on/off news. reflected transmitted stroke 8.0 mm rf power, db piston position (gap width), mm on off...
TRANSCRIPT
ON/OFF news
2 4 6 8 10 1250
40
30
20
10
0
Reflected
Transmitted
Stroke 8.0 mm
RF p
ower
, dB
Piston position (gap width), mm
ON
ON
OFF
OFF
Compact design of the high RF power variable (mechanically) reflector
Radiation through the chokes
The variable reflector is a core element of the PETS ON/OFF mechanism. It is activated when the local termination of the RF power production in PETS is required.
S-pa
ram
eter
s, d
BS-
para
met
ers,
dB
PETS ON/OFF operation (CLIC PETS)
Power to the structure
Power extracted from the drive beam
ON OFF
Open Closed
RF measurements
Broadband high RF power variable reflector prototype
Stroke 8 mm
High power variable short circuit
Originally the reflector was designed to provide reliably the 1800 phase advance.The dynamic range was increased up to about 2200 by further movement of he piston, until the chamber resonance became a danger. +30MHz
ONOFF
PETS output
Structure input
(as predicted by computer simulation)
TBTS PETS layout with internal recirculation for testing the ON/OFF concept.
Movable RF short circuit (for tuning the resonant length)
Variable reflector (for tuning the recirculation coupling)
Variable reflector
Movable RF short circuit
The components have been installed on the PETS tank.
Chat in a corridor:Igor... ‘Roberto, why do we need to run PETS with power levels above 200 MW?’Roberto... ‘ Well, it works, so why do you ask? As well we have showed 150 M/m.’
Few words about TBTS results during the past testing period
200 400 600 800 1000
50
100
150
200
250
MW
ns
Measured RF power extraction
CLIC requirement
Peak power in the PETS
BDR in recycling loop
It did, indeed! With BDR> 0.3 when peak power was > 200 MW!
attenuator
E-bend/split
IN OUT
IN
OUT
phase shifter
E-bend/direct
Highest peak power point
Let’s look inside
attenuator
load split E-bend IN
Observations: All he stainless steel flanges show sort of breakdown erosion on the surface. The copper surfaces in attenuator (GYCOM) are seriously damaged in ALL the channels. In the phase shifter (also made by GYCOM) copper surface is pretty clean.