1. Automation of the 805MHz cavity conditioning procedure Ajit Kurup MuCool Test Area RF Workshop, Fermilab 22 nd August 2007

2. Page 2 Automation of the 805MHz cavity conditioning procedure MuCool Test Area RF Meeting, Fermilab 22 nd August 2007Ajit Kurup Introduction Currently, the 805 MHz cavity button tests conditioning is “done by hand”. Automating this procedure should speed up time to condition the cavity and will perform the conditioning in a systematic way. Existing hardware has been used and a Labview program written to automate the conditioning procedure.

3. Page 3 Automation of the 805MHz cavity conditioning procedure MuCool Test Area RF Meeting, Fermilab 22 nd August 2007Ajit Kurup DAQ Hardware Signal Generator Analogue Oscilloscope Terminal Control Electronics Digital Oscilloscope Log book 10Hz clock

4. Page 4 Automation of the 805MHz cavity conditioning procedure MuCool Test Area RF Meeting, Fermilab 22 nd August 2007Ajit Kurup DAQ Hardware (2) Signal Generator Analogue Oscilloscope Power Amplifier Klystron Modulator Waveguide Directional Coupler Cavity forward power reflected power Fast ~-30dBm attenuator (threshold between reflected power peaks) 10Hz clock Fast Switch (vacc > 6X10^-8 torr || 2 consecutive breakdowns) ACNET Control Electronics vacuum probe voltage probe

5. Page 5 Automation of the 805MHz cavity conditioning procedure MuCool Test Area RF Meeting, Fermilab 22 nd August 2007Ajit Kurup Automation of the Conditioning Procedure Signal Generator Analogue Oscilloscope Power Amplifier Klystron Modulator Waveguide Directional Coupler Cavity forward power reflected power 10Hz clock ACNET Control Electronics vacuum probe voltage probe Digital Oscilloscope rf enable Fast ~-30dBm attenuator (threshold between reflected power peaks) Fast Switch (vacc > 6X10^-8 torr || 2 consecutive breakdowns)

6. Page 6 Automation of the 805MHz cavity conditioning procedure MuCool Test Area RF Meeting, Fermilab 22 nd August 2007Ajit Kurup Logic of the Algorithm A breakdown is identified by looking at the time between the two peaks of the reflected power signal. If this is less than the width of the rf enable pulse (within a certain error) then a breakdown is assumed to have occurred. The program calculates the breakdown fraction over a short period and a longer period. If the breakdown rate is higher than the specified limits then the amplitude is reduced otherwise it is increased. This continues until the target amplitude is reached. The program also checks for consecutive breakdowns and if this is higher than the specified limit then the amplitude is decreased. Once the target amplitude is achieved then the program will either keep monitoring for breakdowns indefinitely or will terminate.

7. Page 7 Automation of the 805MHz cavity conditioning procedure MuCool Test Area RF Meeting, Fermilab 22 nd August 2007Ajit Kurup Front Panel - Initialisation

8. Page 8 Automation of the 805MHz cavity conditioning procedure MuCool Test Area RF Meeting, Fermilab 22 nd August 2007Ajit Kurup Front Panel - Monitor Loop

9. Page 9 Automation of the 805MHz cavity conditioning procedure MuCool Test Area RF Meeting, Fermilab 22 nd August 2007Ajit Kurup Testing the Conditioning Program No rf available during shutdown period –Had to test the program by simulating the reflected power signal using a signal generator (Thanks to Al Moretti) Generate 2 pulses separated by 20  s @ 10Hz repetition rate. Can simulate a breakdown by reducing the time between the 2 pulses. Stability check –Left the program running over the weekend (i.e. from 3:30pm Friday to 11:30am Monday) and the program was still working as normal (i.e. no latency problems or memory leaks).

10. Page 10 Automation of the 805MHz cavity conditioning procedure MuCool Test Area RF Meeting, Fermilab 22 nd August 2007Ajit Kurup Summary and Plans Conditioning program has been written and some basic tests have been done. Need to test the program which finds the resonant frequency of the cavity and include it in the main program. –Al is setting up a “dummy” cavity. Should be ready for testing tomorrow. Look to see if it’s possible to speed up time to adjust the amplitude. Need to include vacuum signals. –Need a daq card (should be purchased soon). May need to make increments and decrements non-linear Include logging routines. Test with the real cavity and rf!