Status of KEK X-band Test Facility and its future plans

Status of KEK X-band Test Facility and its future plans Shuji Matsumoto Accelerator Lab., KEK 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 1

Contents The New X-band Test Facility (XTF) and X- band Klystron Test Stand Ongoing High Power Test at Klystron Test Stand: Narrow Waveguides Other X-band research Future plans and possible collaborations. Summary 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 2

The New XTF (Re-)Construction of New XTF is underway.. The work started in Jan. 2007, moving the equipment to new place, KEKB Injector Area. The operation of New XTF with a single klystron will be ready at the end of July. Half of the power (50MW) is available. The operation with two klystrons is possible after the reinforcement of the wall plug power completes (Additional power line will be placed). The work is planed to be done during this summer. The full power (100MW) operation of New XTF will be ready in September. 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 3

The New XTF New X-band Test Facility (XTF) and X-band Klystron Test Stand New XTF is under construction here. Our old place Our new place X-band Klystron Test Station. Test of Narrow Waveguides is ongoing here. Plan view of KEKB Injector 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 4

The New XTF XTF modulator and X-band ppm Klystrons C-band Exp. Area (bunker) Control Area This hall was used for S-band structure tests first, followed by C-band, and X-band this time. It is possible to use all these frequencies here. Plan view of Acc structure assembly hall, KEKB Injector. XTF Modulator drives two PPM X-band klystrons. The combined power from the klystrons is guided into the experimental area (bunker). The control/monitor station is located between the power source and the bunker. 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 5

The New XTF XTF Modulator Control Area Bunker 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 6

The New XTF Features of the facility (100MW, 400ns, 50pps), 24hr/day 50cm-thick concrete shield room (bunker) Control system will be basically from scratch, adapting control to KEKB Injector area Data acquisition and storage through LINUX and EPICS RF pulse shape recording for BD and preceding pulses Evaluation with stopping operation from the beginning Pulse-to-pulse evaluation to be done later (dep. on money) Phase measurement not yet planned Dark current evaluation Charge by FC, pulse shape with CT and energy by analyzer magnet Acoustic measurement (developed by SLAC) X-ray measurement with small PMT s Q-mass monitoring 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 7

The New XTF Data storage KEKB Inj. control New XTF control system Klystron LLRF Modulator INTLK CCG Safety System control PC Python, Linux Mod. PLC S/H & DC Amp TDS3034B (300MHz) TDS3054B (500MHz) Discri RF crystal X-ray CT DL7480 (500MHz) History 4MW/ch Various signal X-ray Etc. Acc PLC VME Acoustic (SLAC) Acoustic Etc. FPGA (100MHz) DPO7104 (1GHz) Etc. Etc. AM FC New XTF control system: from the beginning, later 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 8

The New XTF XTF Modulator Line-type modulator combined with Inverter charging, Thyratron switched and Pulse Transformer. Conventional design, high reliability. The modulator installs two PFNs and thyratrons in parallel. It enables to drive two klystrons simultaneously. The first modulator was made in 2003 in full spec, while the second one in 2004 mounts a single PFN and is half spec. The first will be used for New XTF. The second is used for klystron testing. It runs at Klystron Test Station (in KEKB Injector) to drive a single klystron. 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 9

The New XTF PFN Voltage(kV) 50 40 30 20 10 0 XTF Modulator (test result and operation) The test was successfully done. Klystron : 1, Inverter PS : 4, Repe. Rate : 150 Hz, Vpfn : 35 kv. PFN Voltage Power Supply Current(Slave) Power Supply Current(Master) -10-0.5-10 -5 0 5 10 15 20 25 Time(ms) 2.5 2 1.5 1 0.5 0 Charging Current(A) Klystron Voltage(kV) -600-2 0 2 4 6 8-50 10 Time(µs) 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 10 100 0-100 -200-300 -400-500 Klystron Current Klystron Voltage Pule width : 4.5 µs Flat-top width : >1.6µs(±0.5%) Rise time : 0.9µs(10-90%) Pulse voltage stability : ±0.15% We have operated both of the modulators for past one to two years. The operation has been stable. We have had no chance to do the two-tube operation so far. This is to be done in NEW XTF. 300 250 200 150 100 50 0 Klystron Current(A)

The New XTF PPM X-band Klystron for XTF Operation Parameters for XTF Operating Frequency 11.424 GHz RF Pulse Width 0.4 µs Peak Output Power 50 MW Beam Voltage 460 kv Repetition Rate 50 pps Efficiency 43 % The klystrons have been developed as prototypes of the GLC 75MW klystron. 4 klystrons are alive. 2 klystrons: waiting for New XTF 1 klystron: running at Klystron Test Stand. We plan to rebuild 1 klystron in this FY. 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 11

Contents The New X-band Test Facility (XTF) and X- band Klystron Test Stand Ongoing High Power Test at Klystron Test Stand: Narrow Waveguides Ongoing X-band research Future plans and possible collaborations. Summary 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 12

Ongoing Test Narrow Waveguides To study the characteristics of different materials (Cu, SUS, Mo, Ti, etc.) on high-field rf breakdown we designed a simplified waveguide, as the field of 200MV/m being realized at rf power of 100MW. Prototype Cu002 had been tested at (Old) X- Band Test Facility (XTF) for about a month. We have observed rf breakdowns by bursts of x-rays, flashes of visible lights and acoustic signals. Test of Type SUS003 has just been started at Klystron Test Stand. 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 13 K.Yokoyama, T.Higo, N. Kudoh

Ongoing Test Design of the Narrow Waveguide 200MV/m@100MW Type of Cu002 Input @100MW To study the characteristics of different materials on high-field rf breakdown. WR90 (the height and the width are reduced) a=22.86 14mm VSWR 1.05 (HFSS) Cu, SUS, Mo, Ti, Cr, etc. b=10.16 1mm 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 14 K.Yokoyama, T.Higo, N. Kudoh

Ongoing Test Breakdown Location and Threshold (Prototype Cu002) (This first test was done at Old XTF.) Locations of PMTs and acoustic sensors Observed BD Threshold was much lower than expected. PMT5 Array of Acoustic Sensors Breakdowns PMT4 PMT3 PMT2 PMT1 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 15 K.Yokoyama, T.Higo, N. Kudoh

Ongoing Test Narrow Waveguides Test has just (re)started at X-band Klystron Test Stand Klystron Test Stand with Narrow Waveguide Test Setup XTF Modulator ~50MW PPM Klystron High Power Dummy Load Apr 16: Installation started Apr 25~27: Baking May 7~: RF ON, system check May 21~: Testing of Narrow waveguides made of SUS (SUS003) Jun. ~: Testing of Narrow waveguides made of Cu (Cu004) Sep. ~: High gradient Testing is started at new XTF(once avilable). 5mm thick Lead Shield Box 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 16 K.Yokoyama, T.Higo, N. Kudoh

Contents The New X-band Test Facility (XTF) and X- band Klystron Test Stand Ongoing High Power Test at Klystron Test Stand: Narrow Waveguides Ongoing X-band research: Surface Treatment and RF BD and/or Dark Current Future plans and possible collaborations. Summary 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 17

Ongoing X-band research Attempt on small amount of dark current and breakdown rate at high gradient by removing particles and metal impurities on the cavity surface Recipe for the surface treatment removing particles and metal impurities techniques - Using a semiconductor wet cleaning solution and Mega-sonic Making thin Cu 2 O layer on the cavity surface - Vacuum baking at 500 deg.c Keeping good cleanness at installation into the high gradient test setup - Making class 100 environment High gradient test structures - Single and 3-cell SW structure Test data analysis - Needs statistically analysis - Single cell : 7 structures, 3-cell : 5 structures should be required 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 18 Yasuo Higashi

Ongoing X-band research Yasuo Higashi removing particles and metal impurities techniques Catalogs data of Si wafer cleaning by KANTO CHEMICAL CO. Ltd. We use Frontier Cleaner W-A02 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 19

Ongoing X-band research Yasuo Higashi 2 nd Single cell SW structure preparation A-02 solution + Megasonic cleaning 960kHz, 600 W, 5 minutes operation Ultra Pure Water All parts were applied megasonic cleaning Assemble envelopment: Class 10 No vacuum leak 300 degc baking, period : 5days Still needs to improve the cleaning techniques These structures may be tested once New XTF starts up. 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 20

Contents The New X-band Test Facility (XTF) and X- band Klystron Test Stand Ongoing High Power Test at Klystron Test Stand: Narrow Waveguides Ongoing X-band research Future plans and possible collaborations. Summary 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 21

Future Plans, Whole plan of X-band activity at KEK 2006 2007 2008 2009 2010 Design electrical and mechanical SLAC short-cell stack Fabrication of CLIC equivalent. acc structure Trial fabrication Fabrication of actual acc Low power test structure Feasibility of CLIC scheme High power test GLC acc structur e High power / high field experiment at New XTF Narrow Basic structure waveguide CLIC acc structure CLIC equivalent, acc structure High power test at SLAC and CERN Compact accelerator fabrication and testing RF Gun for Tokyo U. 2 nd 1MeV 1 st 1MeV accelerator accelerator Several MeV accelerator... Work not related with XTF directly although some members of KEK X- band group are doing this research. 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 22

Future Plans, X-band activities in 2007 Discuss with SLAC and CERN on collaboration High-field test with narrow waveguide Cu with various surface condition Comparison among Cu, SUS, Mo, Ti,. High-field test at new XTF Firstly establishing high-power test system Accelerator structure test High-field tests in general Test fabrication of CLIC structure (with MEC) Acquire the experience of CLIC design Fabrication of cavities for test at SLAC KLY lab. Surface treatment method Fabrication of compact accelerator 1MeV accelerator, RF Gun, etc. 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 23

Future Plans, XTF plan in 2007 KLY test station (50MW level) Apr.-July: Narrow waveguide high-field test Summer~: Continue waveguide components tests Jan.~: Rebuilt klystron test New XTF (100MW level) June-July: Check two klystron operation Aug.-Sept.: Operation with combining two klystrons Oct.: Startup high field study system with an old GLC structure Nov.-Dec.: High-field test of CLIC-related structure As needed: Narrow waveguide test, single-cell test, etc. Welcome any high power test plan 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 24

Summary 1. X-band activity in KEK will continue at least the next few years in close relationship with KEKB Injector RF and ACC groups. 2. 50MW X-Band Klystron Station is running. 100MW New XTF (name not fixed yet) will be ready to go half in summer and full in autumn 2007. 3. We expect 100MW 0.4us 50pps pulses available at New XTF. 4. These X-band facilities are open to (international) collaborations. 5. KEK X-band group conducts basic RF breakdown experiments as well as the accelerating structure and component tests. 6. Development of the key devices or the components, such as a klystron, will be continued (although the budget is very tight.) 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 25

KEK X-Band Group: List of the peoples participate in these researches Mitsuo Akemoto, Shigeki Fukuda, Toshiyasu Higo, Takuya Kamitani, Noboru Kudoh, Shuji Matsumoto, Tetsuo Shidara, Kazue Yokoyama, Mitsuhiro Yoshida Accelerator Laboratory, KEK Yasuo Higashi, Toshikazu Takatomi, Kenji Ueno Mechanical Engineering Center, KEK 5/30/2007 US High Field Gradient Collaboration Workshop, SLAC. 26