Transcript RD_Status_05_15_06

Linac R&D Update
May 15, 2006
L-Band Source
• Consists of a LLRF system (VME/Epics based), a SNS High
Voltage Converter Modulator (on loan), a Thales 2104C
5
MW klystron, a 5 MW isolator (from SPA Ferrite) and
pressurized (30 psig N2, no SF6) waveguide that feed two
experimental areas (one in the NLCTA enclosure that will
power an ILC prototype positron capture cavity, and one for a
coupler test stand).
• Source currently configured with a Thales 2104U klystron
and the waveguide terminated in a load just after the isolator.
– Expect to receive the TH2104C klystron on May 27.
Isolator
Pressurized WG
Load
Lead Box Containing Klystron
Current RF
source layout
with power
terminated in
a nearby load
L-Band Source (cont)
• Have operated the system to produce 3.3 MW, 1 msec rf pulses at 5 Hz.
• System processed quickly although had several arc-monitor faults.
• Discovered arcing on some of the flange surfaces – found the flange
faces were not flat (5-10 mils) – also had properly tighten them.
– Have since learned much more about flanges from industry, DESY,
KEK and FNAL, not all of which is consistent
– For next test, have machined flat the flanges to 1 mil. Will try both
metal-to-metal and metal-metal gasket-metal transitions.
• Have since upgraded SNS modulator using parts provided by Bill Reass
at LANL. In process of testing it with water and resistor loads
SNS HVCM Modulator
Resistive Load and TH2104U Klystron
Waveguide Distribution
Capture Cavity
RF Switch
Coupler Test Stand
Positron Capture Cavity
• Half cell parts complete for body
• Need to braze pairs, do a second machining and then
tune – expect to do in 6 weeks
• First windows available for test in 7 weeks
• Full cavity done in about 3 months (mid-August).
• Still low shop priority as LCLS submits rf work for gun.
• Recently completed installation drawings for NLCTA. Also
Boeing donation of solenoid approved – need to arrange
shipment to SLAC.
ILC Positron Capture Cavity Prototype
As Installed in NLCTA w/o Window
Coupler Development
• Have decided on basic
plan to test coupler
parts.
• Setup uses a
detachable center
conductor and 20 inch
long test sections
• Chris N and Gordon
working on rf and
mechanical design
Design of WG-to-Coax Adaptor
Multipacting Simulation of TTF3 Coupler
“Cold Side”
Bellows
Primaries -Green, Secondaries- Red
SC Quad/BPM Status
• Magnet received from DESY in January after initial testing there in a
vertical Dewar. Gas-filled leads received in March.
• With help of Tom Nicol at FNAL, developed a low heat loss, stable support
design for the He vessel. May adopt similar support structure for the ILC
linac.
• Cryostat currently being built in SLAC shops and magnet / quench system
being configured. Had discussion with Bldg 25 managers as to the logistics
to install He transfer lines (safety review planned). Consider
accelerometers to buy to vibrations tests.
• First tests of new magnet measuring coil planned during the next month
using a NC quad. SC quad measurements planned for August.
• BPM triplet built, installed on girder in ESA and operated during run that
started on April 24.
Cryostat and Cryogenic System
BPM Triplet Results from Recent Run
(0.8 micron resolution, 1.4e10 electrons, Q of 500 for clean bunch separation)
http://ilcagenda.cern.ch/conferenceDisplay.py?confId=366