# Double monochromator MZDD350i

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 While choosing a device configuration a proper selection of diffraction gratings is important. A proper selection of diffraction grating allows one to obtain the best combination of high energetic efficiency and spectral resolution. The basic grating parameters which determine their right choice you can find in the methodical material "Spectral Instrument. Basic Concepts and Characteristics." We propose a wide range of diffraction gratings to be used in MZDD350i.Please, choose a necessary grating from the given below list, or consult our specialists.

#### Basic parameters for correct selection of diffraction gratings:

In the Table “Selection of diffraction gratings” groove density and blaze wavelength belong to a diffraction grating parameters. Other parameters characterize a spectral device together with a selected grating.

• Groove density. The diffraction grating has a periodic structure. Such parameters as resolving power and free spectral range are determined by the periodic structure properties of a diffraction grating. The period of grating is the distance through which grooves are repeated. The reciprocal value of a grating period is called the groove density and displays the number of grooves in 1 mm.

• Blaze wavelength. The reflectivity of a grating depends on the grooves geometry, because the direction to the center of the diffraction maximum is determined by the mirror reflection of the incident beam from the edge of a groove. In spite of rather flat profile of diffraction maximum a blaze wavelength that corresponds to the maximum efficiency of the grating has been adopted as a feature for convenience of calculation.
When selecting a grating it is useful to determine a blaze wavelength for a required grating on the spectral range of limited wavelengths  WL1 and WL2. The blaze wavelength is determined by the ratio:
WLBlaze  = 2 ∙ WL1 ∙WL2 / (WL1 + WL2).

• Reciprocal linear dispersion. The light from a grating in the focal plane of a spectral instrument forms a spectrum. Linear dispersion is used for a spectrum characteristic, which is defined as a reciprocal value of the product of angular dispersion of a grating and focal length of a spectral instrument and shows the spectral range that falls on a single linear distance in a focal plane.

• The spectral resolution.  Limiting resolution of a spectral instrument is equal to the minimum half-width of its instrument function. The instrument function is determined by finite sizes of entrance diaphragm, aberrations and also distortions caused by inaccuracy in manufacturing and adjustment of optical elements of instrument. In addition, instrument function, and thus spectral resolution are dependent on lighting method of entrance slit, used aperture and registration system parameters.

• Operating wavelength range. Energy efficiency range referred to the wavelength region in which grating reflection coefficient is not less than  0.405 of the maximum. In the first order this range is limited by the wavelengths: ⅔ ∙ WLBlaze and 2 ∙ WLBlaze.
Operating range usually corresponds to a grating energy efficiency. In some cases, for gratings with a high groove density and large blaze wavelength, the long-wave border of operating spectral range of instrument is limited by a maximal rotation angle of a grating which is defined by design of instrument.

#### Table for selection of diffraction gratings

 Model Line density,mm-1 Blaze wavelength, nm *Reciprocal linear dispersion, nm/mm Spectral resolution,nm Operating wavelengths range, nm Spectral range limited by the grating rotation angle, nm 773600 3600 hol 0.76** 0.025 185 - 425 425 772422 2400 225 1.17 0.035 185 - 450 640 772427 2400 270 1.16 0.035 185 - 540 640 772770 2400 400 1.11 0.035 270 - 640 640 771827 1800 270 1.57 0.04 185 - 540 860 771840 1800 400 1.54 0.04 265 - 800 860 771850 1800 500 1.49 0.04 330 - 860 860 771875 1800 750 1.29 0.04 500 - 860 860 771225 1200 250 2.36 0.07 185 - 500 1280 771228 1200 280 2.36 0.07 185 - 560 1280 771240 1200 400 2.35 0.07 265 - 800 1280 771250 1200 500 2.33 0.07 330 - 1000 1280 771260 1200 600 2.30 0.07 400 - 1200 1280 771275 1200 750 2.24 0.07 500 - 1280 1280 770623 600 230 4.72 0.14 185 - 460 2560 770630 600 300 4.72 0.14 200 - 600 2560 770640 600 400 4.73 0.14 265 - 800 2560 770650 600 500 4.73 0.14 330 - 1000 2560 770660 600 600 4.73 0.14 400 - 1200 2560 770675 600 750 4.71 0.14 500 - 1500 2560 7704008 400 800 7.09 0.21 540 - 1600 3840 7704012 400 1200 7.06 0.21 800 - 2400 3840 7704017 400 1700 6.94 0.21 1135 - 3400 3840 7704020 400 2000 6.83 0.21 1335 - 3840 3840 7704025 400 2500 6.57 0.21 1665 - 3840 3840 770330 300 300 9.42 0.28 200 - 600 5120 770335 300 350 9.42 0.28 235 - 700 5120 770350 300 500 9.44 0.28 335 - 1000 5120 770360 300 600 9.45 0.28 400 - 1200 5120 770370 300 700 9.45 0.28 465 - 1400 5120 7703010 300 1000 9.46 0.28 665 - 2000 5120 7703015 300 1500 9.42 0.28 1000 - 3000 5120 7703020 300 2000 9.33 0.28 1335 - 4000 5120 7703030 300 3000 8.95 0.28 2000 - 5120 5120 7703035 300 3500 8.65 0.28 2335 - 5120 5120 770235 200 350 14.11 0.42 235 - 700 7680 770240 200 400 14.12 0.42 265 - 800 7680 770250 200 500 14.13 0.42 335 - 1000 7680 770270 200 700 14.15 0.42 465 - 1400 7680 7702015 200 1500 14.19 0.42 1000 - 3000 7680 7702020 200 2000 14.16 0.42 1335 - 4000 7680 7702025 200 2500 14.10 0.42 1665 - 5000 7680 7702030 200 3000 14.00 0.42 2000 - 6000 7680 771547 150 475 18.81 0.56 315 - 950 10300 771570 150 700 18.85 0.56 465 - 1400 10300 7715030 150 3000 18.85 0.56 2000 - 6000 10300 7715045 150 4500 18.52 0.56 3000 - 9000 10300 770165 100 650 28.21 0.84 435 - 1300 15400 770170 100 700 28.22 0.84 465 - 1400 15400 7701010 100 1000 28.26 0.84 665 - 2000 15400 7701020 100 2000 28.36 0.84 1335 - 4000 15400 7701025 100 2500 28.38 0.84 1665 - 5000 15400 7701030 100 3000 28.38 0.84 2000 - 6000 15400 7701042 100 4160 28.31 0.84 2800 - 8300 15400 7701048 100 4840 28.23 0.84 3300 - 9600 15400 7701055 100 5500 28.11 0.84 3700-11000 15400 7701062 100 6200 27.94 0.84 4200-12400 15400 7701072 100 7200 27.63 0.84 4900-14400 15400 7701088 100 8750 26.98 0.84 5900-15400 15400 7701097 100 9700 26.46 0.84 6500-15400 15400 7701103 100 10300 26.09 0.84 6900-15400 15400 7775070 75 7000 37.54 1.12 4700-14000 20600 7775095 75 9500 36.88 1.12 6400-19000 20600 7750010 50 1000 56.37 1.68 700-2000 31000 7750038 50 3800 56.70 1.68 2700-7600 31000 7750063 50 6300 56.75 1.68 4200-12600 31000 7750070 50 7000 56.73 1.68 4700-14000 31000 7750083 50 8300 56.63 1.68 5600-16600 31000 7750124 50 12360 55.89 1.68 8300-24700 31000 7750169 50 16900 54.25 1.68 11300-31000 31000 7750200 50 20000 52.56 1.68 13400-31000 31000 7737028 37.5 2790 75.38 2.24 1900-5500 41200 7737056 37.5 5570 75.63 2.24 3700-11100 41200 7737093 37.5 9260 75.64 2.24 6200-18500 41200 7737156 37.5 15600 74.74 2.24 10400-31200 41200 7724116 24 11600 118.25 3.5 7800-23200 64000 7724144 24 14400 118.19 3.5 9600-28800 64000 7724173 24 17300 117.97 3.5 11600-34600 64000 7724243 24 24300 116.81 3.5 16200-48600 64000 7724285 24 28500 115.65 3.5 19000-57000 64000 7724325 24 32500 114.20 3.5 21700-63000 64000

* For the 1st monochromator at the blaze wavelength

** at the wavelength 225 nm