppliers. Their original location being recorded. The bulk material is split into two halves. One half is then split into five lots of material and
then sent to at least five University "Earth Science Laboratories" More than one type of analysis is employed i.e. Magnetite was analyzed using X-Ray diffraction, Energy Dispersive X-Ray analysis and
ICPAES. The results were checked against a known Magnetite sample.
metals are obtained from suppliers in as pure a form as possible. They range from:
Germanium (Ge) @ 100% pure
Hafnium (Hf) @ 97% Hf, 2.7% Zr with a range of impurities listed in
Compounds come in two categories:
Those which are supplied with certificates showing types of analysis used i.e. x-ray diffraction and Spectrographic analysis.
2. Those compounds where the analysis has been theoretically calculated.
Rare Earth's are
supplied with certificates of analysis and an indication of any difficulties experienced in the production of the material. i.e. inability to produce a single phase material.
Standard Reference Materials (SRM).
Material is obtained
from NIST (formally NBS), MBH, ARMII, BCS & BAS EURO as Standard Reference Material. We can obtain material form other world standard sources as well. These suppliers obtain material from specialist producers all
over the world and some of them have it reanalyzed to confirm the original analysis. This material is supplied with full analysis, tractability and homogeneity certification.
Each order when received and confirmed is allocated a number. This number is recorded for ever at MAC. It is stamped on the base of all but the smallest single standards and at
any time we can access our data base on the history of the order.
The materials are prepared and embedded in their blocks, usually in energy order, with epoxy resin or
Woods metal. Block material can be either Brass, 304 Stainless Steel, Aluminium or Carbon Resin. The block size and shape is to the customers specification. The blocks are embedded inside a laminar flow cabinet fitted
with filters. The epoxy resin suffers no shrinkage
The resin is left to set overnight. When dry the block is ground down on a series of wet and dry papers
with careful washing and inspection at each stage.
After grinding the block is placed on an iron lapping plate, and a series of diamond paste form 14Ám,
6Ám to 3Ám are used on an automatic lapping machine with varying grades of cloths and nap to polish the block and standards on the same plane. In between each stage of polishing the block is washed in degreasing agent
and examined optically to make sure that scratches remaining from previous grades have been removed, and that the standards are as flat as can be obtained within the confines of the different hardness of the materials
The final polishing stage is carried out by hand using experienced personnel, using 1Ám and 0.25Ám diamond paste. When the polishing stage is considered optically to be complete, the block
is washed in an ultrasonic bath and coated with 10 to 20nm of Carbon. This is to reduce charging under the electron beam by making the surface conducting.
Optical, SEM, EDX check.
After coating above, the block of standards is checked for scratches impurities and standard of polish under a good optical microscope.
block of standards is then transferred to the Scanning Electron Microscope (SEM) with Energy Dispersive X-Ray analyzer (EDX) and a spectrum is accumulated for 50 to 100 sec's on all standards material. Each peak is
identified for correct KeV using the K, L and M X-Ray lines with and excitation potential on the electron gun of 15KV. Count rates of 2000 to 2500 cps are selected and the dead time is kept to a minimum i.e. less than
20%. Particular attention is paid to any artifacts that may be present. The block, if found to be OK is packed and shipped to the customer with a Registration numbered book containing Certificates of Analysis, location
map, advice on the care of the block, signed test certificate and an estimated time for a re-polish and re-coat of Carbon. A copy of all this information is held at MAC for ever! A copy of the registered book can be
obtained any time in the future.
We are able to trace all of our standards blocks back over the last 16 years to the first one produced by MAC and still provide certificates of analysis and layout plans for them. In
order for us to supply the customer with the security that we can be as certain as possible that we know what material was used and where we obtained it from we were aware of the need to have a Quality Management
System. In view of this we obtained certification to BS EN ISO 9002:1994 in April 1997 and are currently registered with National Quality Assurance Ltd. (NQA). Our certificate number is 8960. This attention to detail
has gained MAC a reputation for unsurpassed technical excellence during the past 16 years.