1. 09 th April 2003 SINGLE SPLIT DRIVE CHAIN TH116 TH116 or TH526 RS2058 ex SPS AMP 7651 ex RAL SOLID STATE DRIVER LEVEL CONTROL AND SOURCE R.F. LEVEL FEEDBACK POWER SPLITTERS PHASE SHIFTERS CIRCULATORS AND 70db COUPLERS R.A. CHURCH RAL

2. 09 th April 2003 SPLIT DRIVE CHAINS The original suggested Split Drive Chain used 4616 tubes to drive the TH116’s They are capable of a gain of 20db ( x100 in power) and thus reduce the number of tubes. It is possible there may be a long term supply problem with this tube hence the alternative. The benefits from twin chains are :- Better Amplitude and Phase control The ability to start with one chain to drive one set of cavities and for the full project just add another chain with minimum disruption. To start with one would be able to use the Cern TH116 circuit, the ex SPS Amplifier and the RAL first driver. The TH781 can be obtained from Thales complete with 200MhZ hardware. R.A. Church RAL

3. 09 th April 2003 ALTERATIVE SEPARATE DRIVE CHAIN TH116 TH781 RS2058 EX SPS 7651 EX RAL LEVEL CONTROL SOURCE OTHER DRIVE CHAIN 10mW4kW 40kW 400kW4MW DRIVE TO 4 CAVITIES VIA PHASE SHIFTERS AND 70db COUPLERS POWER SPLITTERS AND CIRCULATORS 40 kV 20 kV 12kV5kV R.A. Church RAL

4. 09 th April 2003 TH116 OUTPUT ASSEMBLY CAVITY 70db COUPLER CIRCULATOR PHASE SHIFTER MATCHED POWER SPLITTERS TH116 1 MW LOAD 4MW 1MW FW//REF WAVE R.A. CHURCH R.A.L.

5. 09 th April 2003 ALTERNATIVE TO USING TH116 TUBES It would seem that the R.F. circuit at Cern needs considerable re-stressing and modification before it is suitable for Mice R.F. use. The spare circuit at R.A.L.is incomplete and parts need re-manufacturing. If TH116’s are used they require Power Splitters or Hybrids(which require loads), a Circulator(which also requires a load) and a Phase Shifter, none of these items are inexpensive. The TH116 is also, at 4MW, close to its power limit. 9 3/16 line is also very marginal, in all good but good match conditions at 4MW R.A. Church R.A.L.

6. 09 th April 2003 THE ALTERNATIVE An alternative to the 116’s at 4MW is a 1MW plus source for each cavity. This may seem an expensive solution but there are big savings in the output circuitry when not used as a split 4MW source. It would provide proper isolation for each cavity and truly independent phase and amplitude control at low level. The installation would also be much simpler. A suggested line up could be :- Cavity - 70db coupler - TH526(13db gain 1 to 1.5MW) - TH571 (15db gain 50 to 80 kW) - Solid State Driver (1.6 - 2.6kW) - 10mW from low level controlss Tube cost estimates from Thales U.K. Rep :- TH526 92k Euros Cavity 145k Euros TH571 27k Euros Cavity 52k Euros This is an elegant but expensive solution. A cheaper tube line up Could be :- TH116 - RS2058 exSPS and still achieve a similar result. R.A. Church R.A.L

7. 09 th April 2003 INDEPENDENT DRIVE TO EACH CAVITY R.F. SOURCE TO SEVEN OTHER PHASE AND AMPLITUDE CONTROL SYSTEMS CAVITY 70db COUPLER TH 526 TH 571SOLID STATE DRIVER AMPLITUDE AND PHASE CONTROL R.F. SOURCE 10 mW2 kW 62 kW1.2MW (15 db)(13 db) R.A. CHURCH R.A.L. or ex SPS AMP

8. 09 th April 2003 AVAILABILITY OF EQUIPMENT Reflectometers, Phase Shifters, Power Splitters and circulators, quote from Mega. One TH116 circuit from Cern, other to be built or acquired from other users, enquires being made. Two TH116 tubes to be bought at £26k each. Two TH781 circuits and tubes to be purchased at approx. £80k each I understand ex SPS RS2058 circuits and tubes are available at Cern. 7651 circuits and their solid state drivers are available at RAL Designs for level control, Vg2 pulsers, Cathode Modulators and phase comparators for tuning etc are available at RAL. An amount of 9 inch line is available at Cern I understand but more will be needed I expect. Power Supplies will in general have to bought but need not be highly sophisticated. Rough price guide is 40kV £80k, 1 20kV £30k, 12kV £15k. Other equipment, Heater Transformers, Blowers, Control Systems etc likely to require purchasing. It must be remembered that it takes time to get delivery of a large quantity of power tubes etc. R.A. CHURCH RAL

9. 09 th April 2003 PROBLEMS MODULATING THE TH116 There was a problem cathode modulating several 116’s a year or so ago. The tubes did not turn off between pulses even though the tubes were biased off in the cathode circuit. Current flowed (around 2amps) from some other part of the tube structure (maybe the grid) to the anode. This suggests that some part of the structure was getting hot enough to emit. Thales were contacted but could offer no suggestions as to why the problem had occurred. Subsequent tubes operated successfully with cathode modulation and no between pulse current. Cathode modulation has been used at R.A.L. successfully for a number of years. To add anode modulation to each TH116 power supply could add up to £100k per power supply!!! R.A. CHURCH R.A.L.

10. 09 th April 2003 COST OF SUGGESTED SYSTEMS BASED ON QUOTES FOR MAJOR ITEMS 1. SINGLE DRIVE CHAIN TO DRIVE TWO TH116 TUBES :- £1,667,000 2. INDEPENDENT DRIVE CHAINS FOR THE TWO TH116 TUBES :- £1,864,000 3. SEPARATE 1.5MW DRIVERS FOR EACH CAVITY COMPLETELY NEW SYSTEMS :- £3,041,000 4. SEPARATE 1.5MW SYSTEMS USING 116 TUBES AND SPS CIRCUITS :- £2,237,000 IF IT WAS POSSIBLE TO USE EX-ISIS 116 TUBES and EX-SPS TUBES THE COST OF SYSTEM 4 WOULD BE REDUCED TO £1,869,000 ( ISIS 116 TUBES ARE USUALY REPLACED WHEN THEY FAIL TO GIVE 2.3MW OUT) R.A. CHURCH R.A.L.

11. 09 th April 2003 1MW TEST RIG THE TH116 CIRCUIT WHICH IS AVAILIBLE AT CERN WOULD PROBABLY NEED LITTLE MODIFICATION TO OPERATE AT POWER LEVELS OF 1-1.5MW. (as in separate drive to each cavity) DRIVE COULD BE OBTAINED FROM AN EX-SPS AMPLIFIER LOW LEVEL DRIVE COULD BE OBTAINED FROM AN EX-ISIS DRIVER. A 30kV and 12kV POWER SUPPLY WOULD HAVE TO BE PURCHASED OR OBTAINED. THIS WOULD BE A QUICK WAY TO OBTAIN A HIGH POWER TEST SOUPCE. R.A. CHURCH R.A.L.

12. 09 th April 2003