HEXS Low Energy Micro-WDS

Parallel Beam Low Energy WDS for Micro-Volume XRF Microanalysis with SEM/FESEM -extended energy range.

Our original LEXS (Low Energy X-ray Spectrometer) was especially intended for analysis involving low energy x-rays under 2200eV. Now called HEXS, it has been updated with new optics and extended energy range to 3300eV. It boasts the highest sensitivity, peak to background, and precision for analysis of elements of Be through U using low energy x-rays, with a resolution of better than 5eV. HEXS offers the analyst the unique advantage of working with the smallest analyses volumes possible with e-beam by working at very low KV. Lower voltage confines the analysis to a smaller area and provides more flexibility for depth-profiling of samples as well. Unlike other parallel beam WDS, Parallax's HEXS is relatively insensitive to sample topography and focus (see below: "Advantages of HEXS over Polycapillary-based Parallel Beam Spectrometers"). The HEXS can also be manufactured for ultra-high vacuum environments. This version, the UHV-HEXS, does not use a gas flow detector, so there is no leakage of P-10 gas. Click here for more info on UHV.

HEXS is the most advanced parallel beam WDS available combining new x-ray optics and technology making it the highest performing instrument of it’s kind available. Earlier versions of this technology have been licensed to major vendors of parallel beam WDS and Parallax provides the x-ray optics for these as well. Why not get the latest directly from the original designer and manufacturer?

Pricing: HEXS pricing is very competitive and reflects the fact that we designed our own spectrometer and make all our own components (except the diffractors), so we can pass on the savings to you. In the USA, we offer excellent financing for HEXS starting at approximately $1500 / month. Please contact us to learn more , get a quote, run samples, or see a product demonstration.

Mounted View of HEXS
HEXS Mounted on SEM

HEX Kernel
HEXS WDS (Kernel)

Affordable and cost effective
Patented WDS optics (US Patents 5,768,339 and 5,682,415)
Compact, manageable size and weight
Convenient retrofit / new install on ports greater than or equal to 1inch
Analyze Be - U (100eV - 3300eV) using K, L and M lines
Best Low- Energy Performance of WDS spectrometers
Micro-volume analyses using low KV and current
Fast Scanning Speeds – using independent motor drives
Six Diffractors to cover wider energy range

On-board Vacuum Guage
Better P/B and resolution than previous Parallel Beam Spectrometers
Full Quantitative Analysis with mapping and thin film
HEXS can achieve higher resolution in the 490-590eV region than previous Parallel Beam Spectrometers
HEXS is optimized over its full range because it has six diffractors and two detectors
Operates simultaneously with EDS spectrometers

Advantages of HEXS over previous Parallel Beam Spectrometers

HEXS has a 3-cone x-ray collimating optic for higher energy performance.
HEXS carries six diffractors so the user does not have to compromise his low energy performance to get higher energies.
HEXS achieves low background by using two reflection optics and by using a Direction Cosine Filter optic.
The flow proportional counter has a small window so that the leak rate is extremely low. This means there are no issues about using HEXS on an FESEM.
HEXS uses two independent motors (no cam) to move detector and crystal and scans from one energy region to another very quickly.

Advantages of HEXS over Polycapillary-based Parallel Beam Spectrometers

Over most of the range in which it is optimized, HEXS achieves higher count rates than a polycapillary based system.
HEXS is not nearly as sensitive to mis-alignment as is a polycapillary based system so that it can be used at lower magnification. Sample topography is much less an issue for HEXS than a polycapillary based system.
HEXS does not require a complex interface to maintain alignment.

HEXS Technical Data and Applications: Download PDFs

Q. How does HEXS differ from other high resolution x-ray spectrometers?: A. There are several Wavelength Dispersive Spectrometers (WDS) available, but HEXS is fundamentally different both in the way it collects x-rays and in its response to low energy x-rays. Conventional WDS uses curved crystals to disperse and focus the x-rays onto a detector. HEXS collects a large solid angle of x-rays diverging from the sample and re-directs them into a parallel beam incident on various flat dispersing elements and then into a detector. Some WDS systems are optimized for only one or two elements for each diffractor while HEXS is optimized over its entire range of operation. HEXS produces far greater count rates for low energy x-rays than any conventional WDS. Conventional WDS systems emphasize the use of high accelerating voltages for higher Z elements which is useless for thin films while HEXS is designed for low accelerating voltages.

Diagram of Parallel Beam WDS Optics
Q. I have a light element capable EDS system, Why would I need HEXS?: A. There are two answers: resolution and sensitivity. If you want to analyze very thin films or achieve good analytical resolution, you should be using low accelerating voltages (5 KV or less) to avoid exciting the substrate or lower layers. This means you will be using low energy K, L and M lines. There are so many peak overlaps using these lines that EDS is nearly useless while HEXS will easily resolve most of the necessary peaks allowing you to see spectra of films such as TiN, Strontium Titanate on Si, TaSi, and WSi, etc.
For all K lines for Z<15, HEXS is much more sensitive than conventional EDS. Using L, and M lines, HEXS is usually more sensitive than conventional EDS would be using all K lines. When conventional EDS is forced to use L lines, HEXS is almost always more sensitive.
Q. What is the operational energy range of HEXS?: A. Qualitatively: 100 eV to 3300 eV
Q. What options are available?: A. Any orientation of the spectrometer, right or left handed versions, gate valve between spectrometer and SEM and specialized software for your types of samples.
Q. What about leakage of the argon from the flow proportional counter, especially in FESEM systems.: A. We have recently obtained new proportional counter windows with very low leakage rate. We have also replaced the old polypropylene tubing and hose barbs with rigid steel tubing, PEEK tubing and Swage-Lok connectors to nearly eliminate this problem. However, HEXS is available with an optional stand alone pumping system that is used on a system with a gate valve.
Q. If the window fails or there is other vacuum failure in the HEXS, does it shut down the SEM?: A. With the existing optional gate valve, one would simply withdraw the collimator all the way into the HEXS and close the gate valve to isolate the HEXS from the SEM and continue running the SEM while the HEXS is repaired.
Q. What is the best obtainable resolution with HEXS?: A. We have obtained a resolution of <4 eV at the Si (K) line using a PET diffractor. We routinely obtain 5 eV at this energy. By using second order lines, the resolution can be approximately halved at the expense of reducing the peak intensities by 10X.