ELENA LLRF status update Maria ELENA Angoletta for

ELENA LLRF status update Maria ELENA Angoletta for the LLRF team ECC 19 July 2018

Outline 1. Cycle length 2. RF cycle editor and RF segments 3. Extraction synchro 4. Next tasks & miscellanea LLRF 5. Conclusions M. E. Angoletta “ELENA LLRF STATUS” ECC 19 July 2018 1

1. Cycle length Friday 13/07: LTIM limitation (no trigger for delays > 24 s) was discovered. That has been removed by Mic, v FESA classes + EDSP (LLRF has completed its work) timings now delayed. NB: time is needed @end of cycle to prepare for the next cycle. v v Now EDSP is at ctime 29318. Could be further delayed if cycle is made longer but FESA classes timings need to be changed, too. Call Mic! M. E. Angoletta “ELENA LLRF STATUS” ECC 19 July 2018 2

2. RF cycle editor and RF segments Third RF segment for rebunching (and extraction) after final ecooling setup and validated on Monday 16/07. v Davide wrote MATLAB program that generates RF segments (timings and functions) of programmable length and starting time. It also shows v resulting functions with respect to cycle time (internal stops “unrolled”: what you see is what you get). v MATLAB program adapted on Tue 17/07 to setup also third RF segment. v Additional LLRF FESA class required by Lajos to interface with RF cycle editor (timings and harmonics). The new LLRF FESA class should be ready by the end of week 30 (next week). LLRF functions programmed directly by RF cycle editor. M. E. Angoletta “ELENA LLRF STATUS” ECC 19 July 2018 3

3. Extraction synchro Commissioned for pbars on Wed 19/07. v Synchro @ctimes 22000 & 26000, before ecooling, on extraction plateau during 2 nd RF segment. Loop closed on TPU (used also for PL). Now pbar beam is always @h=1. Added possibility to synchronise to an extraction v reference at h=1, h=2 and h=4. v Reference, for start extraction synchro timing AEX. SFEJSYNC: originally offset wrt extraction forewarning AEX. F 2 k-CT, now offset wrt SGS. v NB: cycle aborted and alarm generated if PL or RL are switched ON/OFF after AEX. SFEJSYNC. M. E. Angoletta “ELENA LLRF STATUS” ECC 19 July 2018 4

3. Extraction synchro - 2 Extraction synchro done at 22 s and at 26 s, during second RF segment M. E. Angoletta “ELENA LLRF STATUS” ECC 19 July 2018 5

3. Extraction synchro - 3 Extraction synchro done at 26 s with h. BEAM = 1 and h. REF = 1. Red: extraction synchro phase Orange: intensity M. E. Angoletta “ELENA LLRF STATUS” ECC 19 July 2018 6

3. Extraction synchro - energy Extraction energy possibly too high. v LLRF snapshots can help! See description here: http: //elogbook. cern. ch/e. Logbook/event_viewer. jsp? event. Id=2430808 v M. E. Angoletta “ELENA LLRF STATUS” ECC 19 July 2018 7

3. Extraction synchro - timings Sergio and CO colleagues will validate the timings generation from AEX. TREV and AEX. TRF on Friday 20/07. v Now LLRF synchronises on AEX. TREV and gives to timings AEX. TRF at h=4. v M. E. Angoletta “ELENA LLRF STATUS” ECC 19 July 2018 2

3. Extraction synchro - timings v Next situation (tomorrow) M. E. Angoletta “ELENA LLRF STATUS” ECC 19 July 2018 8

3. Extraction synchro - timings v Final situation M. E. Angoletta “ELENA LLRF STATUS” ECC 19 July 2018 9

4. Next tasks and miscellanea for LLRF Mic: deliver FEAS class for integration with RF cycle editor. This will allow changing RF harmonic for RF segments (and pbars @h=4 at extraction). v MEA: once ecooling works on extraction plateau, re-commission extraction synchro after ecooling (different bunch shape, different beam h, possibly v slightly different energy after ecooling etc). v If possible, change cavity transfer function compensation table to allow voltage below 142 k. Hz (hence 85 k. V source operation @h=1? ) v If time allows: deploy third LLRF board + software and commission bunched beam intensity meas from RF harmonics (a’ la AD). v NB: frequency program moving average requested by Christian months ago to correct Btrain oscillations. The new feature was implemented and deployed but never really used by ELENA OP. Remember that this is available and use it if it can help! M. E. Angoletta “ELENA LLRF STATUS” ECC 19 July 2018 10

5. Conclusions LLRF delivered (all features) and operational. v Extraction synchro was last feature to be deployed. v q Validated before ecooling for pbars. q To be seen if that is enough after ecooling (different settings only, if needed) or whether new features are needed (ex: DC-coupled phase loop only for extraction operation as for AD? ) M. E. Angoletta “ELENA LLRF STATUS” ECC 19 July 2018 11