670mm focal length monochromator / spectrometer, McPherson Model 207

High Throughput in Low Light Applications

The Model 207 offers the user the most throughput and fastest aperture in a long focal length monochromator. This is ideal for photoluminescence and Raman spectroscopy applications. It is also available in a vacuum compatible version. Used in air and with a selection of gratings, the spectral range of the 207 extends from 185 nanometersm to 20 microns or more. Under vacuum range is extended down to 105 nm (depends on the grating.) Multiple ports are available for mounting accessories or CCD detectors, etc. McPherson SNAP IN gratings allow the alignment-free use of many different gratings. Easily view a wider spectral range or obtain higher resolution! You can retrofit years later and not have to worry about alignment with the McPherson SNAP IN approach. Our dual grating turret also accepts these easy to exchange gratings.

Model 207 PDF Data Sheet

Stigmatic Model 207A Monochromator (with off-axis parabolic optics) Press Release

Specifications & Additional Information:

Optical DesignCzerny Turner with Patented "Snap-In" gratings
Focal Length0.67 meter
Aperture Ratio4.7 (5.8 with smaller grating)
Wavelength Rangerefer to grating of interest for range, in extended position increase top limit 20%
Wavelength Accuracy+/- 0.05 nm (with 1200 G/mm grating)
Wavelength Reproducibility+/- 0.005 nm (with 1200 G/mm grating)
Grating Size120x140 mm (or 110x110mm) - oversize Echelle gratings to 220mm wide
Slit LocationsAxial and lateral with optional entrance and exit port selection mirrors
Focal Plane50 mm maximum width, multiply dispersion by the width of your detector for range

Performance with various diffraction gratings:

Grating (G/mm) (others available) 3600 2400 1800 1200 600 300 150 75 20
Wavelength Range from 185-nm to 435nm 650nm 860nm 1.3um 2.6um 5.2um 10.4um 20.8um 78um
Resolution (nm)1 0.015 0.02 0.03 0.04 0.08 0.16 0.32 0.64 2.4
Dispersion (nm/mm) 0.42 0.62 0.83 1.24 2.48 4.96 9.92 19.84 74.4
First Order Littrow Blaze (nm)2 Holo240nmHolo250nm300nm750nm 1.25um2.0um45um
300nm300nm500nm1.0um 2.5um3.0um
Holo500nm750nm3.0um 4.0um8.0um
750nm1.0um4.0um 6.0um10.0um
1.0um1.85um 8.0um12.0um

1. Tested in scanning mode at 312/313 nanometers with 10 micron wide slits and at slowest aperture ratio
2. Gratings work best from 2/3 blaze wavelength to 3/2 blaze wavelength

Outline Drawing

McPherson Model 207

Select Publications

Abstract: Absorption, fluorescence, and fluorescence excitation spectra of 12-hydroxy-1-azaperylene (HAP) and 1-azaperylene were studied in n-alkane matrices at 5 K. Two stable tautomers of HAP, each of them in n-nonane embedded in two sites, were identified and attributed to the enol and keto forms. Theoretical calculations of the energy and vibrational structure of the spectra suggest that tautomer A, with the (0, 0) transition energy at 18 980 ± 10 cm–1 (and 19 060 ± 10 cm–1 in the high energy site), should be identified as the keto form, whereas tautomer B, with the (0, 0) energy at 19 200 ± 20 cm–1 (19 290 ± 20 cm–1), as the enol form. Observation of absorption and fluorescence of both tautomeric forms and lack of large Stokes shift of fluorescence of the keto form classify HAP as the limiting case of the excited-state intramolecular proton transfer system.
Irena Deperasińska, Daniel T. Gryko, Elena Karpiuk, Bolesław Kozankiewicz, Artur Makarewicz, and Joanna Piechowska
Abstract: We studied absorption and fluorescence spectra and decays of pentacene (Pc) in Shpol'skii matrices of n-heptane (C7), n-nonane (C9), n-decane (C10), n-dodecane (C12), n-tetradecane (C14) and n-hexadecane (C16) in the temperature range 1.7–200 K. The fluorescence quantum yields of Pc in C12, C14 and C16 at 1.7 K were determined to be 20±6%, 26±6% and 22±6%, respectively. The kinetic analysis provided values of the radiative, internal conversion and intersystem crossing rate constants for the relaxation channels of the S1 state of Pc in different matrices. Calculated fully saturated emission rates of single molecule were in very good relation with previous observation of single Pc molecules in Shpol'skii matrices.
M. Banasiewicz, I. Deperasińska, D. Fabjanowicz, B. Kozankiewicz
Abstract: We describe a simple and inexpensive method, which corrects the astigmatism of a Czerny–Turner spectrometer. Initial characterization of the astigmatism for a particular Czerny–Turner spectrometer was performed and the design of the corrective optic is described. The optic is a thin piece of glass, which is used as a one-dimensional waveguide between the light source and the spectrometer such that the sagittal and tangential focal planes are brought to the same position. This method is demonstrated to work well between 360 and 900 nm for an f / 4.7 spectrometer. With appropriate materials, corrections for longer and shorter wavelengths should also be possible. When using an inexpensive glass plate, light intensity lost with this method is approximately 12%. Improved surface finish should reduce this loss.
C. Chrystal, K. H. Burrell, and N. A. Pablant
Abstract: We report graphitic carbon growth on crystalline and amorphous oxide substrates by using carbon molecular beam epitaxy. The films are characterized by Raman spectroscopy and X-ray photoelectron spectroscopy. The formations of nanocrystalline graphite are observed on silicon dioxide and glass, while mainly sp 2 amorphous carbons are formed on strontium titanate and yttria-stabilized zirconia. Interestingly, flat carbon layers with high degree of graphitization are formed even on amorphous oxides. Our results provide a progress toward direct graphene growth on oxide materials.
Sahng-Kyoon Jerng, Dong Seong Yu, Jae Hong Lee, Christine Kim, Seokhyun Yoon, Seung-Hyun Chun
Abstract: The use of lithium-coated plasma facing components for plasma density control is studied in the National Spherical Torus Experiment (NSTX). A recently installed liquid lithiumdivertor (LLD) module has a porous molybdenum surface, separated by a stainless steel liner from a heated copper substrate. Lithium is deposited on the LLD from two evaporators. Two new spectroscopic diagnostics are installed to study the plasma surface interactions on the LLD: (1) A 20-element absolute extreme ultraviolet (AXUV) diode array with a 6 nm bandpass filter centered at 121.6 nm (the Lyman-α transition) for spatially resolved divertor recycling rate measurements in the highly reflective LLD environment, and (2) an ultraviolet-visible-near infrared R=0.67 m imaging Czerny–Turner spectrometer for spatially resolved divertor D I, Li I-II, C I-IV, Mo I, D2, LiD, CD emission and ion temperature on and around the LLD module. The use of photometrically calibrated measurements together with atomic physics factors enables studies of recycling and impurity particle fluxes as functions of LLD temperature, ion flux, and divertor geometry.
V. A. Soukhanovskii1, A. L. Roquemore, R. E. Bell, R. Kaita and H. W. Kugel
Abstract: The new wavelength calibration system of the grating monochrometer was described to research the wavelength characteristic of Model 207 monochrometer which was used in the spectral responsivity measurement.The automatic parts of the facility were all connected with the computer by RS232 or IEEE-488.The wavelength calibration could be carried out automatically,and the monochrometer's performance was also tested.At last the method of processing acquisition data was introduced in the program.The experiment results show that the accuracy of the monochrometer wavelength is 0.02 nm.
Yang Jiajian, Lu Xiaofeng, Feng Xiaodong, Yuan Zundong
Abstract: We present a newly designed soft plasma ionization (SPI) source developed for mass spectrometric study of organic compounds in this study. The SPI cell having a relatively small size consists of a hollow anode and a hollow mesh cathode. The voltage–current characteristic depending on the pressure was investigated, indicating that it has similar characteristics to conventional hollow cathode glow discharges. To investigate the emission characteristics of the SPI source, some molecular band emission spectra (N2, N2+ and OH+) were measured by using argon and helium discharge gases. The SPI source was installed to a commercially used quadrupole mass analyzer for analyzing organic compounds. To demonstrate the SPI source, the mass spectra of some organic compounds (methylene chloride, toluene, benzene, cyclohexane and chloroform) were measured. The organic compounds were ionized with good stability in the plasma, and the fragmentation depended on the applied current. When helium and argon gases were used as the discharge gas, the helium plasma was more suitable for SPI-MS rather than argon because the argon plasma not only suffers from spectral interference but also has lower sensitivity.
Hyunkook Parka, Ickhee Leeb, Kyu Seong Choib, Kazuaki Wagatsumaa, Sang Chun Leeb
Abstract: Plasma electrolytic oxidation of zirconium in citric acid was investigated using optical spectroscopy. A rich emission spectrum consisting of about 360 zirconium and 170 oxygen atomic and ionic lines was identified in the spectral regions 313-320, 340-516, and 626-640 nm. It was shown that the remaining features observed in the spectrum could be ascribed to various molecular species, which involve zirconium, oxygen, hydrogen, and carbon. The temperature of the plasma core (T = 7500 ± 1000 K) was determined using measured Zr line intensities, and the temperature of peripheral plasma zone (T = 2800 ± 500 K) was estimated from the intensity distribution within a part of an OH spectrum. The composition of the plasma containing zirconium, oxygen, and hydrogen, under assumption of local thermal equilibrium, was calculated in the temperature range up to 12,000 K and for pressure of 10(5) and 10(7) Pa, in order to explain the appearance of the observed spectral features
Stojadinović S1, Radić-Perić J, Vasilić R, Perić M
Abstract: Neutral beams based on positive ion source technology are a key component of contemporary fusion research. An accurate assessment of the injected beam species mix is important for determining the actual plasma heating and momentum input as well as proper interpretation of beam-based diagnostics. On DIII-D, the main ion charge-exchange spectroscopy system is used to extract well-resolved intensity ratios of the Doppler-shifted D(α) emission from the full, half, and third energy beam components for a variety of beam operational parameters. In conjunction with accurate collisional-radiative modeling, these measurements indicate the assumed species mix and power fractions can vary significantly and should be regularly monitored and updated for the most accurate interpretation of plasma performance. In addition, if stable active control of the power fractions can be achieved through appropriate source tuning, the resulting control over the deposition profile can serve as an additional experimental knob for advanced tokamak studies, e.g., varying the off axis beam current drive without altering the beam trajectory
Thomas DM, Grierson BA, Muñoz Burgos JM, Van Zeeland MA
Abstract: The neutral-beam induced D(α) emission spectrum contains a wealth of information such as deuterium ion temperature, toroidal rotation, density, beam emission intensity, beam neutral density, and local magnetic field strength magnitude |B| from the Stark-split beam emission spectrum, and fast-ion D(α) emission (FIDA) proportional to the beam-injected fast ion density. A comprehensive spectral fitting routine which accounts for all photoemission processes is employed for the spectral analysis. Interpretation of the measurements to determine physically relevant plasma parameters is assisted by the use of an optimized viewing geometry and forward modeling of the emission spectra using a Monte-Carlo 3D simulation code
Grierson BA, Burrell KH, Chrystal C, Groebner RJ, Kaplan DH, Heidbrink WW, Muñoz Burgos JM, Pablant NA, Solomon WM, Van Zeeland MA
Abstract: To improve poloidal rotation measurement capabilities on the DIII-D tokamak, new chords for the charge exchange recombination spectroscopy (CER) diagnostic have been installed. CER is a common method for measuring impurity rotation in tokamak plasmas. These new chords make measurements on the high-field side of the plasma. They are designed so that they can measure toroidal rotation without the need for the calculation of atomic physics corrections. Asymmetry between toroidal rotation on the high- and low-field sides of the plasma is used to calculate poloidal rotation. Results for the main impurity in the plasma are shown and compared with a neoclassical calculation of poloidal rotation
Chrystal C, Burrell KH, Grierson BA, Groebner RJ, Kaplan DH

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