1. QCAL upgrade status FE electronic replacement actual status future design test E. Santovetti KLOE General meeting 19-20 December 2002

2. E. SantovettiKLOE GM 19-20 December 2002 FE electronics now PM and divider ~ 50 cm far from amplifier for safety reason (PM not accessible). Triaxial cable with signal, ground and HV No shield around the PM Very high noise

3. E. SantovettiKLOE GM 19-20 December 2002 New FE electronics amplifier in the same location of the PM divider Differential amplifier to reduce the noise (transmitter on the PM and receiver on the SDS back plane Change of the signal cable (don’t pass anymore through the blue box ): twisted or double coaxial (to be tested) Amplifier small board removable under investigation (very difficult to access) Quality test of the amplifier chip with at least one month of operation before installation Thin electrical shield around the PM Replacement of the worst 10 photomultipliers (to be delivered): the gain of all 32 PM’s will be measured All the components have been ordered

4. E. SantovettiKLOE GM 19-20 December 2002 Time schedule amplifier in the same location of the PM divider Differential amplifier to reduce the noise (transmitter on the PM and receiver on the SDS back plane Change of the signal cable (don’t pass anymore through the blue box ): twisted or double coaxial (to be tested) Amplifier small board removable under investigation (very difficult to access) Quality test of the amplifier chip with at least one month of operation before installation Thin electrical shield around the PM Replacement of the worst 10 photomultipliers (to be delivered): the gain of all 32 PM’s will be measured All the components have been ordered