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#21
Need help? / Re: Strange vertical 50Hz nois...
Last post by Ji-Gwang Hwang - May 03, 2022, 02:33:16 PM Dear Laura
It is a bit different issue but I have observed the 50 Hz ground motion in our optical table with a vibration sensor. We found that the source was small chillers installed onto a vibration damped carriage. The 50 Hz noise disappeared (please see the attached figure) when the chillers are off for the summer shutdown.
It may possible to check the motion with a vibration sensor. Then, it would be clear that the motion is real or artefact.
Best regards
Ji-Gwang Hwang
It is a bit different issue but I have observed the 50 Hz ground motion in our optical table with a vibration sensor. We found that the source was small chillers installed onto a vibration damped carriage. The 50 Hz noise disappeared (please see the attached figure) when the chillers are off for the summer shutdown.
It may possible to check the motion with a vibration sensor. Then, it would be clear that the motion is real or artefact.
Best regards
Ji-Gwang Hwang
#22
General Discussion / Re: SINGLE ELECTRON MEASUREMEN...
Last post by Ji-Gwang Hwang - May 03, 2022, 01:42:04 PMSimilar work has been done in Metrology Light Source for a primary radiation source standard but with a different approach (scraping from high-current to a single electron and cooled photodiode).
See Figure 12 c of Publication in PRST-AB: https://inspirehep.net/files/6acaafbc9ad41418b82ca9f70109f976
It looks like the previous measurement from MLS has a better signal-to-noise ratio.
What would be the advantage to use the high-efficiency PMT?
See Figure 12 c of Publication in PRST-AB: https://inspirehep.net/files/6acaafbc9ad41418b82ca9f70109f976
It looks like the previous measurement from MLS has a better signal-to-noise ratio.
What would be the advantage to use the high-efficiency PMT?
#23
Announcements / Open post doctoral positions a...
Last post by nicolas.hubert - April 19, 2022, 05:21:24 PMWe have recently opened at SOLEIL 2 postdoctoral positions to work on the design of some SOLEIL-Upgrade diagnostics:
• Photon BPM: https://www.synchrotron-soleil.fr/en/job-offers/post-doctorat-photon-bpm
• Optical diagnostics for the new booster: https://www.synchrotron-soleil.fr/en/job-offers/post-doctoral-position-boosters-diagnostics
Don't hesitate to apply!
Nicolas HUBERT
Head of Diagnostics and Timing Group
Synchrotron SOLEIL – Accelerators & Engineering Division
L'Orme des Merisiers BP 48
91192 Saint AUBIN - FRANCE
http://www.synchrotron-soleil.fr
• Photon BPM: https://www.synchrotron-soleil.fr/en/job-offers/post-doctorat-photon-bpm
• Optical diagnostics for the new booster: https://www.synchrotron-soleil.fr/en/job-offers/post-doctoral-position-boosters-diagnostics
Don't hesitate to apply!
Nicolas HUBERT
Head of Diagnostics and Timing Group
Synchrotron SOLEIL – Accelerators & Engineering Division
L'Orme des Merisiers BP 48
91192 Saint AUBIN - FRANCE
http://www.synchrotron-soleil.fr
#24
General Discussion / SINGLE ELECTRON MEASUREMENTS
Last post by Elena Buratin - March 31, 2022, 09:52:18 AMHello,
At ESRF we have been exploring the possibility to do single-electron control and measurement with the use of 4 screens in TL2 and a simple and low-cost Photon Multiplier Tube (PMT) installed in the visible-light laboratory (ID04). We could inject 1-2-3-4-5 electrons the EBS ring. The first direct application was the measure of the beam purity during MDTs. We are going to install a Pico-Harp and a Time-Correlated-Photon-Counter (TCPC), for a bunch-purity measurement that may allow to cover up to 10e-11 dynamic range during User-mode operation (USM).
Find attached the first measurements.
If you have any question or suggestion, please comment.
Elena
At ESRF we have been exploring the possibility to do single-electron control and measurement with the use of 4 screens in TL2 and a simple and low-cost Photon Multiplier Tube (PMT) installed in the visible-light laboratory (ID04). We could inject 1-2-3-4-5 electrons the EBS ring. The first direct application was the measure of the beam purity during MDTs. We are going to install a Pico-Harp and a Time-Correlated-Photon-Counter (TCPC), for a bunch-purity measurement that may allow to cover up to 10e-11 dynamic range during User-mode operation (USM).
Find attached the first measurements.
If you have any question or suggestion, please comment.
Elena
#25
General Discussion / Re: ICT vs Turbo-ICT
Last post by cozkan - December 13, 2021, 02:51:12 PMHi Fred,
I have experience with both. Feel free to email me.
Best,
Cigdem
I have experience with both. Feel free to email me.
Best,
Cigdem
#26
Need help? / Re: Strange vertical 50Hz nois...
Last post by Benoît Roche - November 24, 2021, 01:47:49 PMIt is indeed quite puzzling. Also it seems that it is not a pure 50 Hz sine wave perturbation, but rather a square signal with varying duty cycle. This suggests that it is not just a coupling with mains power supply.
Can you try to capture the signal seen by each channels (Va, Vb, Vc, Vd) to see if it is present on all of them, or just two? Does the sum signal also have this behavior?
Can you try to capture the signal seen by each channels (Va, Vb, Vc, Vd) to see if it is present on all of them, or just two? Does the sum signal also have this behavior?
#27
Need help? / Re: Strange vertical 50Hz nois...
Last post by Laura - November 24, 2021, 01:24:31 PMThe second graph is what we see when both BPM and corrector were out of the FOFB loop: we could still see the noise and, since they were not in the loop, the jumps were not corrected (i guess). If you zoom at the jump you would see the same 50 Hz pattern (as in the third plot, unfortunately I don't have a zoom of this specific graph).
The first plot is how the noise appear usually when the BPM and the corrector are in the loop.
I think this is a noise that somehow enter in the BPM and then the FOFB try to correct and propagate it through the sector.
The last plot is an FFT of the noise. The 50Hz line appears broader.
What I don't understand is that it appears only in vertical... If it was some random noise leaking in the buttons/cables it would be in both planes.
I am quite lost
The first plot is how the noise appear usually when the BPM and the corrector are in the loop.
I think this is a noise that somehow enter in the BPM and then the FOFB try to correct and propagate it through the sector.
The last plot is an FFT of the noise. The 50Hz line appears broader.
What I don't understand is that it appears only in vertical... If it was some random noise leaking in the buttons/cables it would be in both planes.
I am quite lost
#28
Need help? / Re: Strange vertical 50Hz nois...
Last post by Benoît Roche - November 24, 2021, 12:17:09 PMHello Laura, I hope you are doing well.
I don't remember having a 50 Hz noise perturbation that was not a real perturbation on the beam, here.
Nevertheless, can you describe a little more your graphs? In particular we can see jumps on the second graph, it is not clear to me if those are related to the noise you have.
I don't remember having a 50 Hz noise perturbation that was not a real perturbation on the beam, here.
Nevertheless, can you describe a little more your graphs? In particular we can see jumps on the second graph, it is not clear to me if those are related to the noise you have.
#29
General Discussion / BEAM PHASE MONITOR at ESRF
Last post by Elena Buratin - November 24, 2021, 11:39:14 AMHello,
At ESRF we now re-installed a high quality numeric BEAM PHASE monitor that is achieving very good & useful results.
It is based on a simple Spark-BPM electronics, using the available I and Q buffers in that device.
The resolution is about 1millidegree and it can measure at sampling speeds upto Turn-by-Turn rate (2.8us ESRF)
If you want more information please contact Elena or Kees, or download the available pdf.
At ESRF we now re-installed a high quality numeric BEAM PHASE monitor that is achieving very good & useful results.
It is based on a simple Spark-BPM electronics, using the available I and Q buffers in that device.
The resolution is about 1millidegree and it can measure at sampling speeds upto Turn-by-Turn rate (2.8us ESRF)
If you want more information please contact Elena or Kees, or download the available pdf.
#30
Need help? / Strange vertical 50Hz noise in...
Last post by Laura - November 24, 2021, 11:30:26 AMHello,
I am struggling with this since July: we have one BPMs that sees some strange noise only in the vertical direction. The frequency of this noise is 50 Hz.
The problem is that this BPM is in the FOFB loop and the noise is then spread around the whole sector.
We have:
- Checked and changed the associated corrector (but the noise frequency was already telling us that it was not the guilty one)
- Changed the Libera (even if the noise was only in vertical)
These modification provided no results.
Moreover this noise is not always present. We are sure that it is seen by this particular BPM since we removed corrector and BPM from the FOFB loop and we could see the noise in the vertical BPMs data even when it was out from the feedback. The other BPMs of the sector did not show anything.
I can add that this BPM is located in the middle of a standard sector (no IDs or cavities close by).
I also want to stress that this noise is observed only in the vertical direction.
Has it happens to some of you? Do you have some suggestion.
Thanks in advance,
Laura
I am struggling with this since July: we have one BPMs that sees some strange noise only in the vertical direction. The frequency of this noise is 50 Hz.
The problem is that this BPM is in the FOFB loop and the noise is then spread around the whole sector.
We have:
- Checked and changed the associated corrector (but the noise frequency was already telling us that it was not the guilty one)
- Changed the Libera (even if the noise was only in vertical)
These modification provided no results.
Moreover this noise is not always present. We are sure that it is seen by this particular BPM since we removed corrector and BPM from the FOFB loop and we could see the noise in the vertical BPMs data even when it was out from the feedback. The other BPMs of the sector did not show anything.
I can add that this BPM is located in the middle of a standard sector (no IDs or cavities close by).
I also want to stress that this noise is observed only in the vertical direction.
Has it happens to some of you? Do you have some suggestion.
Thanks in advance,
Laura