1. The ELENA BPM System. Status and Plans.
I am going to talk about the status of the orbit measurement system for the ELENA antiproton decelerator.
Diogo Miguel Louro Alves
(BE-BI-SW)
Ricardo Marco Hernández
(BE-BI-PI)
Lars Søby
ELENA Status for BI
CERN. 27th October 2016

2. ELENA orbit measurement system overview
ELENA further decelerates antiprotons coming from AD from 100 MeV/c to 13.7 MeV/c.
Revolution frequency (fREV) will vary from MHz to 148 kHz.
Cycle duration of about 25 s.
Measurement system.
Based on 20 circular BPMs mounted inside quadrupole and corrector dipoles plus 4 BPMs inside the Electron Cooler.
Low noise head amplifier very close to each BPM will deliver Δ and Σ signals to reception amplifiers.
Digital acquisition system based on the same hardware as the AD orbit system for digitalization and signal processing.
Measurements to implement before/after ELENA commissioning.
First injections with H- source and observation on OASIS
Orbit measurement with bunched beam (first stage): with a resolution of 0.1 mm every 10 ms.
Trajectory data at injection from AD (second stage): with a resolution of 0.1 mm for at least 100 turns after injection. 2016?
Intensity measurement for bunched beam (third stage)
Schottky intensity measurement for coasted beam (fourth stage). 2017
100KeV H- source for commissioning
14th of November
ELENA BASIC DECELERATION CYCLE
BPMs position
(12 x 2)
ELENA further decelerates antiprotons coming from AD from 100 MeV/c to 13.7 MeV/c, as you can see on the ELENA cycle in the upper figure. The revolution frequency will vary a factor of seven, from 1.56 MHz to 148 kHz. The ELENA cycle will last about 25 seconds.
The measurement system for ELENA will be based on 20 beam position monitors distributed along the ring inside quadrupole magnets and corrector dipoles as well as on 4 BPMs placed inside the Electron Cooler, as you can see in the lower figure.
There will be a low noise head amplifier very close to each BPM which will deliver the delta and sigma signals to the reception amplifiers placed about 25 meters away, near the digital acquisition system.
The digital acquisition system, based on the same hardware as the AD orbit system, will digitize and process the delta and sigma signals from each BPM.
The measurements to be performed by the system will be implemented in two stages: before and after ELENA commissioning
The orbit measurement with bunched beam with a resolution of 0.1 mm every 10 ms will be implemented in a first stage before July of this year.
Trajectory data at injection for at least the first 100 turns with a resolution of 0.1 mm will be also implemented in a first stage before September of this year.
In a second stage, the system will perform intensity measurement with bunched beam as well as Schottky intensity measurements with coasted beam.
BPM LOCATION IN ELENA RING
ELENA Status for BI
CERN. 27th October 2016

3. ELENA system layout Frev from LLRF
You can see in this slide the ELENA system layout.
We have the BPMs and the head amplifiers around the ELENA ring as well as the calibration signal splitter and power supply box.
We have two racks (BY01 and BY02) where we accommodate the patch panels for the analogue signals and power supplies, the reception amplifiers, a digital control module, power supplies and the digital acquisition system VME-VXS crate.
ELENA Status for BI
CERN. 27th October 2016

4. BPMs and Head amplifiers
20 BPMs are installed in ELENA ring.
E-cooler not before next year
Tri-axial shields for BPM-Head amplifier cables manufactured.
30 head amplifiers produced and tested.
Head amplifier installation done for 6* quadrupoles
4 Dipoles being installed, followed by BPM electronics
ELENA BPM INSTALLED IN A QUADRUPOLE MAGNET
Regarding the BPMs and the head amplifiers, 24 BPMs have been already installed in the ELENA ring.
The coaxial short cables loaded with ferrites to connect the BPMs with the head amplifiers have been already produced.
This cables will be placed inside an aluminium shield (as you can see in the picture) connected to the head amplifier to minimize the common-mode currents coming from the RF cavities through the support tube.
These shields have been also manufactured.
Thirty head amplifiers were produced and tested in July.
The head amplifiers and the short cables are being installed during this week.
HEAD AMPLIFIER
10 cm 75 Ω COAXIAL CABLE LOADED WITH 8 FERRITES (3E5 MATERIAL FERROXCUBE, μr = 8000)
ELENA Status for BI
CERN. 27th October 2016

5. Other electronics and cabling
Reception amplifiers produced and installed.
Power supplies and digital control module installed.
Structured cable and patch panels installed and connected.
OASIS signal cables pulled and connected.
Digital acquisition VME-VXS crate (cfv- 193-bpmelena) installed.
Fibre connections from LLRF rack (AYE02) to ELENA orbit rack (BYE01) installed.
With regard to other electronics and cabling, the reception amplifiers are already installed in the BY02 rack.
Both the power supplies and the digital control module are ready to install as well.
The patch panels have been installed and the structured cabling connected.
The front-end power and spitter module is produced. It will be installed after and head amplifiers.
As you can see in the picture, the digital acquisition VME-VXS crate is already in the rack and we have the fibre connections from the LLRF rack to the ELENA orbit rack.
ELENA BYE-01 RACK
ELENA Status for BI
CERN. 27th October 2016

6. Digital acquisition hardware
All the hardware required produced and tested: ready for installation next week
7 VXS-DSP-FMC carriers.
7 VXS-DSP-RTM modules.
2 VXS Switch boards.
1 FMC-MDDS board.
1 FMC-SDDS board.
12 FMC-ADC boards.
1 CTRV module.
1 VMOD-TTL board.
Cables and optical transceivers purchased.
84 new FMC-ADC low noise AC coupled boards produced and tested in September.
OASIS digitizers will be used in parallel to the BPM acquisition system during ELENA commissioning.
VXS-DSP-FMC carrier (with FMC-MDDS/FMC-SDDS), VXS Switch board and VXS-DSP-RTM module
30 nV/√Hz
All the hardware required for the digital acquisition system is already produced and tested.
All the cables required as well as the optical transceivers for the connection to the LLRF system have been purchased.
84 new FMC-ADC low noise AC coupled boards were successfully produced and tested in September.
The installation of the hardware is planned for next week.
I wanted to mention that OASIS digitizers will be used during the ELENA commissioning in parallel to the acquisition system.
AC-coupled FMC-ADC board noise density level for input gain 20 dB and input range 302 mVpp.
ELENA Status for BI
CERN. 27th October 2016

7. Digital acquisition firmware
FPGA firmware for orbit measurements ready and tested in AD.
Both Main FPGA and FMC FPGA firmware.
FMC-MDDS, FMC-SDDS and FMC-ADC boards can be handled.
Update for bunched intensity measurements already developed and tested.
Update for trajectory measurements to be implemented: RF colleagues no time. BI development
Update for Schottky measurements to be implemented.
DSP firmware for each VXS-DSP-FMC carrier (M1, M2 and S1-S5) fully developed.
Features frev calculation and programmable B-Train emulation to generate RF clock/TAG signal independently from LLRF crate.
After commissioning of LLRF crate, RF Clock/TAG signal from LLRF crate: small change of DSP firmware to be implemented.
Scripts developed for remote loading of FPGA and DSP firmware via VME.
VXS-DSP-FMC CARRIER BLOCK DIAGRAM
Concerning the digital acquisition firmware, the FPGA firmware for the orbit measurements is ready for both the Main FPGA and the FMC FPGA. This firmware will handle the last version of the required mezzanine boards.
The updated version for bunched intensity measurements has been already developed and tested in the lab.
The firmware update for the trajectory measurements will be implemented depending on the availability of our RF colleagues. They are in charge of the maintenance of the common FPGA firmware used by BI and RF.
More firmware changes will be required for implementing the Schottky measurements.
The DSP firmware for each carrier is fully developed. It currently features the calculation of the revolution frequency and the emulation of the magnetic field in order to generate the RF clock and TAG signals independently from the LLRF crate.
After the commissioning of the LLRF crate, the RF clock and TAG signal will be obtained from them and a small change in the DSP firmware will be implemented.
Finally, we have scripts for the remote loading of the FPGA and DSP firmware via VME to update the system.
FIRMWARE ARCHITECTURE
ELENA Status for BI
CERN. 27th October 2016

8. Software
While only orbit measurements are available, the plan is to use the existing FESA instrument already operational in the AD.
Expert GUI to go with the previous FESA instrument is being developed.
Software updates of both the FESA instrument and expert GUI will be required for trajectory, intensity and Schottky measurements.
Low level scripts for system initialisation already developed: will be called by front-end software at system start-up.
Python scripts to emulate the front-end software developed in May.
To carry out calibration/cycle acquisition and to read out the data from the system.
They will help to verify the system operation independently from the front- end software.
Front-end software can be debugged in parallel.
They are useful to cross-check with front-end software.
The last slide is for the software.
The front-end software (both the Expert GUI and the FESA instrument) will be cloned from the AD orbit software currently being used.
An update of the software will be required for trajectory, bunched intensity and Schottky measurements.
The system initialisation will be performed by several low-level scripts called by the front-end software at system start-up. These scripts have been already developed.
Finally, some Python scripts to emulate the front-end software were developed in May. These scripts allow to carry out calibration and data acquisition with the system. They will help us to verify the system operation independently from the front-end software, which will be able to be debugged in parallel.
ELENA Status for BI
CERN. 27th October 2016

9. Head amplifier installation during next week for 3 dipole BPMs.
Conclusions
To do list...
Head amplifier installation during next week for 3 dipole BPMs.
Digital acquisition hardware installation: starting next week.
Integration of the existing BPMADE class into ELENA (Hw+Sw+FEC configuration, timing, etc.) for orbit measurements only: starting as soon as possible.
Operation RF clock/TAG from LLRF crate: after LLRF system commissioning (2016/2017).
Trajectory measurements :
PI new firmware development
SW: FESA class update
Bunched intensity and Schottky measurements with coasting beam: 2017.
Software (Expert GUI/FESA instrument) development and update for bunched intensity and Schottky measurements: 2017.
And finally, the conclusions which are basically the list of things to finish.
The head amplifiers are being installed during this week.
The digital acquisition hardware will be installed during the next week.
The front-end software for orbit measurements will be implemented after the hardware installation.
The system will operate with the RF clock and TAG signal from the LLRF crate after the commissioning of this system.
The trajectory measurements will be implemented depending on the RF colleagues availability (end of 2016, beginning of 2017).
The bunched intensisty and Schottky measurements with coasted beam will be implemented in 2017.
And, finally, the software development for trajectory, bunched intensity and Schottky measurements will be carried out in 2017.
ELENA Status for BI
CERN. 27th October 2016