We are using laser damage test systems on a production scale to scan large castings of laser glass for the presence of damage-causing platinum inclusions. These systems support glass melting production lines at two plants; one is in the U.S. (Schott Glass Technologies, Inc.) and the other is in Japan (Hoya Corporation). The damage test systems are designed to scan an entire glass casting using the pulsed output from a commercial Nd:YAG laser. The system is fully automated and operates unattended. Following testing, the glass casting is removed from the system and visually inspected for the presence of Pt-damage sites. We routinely test polygonally-shaped castings that are about 0.5 meter in size, weigh approximately 30 kg and contain about 7 liters of glass. It takes roughly 6 to 8 hours to test a piece of this size. To date the systems have been in use about 12 hours-per-day, up to 5 days-a-week for a period of about 15 months. Of the approximately 300 disks that have passed the damage test so far, sixty-two percent of the disks have no platinum inclusions at all and ninety-two percent have an inclusion density of less than 0.2 per liter.

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We developed a gas electron multiplier (GEM) that is highly reliable against discharge using a Low Temperature Co-fired Ceramic (LTCC) as an insulating layer (LTCC-GEM). Because LTCC is an inorganic anti-carbonized material, LTCC-GEM is expected to be strong against breakdown. The gain properties of a single layer of 100 µm-thick LTCC-GEM with an effective area of 100 × 100 mm2 was evaluated in the gas mixture of 70% Ar and 30% CO2 at 1 atm. The maximum gain was approximately 3,500 at an applied voltage of 730 V and the gain variation was less than 3% over 14 hours of operation. In addition, the LTCC-GEM remained unbroken during the experiment despite more than 20,000 discharges at a high applied voltage of 730 V. We confirm that the LTCC-GEM is discharge-tolerant and has the same performance as traditional GEMs.

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