| Popis: |
We corrected three problems with the eIPMs during the summer shutdown. We installed new amplifiers for Run 15. These were charge-sensitive amps designed to integrate over the 200ns-long injected bunches and decay to baseline in one full revolution period, ~2.7us. The input stage was built on a small circuit board which replaced the fast pulse amplifiers used originally in RHIC. We used the existing output drivers on the carrier board which were transformer-coupled to the twisted-pair signal lines leaving the tunnel. With AC coupling, there could be no DC component in the output signal. When the digitizers were triggered on the beam pulse we got good profiles, left. When we moved the trigger point we got 'inverted profiles' from the undershoot, right. In these two examples the trigger signal timing is different by 70° at harmonic number 1. |
