OPERATION TESTS of the 260 MHz 1500 W SOLID STATE RF AMPLIFIER at TARLA FACILITY

Öz Turkish Accelerator and Radiation Laboratory (TARLA) will be the first accelerator-based user facility in Turkey. The facility is under construction at the Institute of Accelerator Technologies of Ankara University. Based on the state-of-art superconducting technology, TARLA accelerator offers a multi-experimental facility providing a variety of accelerator-based radiation sources for users coming from various fields like chemistry, physics, biology, material sciences, medicine and nanotechnology. TARLA consists of two acceleration lines: the first one is the injector that provides high current continuous wave (CW) electron beam at 250 keV energy, and the second one is the main accelerator that comprises of two superconducting (SC) cryomodules separated by a bunch compressor in order to accelerate the electron beam up to 40 MeV energy. Two normal conducting accelerators, so called subharmonic (SHB) and fundamental (FB) buncher cavities whose operation frequencies are 260 and 1300 MHz, respectively, are used to compress the electron bunches from ~600 ps to ~10 ps. SHB cavity is powered by a 1500 W Radio-frequency (RF) power amplifier. Currently, the electron gun training, and superconducting modules acceptance tests, personal safety system, and helium cryogenic system commissioning tests are performed simultaneously. In this study, we present the operation tests of the 1500 W RF amplifier in the scope of the commissioning tests of injector line which showed phase drift coefficents of ~0.5 deg/Co and ~0.67 deg/Co in repeated tests. Moreover, the importance of constancy of the water pressure in the water-cooling line for phase constancy of the delivered power has become evident as a result of current obervations.

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Aksoy, A., Karslı, O. and Yavas, O., The Turkish accelerator complex IR FEL project, Infrared Phys. Technol., 51/5 (2008) 378-81.

Aksoy, A. and Karsli, O. (Eds.), The technical design report of Turkish Accelerator and Radiation Laboratory in Ankara, Technical Report (Ankara University, 2015).

Aksoy, A., Karsli, O., Aydin, A., Kaya, C., Ketenoglu, B., Ketenoglu, D. and Yavas, O., Current status of Turkish Accelerator and Radiation Laboratory in Ankara: the TARLA facility, Can. J. Phys., 96/7 (2018) 837-42.

Karsli, O., Aksoy, A., Kaya, C., Koc, B., Dogan, M., Elcim, O.F. and Bozdogan, M., High power RF operations studies at TARLA facility, Can. J. Phys., Accepted: https://doi.org/10.1139/cjp-2018-0778.

Wangler, T.P., RF Linear accelerators, John Wiley & Sons, 2008.

Karsli, O., Yavas, O. and Dogan, M., Design of L Band 20 kW High Power Solid State Amplifier for TARLA/TAC Project, Известия высших учебных заведений. Физика., 55/10-3 (2012) 154-9.

Karsli, O. and Yavas, O., A design study on high power RF system for the TARLA facility of TAC, Nucl. Instrum. Methods Phys. Res. A, 693 (2012) 215-9.

Wang, F., Liu, K., Feng, L., Lin, L., Zhang, B., Hao, J. and Quan, S., Using a 1.3 GHz 20 kW Solid State Amplifier as RF Power Supply for DC-SRF Photo-injector, 6th Workshop on ERL, New York, USA 2015.

Dillon, S., Schach, C. and Nobel, B., Design of a high speed pulsed 324 MHz solid-state amplifier for use in a beam chopper, IPAC2012, Louisiana, USA, (2012) 2242-4.

Frenzel, L.E., RF power for industrial applications, Pearson Prentice Hall 2004.

SigmaPhi Accelerator Technologies, https://www.sigmaphi.fr/en/produits/ampli-ficateurs-radiofrequence, Accessed: 2019-03-20.

National Instruments, http://www.ni.com/en-tr/shop/labview/labview-details.html, Accessed: 22.03.2019.

Wurlich, A., CERN Accelerator School, CERN-94-01, 1994.

Wiedemann, H., Particle accelerator physics, (Vol. 314), Springer, Berlin, 2007.

Chao, A.W., Handbook of Accelerator Physics and Engineering, 2nd Printing, World Scientific Publishing Co. Pte. Ltd., pp.256, 1998.

Pozar, D. M., Microwave engineering, 4th Edition, John Wiley & Sons, 174 Chapter 4, 2011.

MathWorks, https://www.mathworks.com/products/matlab.html, Accessed: 22.03. 2019.

Akre, R., Temperature Stability of RF Components, (2005). http://slac. stanford.edu/ grp/lcls/controls/global/subsystems/llrf/26sep2005Review/Temperature%20Stability%20of%20RF%20Components%20Apr%2005.pdf Accessed: 13.04.2019.

Akre, R., Emma, P. and Krejcik, P., Measurements on SLAC LINAC RF system for LCLS Operation

PACS2001, Proceedings of the 2001 Particle Accelerator Conference (Cat. No. 01CH37268), 2 (2001) 1453-1455.

Decker, F.J., Akre, R., Byrne, M., Farkas, Z.D., Jarvis, H., Jobe, K., Koontz, R., Mitchell, M., Pennacchi, R., Ross, M. and Smith, H., Effects of temperature variation on the SLC LINAC RF system, IEEE Proceedings of Particle Accelerator Conference, 3 (1995) 1821-1823.

MAX IV Detailed Design Report, https://www.maxiv.lu.se/accelerators-beamlines/accelerators/accelerator-documentation/max-iv-ddr Accessed: 13.04. 2019.

Suelzle, L.R., RF amplitude and phase stabilization for a superconducting linear accelerator by feedback stabilization techniques, High Energy Physics Lab, (1968), https://www.bnl.gov/magnets/staff/gupta/Summer1968/0067.pdf Accessed: 22.03. 2019.