RADIATION STUDIES

A front motherboard (#6), a front and a back summing board and a HV board have been irradiated to 5 Mrad at the BNL Co60 Irradiation Facility. The 5Mrad total dose required a 48 hours exposure. The boards were examined just after irradiation and after 10 days to look for any indication of slower degradation phenomena.

Mother Board

• No effect after irradiation on the DC resistance of the calibration resistor networks as measured at room temperature. Package preserves electrical and physical properties.
• Slight discoloration on the surface of the Aries Series 518 low profile sockets. The sockets are made with Glass Filled Polyester, rated as a radiation hard material up to 10^7 rads. (Source: A Holmes-Siedle: "Handbook of Radiation Effects", and H Sconbacher et al: "Compilation of Radiation Damage test data,Part II", CERN "Yellow Report").
• The socket preserve their electrical isolation properties and do not appear brittle nor fragile.
• PC board material (FR4) is a known radiation hard material.

Summing Board

• No visible damage.
• The plastic strip of the pins appear physically sound, with no change in color.
• Electrical isolation is unchanged.
• PC board material (FR4) is a known radiation hard material.

HV Board

• It uses the same pin strips as Summing Boards.
• The board has a solder mask which shows no alteration after irradiation.
• PC board material (FR4) is a known radiation hard material.

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