Demountable Viewports

Accu-Glass Products' demountable substrate vacuum viewport flanges are an economical "alternative" to fused and/or brazed viewport solutions. They are available with Accu-Sol high-transmission glass or quartz (fused silica) substrate materials. Quartz versions are offered in coated and uncoated configurations. Substrate Transmission varies by material and/or coating option. Accu-Sol glass has greater than 90% transmission over the 350~2200nm spectral range. Quartz substrates are available with specially formulated broadband (BBAR) anti-reflection coatings for better than 99% transmission in the following discrete wavelength ranges... 290~370nm (UV), 350~700nm (A), 650~1050nm (B), 1050~1620nm (C). Uncoated quartz transmission varies from 70~95% over the 200~2200nm range.

The substrate removal (demountable) feature of these vacuum viewports allows optional (custom) optical coatings or for easy cleaning of the window substrate. For high-temperature applications up to 250°C, Kalrez® O-rings can be used. Accu-Glass demountable viewports employ a unique recessed zero profile substrate design, providing the widest viewing angles while offering maximum protection.

Accu-Glass' broadband anti-reflection coated viewports (BBAR) incorporate, precision ground, demountable UV grade fused silica windows that are ideal for use at high vacuum (HV) pressures. These viewports utilize Viton® O-ring elastomer seals to create an air-tight metal/glass seal suitable for pressures down to 10-8 Torr. Window substrates are interchangeable, allowing the user the ability to swap out vacuum windows mounted in our HV CF flanges should cleaning or an alternate AR coating be required.

Windows are available uncoated (185~2100 nm) or with one of four low-loss broadband anti-reflection coatings. Coatings are deposited on both optical surfaces and are optimized for the following ranges: UV (290~370 nm),  A (350~700 nm), B (650~1050 nm), and C (1050~1620 nm). While uncoated windows have typical losses of about 4% per surface, the AR coatings reduce this to Ravg < 0.5%. We have designed these AR coatings for angles of incidence between 0° and 30°.

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AccuSol Demountable Viewports
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AccuSol™ 1.19 Apperture Viewport on CF Flange, 112901
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Demaountable Glass or Fused Silica Substrates
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UHV Conflat® Compatible CF Type Flange
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AccuSol™ .56 Apperture Viewport on ISO NW16 Flange, 112668
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Viton® Elastomer Seal
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Aluminum Substrate Retainer
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Demountable Glass and Quartz Viewports
Accu-Glass’ demountable high transmission glass and quartz viewports are an economical “alternative” to typical ­fused glass or brazed quartz viewports. Transmission is greater than 90% over the 350nm to 1500nm wavelength range. Removable Accu-Sol™ glass and quartz substrates allows for subsequent application of optical coatings and viewport cleaning. For high temperature applications up to 250°C, Kalrez® elastomer O-ring seals are recommended. Demountable substrate viewports employ a unique ­recessed zero profile design... providing the widest viewing angles and maximum protection to glass and quartz substrates.

AccuSol Transmission CurveAccuSol AR Coated Transmission Curves
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Features

  • High transmission Glass or Quartz
  • High Temperature rated to 150°C or up to 250°C with Kalrez® O-rings
  • Stainless steel / aluminum construction
  • Conflat® and ISO NW compatible mounts
  • Custom Solutions on Request

Specifications

Material 
Flanges, Stainless Steel304
Retainer, SubstrateAluminum
Substrate, GlassAccu-Sol™
Substrate, QuartzFused Silica
Seal, ElastomerViton®
Seal, High TemperatureKalrez® 4079
Vacuum Range 1 
HV, High vacuum1x10E-8 Torr
Temperature Range 2 
Seal, Viton® Elastomer-20~150°C
Seal, Kalrez® 4079-20~250°C
Flange, CF (w/Out Seal, Glass)450°C
Flange, ISO NW150°C
T° Gradient, Max/Minute20°C
Transmission 3 
Substrate, UncoatedAccu-Sol™
305~2100nm>90%
2100~2680nm>80%
Scratch-Dig, both faces<40-20
Transmission AR Coated 3 
Substrate, UncoatedFused Silica
200~2000nm, (average)70~95%
290~370nm, UV>99%
350~700nm, Type-A>99%
650~1050nm, Type-B>99%
1050~1620nm, Type-C>99%
  
Notes 
  1. Leak tested to 5x10-10 Standard cc/sec of He.
  2. Overall assembly ratings must be adjusted to that of its lowest rated component.
  3. Transmission curves are provided for reference only. Transmission for individual viewports may vary based on thicknesses, surface finish and/or other condition.
    Windows with BBAR (broadband antireflective) coatings are coated on both substrate surfaces.
  4. Unless specified otherwise, all dimensions are expressed in inches.