1. 1 Task 19 SIS100_3: Semiconductor RF Gap Switch 15.04.2005 P. Hülsmann Problem Description Beam dynamics simulations have shown that the impedance of the non-operating cavities may degrade the quality of the circulating beam at high current operation significantly. Solution  Equip the gaps of the non operating cavities with fast high power switches, generating a short circuit with low intrinsic impedance. Technical Description

2. 2 Task 19 SIS100_3: Semiconductor RF Gap Switch 15.04.2005 P. Hülsmann Requirements on the gap switch Switch is open Frequency1 MHz Voltage25 kV Duty Cycle0,0005 Capacity<100 pF Switch is Closed Current60 A Average Power 500 W Duty cycle3% Resistance < 10 

3. 3 Task 19 SIS100_3: Semiconductor RF Gap Switch 15.04.2005 P. Hülsmann First Tests with MosFet Gap Switch (Behlke HTS 301-12-AC-B + Cooling Fins,Category VII)  Breakdown at 12 kV RF-amplitude (1 MHz) after 3 minutes (open)  Due to dielectric losses, the isolation material at the high voltage output has started to boil. The isolation was damaged, but not the semiconductors.  Average of 50 W reached (closed)  A resistive resistance of 10  reached  RF-characteristics of the switch ok Next Step  Isolation of the switch with oil Status of R&D

4. 4 Task 19 SIS100_3: Semiconductor RF Gap Switch 15.04.2005 P. Hülsmann Work Sharing  GSI  Specification for manufacturing the switch  Low-level tests  Prototype cavity tests (0.8...5.4 MHz)  CERN  Prototype cavity tests (2.8...10 MHz)  Design of passive network for impedance reduction  Shielding experiments for improvement of radiation hardness  Tentative schedule for 2005 available Organizational Issues

5. 5 Task 19 SIS100_3: Semiconductor RF Gap Switch 15.04.2005 P. Hülsmann Schedule (Description of Work)  Personnel not yet available → 5...6 months shifted

6. 6 Task 19 SIS100_3: Semiconductor RF Gap Switch 15.04.2005 P. Hülsmann Costs