FBE-204LT Bunch-by-bunch Feedback Front/Back-End
Contents
1. giftet FBE LT W dimtel FRONTEND i Bunch by bunch feedback front back end HORIZONTAL VERTICAL LONGITUDINAL 1N N IN amp S REFERENCE BACKEND 5i F E 6 e e FBE 204LT Bunch by bunch Feedback Front Back End TECHNICAL USER MANUAL Author Revision Dmitry TEYTELMAN 1 1 July 4 2011 Onn Information in this document is subject to change without notice Copyright Dimtel Inc 2010 2011 All rights reserved Dimtel Inc 2059 Camden Avenue Suite 136 San Jose CA 95124 Phone 1 650 862 8147 Fax 1 603 907 0210 www dimtel com CONTENTS Contents 1 2 Regulatory Compliance Information Introduction 2 1 Delivery Checklist e s s cree a scrisa 2 2 System Overview 2 0 Front Panel Features 2 24 24 265 4 2 4 Rear Panel Features 2 5 Cooling Fan Filter Maintenance 2 6 Getting Started 00 Setup 3 1 Pronteend se esena sancera ra gh 32 Backend sars eos adi e eoa ee eck OR os Specifications Warranty and Support DL VWI ec i sinea p E sord ka ehh O2 DUPPOTt 2 ee en a dee oe Oe we os Glossary 10 Se ee ere ee 10 be ge a ae 11 12 14 aaee i donee ara 14 m E a a 14 15 1 of 15 Regulatory Compliance Information 1 Regulatory Compliance Information This equipment requires a ground connection provided by the power source The exp2. High voltage range 207 253 V 13 of 15 Warranty and Support 5 Warranty and Support 5 1 Warranty Dimtel Inc warranties this product for a period of one year from the date of shipment against defective workmanship or materials This warranty ex cludes any defects failures or damage caused by improper use or inadequate maintenance installation or repair performed by Customer or a third party not authorized by Dimtel Inc Warrantied goods will be either repaired or replaced at the discretion of Dimtel Inc The above warranties are exclusive and no other warranty whether written or oral is expressed or implied 5 2 Support Dimtel Inc will provide technical support for the product free of charge for a period of one year from the date of shipment Such support is defined to include e Gain partitioning e System interconnection issues e iGp iGp12 interface support Free of charge technical support specifically excludes e Commissioning with beam e Feedback algorithm development and testing e Beam dynamics characterization e Operational support related to dynamic system operation 14 of 15 Glossary 6 Glossary Glossary beam position monitor BPM An RF structure that couples to the beam in the accelerator The output signal of such a structure allows measurement of the transverse or the longitudinal beam position 3 5 9 continuous wave CW A signal of constant amplitude and frequency 5 9 1
3. 0 digital to analog converter DAC A hardware device to convert a sequence of digital codes to correspond ing analog voltages or currents 6 general purpose input output GPIO A 32 bit wide digital input output port of the iGp iGp12 3 9 radio frequency RF In the accelerator context a constant frequency constant amplitude signal derived from or phase locked to the storage ring master oscillator 9 12 15 of 15
4. ation Operating the unit without the filter can lead to overheating as well as to premature failure of the cooling fans WARNING Before performing any work on the fan filter power down the system and unplug the AC power cord Fan blades are exposed when the filter is removed The filter should be periodically serviced to maintain adequate air flow Vacuuming washing or replacement are the acceptable maintenance options Replacement filter is manufactured by Qualtek Electronics Corporation part number 06325 M In order to remove the filter undo the four thumb nuts If filter servicing involves washing make sure the filter is completely dry before reinstallation To reinstall orient the filter so that the mesh corrugations are vertical and slide it onto the mounting studs Reinstall and hand tighten the thumb screws 8 of 15 2 6 Getting Started 2 6 Getting Started In this section we will present a quick step by step guide to get your new RF front back end processor running in a minimal single channel configu ration WARNING Before connecting power to the unit make sure the voltage selection switch Fig 3 item 1 is in the correct position 115 or 230 V WARNING Signals beyond 33 dBm CW or 14 V peak can per manently damage the front end input circuitry Before connecting to FBE 204LT measure BPM signals using a high speed oscillo scope at maximum bunch currents to determine the necessary in put attenuation leve
5. for driving the power amplifier and the kicker The FBE 204LT interfaces to the iGp iGp12 digital general purpose input out put GPIO port for control and monitoring Control channels include front and back end attenuators and phase shifters and fan speed Through the GPIO port iGp iGp12 is also able to read out the unique FBE 204LT serial number and to monitor the internal temperature 4 of 15 2 3 Front Panel Features 2 3 Front Panel Features Figure 2 Front panel features 1 Power switch This on off lighted switch turns FBE 204LT on and off 2 Horizontal front end output Baseband output to iGp iGp12 3 Horizontal front end input This input receives the beam signal from the BPM difference hybrid network Maximum continuous wave CW level is 33 dBm For typical beam signal this limitation can be expressed as maximum swing of 14 V 4 Vertical front end output Baseband output to iGp iGp12 5 Vertical front end input This input receives the beam signal from the BPM difference hybrid network Maximum CW level is 33 dBm For typical beam signal this limitation can be expressed as maximum swing of 14 V 6 Longitudinal front end output Baseband output to iGp iGp12 7 Longitudinal front end input This input receives the beam signal from the BPM combiner network Maximum CW level is 33 dBm For typical beam signal this limitation can be expressed as maximum swing of 14 V 8 10 Reference outputs Master oscillator output
6. k signal and its timing relative to the bunch arrival in the kicker 3 Setup As mentioned in Subsection 2 6 the FBE 204LT must be properly phased and timed to the beam In this section several possible methods for achieving proper timing and phasing will be described Let us start with the front end setup WARNING The FBE 204LT must be operated for at least two hours in the installation environment to achieve thermal equilib rium Do not perform phase sensitive front and back end adjust ments before the equilibrium has been achieved 3 1 Front end WARNING Front end circuitry is sensitive to peak and average signal levels Absolute maximum input level is 33 dBm CW or 14 V peak However within these ranges internal amplifier damage is possible if the front end attenuator is set too low for the input signal level Before changing per bunch currents set the front end attenuator to nominal attenuation at that bunch current In order to time the front end to the beam a single bunch filling pattern should be used With a single bunch filled connect the front end output to a scope and adjust front end phase for amplitude detection producing a large pulse in the baseband signal Next connect the signal to the iGp iGp12 input and adjust the timing in 100 ps steps 10 units of 10 ps delay line to produce maximum displacement in the mean offset of one bunch This operation results in somewhat coarse front end timing For more precise adjus
7. l 1 Configure voltage selection switch Fig 3 item 1 Mains supply re quirements for the FBE 204LT are listed in Table 4 2 Connect radio frequency RF clock at 3 dBm nominal level Fig 2 item 5 3 Connect the reference output Fig 2 item 8 to the CLK input of the iGp iGp12 4 Terminate unused reference outputs with wideband 50 2 SMA termi nators 5 Connect the front end input Fig 2 item 3 5 or 7 to the beam signal at the appropriate level 6 Connect the front end output Fig 2 item 2 4 or 6 to the IN or IN of the iGp iGp12 Terminate the unused iGp iGp12 input with a wideband 50 Q SMA terminator 7 Connect the back end input Fig 2 item 6 to the OUT or OUT of the iGp iGp12 Terminate the unused iGp iGp12 output with a wideband 50 Q SMA terminator When using iGp12 place a 4 dB attenuator between the DAC output and the back end input 8 Connect the back end output Fig 2 item 7 to the power amplifier input 9 Using the supplied 68 pin GPIO cable connect the iGp iGp12 interface Fig 3 item 3 to the GPIO connector on the iGp iGp12 9 of 15 Setup 10 Push the power button Fig 2 item 1 to turn on the system At this point your system is ready for use in beam diagnostics and feed back The system must be appropriately phased and timed to the beam This ensures proper phase detection in the front end and correct sampling of the detected signal as well as the correct phase of the kic
8. nd can be considered coarsely timed For finer timing the iGp iGp12 output timing must be adjusted in sub RF period steps to maximize the beam response 11 of 15 Specifications 4 Specifications Table 1 General specifications Parameter Definition Operating frequency 204 MHz RF input level 3 1 dBm Reference output level 7 dB relative to the input Temperature sensing resolution 0 0625 C Fan speed control range Unique ID 1600 4100 RPM Provided by Maxim DS1822 device Table 2 Front end specifications Parameter Definition Detection frequency 1428 MHz Maximum operating input level 9 3 V peak Absolute maximum input level 14 V peak Attenuation range 0 31 5 dB Output level at 1 dB compression 5 dBm 3 dB bandwidth 600MHz Baseband pulse width 1 5 ns Phase shifter range Phase shifter resolution 12 of 15 gt 360 degrees lt 0 2 degrees step Specifications Table 3 Back end specifications Parameter Definition Modulation frequency 1020 MHz Input level 250 mV Attenuation range 0 31 5 dB Maximum output level DC input 4 dBm of 250 mV 3 dBm reference Output filter Output bandwidth Phase shifter range Phase shifter resolution 5 order Bessel band pass 180 MHz gt 360 degrees lt 0 2 degrees step Table 4 Input Power Requirements Parameter Definition Input voltage 115 230 VAC Input current 2 1 A Frequency 60 50 Hz Voltage selection Switch Low voltage range 104 126 V
9. norme NMB 008 du Canada 2 of 15 Introduction N Introduction N Delivery Checklist 1 1 FBE 204LT chassis 2 AC power cord 3 GPIO 68 pin male to 68 pin male cable 4 User manual 2 2 System Overview Front end section Two cycle comb filter Variable Amplifier Mixer Low pass filter attenuator be i From BPM hybrid To the ADC 7X fet li Step recovery diode frequency multiplier Front end channel x3 fit 7x multiplier 5x multiplier SR aa eae ae eae ny iGp GPIO Step recovery diode i A frequency multiplier i A j 5 x tre To the power From the DAC d amplifier I E Mixer Variable attenuator Amplifier Bandpass filter Back end section Figure 1 Bunch by bunch feedback front back end block diagram The FBE 204LT RF signal processor incorporates front end and back end electronics for a complete bunch by bunch feedback system in a storage ring The unit is equipped with three identical front end channels for processing horizontal vertical and longitudinal signals Front end channels are designed for converting the beam position monitor BPM output to the baseband signal which can be directly digitized by the iGp iGp12 Each channel operates at 1428 MHz and uses a 2 cycle comb filter to produce a 3 of 15 2 2 System Overview detected pulse of 1 3 ns The back end channel upconverts the baseband kick signal to 1020 MHz carrier
10. osed metal parts of the unit are connected to the power ground to protect against electrical shock Always use an outlet with properly con nected protective ground FBE 204LT was designed and tested to operate safely under the following environmental conditions e indoor use e altitude to 2000 meters e temperatures from 5 to 40 C e maximum relative humidity 80 for temperature 31 C decreasing linearly to 50 40 C e pollution category I e overvoltage category II e mains supply variations of 10 of nominal FBE 204LT contains no user serviceable parts inside Do not operate with the cover removed Refer to qualified personnel for service NOTE This equipment has been tested and found to comply with the limits for a Class A digital device pursuant to Part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful inter ference when the equipment is operated in a commercial environment This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instruction manual may cause harmful interference to radio communications Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense NOTE This Class A digital apparatus complies with Canadian ICES 008 Cet appareil num rique de la classe A est conforme a la
11. s to baseband processors iGp iGp12 These outputs are 7 dB below the reference input level nominally at 4 dBm 5 of 15 2 3 Front Panel Features 11 Reference input Master oscillator reference This reference drives front and back end local oscillators as well as the outputs to iGp iGp12 Nominal input level is 3 dBm 12 Back end input This input should be driven by one of iGp iGp12 high speed digital to analog converter DAC outputs Nominal swing expected at this input is 250 mV For iGp12 use a 4 dB attenuator 7 Back end output Output to the power amplifier At 0 dB back end attenuation and full 250 mV baseband drive the output level is 4 dBm 6 of 15 2 4 Rear Panel Features 2 4 Rear Panel Features Figure 3 Rear panel features 1 Voltage selection switch Slide switch for selecting appropriate mains voltage 115 or 230 V 2 Power entry socket IEC 320 power input socket Always use an outlet with properly connected protective ground 3 iGp iGp12 interface This 68 pin connector must be attached to the iGp iGp12 for proper operation of the control elements within FBE 204LT 7 of 15 2 5 Cooling Fan Filter Maintenance 2 5 Cooling Fan Filter Maintenance Figure 4 Fan filter mounted using four thumb nuts Cooling fan is located on the left side of the FBE 204LT An stainless steel mesh filter is mounted externally with four thumb nuts WARNING Fan filter protects the system from contamin
12. tment one can use sweep sh script supplied with iGp iGp12 10 of 15 3 2 Back end Once the front end is timed adjust the front end phase for amplitude detection in the horizontal and vertical channels and for phase detection in the longitudinal channel 3 2 Back end Back end timing consists of two parts phasing the back end local oscillator to produce maximum kick and adjusting kick envelope timing to line up the single bunch kick with the beam In the first step configure the iGp iGp12 to generate sinewave drive at the synchrotron frequency using the turn by turn option of the drive generator At this point all bunches should be driven Next adjust back end phase to produce maximum longitudinal excitation as measured by the iGp iGp12 or by an external instrument Drive amplitude might need to be reduced to precisely find the optimal phase At this point we need to determine which bunch in the iGp iGp12 pro cessing is lined up with the beam To do so bisection is typically used Initially our bunch drive pattern might look like 1 64 Select the first half of the ring using 1 32 If the beam is still excited one of the first 32 bunches in iGp iGp12 processing coincides with the beam in the kicker Continue the bisection until one bunch is identified At this point one can adjust the output one turn delay so that the excited bunch number agrees with the bunch number seen in the front end Once such agreement is reached the back e
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