The main task for today is to measure the revolution frequency without RF cavity with the spectrum analyzer.

Start-up of the machine.

After setting the previous setting, the orbit was very different. We checked the injector, the beam also was different (based on the beam images) and based on the RF plots we suspected that the timing of the laser has changed.

We changed the delays, reworked the transport but then it needed much more time to optimize the injection. We made the reseanoble storage but decided  to come back to the original settings (to be consistent in oour studies). After that, not clear why, the orbit came back to the expected values (as it was on Friday).

Start of the spectrum analyzer. Machine is set to the seetings from last Friday. Beam in the ring is not very stable. We had a few kV in the RF cavity for a short period of time.

Measurements without the RF power and one measurement with a small power (a few kV). Plots are attached. The screenshot was done for the different oribt (dipole values).  Prelimenary conclusions: At nominal lattice (with some scaling), we can keep the beam in the ring in the energy range, which corresponds to the attenuation of the RF section of 1.97-2.14 dB (nominal is 2.03 dB). This coresponds to the revolution frequency range of x30 => 500.33 - 500.47 MHz.

At this frequency, the  mean orbit changes from about ~-3 to +3 mm.

Taking into acount this freauency/orbit change (70 kHz - ~3mm), it means that to come to the nominal RF frequency of 500.02 MHz, the mean value of the orbit in radial direction should be increased by about ~18 mm. The calculations show also that to reach teh nominal frequency due to the energy change ~5-7%, the larmor radius in dipoles should be increased by ~20 mm. All this is in agreement with what we have measured today.

=> All this estimations are certainly prelimenary.

Problem with RF cavity. Mohamed tried to solve it during the day, No storing power. We need the RF cavity to continue our studies.

Mercredi 24 j'ai fait un test sur la cavité RF :

    - Au début la LLRF étant ON alors que la cavité était OFF, est ce normale ?

    - Le moteur du plongeur était à 24.91 mm

    - J'ai donc allumé la cavité avec 0V en consigne (sans puissance), il y a tout de même 5kV je crois en résiduel au minimum.

    - J'ai mis le plongeur à 24.4mm et à 500.4MHz, attendu que la cavité se stabilise avec le LLRF

    - J'ai coupé le LLRF, et fait le changement du plongeur à 22.4mm, et ré-accorder la cavité avec la fréquence, j'ai trouvé une fréquence de l'ordre de 500.3MHz.

    - J'ai tout remis comme avant (fréquence : 500.4MHz, plongeur 24.91 et attendu que la LLRF se stabilise) et j'ai tout mis OFF, cavité et LLRF.

A confirmer qu'un delta de 2mm sur le plongeur génère un delta de fréquence de l'ordre de 100 kHz ?

Goal: understanding of teh beam natural revolution frequency. Study the effect of the dipoles.

We have started from the previous setting of the machine. Then we loaded the settings from last december and received better storage. RF cavity is OFF.

By working with the spectrum analyzer, we understood that previous measurements very probably were affected by the noise coming from the synthetizer, so the frequency measured corresponded to the synthetizer frequency.

At the same time, during the investigation, apart of the false peak given by the synthetizer frequency, there was some signals (difficult to interpratete) aroung 500.4 MHz. Investigations are ongoing.

In parallel, we are checking the BPM cabling convention by using the beam to be sure about the orbit readings.

Study of signal on scope:

Yellow: Losses monitor

Green: Sum of 4 electrodes RIC2/BPM.06

Blue: Long open cable (background pickup)

Screenshot from 2023-05-31 15-14-12.png Beam stored only for 1 turn not reaching

Screenshot from 2023-05-31 15-18-05.png: Green (BPM sum) cable disconnected

Screenshot from 2023-05-31 15-19-40.png: Green (BPM sum) cable reconnected

15:30 Checking BPM polarities

16:30 Created IHM to lock position on TL/DG/BPM.02 :  Diags/BPM/lock_position_tl_bpm_02.py

16:32 reload ring recipe

Screenshot from 2023-05-31 16-35-21.png : BPM signal with current in ring

Screenshot from 2023-05-31 16-49-49_I_159_3.png

Screenshot from 2023-05-31 16-51-58_I_161_90.png

Screenshot from 2023-05-31 16-56-12_I_157_90.png

Screenshot from 2023-05-31 17-02-41_I_159_90.png

Screenshot from 2023-05-31 17-03-15_I_161_90.png

Screenshot from 2023-05-31 17-10-02_I_157_90.png

Screenshot from 2023-05-31 17-11-53_I_161_90.png

Screenshot from 2023-05-31 17-13-59_I_157_90.png : We see the markers at the two node position. Delta X = 900ps

Screenshot from 2023-05-31 17-21-18_I_157_90.png : 3ns/div

When we change the dipole current we confirm that time to come back to the BPM change...

17h25: Machine stop

Bonjour,

Pouvez vous enregistrer les images de l'oscilloscope et le donnée brute à la place des screenshots. Il y a une option dans l'interface web pour enregistrer l'oscillogramme "proprement". De même pour les images, cela permet de faire des traitements à posteriori.

Merci.

9:23 Mise en chauffe

Nombreux pb vide dans health check

Acces casemate pour verification polarite RI-C2/DG/BPM.02 pas de probleme trouve.

Observation des soufflets pres de RI-C2/AE/DP.04 ils semblent legerement deformes mais pres de RI-C1/AE/DP.01 aussi.

11:30 Tentative de demarrage mais probleme temperature eau...

12:00 Intervention Maher. Demarrage possible.

Pb declenchement wavecatcher... Resolu (le serveur etait plante)

14:00 BPM polarity studies

15:30 Measure frequency

16:30 To to steer the beam around the chamber

18:20 Stop

===

Programme de la prise de données du 8/06:

0) During warm up:

0a)check physically BPMs where there seem to be a polarity issue (needs 2 persons, a battery and a multimeter).

0b) CHeck vacuum chamber around RI-C2/AE/DP.04

1) Transport to TL/FC.01 (TL/DP.01 off). Record FC  signal

2) Transport to TL/SST.02 and TL/BPM.02. Record BPM adc signal while closing dispersion (for Mouad's studies).

3) Transport to EL/FC.01. Record FC  signal and compare with TL/FC.01. If needed swap filters and compare again.

4) Activate position feedback on TL/BPM.02

5) Inject in ring, no RF power. Record with high res oscilloscope travel time for different magnets settings. If needed use a mixer.

6) Study the effect of correctors around RI-C2/AE/DP.04

7) Use extraction kicker scan to measure beam travel time after several turns

8) Finish BPM polarities study

9) Repeat (5) and (7) with different RF powers at 2 different frequencies (500.0202MHz and 500.4MHz). Look at oscillations on TbtX and TbtY vs frequency.

 

Goal of the shift: Reestablish the good storage at 500.38 and then try to optimize the storage and orbit.

Start up of the machine.

RF cavity start up by Mohamed. Water leakage. Jean-Noel will fix tomorrow mornig. Mohamed also says that aparently the sinal from ring syntetizer is a bit noisy, to be checked with Nicolas.

problem with trigger of the TL BPM. Nicola fixed the problem. The cable was broken.

Load of the machine setting from 19/05. The injection in the ring is very unstable from shot to shot due to the tuning of the cavity. Coming to 100 kV @500.38 MHz synchronized with the ring. RF cavity works stable.

Beam on TL BPM.02 drifts a lot and very fast. See screenshots.

With the previous setting, we did not get the previous orbit. After small reoptimization we received the resonable storage. Still we should work on the orbit correction.

The main idea fo this week is to prepare the beam for the search of the first X-rays.

Quelques changements de phase canon. On voit que quand l'orbite derive vers des valeurs negatives sur Tl/BPM.02/SpX le fait de faire decroitre la phase rattrappe la position...

Le code lock_position_tl_bpm_02.py a ete mis a jour pour prendre cet effet en compte.

Bonjour,

avant d'arrêter completement de la machine il faut absolument fermer le "Gate laser" via

1, LI/OP/OPT.02-LAS.01-ASP.01 - Gate_int -False

ou

2, Plateforme IHM ThomX - Ring- Start for ring - Close laser gate

Viktor.

Bonjour,

avant d'arrêter completement de la machine il faut absolument fermer le "Gate laser" via

1, LI/OP/OPT.02-LAS.01-ASP.01 - Gate_int -False

ou

2, Plateforme IHM ThomX - Ring- Start for ring - Close laser gate

Viktor.

Effet de l'eclairage dans la casemate sur les detecteurs a RX (lumiere eteinte a 15:26:40) => il faut fonctionner avec la lumiere eteinte pour plus de sensibilite.

The main idea fo this week is to prepare the beam for the search of the first X-rays.

Start without RF cavity. Study of the orbit. Orbit correction. We menage to correct hor. and vert. orbit.

We put the RF cavity ON. A lot of interlocks during the day. Difficult to operate i this conditions.

Optimization of the storage.

Orbit corresponds to the disperive orbit. Should look at this. Maybe tune the frequency.

Very good storage was obtained. The Ring dipoles were changed to 160 A to minimize synchrotron oscillations and so improve storage. The orbit did not change.

Beam physics measurements to be started.

The main idea fo this week is to prepare the beam for the search of the first X-rays.

Start machine without RF cavity. During the day several reboot of the libera.02 (TL).

Study of the dispersion. Measurements of the horizontal dispersion by changing the injector energy (RF section attenuator).

Orbit correction.

Study of the tune. Tune response with the steptune. Tune measurements.

First try to measure the horizontal beta function at the quadrupoles.

RF Cavity ON. Good storage at 50 kV 500.38 MHz. Dispersive orbit. SHould understand how to reduce it. 

Different studies on the orbit.

Observations: position at the  TL/DG/BPM.02-LIB.02/SpX drifts a lot (a few mm range) all day long. We should correct it all the time to keep the beam orbit and storage.

The BLM detector boxes were installed in the ring. We connected 3 fibers and 2 scintillator detectors in th ring to be able to observe the beam losses.

Cabling, connection and checks of the BLM without the beam.

Machine start-up. Modulator was switched on at ~9h30.

Good storage.

Check of the injector and injection in the ring. Looking for the signal of the BLM withthe beam. Sucesfully; the signal was found with the fibers (see the screenshot attached).

Strange behaviour with the storage shot-by-shot: better and worse storage.  Nicolas, Jean-Noel and Mohamed is trying to check it. All the chain from the synchro generator to the RF cavity was checked and it is OK. To be investigated.

9h30 Start of the modulator and lasser (GATE is closed).

9h46 Data is taken as background.

Cavity is tuned to 500.38 MHz. Optimization of the energy and phase. 

RF cavity OFF. After previous tuning, the orbit is the same. Based on the simple calculation, to match to orbits, the RF frequency should be reduced by 60 khz.

New tuning of the cavity at 500.32 MHz.

After energy and phase optimization, the storage is obtained with a small dispersive orbit. Probably the real frequency is 500.33 MHz.

Test to decreaase the frequency to see at which frequency we can operate with the FPC if needed. Tuning of the cavity at 500.22 MHz. No storage obtained.

New test at 500.27 MHz. The beam storage is obtained with the dispersive orbit. Machine is depleted. At the moment the lowest frequency at which we can potentially operate is 500.27 MHz.

Coming back to the machine frequency of 500.33 MHz. Storage is obtained. Optimization to be done.

Data are taking at each configiration.

During the shift, we monitored the beam losses measured by 3 connected fibers. The turn-by-turn losses are clearly visible.

9:23: Mise en chauffe

9:29 Cycle magnets

10:20 Acces casemate cavite CFP

10:49 Beam ON Phase=268

11:02 Phase RF linac = 109

11:14 Faisceau dans l'anneau

Recette: all_20230616_16_51_29

11:15 Faisecau stocke

11:30 Reglages cavite RF en cours

11:46 10kW dans la cavite CFP

Ring RF Cavity 60kV

Phase 5.41V sur les deux dephaseurs SY

Freq = 500.33MHz

Recherche des X

16:20 Faisceau dans la ligne d 'extraction apres passage dans l 'anneau.

Transmission dans l 'anneau:

75% a l 'injection

35% en stockage

Rapport de charge EL/BPM.01/TL/BPM.04: 20% (compatible avec les valeurs ci-dessus)

Timing WAC.03 -6.93us.

Recette sauvee sous LI_TL_RI_good_20230622_16_21_36

17h15 Perte faisceau Scan charge vs phase + regage dispoersion  refait

** Au vu de ce shift tres instructif d'aujourd'hui, pour demain:

1) Le sens le moins chronophage des scans table FPC sont:

Partir en Ty negatif, et aller vers Ty pos

Paritr en Tz positifs, et aler vers Tz neg

2) Avoir de visu les panneaux "charge" et "Stockage anneau" sur le meme ecran que l'intensite p-diode xline car aujourd'hui il n'y avait plus rien de stocke pendant un certain temps (inconnu) sans que ceux qui cherchent les X le sachent

3) Se mettre au point de fonctionnement anneau ~90% de stockage et non 30% comme aujourd'hui (facteur 3)

4) Se mettre et faire en sorte de rester a 100 pC, tout le temps, et pas autour de 50 voire moins comme c'etait le cas souvent aujourd'hui (facteur ~2)

** On a scane, sans succes :

Tz de 0 a 1.9 mm . La CFP perd un facteur 2 vers Tz = 1.5 mm, un facteur 10 vers Tz = 1.9 mm

Tz de 0 a ~ -3 mm CFP a delocke ensuite, on a decider de passer a Ty sans aller plus loin en Tz

Ty de 0 a 2.5 mm (maximum autorise)

Tz de 0 a -3.9 mm pour Ty = -2.5mm

Tous ces scans ont ete faits sans savoir en direct quelle etait la charge et le stockage, et donc ils sont a refaire dans les conditions 2), 3) et 4)

8h30 Start of the modumator, laser, magnet cycling

9h45 Beam is ON. Scan charge vs. RF phase.

Attribute Li/OP/OPT.01-ATT.01  is showing value 340mm, this is different from the nominal ones of 300-303. Charge to be remeasured at nominal ones.

Aujourd'hui on a detecte des X en mode desynchro (notre signal correspond a ~ 3.10**6 ph/sec)

*** Pour :