The MWL120 Real-Time Back-Reflection Laue Camera System quickly orients single crystals in seconds

Quick Highlights

• Ideal replacement for the Polaroid XR-7 back-reflection cassette (film no longer available)
• Earlier model MWL110 systems can be upgraded to 120 capability
• Northstar 7 software indexes cubic, hexagonal, ...triclinic crystal systems and creates stereographic projections
• Provides an accuracy of 0.25 degrees in standard mode and 0.05 degrees in high-resolution mode
• Operates best with the MWL motorized orientation stages
• Ideal for industrial process control, research applications, or academic laboratories

Overview

Utilize the real-time detector, motorized orientation stages, and computer analysis of back-reflection images to quickly characterize or determine the orientation of the lattice planes in a variety of crystal materials such as silicon, gallium arsenide, sapphire, high-temperature superconductors, turbine blades, geological minerals, etc.

NorthStar 7 — the newest version of our orientation software — automatically collects images, finds Laue spots, and indexes most back-reflection Laue images. The "Find extra planes" feature even shows the computed plane position oriented behind the collimator that you can't otherwise see when perfectly oriented! NorthStar 7 is the culmination of numerous years of development work and is a great improvement over other available Laue software, especially in the area of ease of use.

1. Accommodates small variations in the film-to-specimen distance
2. Controls the percentage of Laue spots to be indexed (troublesome points can be ignored, if needed)
3. Tries multiple combinations of starting Laue points and selects the best orientation matrix automatically
4. Features "speed icons" for faster manual work and a "macro" facility for one-touch analysis of crystal orientation. Once set with the right conditions, novice users can achieve expert results quickly with very little effort.

How has the MWL120 improved from the older MWL110 system?

• The NIM bin and all NIM electronics neccessary to the MWL110 system have been miniaturized and built directly into the MWL120 detector housing.
  • Eliminated:
  • 1 NIM bin
  • 8 electronic NIM modules (including an oil-filled gas bubbler)
  • 20+ signal cables
• Detector installation is much simpler with the MWL120 system — just connect a cable from the 12 volt DC laptop-style power supply, one polyflow tube from the gas regulator, and a USB cable from the computer.
• A Field Programmable Gate Array (FPGA) has been designed into the detector. Preamplifier signals are immediately digitized, and from there on, all x-ray signal processing is digital, yielding higher-quality Laue images.
• NorthStar 7 supports 512 x 512 as well as the standard 256 x 256 pixel image formats
• Real-time x-ray data, MEMS gas flow sensor readings, ratemeter information, control of the detector HV etc. take place over a single USB2.0 connection to a Windows 7 PC.
• If you need assistance, you can grant per-instance permission for MWL personnel to share control of your computer over the internet. This way, we can quickly access NorthStar and your detector's diagnostic tools.

Collected Images

Collected image of a silicon crystal

Gallium arsenide real-time image in arbitrary orientation

Germanium real-time image showing 3-fold — or 111 — orientation

Stereographic Projection

Northstar 7 automatically detected 22 spots in this example and indexed the Laue image. The Find Extra Planes feature has been turned on for 111 plane (shown in green circle) so that misorientation statistics are given below the indexed image (the 111 plane is 8.9 degrees out from the center, 8.8 degrees to the left and 1.1 degrees up in rectangular coordinates).

A stereographic projection of this orientation is given on the right. The Stereo red spots are the hkℓs (Miller indices) in the Laue image that also appear in the stereographic projection.

Total time to collect and analyze a Laue pattern? About 6 seconds (5 seconds for Laue image, 1 second analysis time).