Low Temperature Properties of 20 K Cooled Test Cavity for C-band 2.6-cell Photocathode RF Gun
| Autor: | Tanaka, Toshinari, Fukuda, Masafumi, Inagaki, Manabu, Nakao, Keisuke, Nogami, Kyoko, Sakai, Takeshi, Satoh, Daisuke, Shintomi, Takakazu, Takatomi, Toshikazu, Urakawa, Junji, Yoshida, Mitsuhiro |
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| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: | |
| DOI: | 10.18429/jacow-ipac2015-wepwa014 |
| Popis: | A cryogenic C-band 2.6-cell photocathode RF gun, which operates at 20 K, is under development at Nihon University for future possibility of use in a compact linac-driven X-ray source. The cavity material is 6N8 high purity copper, the RRR of which being expected to be higher than 3000. A 2.6-cell pi-mode test cavity was fabricated for investigation of the properties under low temperature of 20 K*. Ultraprecision machining and diffusion bonding of the cavity were carried out in KEK. The operating frequency of the RF gun cavity is 5712 MHz. The machining dimensions of the test cavity were determined by taking into account the contraction of copper from room temperature to 20 K by approximately 0.33 %. The resonant frequency observed at around 21 K was 5711.761 MHz, which is 185 kHz higher than the expected value that was deduced from the resonant frequency obtained at 23.5 degree C in vacuum and the linear expansion coefficient data for OFC copper by NIST**. The unloaded Q-value of 64500 obtained at 21 K is in agreement with the SUPERFISH calculation when the surface resistance of the RRR=3000 copper was specified with taking the anomalous skin effect into account. Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA |
| Databáze: | OpenAIRE |
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