D bb llF b i ti dT i Dumbbell Fabrication and Tuning Dumbbell Fabrication and Tuning Dumbbell Fabrication and Tuning J Gao Y L Chi J Y Zhai J Yu Z Q Li T X Zhao J R J. Gao, Y. L. Chi, J. Y. Zhai, J. Yu, Z. Q. Li, T. X. Zhao, J. R J Z Ch J Q Qi B iji H ji liS i dT J. Z. Chen, J. Q. Qiao, Beijing Hejieli Science and T J. Z. Chen, J. Q. Qiao, Beijing Hejieli Science and T H Yuan H Yu J X Wang Beijing Institu H. Yuan, H. Yu, J. X. Wang, Beijing Institu W P Xie Ningxia Orient Tantalum In THPPO067 W. P. Xie, Ningxia Orient Tantalum In THPPO067 As the key component of the “IHEP 1 3 GHz SCRF Accelerating Unit and These problems were due to the differ As the key component of the IHEP 1.3 GHz SCRF Accelerating Unit and These problems were due to the differ Horizontal Test Stand Project” a low-loss shape bare tube 9-cell cavity grains with different crystal orientation Horizontal Test Stand Project , a low-loss shape bare tube 9-cell cavity grains with different crystal orientation using Ningxia large grain niobium is being fabricated at IHEP This paper supposed to be eliminated by CBP on th using Ningxia large grain niobium is being fabricated at IHEP . This paper supposed to be eliminated by CBP on th presents the fabrication procedure and frequency tuning method of the adjusted the roundness of the half cells presents the fabrication procedure and frequency tuning method of the d bb ll f thi it D t th il ti f th l i adjusted the roundness of the half cells Th fi l d l th 0 2 dumbbells of this cavity . Due to the special properties of the large grain The final roundness was less than 0.2 m material se eral mechanical and RF problems ere fo nd and s ccessf ll The final roundness was less than 0.2 m material, several mechanical and RF problems were found and successfully solved After equator welding this cavity will be surface treated late this year solved. After equator welding, this cavity will be surface treated late this year and tested early next year and tested early next year . L L L G i 9 ll C it L L L G i 9 ll C it Low Loss Large Grain 9-cell Cavity Low Loss Large Grain 9-cell Cavity Low Loss Large Grain 9-cell Cavity Low Loss Large Grain 9-cell Cavity The combination of the low-loss shape and large grain niobium material is The combination of the low loss shape and large grain niobium material is expected to be the possible way to achieve higher gradient and lower cost expected to be the possible way to achieve higher gradient and lower cost f ILC 9 ll iti Th t d ti f th l i i bi iti D bb D bb for ILC 9-cell cavities. The cost reduction of the large grain niobium cavities Dumbbe Dumbbe lies in eliminating electro polishing process and the ne l de eloped m lti Dumbbe Dumbbe lies in eliminating electro-polishing process, and the newly developed multi- wire slicing technique on large grain niobium ingots at KEK We chose two half cells with similar iris wire slicing technique on large grain niobium ingots at KEK. We chose two half cells with similar iris outside EBW were performed on the iris A low-loss 9-cell cavity with full end groups is also under development. outside EBW were performed on the iris A low loss 9 cell cavity with full end groups is also under development. Th d ll h th HOM l d th d lt ill b ti i d t problems in spite of the large iris wall th The end cell shape, the HOM couplers and the end plate will be optimized to problems in spite of the large iris wall th damp higher order modes and red ce high field Lorent force det ning dumbbell length after iris and stiffening ri damp higher order modes and reduce high field Lorentz force detuning dumbbell length after iris and stiffening ri according to ILC requirements This cavity will be installed into the future according to ILC requirements. This cavity will be installed into the future short cryomodule (HTS) for the horizontal test at IHEP short cryomodule (HTS) for the horizontal test at IHEP . Dumbbell Freque Dumbbell Freque Dumbbell Freque Dumbbell Freque Dumbbell Freque Dumbbell Freque The contact surface between the old d The contact surface between the old d Ni bi I ti Ni bi I ti and the equator surface was a 3 mm thi Niobium Inspection Niobium Inspection and the equator surface was a 3 mm thi Niobium Inspection Niobium Inspection cells and dumbbells were below 1000 cells and dumbbells were below 1000, li d h d d h plain and hard contact need much more Ultrasonic and eddy current scanning were both performed on some of the plain and hard contact need much more th fi t ith di l lt Ultrasonic and eddy current scanning were both performed on some of the thus a new fixture with radial slots on large grain niobium disks provided by OTIC Ningxia Some initial results of fabricated for good RF contact With the large grain niobium disks provided by OTIC, Ningxia. Some initial results of th lt i i d t h t df t f th t il fabricated for good RF contact. With the the ultrasonic scanning seemed to show no apparent defects of the material, values of the half cells and dumbbells the ultrasonic scanning seemed to show no apparent defects of the material, hil f th i ti ti d i t f th i ti th d values of the half cells and dumbbells while further investigation and improvement of the inspection methods are stable at kHz needed The measured RRR value of the large grain niobium is 430 stable at kHz. needed. The measured RRR value of the large grain niobium is 430. D bb ll R h D bb ll R h Half Cell Fabrication and Reshaping Half Cell Fabrication and Reshaping Dumbbell Reshap Dumbbell Reshap Half Cell Fabrication and Reshaping Half Cell Fabrication and Reshaping Dumbbell Reshap Dumbbell Reshap Half Cell Fabrication and Reshaping Half Cell Fabrication and Reshaping S l bl f d d i th fbi ti f h lf ll f l With a special jig we reshaped the dum Several problems were found during the fabrication of half cells from large With a special jig, we reshaped the dum grain material Earrings and steps were found in the equator area Large the parallelism to be less than 0 2 mm grain material. Earrings and steps were found in the equator area, Large the parallelism to be less than 0.2 mm cracks and unsmooth were found between adjacent grains in the iris area sum of the two half cells length before w cracks and unsmooth were found between adjacent grains in the iris area. sum of the two half cells length before w Iris wall thickness was not uniform after trimming (the largest thickness the perturbation method [1] we mea Iris wall thickness was not uniform after trimming (the largest thickness the perturbation method [1], we mea i di id l f f h h lf ll difference is nearly 1 mm) The spring back after deep drawing of the half individual frequency of the half cells o difference is nearly 1 mm). The spring back after deep drawing of the half individual frequency of the half cells o 50 kH cell was large according to 3D measurement and the equator became oval was 50 kHz. cell was large according to 3D measurement and the equator became oval d t it l t due to internal stress. f th IHEP L G i 9 ll C it g of the IHEP Large Grain 9 cell Cavity g of the IHEP Large Grain 9-cell Cavity g of the IHEP Large Grain 9 cell Cavity R Zhang J Gu M Hou J P Dai IHEP Beijing 100049 China R. Zhang, J. Gu, M. Hou, J. P. Dai, IHEP, Beijing 100049, China T h l D l tC Ltd B iji 100026 Chi Technology Development Co. Ltd., Beijing 100026, China Technology Development Co. Ltd., Beijing 100026, China ute of Aviation Materials Beijing 100095 China ute of Aviation Materials, Beijing 100095, China ndustry Co Ltd Shizuishan 753000 China ndustry Co. Ltd., Shizuishan 753000, China rent mechanical properties of the large Then according to the DESY cavity tuning method [2] and the estimated rent mechanical properties of the large Then, according to the DESY cavity tuning method [2] and the estimated n The steps and unsmooth area are 9 cell cavity frequency and length evolution we calculated the trimming n. The steps and unsmooth area are 9-cell cavity frequency and length evolution, we calculated the trimming he 9-cell cavity For the oval shape We length for each half cell of the dumbbell The tuning target frequency of the he 9-cell cavity . For the oval shape, We length for each half cell of the dumbbell. The tuning target frequency of the by reshaping the equator with a fixture dumbbell π mode was 1298 277 MHz and the target length was 57 96 mm by reshaping the equator with a fixture. dumbbell π mode was 1298.277 MHz, and the target length was 57.96 mm. D t th l ti l bi tt i f th h lf ll l th d f mm. Due to the relatively big scattering of the half cell length and frequency, we mm. Due to the relatively big scattering of the half cell length and frequency, we ill k d bb ll t hi f t EBW di t b th th t will make dumbbell matching for equator EBW according to both the equator diameter and the tuning requirement diameter and the tuning requirement. Dumbbell Tuning Example Dumbbell Tuning Example 1.5 mm Dumbbell Half cell Trimming Pretuning Dumbbell # Length Half cell # frequency length Length Dumbbell # Length / mm Half cell # frequency / MHz length / mm Length / mm / mm / MHz / mm / mm #7 1298 721 0 45 0 29 #7 1298.721 0.45 0.29 ll EBW ll EBW #7-14 117.95 ell EBW ell EBW #14 1298.072 0.88 0.41 ell EBW ell EBW #14 1298.072 0.88 0.41 diameter to form a dumbbell Inside and diameter to form a dumbbell. Inside and s The EBW of the iris did not meet big Cavity Frequency Change and Control s. The EBW of the iris did not meet big f / MH Final Frequency Target ickness difference The shrinkage of the f / MHz Key Frequency Point ickness difference. The shrinkage of the Measurable Frequency Point ng EBW is about 2 mm Unmeasurable Frequecy Point Horizontal Test Tuner Tuning Range, typically Slow tuner 500 kHz, Piezo 1 kHz ng EBW is about 2 mm. Controllable Frequecy Change 1300 000 C it i C dl Uncontrollable Frequency Change VT Power Source Range 1300.000 Cavity in Cryomodule Equator Tuning Available Region 0 1 1 Cryomodule Vacuum Shrinkage Tuning Available Region 0 -1 1299.500 10 2 LHe Pressure CBP 11 13 Cavity Vertical Test 1 13 9 EP or CP -1 2 8 9 Dumbbell Deform and Reform EP or CP -2 3 Temperature Pretuning 7 8 Annealing Temperature Pretuning Target Pretuning Target 12 EP or CP Dumbbell Ti i 4 6 Permittivity Trimming Stiffening Ring Shrinkage 5 to 2 5 Pressure Iris Shrinkage 14 0 Tuner Preload (HT) 1297.350 & Deformation 15 0 Tuner Preload (HT) ency Measurement ency Measurement EP or CP limit ency Measurement ency Measurement Field Flatness Tuning ency Measurement ency Measurement L / HALF CELLS 9-CELL CAVITY DUMBBELLS L / mm dumbbell frequency measurement fixture Pretuning Length Tolerance Range Half cell Length Dumbbell Reform Length Target Dumbbell Length Target Cavity Length Range (~ 2 mm) dumbbell frequency measurement fixture Tolerance Range Length Target Target ( 2 mm) ck niobium plate The Q values of the half ck niobium plate. The Q values of the half S and the frequency was not stable The Summary Summary and the frequency was not stable. The d d f fl Summary Summary e press and good equator surface flatness, e press and good equator surface flatness, thi lt d l ti h a thinner plate and elastic washers was e new fixture and about 10 kg press the Q Several problems have been solved during the fabrication EBW and e new fixture and about 10 kg press, the Q Several problems have been solved during the fabrication, EBW and t i f 13 d bb ll f th IHEP l i l l h 9 ll s are above 5000 and the frequency is tuning of 13 dumbbells for the IHEP large grain low-loss shape 9-cell s are above 5000, and the frequency is tuning of 13 dumbbells for the IHEP large grain low loss shape 9 cell it Th hl it ill b ld d d t td i lt 2009 d cavity . The whole cavity will be welded and treated in late 2009, and tested in KEK next spring tested in KEK next spring. Large grain niobium cavity fabrication has many special issues Large grain niobium cavity fabrication has many special issues. Dimension and frequency control related to material mechanical Dimension and frequency control related to material mechanical properties is important and needs more investigation properties is important and needs more investigation. [1] A S t l A th d t th f i f i di id l h lf ll i d bb ll it [1] A. Sun et al. A method to measure the frequencies of individual half cells in a dumbbell cavity . Review of Scientific Instruments 79 104701 2008 Review of Scientific Instruments, 79, 104701, 2008 [2] G Kreps et al Half cell and d mbbell freq enc testing for the correction of the TESLA ca it length [2] G. Kreps et al. Half-cell and dumbbell frequency testing for the correction of the TESLA cavity length. i dT i i dT i 9th workshop on RF superconductivity, Santa Fe, New Mexico, U.S.A, 1999 ping and Tuning ping and Tuning 9th workshop on RF superconductivity, Santa Fe, New Mexico, U.S.A, 1999 ping and Tuning ping and Tuning Acknowledgement Acknowledgement mbbells to the target length and adjusted Acknowledgement mbbells to the target length and adjusted m The reshaping target length was the We would like to thank K. Yokoya and H. Hayano of KEK, B. Kephart and S. m. The reshaping target length was the We would like to thank K. Yokoya and H. Hayano of KEK, B. Kephart and S. Mi h f F il b d th k t K S it d F F t f KEK f welding minus iris EBW shrinkage With Mishra of Fermilab, and many thanks to K. Saito and F . Furuta of KEK for welding minus iris EBW shrinkage. With i t t ti th 9 ll it fbi ti T Kh bib lli f asured six frequencies to calculate the important suggestions on the 9-cell cavity fabrication, T . Khabiboulline of asured six frequencies to calculate the f d bb ll Th b i Fermilab for the information of the dumbbell frequency measurement of a dumbbell. The perturbation amount Fermilab for the information of the dumbbell frequency measurement of a dumbbell. The perturbation amount fixture fixture.