Test of ATLAS SCT barrel modules with Nd:YAG laser

As a part of the quality assurance procedure of the ATLAS SCT (Semiconductor Tracker) barrel modules, the response of the microstrip detector is measured by injecting focused Nd:YAG laser at each strip. The test is sensitive to sensor originated problems and a cross check to the results obtained from the electrical tests performed with the test pulse system implemented in the readout ASICs. Combining these results with the probing results obtained by the silicon sensor manufacturer, we verified the reliabilities of these tests and classified the type of defects for overall performance evaluation of the modules.