Booster-Test December 2021

TL;DR

For 'booster mode':
  • timing the beam transfer from UNILAC to SIS18 works with ~98% efficiency, if rf-conditioning at UNILAC is active
  • timing the beam transfer from UNILAC to SIS18 works with 100% efficiency, if rf-conditioning at UNILAC is switched off

Introduction

Shortly before Christmas, the facility is operated with a 'dry' pattern DRYRUN_202111_SIS18_FAST_HHD_BOOSTER, requesting 'dry beam' from UNILAC to SIS18 and downstream to cave HHD. The measurement scenario is identical to the first booster-mode test performed in November 2021 (click). The only other pattern operated in parallel is DRYRUN_202111_SIS18_FAST_QKICKER (but without beam request UNILAC).

Raw data are available here //.../dryRun_2021-dec/booster/booster-*-2021-12* .

Further reading:

Measurement Settings

The measurements done during the November 2021 dry-run have been repeated but with slightly different settings given in the table below. As a main difference to the November dryrun, the event CMD_UNI_BREQ_NOWAIT is scheduled earlier.

MID start time [UTC] end time [UTC] delay BREQ [ms] offset(BREQ, BPREP) [ms]Sorted ascending UNILAC rf-conditioning remark
6 2021-12-23 08:00 2021-12-24 23:00 2 -48 ON raw data files marked by '2021-12-23_07-32'
5 2021-12-22 07:29 2021-12-23 06:36 3 -47 ON raw data files marked by '2021-12-20_13-15'
3 2021-12-20 12:19 2021-12-21 07:24 4 -46 OFF raw data files marked by '2021-12-20_13-15'
4 2021-12-21 11:35 2021-12-22 07:03 4 -46 ON raw data files marked by '2021-12-20_13-15'
7 2021-12-25 12:34 2021-12-31 08:30 4 -46 ON raw data files marked by '2021-12-25_13-34'
8 2021-12-31 08:30 2022-01-02 06:00 4 -46 ON raw data files marked by '2021-12-31_09-30'
2 2021-12-17 11:49 2021-12-20 06:40 5 -45 ON raw data files marked by '2021-12-17_12-30'
1 2021-11-24 13:27 2021-11-25 07:43 10 -40 ON dryrun November 2021; shown here for comparison
Table: Measurement Settings for Measurement ID (MID) 2-4. The settings of the November dryrun are shown for comparison (MID 1). Shown are the Measurement ID (MID, 1st column), time (columen 2,3), the delay of CMD_UNI_BREQ_NOWAIT with respect to the start of an UNILAC cycle (column 4), ParamModi offset for CMD_UNI_BREQ_NOWAIT and CMD_UNI_BPREP (column 5) and and information if RF-Conditioning in UNILAC is present (column 6).

Data

Snooped Timing Messages

A detailed analysis of snooped timing messages will be done in January 2022.

Diagnostic Logging

A quick analysis has been done using data written to diagnostic logging (graylog). Log messages are exported as CSV for further processing.

DM-UNIPZ Gateway

Each log message contains timing information about the 4th booster cycle. Shown below are two examples: The first one contains data for a good injection from UNILAC, while the second line contains data of a bod injection where UNILAC delivers beam one cycle too late. As a hiccup, the important time difference between CMD_UNI_BRERQ_NOWAIT and EVT_MB_TRIGGER is rounded to the full millisecond (sorry for that). Details on the output are described elsewhere (click).
good: dmunipz-daemon: dm-unipz: TRANS 00357744,  1415( 21)ms, va  6( 6)/1 | INJ 00001/00003(04/06),   55(0.008/  21/  45 -> 9.920)ms | DG 1.459ms | 1 1 1 1 1 1 1 1, OpReady    (     0), OK   (153453)
bad : dmunipz-daemon: dm-unipz: TRANS 00357020,  1424(  8)ms, va  6( 6)/1 | INJ 00001/00003(04/06),   77(0.008/  22/  67 -> 9.920)ms | DG 1.463ms | 1 1 1 1 1 1 1 1, OpReady    (     0), OK   (153453)
                                                                                                       '          '    '    ' 
                                                                                                       '          '    '    '- time difference [ms]: EVT_MB_TRIGGER - EVT_READY_TO_SIS
                                                                                                       '          '    '- time difference [ms]: EVT_READY_TO_SIS - CMD_UNI_BREQ_NOWAIT
                                                                                                       '          '- time difference [ms]: acknowledge of beam request by UNIPZ - CMD_UNI_BREQ_NOWAIT
                                                                                                       '- time difference [ms]: EVT_MB_TRIGGER - CMD_UNI_BREQ_NOWAIT <-- IMPORTANT!!!

WR-UNIPZ White Rabbit Pulszentrale

Log messages are written to diagnostic logging every 10 seconds. Shown below is an example. Details on the output are described elsewhere (click).
wrunipz-daemon: wr-unipz: ST 0026188461 1100011100000011 1111111 |DG 50.015 02089 00000 |, OpReady    (     0), OK   (     0)
                                                                          '
                                                                          '- UNIPZ cycle rate [Hz]

Results

Qualitative

boosterb zoom1.png
Figure: Measured data for test. The UNILAC operation rate is shown in blue (left y-axis). The delay of beam injection into SIS18 following a beam request to UNIPZ is shown for timely delivery (green, right y-axis) and delayed delivery (red, right y-axis); these data are taken for the 4th booster cycle. Please note the right y-axis is reversed. Details see text.

The figure above show operation rate of UNIPZ (and UNILAC) as blue curve. Typical variations are within a window of 50Hz +/- 0.1 Hz. An interesting effect is the sudden drop typically happening at full hours.

The figure also shows information on the delay of beam injection into SIS18 following a beam request at UNILAC. The data are only shown for the 4th booster cycle and the data have a precision of 1 ms only.

'Good' injections into SIS18 are marked by a green square. Here, the injection happens at about 54 ms following the beam request from SIS18 to UNILAC.

'Bad' injections into SIS18 are indicated as red rhombus. These always happen always one UNILAC cycle (20ms) too late at about 75 ms following the beam request. It is interesting to note that 'delayed injections' into SIS18 are always associated with sudden drops of the UNILAC operation rate.

As a caveat, it is sometimes observed that UNIPZ gets 'trapped' in a state, where 'late' injections happen every 28s, while all other injections are fine. This can be seen in the figure above from 2021-12-21 23:00 to 2021-12-22 00:00 ('trap' ended with negative jump) and in more detail in the figure below ('trap' ended by a positive jump). Presumably, this is caused by some interference with rf-conditioning at UNILAC and/or other patterns requesting other virtual machines at UNIPZ.

boosterc zoom2.png
Figure: Example of 'trapped' UNIPZ. 'Trapping' manifests itself by periodic 'late' injections every 28 seconds and ends at the next positive or negative frequency jump.

Remark: UNILAC is coupled to the 50 Hz mains frequency [1]. This is achieved via the module FX 201.021 [2], which provides some smoothing of the mains 50 Hz. The drops in UNILAC operation rate can not be due to green energy harvesting. Change in solar power can be excluded as sun-set happened around 15:25 UTC and wind powered energy is unlikely the cause due to a high pressure zone across Europe with little and smooth pressure gradient during the time window shown above. According to [3, 4], the sudden drops are most likely a consequence of 'energy trading' on the stock market.

[1] https://www-acc.gsi.de/data/documentation/eq-models/pzus/gm-pzus.pdf

[2] https://www-windows.gsi.de/belab/FG_DB/

[3] P. Gerhard, private communication

[4] https://www2.ipp.mpg.de/ippcms/ep/ausgaben/ep201801/bilder/0118_netz_2_dia.html

Quantitative

MID settings success [%] good bad UNILAC operation rate Remark
Delay BREQ [ms] UNILAC RF-Conditioning n ave [ms] sdev [ms] max [ms] min [ms] n ave [ms] sdev [ms] max [ms] min [ms] ave [Hz] sdev [Hz] max [Hz] min [Hz]
1 10 ON 89.06 25631 48.944 0.459 50.967 46.007 3147 68.947 0.456 70.182 67.003 49.997 0.022 50.141 49.902 dryrun November 2021; shown here for comparison
2 5 ON 98.11 42034 53.404 0.536 56 51 808 73.667 0.705 75 73 49.998 0.020 50.088 49.902
3 4 OFF 100.00 12064 54.487 0.600 56 52 0 n/a n/a n/a n/a 49.994 0.024 50.103 49.907
4 4 ON 98.40 12100 54.510 0.573 56 53 197 75.051 0.698 76 74 49.994 0.022 50.074 49.909
5 3 ON 94.80 13845 55.534 0.585 58 53 759 75.513 0.962 95 75 49.993 0.022 50.116 49.880 UNIPZ 'trapped' for a few hours; 50 Hz mains bumpy
6 2 ON 98.64 24295 56.386 0.702 58 54 334 76.668 0.702 78 76 50.003 0.021 50.087 49.914 UNIPZ 'trapped' on 24 December @ 23:00 UTC (stop data taking)
7 4 ON 99.64 88058 54.193 0.482 57 52 316 74.858 0.778 77 74 50.007 0.019 50.114 49.89
8 4 ON 99.43 29203 54.221 0.452 56 53 168 77.000 0.000 77 77 50.004 0.016 50.092 49.908
Table: Measured data. Shown are a variety of data for different settings of 'delay of beam request' and 'rf-conditioning'. Information on statistics is given for 'good' and 'bad' injections as well as for UNILAC operation rate.

Discussion

Two parameters are important
  • delay of beam request at UNILAC
  • UNILAC is operated with or without rf-conditioning

rf-conditioning OFF: With properly chosen delay, it was possible to operate the transfer from UNILAC to SIS18 without a single failure for about 19 hours.

rf-conditioning ON: Even with rf-conditioning on, an acceptable rate of good injections exceeding 98% can be achieved.

In general it is observed, that - with rf-conditioning ON - 'bad' injections are triggered by sudden drops of the UNILAC operation frequency, which is coupled to 50 Hz mains. Moreover, 'bad' injections tend to happen in groups. In between those incidents it is possible to transfer beam from UNILAC to SIS18 for hours without failure. This said, measurements for such phenomena should be done for a long time (~ one day), considering that sudden drops of the 50 Hz seem to happen more frequently in the evenings until past midnight.

Important: The data presented here is relevant for booster injection #4. For the booster injections #2 and #3 it is expected to work even better smile .

-- DietrichBeck - 13 Jan 2022

I Attachment Action Size Date Who Comment
boosterb_zoom1.pngpng boosterb_zoom1.png manage 143 K 22 Dec 2021 - 10:53 DietrichBeck booster test
boosterc_zoom2.pngpng boosterc_zoom2.png manage 87 K 23 Dec 2021 - 07:59 DietrichBeck trapped UNIPZ
This topic: Timing > WebHome > TimingSystemDocumentation > TimingSystemDocuments > TimingSystemDocumentsReportsAndMeasurements > TimingSystemDocumentsRep20211222
Topic revision: 13 Jan 2022, DietrichBeck
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