Task 2: Calorimeter Calibration Studies and Prototyping

(Cremaldi, Reidy, student, 2/3 postdoc)

(a) Event-based -- Mississippi has initiated studies of Bhabba rates in the Babar CsI crystals for calibration purposes. We are studying both direct bhabba and radiative decays. We will also evaluate the role that [[pi]]^o--> [[gamma]][[gamma]] may play in the overall calibration scheme of the CsI calorimeter.

(b) Pulsed Laser Studies -- A number of experiments have had considerable success using pulsed laser systems for calibration which has led a number of new experiments such as KTEV and CMS to develop similar systems for calibration. Besides calibration such systems also have the capability of providing for timing studies and separate electronics calibrations and monitoring. It has been demonstrated that pulsed laser systems can provide for calibration at the 0.1-0.2% level which is sufficient for the BaBar calorimeter. Based on our experience in working with similar systems in GEM and currently on prototyping calorimeter/polarimeters for SLD we propose to develop a pulsed laser system for the BABAR calorimeter which can be expanded into a prototype set-up for testing with the prototype calorimeter module in a test beam. This time frame dictates the necessity of involving a postdoc in this effort. However, the same postdoc will also participate in

the light collection studies since these studies are dirctly applicable to the calibration work.