ASTA roadmap to EPICS and other upgrades

Remote monitoring and controlDAQ

Machine protectionDark current energy spectrometer

ASTA: Accelerator Structure Test Area

High gradient X-band testing of accelerator structures (regularly exceeding 100 MV/m gradient)

Up to ~200 MW peak power delivered to the structure by combining the power of two XL4 klystrons into a delay line SLED system.

Consists of two modulators, two klystrons, delay lines for SLED, a radiation enclosure, PPS system, interlocked vacuum and cooling water systems, llrf system, diagnostics and data acquisition..

In the past used for S-Band RF gun testing incorporating a cathode laser system and small beam line with a beam spectrometer.

SRS60 Hz

AFG

AFGTWT K

TWT K

llrf configuration

I&QMIXER

I&QMIXER

SRSDG645

4 port combiner

no SLED

SLED

K

K

high power rf configuration

Breakdown rates vs gradient

forward powerreflected powerfaraday cup 1faraday cup 2

Faraday cup signals register breakdowns and inhibit further pulses to prevent damage to the structure. Gradient is calculated.

DAQ/MPSexisting configuration

VAC controllersVAC1-2: Klystron

VAC3-16: WG to DUT to load

Power meters Faraday cup signalsDUT FE/REKlystron RE

MPSTrigger inhibit(soft)

Modulator trip(hard)

DAQ/MPS issues• High bandwidth DAQ and MPS handled by one windows computer

running several labview/C++ programs– data bottleneck causes missed MPS triggers– no data sharing or analysis possible during running– Complexity of the labview programs cannot be easily modified or scaled up

Control centerelectrically and acoustically noisy, hot

Upgrading ASTAOperational upgrades are required to satisfy existing and new user demands:

SLAC X-band program, CERN, Japan, LCLS RF gun cathode characterization.

Improved DAQ: user and operations access to real time and archived data: (EPICS a la LCLS, dedicated network). Correlate everything with everything else.

Extract phase information to track breakdown locations within the structure.

Real measurement of achieved gradient and dark current energy spectrum.

Unattended and remote operations (a la NLCTA with a fire suppression system)

Go to PAC/PAD llrf system

Reestablish S-band RF and UV laser systems

DAQ/MPSproposed configuration

VAC controllersVAC1-2: Klystron

VAC3-16: WG to DUT to load

Power meters Faraday cup signals

DUT FE/REKlystron RE

MPSTrigger inhibit

Modulator trip(hard)

DAQ/MPS upgrades

• EPICS handles most of the DAQ and MPS– Remote monitoring and operation– Complex labview programs continue to operate

with EPICS IO Server for LabVIEW– Move LabVIEW functionality to EPICS

Gradient measurements

Existing spectrometer is a damping ring magnet designed for 200 MeV gun testing. Unwieldy.

Maximum of ~20-40 MeV of dark current expected for single small accelerator structure testing. which could be handled by a more compact spectrometer.

Use spare NLCTA chicane magnet

2 hours of work to put together (D. Walz)

Where we are with DAQ/MPS

Infrastructure:ADC modules, VME crate, terminal server, GPIB

interface, EPICS computer, network switch and network are on hand or in place.

Set up EPICS:Require some expertise in setup. Install and configure

the EPICS software. Write or install drivers.

Where we are with phase extractionFeasibility study shows phase can be extracted. Further study ongoing to see

if we have the resolution to determine breakdown location.

Implementation is next (January 2011). Reflected energy envelope during a breakdown

Computed phase

Upgrading ASTA: big ticket items•Real measurement of achieved gradient and dark current energy spectrum:• Magnet is available. Vacuum chamber in preliminary design stage. After $, its

a one month timescale for final design and fabrication

•Unattended and remote operations (a la NLCTA with a fire suppression system)• Modulators have been evaluated for fire protection. $$• BAS ASE changes to follow NLCTA precedent.

•PAC/PAD system being implemented in NLCTA. Can it be used for experimental DAQ?

•Reestablish S-band RF and UV laser systems. $$$• Waveguide can be reconnected.• TS1 changed to dedicated S-band• PPS upgraded and/or re-commissioned• Laser systems• EPICs will allow easy porting of LCLS apps