YT-2440 High-OH Synthetic Quartz Tube — UV Light Source Envelope Fused Silica for UV Curing, Xenon and Phototherapy Lamps
LUMIGLAS® YT-2440 is a high-OH synthetic quartz tube engineered for UV electric light source envelopes operating in the 200–400 nm wavelength range. Produced from 6N synthetic fused silica with OH hydroxyl content of 400–1000 ppm and ppb-level metallic impurities, it delivers high UV transmittance and low UV absorption across the UV-A and UV-B bands — directly supporting longer lamp service life. Standard OD range φ1–90 mm, wall thickness ≤30 mm, maximum length 2000 mm. Custom dimensions available on request.
Description
The LUMIGLAS® YT-2440 high-OH synthetic quartz tube is a UV-grade fused silica tube that Lumistar produces for UV electric light source envelopes operating in the 200–400 nm wavelength range. With OH hydroxyl content of 400–1000 ppm and ppb-level metallic impurities, it delivers high UV transmittance, low UV absorption and proven resistance to UV-induced solarisation — the combination that directly determines lamp UV output stability and service life. Compared to the lower-OH YT-2430 grade, the YT-2440 has a longer UV cut-off wavelength of approximately 185 nm, making it the correct specification for UV curing lamps, xenon UV lamps, halogen UV sources and UV phototherapy equipment operating above 280 nm.
In UV lamp design, matching the OH content of the envelope tube to the lamp’s operating wavelength is standard engineering practice. Because the YT-2440 positions its UV transmission edge at approximately 185 nm, it offers excellent transmittance across the full UV-A (315–400 nm) and UV-B (280–315 nm) bands without the unnecessary cost of the ultra-low OH content required only for deep-UV germicidal applications. Furthermore, the ppb-level metallic impurity control suppresses UV-induced browning during service life, supporting stable UV output over the rated lamp operating hours. The tube is available in a wide OD range from φ1 mm to φ90 mm, covering everything from small discharge capillaries to large lamp outer sleeves.
Technical Specifications — YT-2440 High-OH Synthetic Quartz Tube
| Parameter | Value / Grade |
|---|---|
| Product Type | High-OH synthetic quartz tube / UV light source envelope fused silica |
| Material | Synthetic fused silica, SiO₂ ≥99.9999% (6N grade) |
| OH Hydroxyl Content | 400–1000 ppm — high-OH grade optimised for 200–400 nm UV lamp applications |
| UV Cut-off Wavelength | ~185 nm — longer cut-off than YT-2430, optimised for UV-A / UV-B lamp designs |
| UV Transmittance | High across the 200–400 nm band (UV-A and UV-B) — low UV absorption |
| UV Radiation Resistance | High — ppb metallic impurities suppress solarisation; stable UV output over lamp service life |
| Max. Service Temperature | ~1200°C continuous service |
| Thermal Expansion | 0.55 × 10⁻⁶ /°C — near-zero thermal expansion |
| OD Range | φ1 – 90 mm |
| Wall Thickness (WT) | ≤30 mm |
| Max. Length | 2000 mm |
| Material Certificate | Full impurity analysis Certificate of Conformity (CoC), supplied as standard |
Major Metallic Impurity Content & Hydroxyl — YT-2440
All values in ppm (wt). ppb-level metallic impurity control suppresses UV-induced solarisation during lamp service. Full impurity analysis CoC provided as standard with every order.
| Grade | Li | Na | K | Mg | Ca | Cu | Al | Cr | Fe | Ti | OH (ppm) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| YT-2440 | <0.01 | <0.01 | <0.002 | <0.001 | <0.01 | <0.001 | <0.002 | <0.001 | <0.002 | <0.005 | 400–1000 |
The high OH content (400–1000 ppm) positions the UV cut-off at approximately 185 nm — optimised for UV curing, phototherapy and longer-wavelength UV lamp applications. For deep-UV germicidal lamps requiring a shorter cut-off (~175 nm), specify the YT-2430 (~200 ppm) instead.
YT-2430 vs YT-2440 — Selecting the Correct OH Grade for Your UV Lamp
Both grades share the same 6N synthetic fused silica base and ppb-level metallic impurity control. The OH content is the key differentiator — choose the grade that matches your lamp’s operating wavelength.
| Parameter | YT-2430 (Low-OH) | YT-2440 (High-OH) |
|---|---|---|
| OH Content (ppm) | ~200 | 400–1000 |
| UV Cut-off Wavelength | ~175 nm (shorter) | ~185 nm (longer) |
| Deep-UV (160–180 nm) Transmittance | Higher | Lower |
| UV-A / UV-B (280–400 nm) Transmittance | High | High |
| Typical Lamp Types | UVC germicidal, excimer UV (172–280 nm) | UV curing, xenon, halogen, phototherapy (280–400 nm) |
| OD Range / Max. Length | φ1–90 mm / 2000 mm | φ1–90 mm / 2000 mm |
If you are uncertain about the correct grade, provide Lumistar with your lamp’s operating wavelength and power specification. Our engineers will recommend the appropriate OH grade for your design.
UV Transmittance Comparison — YT-2440 vs YT-2430 vs YT-2120
Transmittance curves measured at 2 mm wall thickness, showing how OH content shifts the UV cut-off across the three grades.
Transmittance T (%) vs. Wavelength (nm) — measured at φ2 mm wall thickness
Curves: YT-2120 (green) · YT-2430 (red) · YT-2440 (blue — longest UV cut-off)
The YT-2440 (blue curve) has the longest UV cut-off of the three grades at approximately 185 nm. Above 200 nm, however, all three grades deliver comparable high transmittance — confirming that the YT-2440 fully covers the UV-A and UV-B bands required by UV curing, phototherapy and xenon UV lamp applications.
Why High-OH Fused Silica Suits UV Curing and Phototherapy Lamps
UV curing and phototherapy lamps typically operate at wavelengths from 280 nm to 400 nm — well above the UV cut-off of both the YT-2430 and YT-2440 grades. Because both grades provide comparable transmittance above 200 nm, the additional cost of achieving ultra-low OH content (as in the YT-2430 or YT-2120) brings no optical benefit for these applications. Instead, the YT-2440 directs the performance investment into the parameters that actually matter for UV curing and phototherapy lamps — namely ppb metallic impurity control to suppress solarisation, high geometric precision for reliable lamp assembly, and a bubble-free wall to ensure mechanical integrity under the high-temperature and UV-irradiation cycling of production lamp service conditions.
How ppb Metallic Impurities Extend UV Lamp Service Life
Metallic impurities — particularly iron, titanium and other transition metals — are the primary cause of UV-induced browning in fused quartz lamp envelopes. Under UV irradiation, these impurities form absorption centres in the silica matrix through a process called solarisation, progressively reducing UV transmittance over the lamp’s operating life. In contrast, Lumistar controls all metallic impurities in the YT-2440 to ppb levels. As a result, the density of potential absorption centres in the glass is dramatically lower. Consequently, lamps made from YT-2440 maintain more stable UV output throughout their rated service hours — a direct benefit to end-users in terms of consistent UV dosage and longer replacement intervals.
High UV Transmittance 200–400 nm
Excellent transmittance across the full UV-A (315–400 nm) and UV-B (280–315 nm) bands — covering the operating wavelength of UV curing lamps, xenon flash lamps, halogen UV sources and UV phototherapy equipment.
Long UV Service Life
ppb-level metallic impurity control suppresses UV-induced solarisation — maintaining stable UV output over the rated lamp service life and reducing the frequency of lamp replacement for end-users.
OH 400–1000 ppm — Correct Cut-off for UV-A / UV-B Lamps
The ~185 nm UV cut-off of the YT-2440 is optimally matched to UV curing and phototherapy lamp designs — providing the necessary UV transmittance without the cost premium of unnecessarily low OH content.
φ1–90 mm — Full Lamp Size Range
From narrow capillary discharge tubes at φ1 mm through to large outer sleeves at φ90 mm — the YT-2440 covers the full range of UV lamp envelope dimensions in a single qualified material grade.
Typical Applications
- ▸UV curing lamp envelopes — outer tube and discharge envelope for medium- and high-pressure UV curing lamps used in printing, coating, adhesive bonding and composite manufacturing at 315–400 nm
- ▸Xenon UV flash lamp envelopes — fused silica envelope for xenon flash lamps used in photography, industrial strobe lighting, optical pumping and pulsed UV sources
- ▸UV phototherapy lamp envelopes — lamp envelopes for narrowband UVB (311 nm) and broadband UV phototherapy equipment in dermatology, vitiligo treatment and seasonal affective disorder therapy
- ▸High-pressure mercury UV lamp outer sleeves — containment and UV filter sleeves for high-pressure mercury arc lamps in UV curing, water treatment and photochemical process systems
- ▸UV ageing and weathering test lamp envelopes — envelope tubes for UV-A and UV-B accelerated weathering test lamps used in material durability and coatings testing (ASTM G154, ISO 4892)
- ▸Halogen UV light source envelopes — outer envelope and reflector tubes for halogen UV light sources used in analytical instruments, projectors and UV inspection systems
Technical Document & Download
📄 Technical Datasheet — YT-2440
Full impurity data, OH grade comparison with YT-2430, UV transmittance performance chart and ordering specification.
Frequently Asked Questions
Request a Quote — LUMIGLAS® YT-2440 High-OH Quartz Tube
Specify: OD × WT × Length (mm) · OH 400–1000 ppm · Custom dimensions welcome
