260 likes | 289 Views
LFB, LLRF, TFB update. Alessandro Drago XIII SuperB General Meeting Isola d’Elba, 5/30-6/4 2010. Topics. Longitudinal dynamics simulator: beam + RF + LFB Longitudinal growth rate evaluation Power amplifiers evaluation LLRF update Transverse dynamics simulator Hardware update.
E N D
LFB, LLRF, TFB update Alessandro Drago XIII SuperB General Meeting Isola d’Elba, 5/30-6/4 2010
Topics • Longitudinal dynamics simulator: beam + RF + LFB • Longitudinal growth rate evaluation • Power amplifiers evaluation • LLRF update • Transverse dynamics simulator • Hardware update
Feedback design basic points • Hardware refresh (to avoid obsolescence) • Legacy/diagnostics from the previous feedback systems • Unified project for transverse and longitudinal systems • Evaluation of feedback impact on ultra-low emittance beams • Signal/noise ratio (included crosstalk from other bunches) of the order of ~40 dB • System dynamic range of the order of ~75/80 dB
Data base in SIMUL2 longitudinal simulator are: RF power, 11 HOM in RF cavities,beam paramenters (charge x bunch, harmonic number, #bunches, gap, injection error) and Longitudinal feedback parameters (gain, power, FIR transfer function with coefficients)
The longitudinal simulator upgrade • MATLAB program have been upgraded and rewritten to make a fast data entry and also to measure growth and damping rate from the raw output data
Summary of long. growth rates • 4A in 1956 bunches generates at every new charge injection very fast instability • Injecting bunch #2 the instability growth rates are faster in the nearby bunches than in the others along the bunch train • Bunch #11 178 turns, 0.75 msec • Bunch #1225 673 turns, 2.82 msec • Bunch #1955 691 turns, 2.93 msec
High current case (4A), bunches spaced by 1:lfb needs a total power of 1kW, implemented by four 250W amplifiers feeding one cavity kicker with Rs>500Ohm. This power should be sufficient to control the beam longitudinal dynamics at 4A in LER
LLRF - Low Level RF System description (from CDR2 by Sacha Novokhatski) • A low-level RF system provides control and feedback for stable multi-bunch high current operation. There are several feedback loops. BLOCK DIAGRAM OF LLRF CIRCUITS
LLRF update by the Grenoble Team in the next SuperB General Meeting
Beam transfer function[transverse resistive wall instability] • Grate = modal instability hypothetical growth-rate [from real example: DAFNE or CESR-TA] • In DAFNE, the e+ ring fastest measured Grate is ~20 revolution turns • Wx = angular betatron tune frequency [2*pi*betatron_tune_fractional_part*rev_freq] • G = gain (function of impedances & wakefields, RF_frequency^2, bunch_spacing,…) - in the preliminary phase is put to 1
C.S.N.V approves SFEED in Sept/09 • Only for the year 2010 • 2K euro for mission outside Italy • 16 k euro for hardware/software and assembly
Finally a Virtex-6 FPGA evaluation board is now on sale:Xilinx ML605
Finally a Virtex-6 FPGA evaluation board is now on sale • Xilinx ML605 – similar to previous project based on Virtex-5 • Part number AES-V6DSP-LX240T-G • http://www.xilinx.com/products/devkits/AES-V6DSP-LX240T-G.htm • Expensive cost: 2995 $ + VAT cointaining • Xilinx ML 605 Development Board including Virtex-6 LX240T FPGA. • http://www.xilinx.com/products/devkits/EK-V6-ML605-G.htm • Only the board: 1995 $ +VAT.
14 bit ADC / 16 bit DAC • ADC (analog input signal): ADS5474 byTexas Instruments, [14-bit, 400 MSPS] • http://focus.ti.com/lit/ds/symlink/ads5474.pdf • It has 14 differential digital output LVDS on a unique register then better than the previous project that was using 16 digitalc output beacasuse was based on 2 registers • ADS5474 has an evaluation board: • http://focus.ti.com/lit/ug/slau194a/slau194a.pdf • DAC: Maxim MAX5891 http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4622 • 16-Bit, 600Msps High-Dynamic Performance DAC with LVDS Inputs and DAC evaluation board: • http://datasheets.maxim-ic.com/en/ds/MAX5889EVKIT-MAX5891EVKIT.pdf • The evalutation board has 16 differential LVDS input with a single connettor while clock and analog output signal are SMA
14 bit ADC / 16 bit DAC • It is necessary to assembly 3 boards designing an interface board connecting all the evaluation boards ( ADC@14bit, FPGA with Virtex-6, DAC@16bit). • The software, firmware and gateware for the FPGA board ML 605 should be also designed
14 bit ADC / 16 bit DAC • An order for these 3 boards has still NOT signed by LNF top management (I am waiting since more than 1 month) • Why???
DIMTEL order • An order to DIMTEL has made in last January for two longitudinal front end modules and two 12-bit ADC processing unit • It is an upgrade from IGP to IGP-12 • It is based on Virtex-5 not on Virtex-6 • The order is in progress and we are still waiting for the material • Material is sold as a black box (no info about code)