Jelight J-225

is a self-powered analog UV intensity meter designed for measuring shortwave ultraviolet sources, with peak sensitivity at approximately 254 nm. Its remote photovoltaic sensor and dual measurement scales make it well suited for germicidal lamp monitoring, UVC source verification, laboratory measurements, quality control, and routine UV lamp performance checks.

Applications

Germicidal Lamp Monitoring

The J-225 is designed for measuring shortwave ultraviolet output from germicidal lamps, allowing users to monitor lamp intensity, compare sources, and identify declining UVC performance over time.

254 nm UVC Measurement

With peak sensitivity near 254 nm, the J-225 is well suited for measuring low-pressure mercury UV sources and other shortwave lamps operating within its spectral response range.

UV Lamp Maintenance and Quality Control

Repeatable irradiance measurements can be used to monitor lamp aging, verify output after maintenance, compare replacement lamps, and support routine quality-control programs involving shortwave UV sources.

Laboratory and Optical Measurements

The J-225 supports laboratory testing, shortwave UV source comparison, optical filter evaluation, research, and other applications requiring direct measurement of UVC irradiance.

Features

• Designed for shortwave ultraviolet and germicidal lamp measurements.
• Spectral response from approximately 220 to 280 nm.
• Peak spectral sensitivity at approximately 254 nm.
• Dual analog measurement scales covering up to 12,000 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.
• Includes sensor, attenuation screen, and filter.
• Compact analog meter design for laboratory, production, maintenance, and field use.
• Individual meter and sensor calibration traceable to NIST standards.

Specifications

FAQs

What measurement range does the J-225 provide?

The J-225 uses two analog measurement scales. The A scale covers approximately 0–2,400 µW/cm², while the B scale covers approximately 2,000–12,000 µW/cm².

Can the J-225 measure 254 nm germicidal lamps?

Yes. The J-225 has peak sensitivity near 254 nm and is specifically suited for monitoring the output of germicidal and other shortwave mercury UV lamps.

What is the attenuation screen used for?

The attenuation screen reduces the amount of ultraviolet radiation reaching the detector when measuring high-intensity sources. Measurements made using the reduction screen should be interpreted according to the Jelight operating instructions.

How can the J-225 be used to monitor germicidal lamp aging?

Users can take measurements at consistent locations and distances from a germicidal lamp and compare the results over time. Declining readings can help identify decreases in lamp output and support maintenance or replacement decisions.

Is J-225 calibration traceable to NIST?

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

Warranty

The Jelight J-225 254 nm Shortwave 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.