Entrance Slit for Spectrometers - Adjustable Aperture Component

Product Specifications

Technical details and manufacturing context for Entrance Slit

Definition

The entrance slit is a critical optical component within a spectrometer unit that defines the initial light beam characteristics. It serves as the entry point where light from the source is admitted into the optical path. By precisely controlling the slit width, it determines the spectral resolution and the amount of light energy entering the system, directly impacting the instrument's sensitivity and accuracy. The slit is typically constructed with blades made of stainless steel, tungsten, or quartz, offering durability and corrosion resistance. The adjustable width range is 0.005–3 mm, with a fixed height ranging from 1–10 mm. Width adjustment accuracy is ±0.001 mm, and repeatability is ±0.002 mm. The blade material is often stainless steel 304, conforming to ASTM A240, with an edge sharpness of 0.1 μm to minimize light scattering. The operating temperature range is -20 to 60 °C, storage temperature -40 to 85 °C, and relative humidity up to 95% non-condensing. The product's weight varies from 0.5 to 2 kg, and dimensions range from 50x50x30 mm to 100x80x60 mm. For motorized versions, motor voltage is 12–24 V DC with power consumption of 2–5 W. The IP rating is IP40–IP54 per IEC 60529. These specifications are reference ranges; actual values must be confirmed with the manufacturer for specific models and applications. The entrance slit is essential for optimizing spectral resolution and throughput in various optical instruments, including spectrometers used in analytical chemistry, environmental monitoring, and material analysis. Proper selection and maintenance are crucial for reliable performance.

Working Principle

The entrance slit operates by allowing only a narrow, well-defined beam of light to pass through its adjustable aperture. The width of the slit is mechanically controlled, often via a micrometer screw or motorized actuator, to vary the size of the light beam. A narrower slit provides higher spectral resolution by limiting the range of wavelengths entering at once but reduces light throughput. The slit edges are typically straight, parallel, and precisely aligned to ensure a clean, collimated input for the subsequent dispersive element (grating or prism). The adjustment mechanism allows precise setting of the slit width, with accuracy and repeatability as specified. The slit height is fixed but can be selected based on light collection needs. The materials used for the blades are chosen for durability and minimal scattering. The operating principle ensures that only the desired portion of the light enters the spectrometer, enabling accurate spectral analysis.

Common Materials

Stainless Steel, Tungsten, Quartz

Technical Parameters

Parameter	Typical range	Notes & selection driver
Slit Width Range	0.005–3 mm	Adjustable width for controlling light throughput and resolution.
Slit Height	1–10 mm	Fixed height; larger height increases light collection.
Width Adjustment Accuracy	±0.001 mm	Precision of the micrometer or motorized adjustment.
Repeatability	±0.002 mm	Consistency of width setting over multiple adjustments.
Blade Material	Stainless steel 304	Corrosion-resistant and durable for optical applications.ASTM A240
Blade Edge Sharpness	0.1 μm	Edge radius for minimal light scattering.
Operating Temperature	-20–60 °C	Range for reliable operation without thermal drift.
Storage Temperature	-40–85 °C	Non-operating storage conditions.
Relative Humidity	0–95 % RH	Non-condensing; condensation may affect performance.
Weight	0.5–2 kg	Depends on size and motorization.
Dimensions (W x D x H)	50x50x30–100x80x60 mm	Overall footprint; varies with model.
Motor Voltage	12–24 V DC	For motorized slits; manual slits have no motor.
Motor Power Consumption	2–5 W	For motorized slits; manual slits have no motor.
IP Rating	IP40–IP54	Protection against dust and water; higher for harsh environments.IEC 60529

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Components / BOM

Fixed Jaw Part
Provides one stationary edge of the slit aperture.

Material: Stainless Steel
Movable Jaw Part
Provides the adjustable edge, controlled by a micrometer or actuator to set the slit width.

Material: Stainless Steel
Adjustment Mechanism
A screw, lever, or motorized system that precisely moves the movable jaw.

Material: Stainless Steel, Brass
Slit Mount/Housing
A rigid frame that holds the jaws in precise alignment and allows mounting to the spectrometer.

Material: Aluminum Alloy

Applied To / Applications

This component is essential for the following industrial systems and equipment:

Spectrometer Unit

View system integration details

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Frequently Asked Questions

What is the function of an entrance slit in a spectrometer?

The entrance slit controls the width and alignment of light entering the spectrometer, defining the initial beam characteristics. It determines spectral resolution and light throughput, impacting sensitivity and accuracy.

What materials are available for the slit blades?

The blades can be made of stainless steel, tungsten, or quartz. Stainless steel 304 is commonly used, conforming to ASTM A240, offering corrosion resistance and durability.

How is the slit width adjusted?

The slit width is mechanically controlled via a micrometer screw or motorized actuator. The adjustment accuracy is ±0.001 mm, and repeatability is ±0.002 mm.

What are the operating temperature and humidity limits?

The operating temperature range is -20 to 60 °C, storage temperature -40 to 85 °C, and relative humidity up to 95% non-condensing. Condensation may affect performance.

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pressure:	Atmospheric only
other spec:	Slit width range: 5μm to 2000μm, wavelength range: 180nm to 20μm
temperature:	-20°C to 80°C

Entrance Slit

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