See slides attached to the indico page https://indico.ijclab.in2p3.fr/event/8885/

Pb with BPM => visual check of electrodes + hardware swap

Pb with steerer => Need to identify who will do the intervention and when

Nicolas will ask Kevin for support.

Alignement: Slava got the data from Denis. Alignment is close from nominal values.
The beam quality is good enough to start working with the RF cavity. Even with low power in  RF cavity we would like to have a first control of voltage and phase from the control room (Thursday or Friday afternoon).

Some energy instabilities have been observed. Look at correlations (Vincent's measurements) + check that the current operating phase is optimal.

=> Check if position fluctuations are the same with one steerer on, TL/DP/PS.01 off + TL/SST1 and steerer off, TL/DP/PS.01 on + TL/SST2.

Optimum injection trajectory has been recorded on Friday.

Next meeting: 7th Novembre

En complément du message de Hayg, client 4 et 5 ne fonctionnent pas non plus (en plus de client 1).

Nicolas

Status slides presented by Iryna available on indico at https://indico.ijclab.in2p3.fr/event/8749/

The beam parameters required for a good injection in the ring were discussed.

The following required parameters were identified:

- At least 80pC on TL/DG/ICT.01

- At least 20pC on TL/DG/ICT.02

- Energy in the TL must be checked and must be 50 MeV.

- Beam position must be checked on TL/DG/SST.01, TL/DG/SST.02 and TL/DG/SST.03 and be within the acceptance (see tickbox acceptance on IHM_SST).

- Beam size must be measured on TL/DG/SST.03 and be < 2mm FWHM

- Beam recipes for the LI and for the TL must be saved.

- Health check must be checked (no red entry).

- Beam centered on the last quadrupole of the transfer line.

ACTION: Nicolas will create an interface that displays as many as possible of the required parameters.

Suggestion by Viktor: check phase noise at the gun entrance: there might a phase noise issue.

=> Vincent (VC) is going to do that with Viktor (VI) during RF studies on 26th September

Planning for the coming week:

- Wednesday: Slava (+Iryna after the CoDEC)

- Thursday: Nicolas + all

- Friday: AG Pole. Alexandre and Vincent plus Slava

Current objectives:

1) Re-establish beam transport to ring

2) Scan in time the septum

3) Scan in voltage the septum

4) Adjust timing of kicker by looking at induced noise on ICTs

5) Scan in time the kicker

6) Scan in voltage the kicker

7) Transport further in the ring by playing with correctors

Note: When possible Alexandre will test his feedback code.

This entry is to be updated as the work progresses.

1) Re-establish beam transport to ring

2) Scan in time the septum

see script git/panneaux/Synchro/scan_septum.py

3) Scan in voltage the septum

4) Adjust timing of kicker by looking at induced noise on ICTs

5) Scan in time the kicker

git/panneaux/Synchro/scan_kicker.py

6) Scan in voltage the kicker

7) Transport further in the ring by playing with correctors

Note: When possible Alexandre will test his feedback code.

Slides are at https://indico.ijclab.in2p3.fr/event/8750/

- There is a difference in BPM numbering in Tango and MML => we should stick to Tango names.

- Beam was very unstable during the past week

- Difficulties to have full current on RI-C1/BPM.01. Signal drops already significanty before RI-C2/BPM.06

- Fluctuations may have been observed on the RF Gun power => to be confirmed

- Fluctuations have been observed on the kicker => may be due to energy jitter

To do:

- Monitor incident power on RF Gun

- Re-establish transport

- Try to inject with optimised TL transport

- Compare single pass and TbT BPM signals

- Check energy jitter in TL/BPM.02 and TL/SST.02

- Scan correctors to increase current on RI-C1/BPM.01 and RI-C2/BPM.06

- Start align beam in quadrupoles

(1),  (2), (4) and (5) from last week have been done other items in progress.

New to do list:

(0) Re-establish beam transport to ring

(1) Monitor incident power on RF Gun

(2) Check energy jitter in TL/BPM.02 and TL/SST.02

(3) Use TL optimised transport when available

(4) Compare single pass and TbT BPM signals

(5) Test Alexandre's feedback code.

(6) Scan correctors to increase current on RI-C1/BPM.01 and RI-C2/BPM.06

(7) Start align beam in quadrupoles
 

Shift summaries for the ring for last week are at

https://elog.lal.in2p3.fr/THOMX/Commissionning/568

https://elog.lal.in2p3.fr/THOMX/Commissionning/570

https://elog.lal.in2p3.fr/THOMX/Commissionning/571

The problem with the pulse jumpis with 12ns delays has been identified and fixed (it was related to the synchronisation system).

The main issue identified last week is a problem with RI-C2/PS/QP.09, RI-C2/PS/QP.10 and RI-C2/PS/QP.12 which has been addressed after the meeting (see https://elog.lal.in2p3.fr/THOMX/Commissionning/572).

It is important that the laser energy and linac beam charge are checked and optimised every week.

New to do list:

(0) Re-establish beam transport to ring

(0bis) Check energy jitter in TL/BPM.02 and TL/SST.02

(1) Try to merge TL optimised transport with ring injection transport => record beam size on TL/SST3 and position on TL/BPM.03 and TL/BPM.04 for current ring transport

(2) Reduce betatron oscillations

(3) Measure and correct orbits

(4) Measure Tune

(5) BBA

(6) Improve charge transport at injection

(7) Start MRSV

To do list:

(0) Re-establish beam transport to ring

(0bis) Check energy jitter in TL/BPM.02 and TL/SST.02

(0ter) Measure emittance on TL/SST.03

(1) Try to merge TL optimised transport with ring injection transport => record beam size on TL/SST3 and position on TL/BPM.03 and TL/BPM.04 for current ring transport

(2) Improve charge transport at injection

(3) Measure and correct orbits

(4) Start MRSV

(5) Measure Tune

The ring orbit has been re-established despite some difficulties after the shutdown.

The ring cavity has been started. Whatever the phase it kills the beam.
Two hypothesis:

1) It can be a frequency problem

2) It can be a transverse kick given by the cavity

About 1:

- Magnet current and frequency have been scanned but no effect.

About 2:

- We see betatron oscillation.

We see the beam lost by steps, not a continuous decrease.

https://elog.lal.in2p3.fr/THOMX/Commissionning/221202_190728/Screenshot_from_2022-12-02_18-02-36.png shows betatron oscillation with cavity tuned.

Next steps:

- Mesure FFT of BPM signal (VM, VC)

- "Open the ring" (kick the beam out of the ring) and study the effect of the cavity (phase, power) on the BPMs. (VK, IC)

- Scan betatron oscillation vs phase, orbit, power and frequency

- Slava: To catch the beam you should think like a beam.

Actions:

- Try to get remote control of RF synthetizer (ND)

Regarding the remote control of the RF synthetizer: it can only be controlled via GPIB and RS-232.

=> Phase shift will be done from the synchro synthetiser

=> Power control can be done with a variable attenuator controlled by the synchro synthetiser or a delay generator.

Notes from last week:

• Beam was very unstable (probably energy instabilities), lot of time was spent tuning the injector.
• Beam instabilities prevented us from having a good storage.
• Unable to start the extraction line dipole.

Comments:

• It seems too early to plan radioprotection checks as:
  • we have not yet been able to store the beam and then extract it in a working extraction line.
  • beam is too unstable.
• Beam instabilities prevent progress on the ring studies.
• Beam stability characterisation of the upstream parts of the accelerator are necessary.

Summary of last week:

- On Thursday the beam energy was very different from usual (magnets current higher 172A for TL; 176A for RI) => made it impossible to re-use previous settings for the ring and to find new settings.

- On bith days, beam was unstable at TL/SST.02 and at the entrance of the ring. Part of the stability (but not enough) was recovered by setting TL/QP.4 and TL/QP5 to the same value.

=> not able to keep the beam in the ring for more than 500us or to inject more than 50pC.

Requirements to discuss on Friday:

- Get the results of the klystron power measurements

- Energy and charge stability

- Establish a working point for the lines.

- Linac alignement

Measurements to be done and documented:

- Stability of dark current (VM on 2/2)

- stability shot to shot and hourly-stability  (laser power, laser position, phase gun-laser [VC is working on it], phase gun-entrance section, phase gun-exit section, charge at the exit of the gun, charge at the exit of the section, energy and charge in the dispersive line)
=> charge stability measurement ND on 2/2 + 9/2.

- Dipole power supplies and dipole field

- RF power stability (Klystron, ...)

- Data alignement (ND on 2/2 + 2/9)

No beam last week. No beam this week.

Machine recovery on 2/2 => Nicolas may try to tune the machine with students.

Data taking on 9/2 for diags and machine characterization.

Next shift for the ring on Friday 17/2 + Friday 24/2 + Friday 10/3. No beam on 3/3 (winter vacation).

Beam on 9/3 will be dedivcated to BPM training for PERLE.

Reminder for the previous ring meeting - Measurements to be done and documented:

- Stability of dark current (VM on 2/2 or 9/2; ND to prepare the measure with ICT+WAC ; IC will prepare measure with scope)

- stability shot to shot and hourly-stability  (laser power, laser position, phase gun-laser [VC is working on it], phase gun-entrance section, phase gun-exit section, charge at the exit of the gun, charge at the exit of the section, energy and charge in the dispersive line)
=> charge stability measurement ND on 2/2 + 9/2.

- Data alignement (ND on 2/2 + 2/9)

Next ring meeting 13/2

Present: IC, VK, VM, VC, SC, MEK, KD, MJ, HG, ND, MO (sous réserve d'oublis)

Visio: CB

L'ordre du jour et les transparents présentés en réunion sont sur: https://indico.ijclab.in2p3.fr/event/9205/

Actions à faire:

- Vincent a montré que le laser met ~1h avant de se stabiliser en phase par rapport au signal de synchronisation 3GHz. Il faut donc démarrer le laser (START_AMPLI) dès la mise en chauffe du modulateur.

- Mise en place d'un système de retroaction en salle laser (Vincent)

- Campagne de mesure détaillée du klystron prévu pour la semaine commeçant le 30 janvier.

- Pour trouver la phase d'énergie maximale, il faut calculer le déphasage Canon-Laser PC par rapport à la chute de charge lors du balayage en phase. Christelle va circuler la valeur recommandée.

- Accorder la section RF linac à l'energie maximale (Mohammed?)

- Refaire des mesures de courant d'obscurité (Vincent + Viktor M. + Nicolas)

- Circuler les sorties Astra en fin de linac à 100pC pour permettre des simulations de la propagation du faisceau dans la TL (Christelle)

- Il faut toujours faire fonctionner la ligne de transfert avec le même courant dans les aimants. Slava va circuler la valeur à utiliser.

- La maille LI+TL actuelle a été calculée pour 1nC. Il faut terminer définir la maille LI+TL à 100pC et vérifier sa validité (Christelle + Sophie)

- Circuler la maille LI+TL et des images donnant les taille de faisceau attendues sur chaque écran SST.

- Améliorer la stabilité (charge, énergie, position) de la ligne de transfert, surtout dans sa partie dispersive.

- Il faut calibrer les écrans SST (Nicolas)

L'IHM de verification des variables pour l'anneau a ete mis a jour.

Il est accessible dans plateforme IHM section "Outils", éeme collone, "eme ligne: "Check vars for RING".

Utilisation de l 'IHM (voir copie d'ecran ci-joint):

-Chaque ligne donne une valeur et (lorsque c'est pertinent) sa std ainsi que le besoinde l'anneau sur cette variable.

- Si la variable est dans la plage acceptable, la diode devient verte.

Pour inclure l'image dans le e-log cliauer sur "Take screenshot". L'image est sauvee dans  /data/shared/Commissioning_tools/Mesure/today/

This week: beam on Thursday.

So far we did not see any screenshot of Ring variables check.

Looking at last week's data, shot to shot charge instability seems to be > 15%

We need transverse emittance measurement for the ring shift (Thursday).

Présent: VK, SC, KD, MJ, HG, ND

Présentation par Marie. Cf indico https://indico.ijclab.in2p3.fr/event/9242/

Demo par Slava.

Prochaine réunion le 24 mars.

Excitation (betatron oscillation) on the beam observed by exciting it with the extraction kicker => initial measures of the tune.

Tune measured close from expected value.

Reason for oscillation damping is not understood.

The attenatuator of the RF section has to be tuned from time to time to keep the beam energy (beam position on TL/BPM.02).

Energy tolerance of the ring lattice: +/- 1% (but this may affect the transport upstram in the TL).

Next steps:

- Measure oscillations at different cavity power to see how they are affected.