CEBAF upgrade cryomodule component testing in the horizontal test bed (HTB)

Campisi, I.E.; Carpenter, Brian; Davis, G.; Delayen, Jean; Drury, M.; Feldl, E.; Fischer, J.; Guerra, A.S.; Hiatt, T.; Hovater, C.; Macha, K.; Mammosser, J.; Nguten, V.; Phillips, H.L.; Preble, J.

doi:10.1109/pac.2001.986605

Cited by 3 publications

(3 citation statements)

References 6 publications

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“…The CEBAF cryomodules use a waveguide (WG) with rectangular cross-section as a fundamental power coupler (FPC) [1,2] (Figure 1). In C100 cryomodules, the cold waveguide connects to the cavity flange directly [3]. In C20 and C75 style cryomodules, the FPC waveguide connects to the cold section at a flange on the helium vessel.…”

Section: Introductionmentioning

confidence: 99%

Copper plating qualification process for the fundamental power coupler waveguides for CEBAF cryomodules

Zhao,

Cheng,

Wilson

et al. 2023

SRF2023 (21st International Conference on Radio-Frequency Superconductivity), Grand Rapids, MI, USA, June 25, 2023

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To provide sufficient energy for CEBAF operation, cryomodules and components are being refurbished yearly as necessary. Copper-plated fundamental power coupler waveguides are important components of the cryomodules. The integrity and quality of copper plating is critical to reduce the heat load from the waveguides into the He bath at 2.07 K. A search of copper plating resources is underway for plating or re-plating CEBAF-style waveguides. This effort ensures a continuous capability of copper plating on cryomodule components, especially on waveguides. To qualify plating vendors, the waveguide copper plating specifications were revisited, and a thorough plating evaluation process is being developed. The evaluation process ranges from coupon testing to sample waveguide qualification. Recent results are summarized and future work is planned.

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Section: Introductionmentioning

confidence: 99%

Copper plating qualification process for the fundamental power coupler waveguides for CEBAF cryomodules

Zhao,

Cheng,

Wilson

et al. 2023

SRF2023 (21st International Conference on Radio-Frequency Superconductivity), Grand Rapids, MI, USA, June 25, 2023

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“…A prototype of the tuner, coupler, and cavity were tested at 2K in a Horizontal Test Bed (HTB) [2] constructed for this purpose. The cavity was locked to its resonant frequency with a phase locked loop (PLL).…”

Section: Prototype Testingmentioning

confidence: 99%

Development and testing of a prototype tuner for the CEBAF upgrade cryomodule

Davis

Delayen²,

Drury³

et al.

PACS2001. Proceedings of the 2001 Particle Accelerator Conference (Cat. No.01CH37268)

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An upgrade cryomodule is being developed for CEBAF at Jefferson Lab. The high-gradient, low-current operation of the superconducting cavities puts stringent requirements on the accuracy of the frequency tuner: a resolution of 1Hz over a range of 400kHz. We have developed and tested such a tuner; it consists of a steppermotor-driven coarse tuner, operating in series with a piezo-actuator-driven fine tuner. Tuner test procedures and results are summarized, including frequency resolution, range, and linearity (i.e. frequency vs. tuner position), as well as microphonic effects resulting from tuner operation. TUNER REQUIREMENTS AND SPECIFICATIONSThe tuning system has been divided into two parts: a coarse tuner with a range of +/-200kHz and resolution of 100Hz that is expected to be used infrequently, and a fine tuner with a range of +/-1kHz and resolution of 1Hz that will be used during normal operation [1]. Fig. 1: CEBAF Upgrade Tuner MECHANICAL DESIGNThe fine tuner makes use of piezoelectric actuators for continuous small corrections to the cavity frequency. A stepping motor, via a harmonic drive reducer and ball screw, actuates the coarse tuner. In order to make them accessible for maintenance and repair, both systems are at ambient temperature, and are outside the vacuum enclosure. The tuning motion of the drive system enters the cryostat through two thin-wall concentric tubes (Items 1 & 2, Fig. 1). The tubes are connected to the upper and lower arms (Item 3 & 4, Fig. 1) of a scissors type jack. The axial motion of the tubes translates into a linear stroke parallel to the cavity center line [1]. To eliminate friction, motion within the vacuum is by flexing Ti plates. PROTOTYPE TESTINGA prototype of the tuner, coupler, and cavity were tested at 2K in a Horizontal Test Bed (HTB) [2] constructed for this purpose. The cavity was locked to its resonant frequency with a phase locked loop (PLL). Tuner range and hysteresis (cavity frequency vs. tuner position, Fig. 2) were measured with a frequency counter. Tuner resolution (Fig. 3) was measured using a Cavity Resonance Monitor (CRM) instrument: a custom-built IQ demodulator which outputs a voltage proportional to the difference in frequency between the PLL and a reference LO (local oscillator). Test results are summarized in Table 1. Additionally, tests were performed on both tuners to analyze possible tuner-induced microphonics; these frequency shifts measured less than 0.3Hz peak. Finally, the dynamic response of the fine tuner was tested. Coarse TunerThe stepper motor was driven using a micro-stepping indexer which drives the stepper motor in 1/125 fractions of a whole motor step (µstep). Simultaneously, the cavity frequency was measured with a frequency counter. The cavity was exercised over the operating range of the tuner. This range is bounded at one end by the requirement to operate the cavity in tension, and at the other end by tuner mechanical limits. Testing showed a range of 343.8kHz. The coarse tuner range was less than the 400kHz design specificati...

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“…The CEBAF upgrade cryomodule assembly was tested in a Horizontal Test Bed (HTB) [1] to characterize the effects of vibrations on the cavity resonant frequency. Cavity vibrations cause small dynamic changes in cavity dimensions.…”

Section: Introductionmentioning

confidence: 99%

Microphonics testing of the CEBAF upgrade 7-cell cavity

Davis

Delayen

Drury

et al.

PACS2001. Proceedings of the 2001 Particle Accelerator Conference (Cat. No.01CH37268)

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An upgrade cryomodule is being developed for CEBAF at Jefferson Lab. In support of this effort, vibration testing was performed on a single SRF cavity at cryogenic temperature in a Horizontal Test Bed. The tests included response to excitation from background vibration, swept sinusoids, high-power RF pulses, and mechanical impulses. Test procedures, apparatus, and results are presented, along with a description of planned follow-up tests.

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CEBAF upgrade cryomodule component testing in the horizontal test bed (HTB)

Cited by 3 publications

References 6 publications

Copper plating qualification process for the fundamental power coupler waveguides for CEBAF cryomodules

Copper plating qualification process for the fundamental power coupler waveguides for CEBAF cryomodules

Development and testing of a prototype tuner for the CEBAF upgrade cryomodule

Microphonics testing of the CEBAF upgrade 7-cell cavity

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