Calorimetric Power Measurements in Xbox-1 Xiaowei Wu

Preface  What? Measure the extraction power after the structure  Why? Cross check with the directional coupler Complement directional coupler results  How? Use flowmeters and temperature sensors to build 22calorimeter

Outline  Introduction to Xbox-1 and calorimeter system  HFSS and ANSYS simulation of the load  Experiment results and analysis  Conclusion and future work

Outline  Introduction to Xbox-1 and calorimeter system  HFSS and ANSYS simulation of the load  Experiment results and analysis  Conclusion and future work

Xbox-1 Layout Clockwise from top-left: Modulator/klystron (50MW, 1.5us pulse) Pulse compressor (250ns, ratio 2.8) DUT + connections Acc. structure Bunker Gallery B.Woolley, “High-gradient testing in Xbox-1”, CLIC workshop 2014, Geneva, Switzerland

Concept of the Calorimeter

Outline  Introduction to Xbox-1 and calorimeter system  HFSS and ANSYS simulation of the load  Experiment results and analysis  Conclusion and future work

Review of the SS430 Load Cross Section of ¼ load Model of ¼ load Water outlet Water inlet Power input

Review of the SS430 Load 93.8 WG taper Matching section Regular part 265 WR Total 892 End cup Material information: SS430: σ = S/m, μ =6 Regular part: 50dB/m loss Regular part’s cross section S.Matsumoto et.al., “High power evaluation of X-band high power loads”, LINAC10, Tsukuba, Japan

Electromagnetic Simulation for the Load

Thermal Simulation for the Load  HFSS and ANSYS coupling simulation  Electromagnetic field simulation in HFSS  Export surface loss results into ANSYS workbench  Use Steady-state thermal analysis module to calculate the heat distribution of the load ANSYS workbench panel

Convection Calculation for the Flow From fluid dynamics knowledge… Re and Pr are known for fixed flow in pipe

ANSYS Simulation Results 117W for ¼ load with 11.9L/min, 25 degree flow Matching part is hottest! Temperature along the welding joint line

Outline  Introduction to Xbox-1 and calorimeter system  HFSS and ANSYS simulation of the load  Experiment results and analysis  Conclusion and future work

Setup for the Calorimeter System Calorimetric measurement was done in new CPI klystron’s commissioning Time: ~ Output peak power reached almost 23MW, pulse width 1us Schematic diagram of the Calorimeter Load tree two X-band high power loads Flowmeter SMC-PF3W720F04ETM

Xbox-1 Layout Modulator/klystron (50MW, 1.5us pulse) Pulse compressor (250ns, ratio 2.8) DUT + connections Acc. structure Bunker Gallery

Calorimetric Measurement Lay-out Xbox-1 Modulator & KlystronLoad “Tree” Modulator/CPI new klystron Load Tree + connections

Full History of Calorimetric Measurement  Data from h~ h Directional Coupler Measurement Calorimetric Measurement Peak pulse power 14MW~22.6MW Pulse width 942ns Flow rate 11.9L/min

Full History of Calorimetric Measurement Average power comparison Directional coupler ~ peak power*pulse width*repetition rate Calorimeter ~ specific heat*flowrate*temperature difference

h~ h, 8 hours’ data Seems not very good at the beginning… 15% difference compared with directional coupler’ results

h~ h, 8 hours’ data Becomes better when input power becomes more stable ~10% difference compared with directional coupler’s results

h~ h, 8 hours’ data Difference decreases to less than 7% when input power is stable

h~ h, 8 hours’ data Calorimetric results fit with directional coupler’s results in steady state Less than 7% difference between the two results Less than 7%!

h~ h, 8 hours’ data Calorimetric results fit with directional coupler’s results in steady state Less than 7% difference between the two results Less than 7%!

More Analysis about the Results  Time delay is observed when power ramping up again due to the breakdown  In average power of 938W with flow rate of 11.9L/min, time delay is about 50 seconds  Cause big difference compared with directional coupler results 50s

Temperature Distribution Measurement  Add temperature sensors along the welding joint line  Five sensors on each load 938W average power with 11.9L/min flow Experimental result fits well with ANSYS simulation!

Error Analysis  Flowmeter’s error~3% accuracy, 2% repeatability(can be serious…)  Heat insulator is not perfect (caused heat leakage)  Power lost in the transportation system (waveguide/splitter…) Same flow, but different display in flow rate and temperature  Energy loss Splitter temp is a bit high

Outline  Introduction to Xbox-1 and calorimeter system  HFSS and ANSYS simulation of the load  Experiment results and analysis  Conclusion and future work

Conclusion  First calorimetric measurement in Xbox  HFSS-ANSYS coupling simulation is feasible  Calorimetric results fit well with electromagnetic measurements

Future Work  Redo the calorimetric measurement in Xbox-2 Flowmeter is already installed in Xbox-2, cabling work  Measure the energy in different flow rate/water temperature/peak power/pulse width In our measurement, flow rate and pulse width keeps constant   Make calibrations for flowmeter with known flow Increase the accuracy of flow rate’s reading  Use more precise flowmeter

 Thanks for your attention!