ELOG Commissionning Preparation

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)

- Dipole power supplies and dipole field

- RF power stability (Klystron, ...)

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

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

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 Oct 17 10:02:07 2022

VK, IC, VI, JH, SC, ND

Reference Solution

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 Oct 10 10:04:49 2022

Summary of the ring commissioning meeting #4

- 300 turns achieved.

- Probably more but limited by libera cut-off frequency.

- Need to measure the injection axis

- Need emittance measurement from the transfer line

- Several measurements are not possible because of lack of progress on the transfer line

Mon Jun 26 09:57:52 2023

VK, IC, JH, VM, LS, MB, ND

Discussion mécanique

- Tous les dipoles ont été alignés par rapport à des surfaces de référence

- Le décalage du centre magnétique par rapport au centre mécanique a été mesuré par Cynthia et pris en compte lors de l'installation

- Difficile de décaler les dipoles de l'IP car la table a été ajoutée après et bloque le déplacement des dipoles.

- Pour déplacer tout le demi-anneau RI-C2 l'un des soufflets (près du septum risque d'être limitant). Très long temps d'approvisoinnement si l'on veut de nouveau soufflets.

- Le plus simple pour Rodolphe: bouger les 4 dipoles d'extremité (RI-C[1-2]DP.0[1,4]): 1 heure de travail (pour un test approximatif). Par contre pour revenir à une position intiale c'est 1/2 journée par dipôle.

- Pour réaligner les dipôles il faut que Denis calcul les nouveaux coordonnés.

Question à vérifier:

- est-ce que l'on a de la marge à l'IP pour déplacer les dipôles vers l'extérieur? [Mesure mardi matin avant 10h]

- quelle est la course possible pour le soufflet près du septum?

- Est-ce qu'il est possible de rattraper le fait que la chambre de RI-C2/DP.04 soit trop courte?

Stratégie:

(1) Mesure de la course possible vers l'extérieur des dipôle de l'IP

(2) Calcul par Denis des nouveux coordonnées de tous les dipôles décalés de 1mm vers l'extérieur radialement

(3) Si possible, décalage des 8 dipôles, sinon décalage de 4 dipôles.

Autre besoin:

- Faire étude sur dipôle de rechange en ajoutant des plaques en acier.

===

Objectifs de la semaine:

- Avancer sur l'orbite à 500.33MHz

- BBA

- Déplacement orbite dans IP (avec CFP)

- Vérifier/améliorer transport amont anneau

- Opérations avec ligne d'extraction

Tue May 30 10:12:30 2023

analyse

Summary of the ring commissioning meeting #2

Main studies:

- Measure bucket width in phase on Thursday at 500.02MHz => no storage beyond 45kV

- Measure frequency with spectrum analyser => 500.39MHz

- Preliminary study of BPM polarity

Next studies:

- Study again BPM polarities

- Redo spectrum analyser/FFT measurements of orbits at injection

- Study magnetic elements in balistic mode

- Visually look at the ring to see possible issues and changes to make

- Continue to do beam physics at 500.40MHz especially dynamic aperture

- Try to localize where losses occur during operations

Mon Sep 26 09:39:15 2022

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

Wed Sep 28 09:56:44 2022

Steerers and BPM map for the ring

See attached files.

Attachment 1: BPM_ring.png

Attachment 2: BPM_ring.pptx

Tue Sep 27 17:45:54 2022

Under Process

RE: Beam requirements for the ring

docs

An IHM to check some of these parameters has been created (git/panneaux/StatusInfoIHM_ring_vars.py) and added to Plateforme_IHM...

Quote:

The following parameters are required for ring operations:

- At least 80pC on TL/DG/ICT.01 with std <20pC

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

- Energy in the TL must be checked and must be 50 MeV => TL/BPM.02 SpX, SpY <1mm with Std(SpX, SpY) <1mm with nominal value for TL/PS/DP.01

- 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.

This list will evolve as we progress in the ring commissioning.

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)

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

Fri Feb 24 10:34:58 2023