CIEMAT CONTRIBUTION TO TBL PETS (January 2009)

David Carrillo on behalf of the Accelerators Team

TBL - PETS (Test Beam Line - Power Extraction & Transfer Structure)

• CIEMAT is responsible for TBL PETS prototype • PETS should generate 12 GHz RF power in interaction with the drive beam• 16 PETS will be placed at TBL to test stability of the decelerated beam

PETS RF designs

30 GHz PETS designed by D.Carrillo (CIEMAT) & I.Syratchev (CERN)

12 GHz PETS designed by I.Syratchev(CERN)

•Single choke mirror•Two waveguide extractor

PETS: General layout

Copper rods

Power extractor Vacuum port

WR90 waveguide

Supports

Fiducials

Cooling pipes

Copper rods

• Each PETS is made of eight OFE copper rods (800 mm)• These are the most difficult parts to fabricate: overall tolerance is +/- 0.02 mm and

roughness should be better than 0.4 micron• The coupling cell is smaller: two different tools are necessary• Two intermediate thermal treatments to release internal stresses

Copper rod

Single rod RF test bench

• A special test bench has been designed to do RF measurements on each rod• Dummy rod phase slip was 121° for 123 cells, that is, about 1° per cell• Results agree with 3-D measurements

Mode TE10

HFSS modelE field and probe

Phase S31 vs position

RF absorbers

• Several samples from different companies (SiC, AlN composite) were tested at CERN and CIEMAT

• The present PETS prototype will not have absorbers. Further work is necessary for the future

Measuring electrical properties of ceramics

RF absorbers

Power extractor• It consists of three disks of 140 mm

diameter• They will be brazed with a 1 mm

wire, 78Ag22Cu alloy• The waveguides have three

flanges, the two outermost of them should be vacuum tight

• A special test bench has been designed to measure the assembly of rods

• Mode launchers have been optimized to create the working mode in the PETS, using the coaxial cable coming from the network analyzer

• A coaxial antenna will measure the field through the slots between the rods

Eight rods RF test bench

• 316LN CF flanges• Two pumping ports: ionic and turbo• Instrumentation ports: temperature

sensors and four for assembly and free for future uses

• Reference pins at the endplates

Vacuum tank

• Round ¼” OFE copper pipe• 1 m/s, 0.3 bar pressure drop, four

circuits, 2°C estimated temperature increase

• Vacuum-tight stainless steel connectors brazed to copper pipes, using Helicoflex gaskets

Cooling

CIEMAT contribution to a Race Track Microtron: LINAC

David Carrillo on behalf of the Accelerators Team

RTM (Race Track Microtron) Layout

• RTM IORT (Intraoperative radiation therapy ) • Electron beam up to 12 MeV• CIEMAT is responsible for LINAC

124

57

6

(1) Electron gun(2) LINAC(3) (4)end magnets M1 & M2 (5) Quadrupole lens (6) Extraction magnets (7) Extracted beam

RTM (Race Track Microtron) LINAC design

Biperiodic structure

f = 5.712 GHz

H field

E field

HFSS model

Solid works model Cavity test RF measurements

Accelerating cell without nose cones for testing

Conclusions Eight 800 mm long copper rods (1 PETS) have been machined

and will be assembled and measured next month

Two RF measurement benches, both for a single rod or eight ones, have been developed

No material has been identified as a good RF absorber up to now: it is necessary for CLIC PETS

CERN and CIEMAT will share the production of the next seven PETS units to be installed before the end of 2010

CIEMAT is responsible for a small LINAC for an RTM with medical purposes