RFCC Module Design Update automatic tuners cavity suspension cavity installation

RFCC Module Design

Update automatic tuners

cavity suspension

cavity installation

Steve VirostekLawrence Berkeley National Lab

MICE Collaboration Meeting 18 June 13, 2007

RF Cavity and Coupling Coil Module Design Update

Page 2Steve Virostek - Lawrence Berkeley National Lab

RF Cavity & Coupling Coil Modules in MICE

RFCC Modules



Updated RFCC Module 3D CAD Model



Updated RFCC Module 3D CAD Model

201 MHz RF cavity

Automatic tuners

Cavity suspension



Cavity End View with Tuners and Struts•Six tuners per

cavity provide individual frequency adjustment

•Tuning automatically achieved through a feedback loop

•Six struts per cavity provide a kinematic mounting system

•Struts fix cavity position without over-constraint



Cavity Tuner Design Features

•Tuners are spaced evenly every 60º around cavity

•Layout is offset by 15º from vertical to avoid conflict with cavity ports

•Tuners touch cavity and apply loads only at the stiffener rings

•Tuners operate in “push” mode only (i.e. squeezing)



Four Cavity Layout in Vacuum Vessel •Clocking of tuner

position between adjacent cavities avoids interference

•Actuators offset from cavity center plane due to width of coupling coil

•Soft connection only (bellows) between tuner/actuators and vacuum vessel shell



Cavity Tuner Section View

Ball contact only

Dual bellowsfeedthrough

Tuner actuator(likely air)

Pivot point

Fixed (bolted)connection



Tuner component Details

Fixed arm

Pivoting arm

Actuator& bellowsassembly

Forces are transmitted to the stiffener ring by means of “push/pull” loads applied to the tuner lever arms by the actuator assembly



Cavity Tuning Parameters

The following parameters are based on a finite element analysis of the cavity shell. Tuning range is limited by material yield stress.

•Overall cavity stiffness: 6120 N/mm

•Tuning sensitivity: +115 kHz/mm

•Tuning range: 0 to -460 kHz (0 to -4 mm)

•Number of tuners: 6

•Maximum ring load/tuner: 4.1 kN

•Max actuator press. (50 mm): 1.6 MPa (230 psi)



Cavity Suspension System

•Six strut system provides kinematic cavity support

•Orthogonal layout of struts allows accurate cavity alignment and positioning

•Kinematic mounts prevent high cavity stresses caused by thermal distortion and over-constraint



Cavity Suspension System

1 vertical strut

2 horizontal struts

3 axial struts



Strut End Connection Details

One end of the struts is attached to a fixed lug welded to the ID of the vacuum vessel

The cavity end of the vertical and one of the horizontal struts are attached directly to the stiffener ringThe cavity end of the axial and one of the horizontal struts are attached to the fixed leg of a tuner



Four Cavity Layout in Vacuum Vessel •Each cavity

contains a dedicated set of suspension struts

•No contact between pairs of close packed cavities

•Struts designed to axially fix outside end of cavity pairs

•Tuning deflections increase cavity gap



Cavity Installation Sequence

•Pre-assemble cavities with Be windows and tuners (w/o actuators)

•Slide inner cavities into vacuum vessel using spacer/alignment blocks

•Shim cavity to align tuner & coupler vacuum feedthus with tuner mounts and cavity ports

•Install struts, tuner actuators and RF couplers

•Repeat same process for outer cavities

Documents

RFCC Module Design Update automatic tuners cavity suspension cavity installation