Status of Vertical Test Stand at RRCAT P Shrivastava, P Mohania,D.Baxy, Vikas Rajput S C Joshi, S Raghavendra,S K Suhane RRCAT, Indore November 26, 2012

VTS RF System Block Diagram & Software Description

Basic Requirements of VTS RF System To provide stable RF Power to the SCRF cavity under cryogenic conditions with control over phase, frequency and amplitude Measure the Incident, Reflected and Transmitted power from the cavity and deduce cavity performance parameters ( Quality Factor vs Electric Field Gradient, Quality Factor vs Temp) from these. Record the test conditions for the cavity undertest Facility for automatic data acquisition and display of test results Provide interlocks for personnel safety

Constituent of RF System RF System of VTS consists of following functional modules which can be independently tested RF Source Control Module Transmitted Power Network Power Measurement Module High Power/ Low Power Amplifier Switching Network Diode Detector interface/Buffer Amplifier A High Power CW RF amplifier which provides the necessary amplification to generate required Electric Field Gradient inside the cavity structure. RF Signal Generator, Frequency Counter and Power Meters connected over GPIB A NI LabView based control and data acquisition system

Development of RF System at RRCAT for VTS -Procurement process for the components and instruments for the system had been completed. All items except for the SiO2 RF cable assembly ( pending due to manufacturing delay) had been received. An alternate cable identified. -All submodules for the VTS have been fabricated and tested except for the RF Source Control Module. RF source control module contains a “Loop Amp” PCB which sets the gain for the PLL loop and displays it. The PCB designs received for the PCB contained some errors, the problems were reported to FNAL. The solution suggested were tried but PCB was not functioning. As an alternate another PCB was designed by RRCAT engineers, the same is under fabrication. We have designed and developed our own high power 500W, 1.3GHz sold state amplifier system, the amplifier has been tested and assembled with High Power/ Low Power Amplifier Switching Network and Power supplies to develop High Power RF Supply Rack. -All Instruments have been interfaced with the LabView based control system.

High Power RF Supply - High power RF Supply for VTS has been developed and tested on passive load. Front ViewRear View Driver Amplifier High Power Amplifier HP Switching Network Circulator and load Power Supplies

The RF supply consists of a 500W High Power Stage with a 50W driver amplifier, The amplifier is protected with a circulator at the output. The driver stage is air cooled while the high power stage is watercooled. 50 W Amplifier Module500 W Amplifier Module High Power RF Supply

VTS STATUS Power Measurement Module Power Meters Frequency Counter RF Signal Generator Source Control Module Diode Detector Interface Transmitted Power Network PXI Interface

Upgrade of Solid State Amplifier for VTS A new dual SSPA is under development at RRCAT which would have high power stages of 1.3GHz at one side and high power stage of 650MHz on the opposite side. 1.3GHz Amplifier will be mounted below the heat sink 650MHz amplfier mounted on top side of heat sink 650MHz amplifier under test

RRCAT Difficulties faced Lack of practical exposure to similar systems. Visit of personnel shall help Missing interface circuit information (PXI-digital-IO interface card) - Problem reported to FNAL, in absence of information PCB was analyzed and components identified. - After assembly PCB is functional. Minor software issues -In main LLRF control software some data acquisition linking and loops needs further clarifications. “Loop Amp” PCB file received contains several errors - Problem reported to FNAL - Response received containing corrections to be made. Changes were implemented however Short circuit between supply and GND still remains. - New PCB designed, fabrication underway. PCB for IQ modulator contains errors - After analysis problems were identified and connections were rectified. - PCB functional now

PCB connection errors shown in white

RRCAT Cavity Insert Assembly All the components of the insert assembly have been fabricated Assembly of the insert is in progress Insert Assembly Thermal baffle assembly of insert

RRCAT Installation of staging towers The installation of staging towers for cavity insert assembly is in progress. Two staging towers have been erected. Installation of filters, anti-static PVC curtains etc is in progress. Staging Towers

RRCAT External Magnetic Shield External magnetic shield segments have been fabricated One half of the shield has been trial assembled on the Vacuum vessel (in horizontal position) Final assembly shall be carried out once the cryostat is moved in vertical position

RRCAT Assembly of Heaters Heaters Heaters required during LHe boil off have been assembled. Power supply for the heaters have been tested. Multi pin connectors for Cernox RTDs installed in the instrumentation tubing have been soldered & tested. Multi pin connectors

RRCAT Cryogenic system for VTS  Installation of helium gas recovery lines is in progress.  Procurement for Helium gas compressor for pumping recovered helium gas into high pressure storage cylinders is under advance stage.

Thank You