PN 350-025004-09
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material and discoloration of the metal plate can occur. Once the measurement has been made, remove
the sample from the crystal and clean the surface of the crystal and the surrounding plate area with a
suitable solvent.
NOTE: The MIRacle high-pressure clamps have the ability to swing sideways for ease of accessing the
crystal surface for cleaning.
Configuration for Solid Sampling
For measurements of soft pliable films and selected solid samples, the sample is placed onto the surface
of the crystal. Since the ATR effect only takes place very close to the surface of the crystal, an intimate
contact has to be made by the sample on the ATR crystal surface. This is achieved by using the pressure
clamp ordered with your MIRacle system. Mount the pressure clamp to the backside of the accessory
using the two alignment dowel pins on top of the MIRacle base and fasten using the two captive
thumbscrews on the clamp frame. With the sample in place on the crystal, lower the pressure tip so that
it is in contact with the sample. With the micrometer clamp or digital readout high-pressure clamp, it is
possible to achieve reproducible sampling by applying the same amount of pressure to your samples.
This is done by using the same settings on the micrometer screw or by using the electronic digital
display, respectively. However, in most cases, it is recommended to apply the maximum pressure
allowed to ensure the best contact and highest sampling sensitivity. The maximum force applied by the
micrometer pressure clamp is 8 pounds (>2000 psi). The maximum force applied by the high-pressure
clamps is 40 pounds (>10,000 psi). The high-pressure clamps have the additional advantage of a slip
clutch mechanism to avoid over tightening.
CAUTION: Care must be used in operating the pressure clamps since the pressure device may slide the
sample over the crystal. If the sample contains grit or abrasive materials, the sample motion may
damage the surface of the crystal while pressure is being applied. Ensure that the sample remains
stationary while applying load to the clamp. In addition, softer ATR materials, such as ZnSe, need to be
handled with care when running hard or sharp sample types. Do not apply the maximum pressure to
these types of samples on softer ATR plates to avoid scratching or denting.
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