McPherson

01/25/2025

Wavelength calibration in the vacuum ultraviolet (VUV) region can be challenging. Many materials are sensitive to energetic ultraviolet light and are easily contaminated. However, in the VUV region it is possible to obtain wavelength calibration and intensity calibration. Intensity, if radiometric data is required in the experiments. In the 5 to 10 eV energy region we can use deuterium and mercury light sources for wavelength calibration. For radiometry, NIST-traceable calibration done at the SURF-III synchrotron allows us to use Silicon photodiodes in this region and more.

Graphics show emission from deuterium and mercury lamps. Some wavelength markers are obvious at 121.5, 161, 184.9 nanometers. Second tile shows A/W response of a calibrated Silicon detector. Data is different at each unique device so these values are only for reference. Both the light sources and the detector may be used in a variety of experimental configurations, for analytics and diagnostics.

For more information about the sources https://lnkd.in/eWaqk5X7 and for detectors https://lnkd.in/eN4wVsJm

12/20/2023

Warmest wishes for the holidays and all of 2024!

Merry Christmas everyone! This is the 10 year anniversary for this particular XKCD cartoon. Have fun trying to sort the various spectra. https://www.explainxkcd.com/wiki/index.php/1308:_Christmas

09/13/2022

Not a nightclub. Not a neon lamp. This is a view into an ultraviolet scrubber. It uses UV light to clean, in our case, optical samples. It is a non-contact technique suitable for use with delicate optical materials and surfaces. The light comes from a mercury discharge. Its UV emissions make ozone and atomic oxygen. Organic contaminant molecules are excited or dissociated by the absorption of the 254 nm wavelength UV. The excited organic contaminants react with the atomic oxygen to form volatile products such as CO2, H2O, etc. The whole process takes place at essentially room temperature in just a few minutes.

Second picture shows the change in transmission of a Barium Fluoride (BaF2) glass window. This significant change was measured by our VUVAS-Spectrophotometer after just a few minutes in our UV scrubber.
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06/29/2022

Precision calibration of absorbance cells in the deep ultraviolet Lyman-alpha

A Lyman-α reference beam from a deuterium lamp is measured with a McPherson 1.33 m scanning monochromator, with the measurement repeated after full system shutdown, purge, and fast pump-down to ~10-6 Torr. The 0.03 nm separation of the Deuterium and Hydrogen peaks is clearly visible and enables this monochromator to definitively calibrate the gas cells intended for space flight missions.

Since gas absorption cells work as attenuators, verifying their function, accuracy, and spectral band pass during development and before spaceflight requires careful calibration—most critically a measure of gas-cell heater current versus transmission. Thus, there is a need for an accurate and stable ground support spectrometer-in this case, the McPherson model 209 vacuum ultraviolet monochromator. High spectral accuracy, repeatability, and measurement stability are critical during development and testing, as the satellite mounted photometer can necessarily only be as accurate as the tools used to test the absorption-cell response.

02/24/2022

Multi-spectral Scene Painting | Double monochromator for development of EO/IR systems and sensor development in intelligence, surveillance and reconnaissance (ISR), and missile defense sectors. Applications including optical counter measures, threat detection, scene painting, sensor training can be accomplished.

McPherson’s double subtractive monochromator 2035DS with interchangeable shaped apertures at intermediate slit position is a useful multi-spectral scene illuminator. The spectral content of the illuminated scene can be varied, or weighted, by the apertures shapes. Optimum throughput may be optimized for most common optical wavelength bands, e.g. UV-Vis, NIR, MWIR and LWIR.

Data sheet available : mcphersoninc.com/systems/spectralcalibration.html

Spectral light illumination is useful for test and evaluation of sensor performance. Generally counter measures, threat detection, scene painting, sensor training, as well as spectral detection may all be accomplished. The emitted bespoke mixed wavelength represent a target or other device emitting any of the UV, VIS, SWIR or MWIR, and LWIR bands. The mixture of bands and intensities is variable to simulate a wide variety of devices or platforms. Coupled to a collimator with target wheel for scene projection, users have the ability to control formation of the scene and its spectral content. If a spatial light modulator is used the wavelength content of the scene can be varied dynamically.

10/27/2021

The ‘Deep UV Spectrophotometer’ from McPherson … now you can see how it works at https://youtu.be/290PSuFhVYI

***The vacuum ultraviolet and 'Deep UV Spectrophotometer' from McPherson is described in this video. See how it works! Elements of the system from sample installation to load lock are described and demonstrated***

Do you test transmittance and reflectance in the Vacuum ? Do you provide optics, coatings, photo resist materials, and substrates for the energetic ultraviolet?
https://youtu.be/290PSuFhVYI

The McPherson deep UV spectrophotometer measures reflectance, transmittance, and scatter properties of samples in the deep ultraviolet wavelength range. The McPherson deep UV spectrophotometers operate from 120 to 350 nanometers and deliver performance, sampling flexibility, and ease-of-use. These instruments have high throughput, strong signal levels and excellent reliability; we have the solution for every laboratory need from routine materials characterization to cutting-edge research and development. Whether you are conducting industrial R&D or working in fundamental science, the spectrophotometer provides proven, trustworthy results.
The McPherson Deep and Vacuum Ultraviolet Spectrophotometer delivers:
• Computer Optimized UV Design
• Vacuum or Operation Available
• Adjustable sample and detector angles
• 115 to 350 nm range (optionally to 800 nm or more)

For more information contact https://www.McPhersonInc.com or call 1-978-256-4512 today.

06/22/2021

spectral test and measurement from McPherson - https://mailchi.mp/8a19a3fea750/spectral-test-and-measurement-from-mcpherson - The summer solstice just happened! About half of 2021 has zoomed right by. Everything is ‘opening’ here, and it is great. It also seems like a . . .

06/20/2021

Diffraction effects and more . . .

Some of the colors we see on creatures such as blue jays and poison-dart frogs aren’t created by pigments at all.

05/05/2021

spectrometers, UV to LWIR from McPherson - https://mailchi.mp/638405f9a948/spectrometers-uv-to-lwir-from-mcpherson - May the 4th be with you has become a thing. Will revenge of the 5th become popular too? Let’s comb the desert for related treasure . . .

05/04/2021

We’re having fun trying out the McPherson 251MX soft x-ray spectrograph with aberration corrected gratings for improved performance AND as special treat, catching the spectra with a new EAGLE 47-10 direct-detection CCD from -Photonics in Northern Ireland. The new 120 g/mm diffraction grating for the Model 251MX provides great wavelength coverage, 50~200 nanometers or more on a 25 mm wide sensor. This Raptor Photonics EAGLE uses a 13.3 mm wide sensor truncates the range from to about 80 nm simultaneous. Still, plenty enough wavelength range to see the complete deuterium emission spectrum. We were pleasantly surprised that this combination of direct-detection CCD and grating allows for simplified setup too!

-X-ray

03/24/2021

spectral characterization from McPherson - https://mailchi.mp/107140a012ad/spectral-characterization-from-mcpherson - testing seekers and imaging sensors at wavelengths from 0.2 to 14 microns! And much more . . .

03/16/2021

Anodes made from solid materials are used in the McPherson electron impact source for photo excitation and physics experiments in the SXR and XUV regime. They are excited by an e-beam with adjustable power. By calculating the pe*******on depth of exciting electrons, we can visualize the volume of emitting area! The electrons interact with the anode material and consequently decrease energy. Elastic and inelastic scatterings along the electron beam are described with the Bethe equation in power law [1]. The pe*******on of incident electrons is determined by ‘electron stopping power’ that decreases with increasing atomic number. Pe*******on depth of incident electrons is given by the Kanaya-Okayama formula [2].

Ready for some fun? = R = 0.0276 * A * Eo^n / (z^0.89 * p)

R pe*******on depth, A atomic weight (g/mole), Eo electron beam energy, Z atomic number, p density (g/cm)^2, and n a constant, ~1.35 when the primary beam energy is < 5 keV, and be 1.67 when > 5 keV

[1] H. Bethe, Handbook of Physics, Springer, Berlin Heidelberg New York, 1933
[2] K. Kanaya, S. Okayama, J. Phys. D., J. Appl. Phys. 1972, 5, 43