Model 225 Vacuum Ultrviolet Monochromator
- Minimal Astigmatism and Polarization
- Maximum Flux Density
- Works as Spectral Camera with CCD or Microchannel plate intensifiers
- Optional - Multiple Port Versions
- Optional - Ultra High Vacuum Versions
- Optional - Long 3, 4, 5, 6.6m Focal Length Versions
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the McPherson 15° ... The 225 is a 1m normal incidence (NIM) vacuum ultraviolet monochromator and has 15° between entrance and exit slits. This design, also known as the McPherson 15°, uses a spherical grating to collect and focus energy. It provides maximum flux density with minimal astigmatism and polarization. This is an ideal imaging instrument for use with microchannel plate intensified or CCD array detectors. The 225 features a stainless steel vacuum chamber. This is an very clean design - the wavelength drive is outside the vacuum vessel. It works with single gratings as well as double and triple grating turrets. It can be used to vertically or horizontally disperse. The grating drive automatically focuses to maintain highest performance throughout the range of interest. The 225 normal incidence design is built in vacuum (10^-6 torr) and ultra high vacuum (10^-10 torr) versions, in focal lengths of 1m and longer. Resolving powers of 78,000 have been obtained at 46.4nm with the a 6.65m version. The grating rotation is controlled by our Model 789A-3 digital stepping drive.
Gratings are concave ruled replica or holographic. Single grating with kinematic mount standard and double or triple grating turrets are available options.
| Multiple Ports The Model 225 can be supplied with an additional entrance or exit port for flexibility in optical path configuration. This can simplify work in the vacuum ultraviolet for mounting line spectra calibration sources or ancillary detectors. In the photo at right a Model 225 is prepared for 'semi' ultra high vacuum (UHV) operation. Most of the access and accessory ports use metal seal flanges. Some elements of the drive system and one of the slits uses o-ring seals. This type of instrument usually pumps to the low 10^-7 torr region. This instrument uses two entrance ports, one for calibration, one for the experiment and a single exit port equipped with a vacuum ultraviolet and soft x-ray sensitive CCD. |
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PDF format Data Sheet for:
Model 225 Monochromator
Specifications
McPherson Model 225 1m focal length vacuum ultraviolet Monochromator
| Focal Length | 1m, Normal Incidence (NIM) design |
| Angle between Entrance and Exit Beams | 15 degrees (multiple port positions vary) |
| f / No. | 10.4 |
| Grating Size | 56 x 96mm concave ruled replica or holographic gratings. Single grating with kinematic mount standard, double or triple grating turrets are available, please inquire. |
| Wavelength Accuracy | +/-0.10 nm (with 1200 G/mm grating) |
| Wavelength Reproducibility | +/- 0.005 nm (with 1200 G/mm grating) |
| Focal Plane | 50-mm maximum width, angle for maximum resolution varies with wavelength. Multiply dispersion of the selected grating by width of your CCD or MCP (IN mm) to determine range collected per acquision. |
| Wavelength Range | refer to grating of interest |
Performance of the Model 225 with various gratings:
| Grating (G/mm) (others available) |
3600 |
2400 |
1800 |
1200 |
600 |
300 |
| Wavelength Range from about 30-nm to |
100-nm |
150-nm |
200-nm |
300-nm |
600-nm |
1.2-um |
| Resolution (nm) at 313.1-nm |
0.005 |
0.008 |
0.01 |
0.015 |
0.03 |
0.06 |
| Dispersion (nm/mm) |
0.28 |
0.42 |
0.56 |
0.83 |
1.66 |
3.33 |
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Ultra High Vacuum (UHV) & Contaminant Free The 225 is available in clean, all metal sealed versions offering ultra-high-vacuum (UHV) vacuum pressures to 10^-10 torr. These optical instruments are baked and Residual Gas Analyzer (RGA) certified before shipment and offer the lowest contamination levels. McPherson normal incidence vacuum ultraviolet monochromators set and transfer radiometric standards for national metrology labs around the world. NIST (USA) uses a 2 meter version and the Physikalische Technische Bundesanstalt (PTB, Germany) uses a 1 meter. The 1m is most popular and is also in use at NASA, JPL, LLNL, Sandia and many prestigous laboratories. |
| Focal Plane Arrays The 225 uses produces an nice range of spectra at the focal plane. It can be used as an ultraviolet spectral camera with microchannel plate (MCP) or CCD detectors. The focal plane angle varies from ~1 to 12degrees off normal. Adjustable and fixed angle adapters are available. The Model 225 offers a clean, contaminant free finish for rapid pumping and a clean operating environment - safe for MCPs! |
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Long Focal Length for Exceptional Vacuum Ultraviolet (VUV) Resolving Power The McPherson Normal Incidence Monochromators have been built in focal lengths from 1 to 6.65m. Here is the nominal performance for some popular models. All are optionally available prepared for ultra high vacuum (UHV, 10^-10 torr) operation.
| Focal Length (m) (others available) |
2 |
3 |
5 |
| Range from about 30-nm to |
300-nm |
300-nm |
300-nm |
| Resolution (nm) at 313.1-nm |
0.007 |
0.005 |
0.003 |
| Dispersion (nm/mm) |
0.42 |
0.28 |
0.17 |
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Most of our instruments are used in research. We try to collect the publications of authors which used our instruments in order to provide ideas of applications to our customers. Bellow are few of them:
