21 research outputs found
Quality Factor Enhancement of 650 MHz Superconducting Radio-Frequency Cavity for CEPC
Medium-temperature (mid-T) furnace baking was conducted at 650 MHz superconducting radio-frequency (SRF) cavity for circular electron positron collider (CEPC), which enhanced the cavity unloaded quality factor (Q0) significantly. In the vertical test (2.0 K), Q0 of 650 MHz cavity reached 6.4 × 1010 at 30 MV/m, which is remarkably high at this unexplored frequency. Additionally, the cavity quenched at 31.2 MV/m finally. There was no anti-Q-slope behavior after mid-T furnace baking, which is characteristic of 1.3 GHz cavities. The microwave surface resistance (RS) was also studied, which indicated both very low Bardeen–Cooper–Schrieffer (BCS) and residual resistance. The recipe of cavity process in this paper is simplified and easy to duplicate, which may benefit the SRF community
SRF Cavity Searches for Dark Photon Dark Matter: First Scan Results
We present the first use of a tunable superconducting radio frequency cavity
to perform a scan search for dark photon dark matter with novel data analysis
strategies. We mechanically tuned the resonant frequency of a cavity embedded
in the liquid helium with a temperature of K, scanning the dark photon mass
over a frequency range of MHz centered at GHz. By exploiting the
superconducting radio frequency cavity's considerably high quality factors of
approximately , our results demonstrate the most stringent constraints
to date on a substantial portion of the exclusion parameter space, particularly
concerning the kinetic mixing coefficient between dark photons and
electromagnetic photons , yielding a value of .Comment: 11 pages, 7 figure