ELOG Commissionning Preparation

Summary of the ring commissioning meeting #5

resumes

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.

Suggestion: Since the magnetic field stability of the bending magnet which is being used to measure the beam energy is still questioned, it is suggested to wind a wire into a small, flat, electric coil and to place it in the magnet gap or close to it so that the field crosses orthogonally the coil plane, and to monitor the voltage across the coil with an oscilloscope (the e- beam being turned off and the bending magnet being powered, of course). Some dimensional calculation would be needed.

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

Mon Nov 7 23:53:29 2022

Discussed recent orbit correction of the expanded orbit.

Need to make run with cavity detuning from its resonant conditions used in the conditioning.

Discussed measurement of tune, and possible origins of inconsistant/noisy measurements. Either BPMs signal processing or weak excitation. Beam size?

Need to do measurements with scope, to see if we can interpret TbT data in post-processing. Will ask Vincent to help with scope and measurements.

Need of RF cavity operation to continue ring commissioning.

Mon Dec 5 10:05:11 2022

VK, IC, VM, JH, KD, ND

analyse

Programme linac semaine 5 décembre

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)

Mon Dec 5 17:42:51 2022

Lundi 5 décembre : redémarrage technique

Pb refroidissement  Pb réglé le mercredi matin concomitance (anneau/linac), sensible à la pression qui est dans le réseau primaire, à surveiller

Attention connectique Profibus des alimentations

Point de fonctionnement du canon à 31 degrés à 1070 V: prévoir une vérification au prochain redémarrage technique selon la tension du klystron

Absence de tableau de conversion Puissance redpitaya  gradient (KD, VC)

Réglage du laser  vérifier à la prochaine redémarrage technique

Soleno  campagne de réalignement (pas prioritaire)

Modèle mis à plat dans MML, on a fait des premières mesures seulement QP1, 2 puis le 3

Mardi 6 décembre

Point de fonctionnement, à creuser consigne température/tension klystron

Test hors MML/lentille épaisse  ca concorde

Des scans avec un seul quadrupole, QP1

Mercredi 7 décembre

Scan systématique QP1 en fonction de coil2

Kevin a retravailler le traitement des images

Iris de 0.7, halo important

Premier résultat satisfaisant d’analyse des Twiss

Améliorer la partie analyse d’image (KD)

Chercher quad à fait à appliquer en unité physique, switch2physics ou setpv avec argument (units, ‘’Physics’), NB : TL, par défaut en online

Vérifier que les valeurs concordent, scan avant (pour checker conditions)

Mettre QP1, puis QP2, puis QP3

Améliorer : prise en compte du cyclage dans ce genre de mesure, vérifier les mesures, (KD, vérifie mesure disponibles)

Tue Dec 6 00:15:55 2022

RE: Summary of the ring commissioning meeting

analyse

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.

Quote:

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)

Mon Jan 9 10:12:40 2023

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.

Attachment 1: 20_injections.jpg

Mon Jan 16 09:38:16 2023

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)

Mon Jan 23 09:54:14 2023

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)

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

Next ring meeting 13/2

Tue Jan 24 10:14:20 2023

Notes from ThomX Physics meeting

Prise de donnees

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)

Thu Feb 9 12:16:41 2023

Verification variables pour l'anneau

Prise de donnees

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/

Attachment 1: ring_vars_2023_02_09_12_15.png

Mon Feb 20 10:06:36 2023

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).

Fri Feb 24 10:34:58 2023