High gradient studies for ILC with single-cell re-entrant shape and elliptical shape cavities made of fine-grain and large-grain niobium

Geng, Rongli; Eremeev, Grigory; Shemelin, Valery

doi:10.1109/pac.2007.4441242

Cited by 28 publications

(25 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4 [13], [14]. A new RE cavity shape with the same aperture as the LL shape has reached 59 MV/m in a Cornell/KEK collaboration [11], [15].…”

Section: A Cavity Shapesmentioning

confidence: 99%

Superconducting RF Cavity Development for the International Linear Collider

Yamamoto

2009

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

The International Linear Collider is planned as the next energy-frontier electron-positron accelerator. The main linacs of the collider are based on superconducting radio-frequency cavity technology, and will accelerate electron and positron beams up to 250 + 250 GeV at the center-of-mass energy. Based on the Reference Design Report issued in 2007, the ILC Global Design Effort has moved into the Technical Design phase. This paper describes the status of the design, R&D efforts, and plans of the superconducting RF cavity for the ILC.

show abstract

“…4 [13], [14]. A new RE cavity shape with the same aperture as the LL shape has reached 59 MV/m in a Cornell/KEK collaboration [11], [15].…”

Section: A Cavity Shapesmentioning

confidence: 99%

Superconducting RF Cavity Development for the International Linear Collider

Yamamoto

2009

IEEE Trans. Appl. Supercond.

View full text Add to dashboard Cite

show abstract

“…8) To the best of author's knowledge, the highest gradient with bulk Nb cavities obtained so far is 59 MV/m which corresponds to peak surface magnetic and electric fields of 206.5 mT and 125 MV/m, respectively, with a so-called re-entrant shape 1.3-GHz 1-cell cavity at Cornell. 9) The effort to raise cavity Q0, quality factor that is inversely proportional to the RF surface resistance, has been the focus of bulk Nb cavities in the recent years especially since nitrogen doping was discovered to be effective in raising the Q0 dramatically up to a relatively high field. 10) Another effort to reduce the cost and possibly improve performance is to use large-grain Nb sheets sliced from ingot.…”

Section: Introductionmentioning

confidence: 99%

Application of MgB<sub>2</sub> to Superconducting Radio-Frequency Cavities

Tajima

2022

TEION KOGAKU

View full text Add to dashboard Cite

Synopsis: Advances in the research and development on MgB2 toward the application to superconducting radio-frequency (SRF) cavities for particle accelerators are reviewed. Evaluations using small flat thin film samples have shown promising results and the techniques to coat the interior of SRF cavities with MgB2 are being developed. We will probably see some results of standard 1.3-GHz cavities coated with MgB2 within 5 years. If MgB2 coated cavities are successfully developed, a new class of SRF cavities operated at ~20 K with cryocoolers will be possible. Such accelerators can be used more easily at 20 K than at 4 K since higher capacity cryocoolers are available and the static heat load is more tolerable. Future applications of such accelerators include, but not limited to, environmental remediation and national security in addition to physics and material science.

show abstract

“…Reduction of R s (or improvement of Q) has been the primary interest of researchers of resonant cavities over the last decades. Vortex-free Nb cavities [50][51][52][53][54][55] exhibit huge quality factor Q ∼ 10 10 -10 12 at T < 2 K [56][57][58][59] even under the strong rf current [60][61][62][63] close to the depairing current density. The depairing current density J d is related to the bias current of SSPD and is the maximum current that SRF cavities and superconducting cables can support.…”

Section: Introductionmentioning

confidence: 99%

Effects of nonmagnetic impurities and subgap states on the kinetic inductance, complex conductivity, quality factor and depairing current density

Kubo

2021

Preprint

View full text Add to dashboard Cite

We investigate how a combination of a nonmagnetic-impurity scattering rate γ and finite subgap states parametrized by Dynes Γ affects various physical quantities relevant to to superconducting devices: kinetic inductance L k , complex conductivity σ, surface resistance Rs, quality factor Q, and depairing current density J d . All the calculations are based on the Eilenberger formalism of the BCS theory. We assume the device materials are extreme type-II s-wave superconductors. It is well known that the optimum impurity concentration (γ/∆0 ∼ 1) minimizes Rs. Here, ∆0 is the pair potential for the idealized (Γ → 0) superconductor for the temperature T → 0. We find the optimum Γ can also reduce Rs by one order of magnitude for a clean superconductor (γ/∆0 < 1) and a few tens % for a dirty superconductor (γ/∆0 > 1). Also, we find a nearly-ideal (Γ/∆0 ≪ 1) clean-limit superconductor exhibits a frequency-independent Rs for a broad range of frequency ω, which can significantly improve Q of a very compact cavity with a few tens of GHz frequency. As Γ or γ increases, the plateau disappears, and Rs obeys the ω 2 dependence. The subgap-state-induced residual surface resistance Rres is also studied, which can be detected by an SRF-grade high-Q 3D resonator. We calculate L k (γ, Γ, T ) and J d (γ, Γ, T ), which are monotonic increasing and decreasing functions of (γ, Γ, T ), respectively. Measurements of (γ, Γ) of device materials can give helpful information on engineering (γ, Γ) via materials processing, by which it would be possible to improve Q, engineer L k , and ameliorate J d .

show abstract

High gradient studies for ILC with single-cell re-entrant shape and elliptical shape cavities made of fine-grain and large-grain niobium

Cited by 28 publications

References 5 publications

Superconducting RF Cavity Development for the International Linear Collider

Superconducting RF Cavity Development for the International Linear Collider

Application of MgB<sub>2</sub> to Superconducting Radio-Frequency Cavities

Effects of nonmagnetic impurities and subgap states on the kinetic inductance, complex conductivity, quality factor and depairing current density

Contact Info

Product

Resources

About