Studies of radiation damage to CAMEX64 preamplifiers exposed to γ-rays at the Cornell High Energy Synchrotron Source

CAMEX64 preamplifiers, developed for use in the readout of silicon strip detectors, have been exposed to well-measured doses of monochromatic γ-rays from the Cornell High Energy Synchrotron Source (CHESS), and measurements of the resulting radiation damage have been made. Silicon strip detectors with their associated CAMEXes will be installed close to the interaction region in the CLEO experiment at Cornell University, where they will be exposed to both charged particle and photon fluences. Powered and unpowered CAMEXes were irradiated and after each exposure measurements of pedestals, gains, and coherent and incoherent noise were made until the devices could no longer be read out. Results are presented for noise and gain degradation as a function of dose. Using well-controlled and calibrated 20 keV synchrotron radiation, failure begins at 20 krad in powered CAMEXes and between 60 and 120 krad in unpowered CAMEXes. These failure levels are considerably larger than the projected radiation dose