CIEMAT contribution toPETS

David Carrillo

CTF3 Collaboration MeetingCTF3 Collaboration MeetingJanuary 2007January 2007

PETS: 30 GHz design

PETS

Matching Section

Wakefields

EXTRACTOR

Reflection and transmission72º phase advance per cell

15 mm aperture PETS

Damping of dangerous modes

Number of cells not to scale

Reflection of decelerating mode

400 mm long PETS

2 octants of PETS were ordered to two Spanish firms, only one was successful.

Critical zones: undulated profile and fillet radius EDM used to create sinusoidal profile Profile shifted but good (shift produced by a first milling process of the

flat surfaces in a non controlled-temperature environment) Roughness 0.8um > specifications (0.2um)

by courtesy of Mauro Taborelli. CERN

400 mm long PETS

Milling was used for fillet radius, but it wasn’t well done on the valleys: there were problems with positioning and with CAD/CAM machine system

Pictures by courtesy of Mauro Taborelli. CERN

Next pieces

One piece of 40 mm long has been made by a different company. Completely produced by milling.

This piece is being measured at CERN at the moment. Preliminary results show inaccuracy on the top and the bottom of valleys. Company used a conventional milling machine with a multiplier (error due to vibrations).

Same piece has been ordered to the company which produced the best 400mm PETS.

For this piece, high speed milling machine will be used (14000rpm)

By courtesy J. Gomez, Vacuum Projects

CONCLUSIONS A 30 GHz PETS design was realized

Structure optimized for decelerating mode Good extraction of power Damping of dangerous modes

Two 400 mm octants were machined with EDM + milling Roughness specification of 0.2um was not achieved (0.8um) Profile of undulation was accurate

One 40 mm octant was machined with conventional milling

One 40 mm octant will be machined with high speed milling We are confident in achieving accurate profile and roughness If so, an octant of 400 mm will be the next step

Latest news (12GHz) Tolerances now are relaxed, so the profile of the new design it

seems easier to machine… but it must be studied.