Jelight J-221

is a self-powered analog UV intensity meter designed for measuring longwave ultraviolet sources from 300 to 400 nm, with peak sensitivity at approximately 365 nm. Its remote photovoltaic sensor and dual measurement scales make it well suited for UV lamp monitoring, fluorescence applications, quality control, comparative testing, and routine verification of UV-A sources.

Applications

UV-A Lamp Monitoring

The J-221 provides direct measurement of longwave ultraviolet intensity for routine monitoring of fluorescent UV-A lamps, blacklights, inspection lamps, and other sources operating within the 300–400 nm response range.

Fluorescence and Inspection Systems

With peak sensitivity near 365 nm, the meter is well suited for checking UV-A sources used in fluorescence inspection, non-destructive testing, leak detection, laboratory examination, and related inspection processes.

Quality Control and Lamp Performance

The J-221 can be used to monitor lamp output over time, compare UV sources, identify declining lamp intensity, and support routine quality-control procedures where repeatable UV-A exposure is important.

B-100 Series UV Lamp Measurement

The J-221 can be used with 365 nm line sources such as Blak-Ray B-100 Series UV lamps. For these sources, Jelight/UVP documentation specifies multiplying the displayed reading by 0.74 to obtain the corrected irradiance value.

Features

• Measures longwave ultraviolet radiation from 300 to 400 nm.
• Peak spectral sensitivity at approximately 365 nm.
• Dual analog measurement scales covering up to 6,000 µW/cm².
• Minimum detector response of approximately 20 µW/cm².
• Self-powered photovoltaic design requires no batteries or external power supply.
• Remote sensor with 1.2 m (4 ft) cord supports convenient positioning at the measurement point.
• Compact analog meter design for laboratory, inspection, production, and field use.
• Individual meter and sensor calibration traceable to NIST standards.
• Supports optional attenuation and contrast accessories for specialized measurement conditions.

Specifications

FAQs

Does the J-221 require batteries?

No. The J-221 uses a photovoltaic detector and is self-powered, eliminating the need for batteries or an external electrical power supply during measurement.

Can the J-221 measure a Blak-Ray B-100 lamp?

Yes. When measuring a 365 nm line source such as a Blak-Ray B-100 Series lamp, Jelight documentation specifies multiplying the displayed J-221 reading by 0.74 to obtain the corrected irradiance value.

Why is a correction factor required for B-100 lamps?

The J-221 is calibrated for longwave phosphor-coated UV lamps. A concentrated 365 nm mercury line source produces a different detector response, causing the meter to read higher than the actual irradiance unless the specified correction factor is applied.

Is J-221 calibration traceable to NIST?

Yes. Jelight provides individually serialized UV meters and sensors with calibration traceability to NIST standards.

Warranty

The Jelight J-221 365 nm Longwave UV Intensity Meter is warranted against defects in materials and workmanship under normal use and service. Please inspect all protective equipment before each use. For warranty assistance, replacement parts, product support, or application guidance, contact ScienceLighting technical support. Warranty valid for 12 months.

Ordering

Have additional questions? Contact ScienceLighting at (650) 961-9031 or sales@sciencelighting.com.