The Sciencetech focused beam arc lamp housing is designed for use with high pressure, short arc lamps up to 300W. The arc lamp housing has an efficient F/4.5 ellipsoidal reflector to focus the light at a fixed point in front of the lamp housing. This reflector is made of machined solid aluminum from a diamond turned process for uniform thermal expansion and precision focusing. The standard model has a safety quartz window at the output port to eliminate harmful UVB rays, and to contain any harmful ozone that may be generated by the lamp within (from ozone producing lamps only). This safety quartz window can be replaced with UV grade fused silica window if the application requires UV light to pass through or BK7 glass window if no UV light is required. The Model 200-100 is typically air cooled, although an optional water cooled version is available for use with ozone producing lamps.
Please note that the short arc lamp, variable DC power supply, and igniter are sold separately.
 
Optical Configuration

The model 200-100 accomplishes its focused beam through an ellipsoidal reflector, the most efficient geometric shape for collecting light from a point source and refocusing it to another focal point some fixed distance away. Since an arc lamp is not a perfect point source, the resulting focal spot size is not infinitesimally small. Practically speaking, it is about 7-10mm in diameter depending on the wattage and arc gap size of the arc lamp itself. Another restriction of the focused beam arc lamp housing is its fixed aperture as determined by its f/4.5 ellipsoidal reflector. For optimum light transfer, the component being illuminated should have a matching aperture value. Fortunately, Sciencetech manufactures sample chambers and monochromators/spectrographs that also have an f/4.5 input aperture. For such components, the model 200-100 is an ideal light source for its efficient light collection and optimal light transfer capability. However, it is still not recommended for applications that require a very small focal spot.

 
Ellipsoidal Reflector

The f/4.5 ellipsoidal reflector is the most expensive component of the arc lamp housing and accounts for over 50% of its manufacturing cost. It is made of a precision diamond turned solid aluminum piece to bear the exact geometry of an ellipsoidal surface for accurate refocusing of the arc lamp light to the small focal point in front of the housing. It is also thermally balanced to assure it does not warp under tremendous heat from the arc lamp as the interior of the arc lamp housing can reach over 100˚C. It is also specially coated to reflect all wavelengths ranging from ultraviolet to infrared.
 
Comparing with model 201-100

The difference between the models 200-100 and 201-100 high power arc lamp housings is the geometry of the output beam. The 200-100 puts out a focused beam while the 201-100 produces a collimated parallel beam. However, the 201-100 can also produce a focused beam by attaching refractive condensing optics to its exit port. The advantage of the model 200-100 is its efficient light collection ability which allows it to focus more light power onto a point. The advantage of the model 201-100 (with refractive condensing optics so that it also generates a focused beam) is its smaller focal spot, ability to generate any f number aperture by attaching different refractive condensing optics, and a more uniform beam. For very fine focal spot applications, the model 201-100 actually achieves higher power density than the model 200-100.
Safety
 
Exit Port Window

The exit port is covered with a 3" diameter x 1/8" thick G1 quartz window to filter out harmful UVB rays. However, UVA rays down to 270nm can still pass through. If no UV rays are desired, an optional BK7 glass safety window is available to filter out most harmful UV rays below 360nm. For UV applications, this G1 safety quartz window can also be replaced with an optional fused silica version which allows all wavelengths including UV light above 200nm to pass through. These safety windows also protect the user against glass shrapnel should the high pressure arc lamp explode inside.

 
Cooling

The interior of the focused beam arc lamp housing can get very hot. To keep it cooled, a fan at the rear draws air from the back of the housing and blows it over the arc lamp. Please note that forced air-cooling should not be used on ozone producing arc lamps as it would blow the corrosive and hazardous ozone gas to the outside work environment. For ozone producing lamps, a water-cooled option is available such that the ozone can remain inside the arc lamp housing. Although cooling may not seem necessary for low wattage lamps like 75W and 100W, we have experimental results that show that such lamps have better temporal stability and much faster settle time when cooled. Please ask a Sciencetech Applications Sales Specialist for this technical report.
 
Optical Beam Height
The center beam line of the exit port is 114.3mm (4.5 inches) above the base of the lamp housing.

 
Supported Arc Lamps (Xe and HgXe but not Hg)

The arc lamp is mounted in a horizontal position inside the focused beam arc lamp housing. The exit port is at the cathode end of the lamp and shines horizontally outwards. Due to this orientation, mercury arc lamps are not recommended as their service life is greatly shortened in horizontal operation. Unless of course, the user mounts this arc lamp housing such that the beam points upwards, maintaining the vertical operation of the mercury arc lamp. The service life of xenon arc lamps are not affected by orientation. The 201-100 accommodates short arc lamps ranging from 75W to 300W which are sold separately. Since each arc lamp type and wattage has its own socket style and cooling shroud requirement, it must be specified at the time of ordering. The arc lamp housing will not be able support another type or wattage of arc lamp after it is manufactured.

 
Power Supply

The model 200-100 arc lamp housing is designed to work with Sciencetech model 500-300 adjustable power supply.  Alternatively, model 500-200 adjustable power supply with external model 500-IG igniter can be used for 75W or 150W lamps. This is a highly stabilized linear DC power supply capable of producing 0W-200W (adjustable). An optional Optical Feedback Unit (model FS-02) with a built-in fiber optic light sensor is also available to monitor the light intensity of the arc lamp and automatically adjust the power supply to maintain a consistent non-fluctuating intensity. The model 200-100 arc lamp housing can also be used with other non-Sciencetech DC arc lamp power supplies as long as the power supply provides both DC output for lamp (typically 12-30VDC) and a separate 115VAC for its cooling fan. The power supply must also have its own arc lamp ignition. The model 550-200 power supply is available in both 120VAC and 230VAC versions.

 
Cable Connections
There are three cable connections to the arc lamp housing. The positive and negative lamp cables require male Pomona 4986 connectors which plugs into the female Pomona 6387-ST-T terminals on the arc lamp housing. The cooling fan utilize 120VAC and has a separate Amphenol C16 connector for connection to the Sciencetech model 500-200 power supply. The arc lamp housing ground follows the cooling fan ground via the Amphenol C16 connector.

 
Other Arc Lamp Housing Models

Please consider the model 200-1K arc lamp housing for high wattage lamps between 450W-1500W. The model 200-1K has the same ellipsoidal reflector design as the model 200-100 for efficient light collection and focused output beam. Also available is the model 201-100 arc lamp housing that produces a collimated parallel output beam. The model 201-100 supports the same set of 75W-300W arc lamps and is compatible with the same models 500-300 or 500-200 adjustable power supply as the 200-100. The model 201-100 is less efficient in light collection, but can achieve a smaller focal spot of any f number with refractive condensing optics attachments and produces a more uniform intensity beam.
 
Customization

Sciencetech has built many customized versions of the model 200-100 arc lamp housing. Examples include a vertically mounted version for mercury lamps, and even a gold coated reflector version for IR applications. If you require a certain feature in this arc lamp housing that is not shown, please contact our Applications Specialists at sales@sciencetech-inc.com for a custom quotation.
 
Technical Specifications

3" diameter exit port with standard G1 quartz safety window

Available UV fused silica safety window

Available BK7 glass safety window for no UV rays

Ellipsoidal reflector aperture: f/4.5

Approximate focal spot location: 239mm in front of exit port

Spot size: 9mm for 1000W Xe lamp

Removable back panel for lamp replacement

Painted aluminum body

+ and - terminals for arc lamp power (12DC~30VDC typical)

Live and neutral terminals for cooling fan (115VAC)

Center beam line height: 76.2mm (3") above base

Dimensions: 19 x 10.5 x 10.9cm