Pike ATRMax II Variable Angle ATR


The ATRMax II is a high throughput, variable angle horizontal ATR accessory. The design employs a unique optical layout which enables samples to be analyzed over a range of incident angles from 25 to 65 degrees.

  • Selectable angle of incidence
  • 3-12 reflections
  • Flat and trough plates
  • Motorized and temperature controlled options




Proprietary beam path within the ATRMax II FTIR sampling accessory

The ATRMax II is a high throughput, variable angle horizontal ATR accessory developed for use in FTIR spectrometers. The design employs a unique optical layout (U.S. patent 5,105,196) which enables samples to be analyzed over a range of incident angles (from 25 to 65 degrees). Variable angle of incidence provides experimental control over the depth of penetration of an IR beam into the sample and the number of beam reflections in the ATR crystal, which in turn determines the effective IR beam pathlength for a given experiment. Adjustable angle of incidence allows immediate optimization of measurements for otherwise difficult to analyze samples. The ATRMax can be used for depth profiling studies where spectral composition can be analyzed relative to depth of penetration as the angle of incidence is changed.

Two crystal configurations, flat plate and trough plate, are available for the ATRMax II. The flat plate design is used for the analysis of coatings, films and solids. Typical applications include depth profiling studies and optimization of ATR spectral data. A sample clamp is required to provide intimate contact between the sample and crystal surface.


Liquid cough syrup sample run with the ATRMax II accessory using the
ZnSe trough plate and a 40 degree angle of incidence.

The trough crystal plate is recommended for use with liquids, pastes and powdered samples. Typical applications include the analysis of oils, detergents, and other liquid samples. A volatiles cover and powder press are included with the ATRMax II for use with this crystal mount.

The ATR crystals for the ATRMax II are of trapezoidal shape and 56 mm long, 10 mm wide and 4 mm thick. Standard bevel angles at each end of the crystal are available in 30, 45, and 60 degree versions. Coupling the variable angle of incidence of the ATRMax II with the variable crystal face angles, one can select effective angle of incidence ranging from 25 to 65 degrees and the range in number of reflections from 3 to 12. 

AutoPRO Software control of ATRMax angle of incidence

The variable angle of incidence can be controlled manually or with an optional motorized attachment for the ATRMax II. Multiple ATR measurements at different angles of incidence can be fully automated with the motorized version and PIKE Technologies AutoPRO software. Automation streamlines the collection of spectra from multiple angles of incidence. With the automated ATRMax accessory, the entire experiment can be pre-programmed and executed by the computer.

Advantages of the automated ATRMax II system include:

  • Computer controlled precision, accuracy and repeatability
  • Synchronization of mirror position changes with collection of sample spectra
  • Full integration of the PIKE Technologies AutoPRO software with FTIR spectrometer programs
  • Tailor made, predefined experiments
  • “Hands-free” operation



For special applications where you need to look at coatings on an ATR crystal, PIKE Technologies offers the RCPlate™ option. The new RCPlate is designed to enable easy removal and reinsertion of the ATR crystal. Applications include analysis of coatings, mono-molecular layers, or bio-films deposited directly upon the ATR crystal. With these new RCPlates, it is easy to collect the background spectrum on the clean crystal, remove the ATR crystal from the RCPlate, coat the crystal and then reposition it into the RCPlate to collect the sample spectrum.


Optional resistively heated crystal
plates are available for the ATRMax II
trough, flat and flow cell versions.
These heated crystal plates are driven
using PIKE Technologies Temperature
Controllers available in digital and
digital PC versions. The digital PC
version includes PIKE TempPRO software
for graphical setup and data
collection for kinetic experiments.

Ambient temperature and liquidjacketed
flow cells are available for
the ATRMax II. With the liquid-jacketed
version one can measure samples at
heated or cooled temperatures using
a circulating water bath.


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