Dear all,

last evening Suren Karabekyan and myself did a short notice ZZ access to XTD1. The reason is that machine operators detected the lack of response on the Cell 17 Phase Shifter. The intervention was successful and around 20:30 we left the tunnel.

Regards,

R.

Dear all,

please find here a summary of the status on this critical topic provided yesterday evening (around 19:15) by Zunaira Ansari (extract from her e-mail).

"Dear colleagues,

Thank you very much for your cooperation. SEPS interlock tests are completed in all SASEs except SASE3. AIBS interlock tests are complete in all hutches.

SASE3 SEPS interlock will be tested on Monday the 30th of January strating from 9a.m.

I kindly request the use of the SQS control hutch for the testing.

All SASE3 hutches will be interlocked on Monday morning.

@Maurizio and Bernard/ Nerea: Could you please be present during the testing? IIt will be much appreciated.

I would very much like to thank Eric, Nerea and especially Bernard for helping with the interlock tests today.

Best regards,

Zunaira

Status of machine SASE tuning (just before switching off for monday maintenance):

SASE1 blocked to 1 bunch/train by EPS interlock (sic, not 2 but 1) --- PARTIALLY RESOLVED

Several issues:

1) MODEM device is broken, in state UNKNOWN, see ATT#1 and ATT#2. Fixed with deinstatiating and then using BECKHOFF_ASSISTANT to re-instantiate. --> ATT#3

2) Several devices in XTD9 are causing that MODES is interlocked: I restart broken devices of the FXE-PBLM and SPB-PBLM.
Then there is a broken MDL of SPB_XTD9_SCR called SPB_XTD9_SCR/MDL/BIU. This MDL is not in the SA1-topic system topology but shown with (X) on the SA1_MAIN scene, and this screen is blocking the interlock (see ATT#4)

SPB_XTD9_SCR/VSWITCH/HOLSTER_X_LIMITL is triggering the interlock SA1_SYS_EPS2MPS/DCTRL/MODES and causing that the machine cannot go to more than 2 bunches per train.
Even when going to SPB-topic this issue cannot be solved - all devices in SPB-topic related to this SCR seem fine.

3) To allow SASE1 tuning by the machine, BKR is closing shutter XS3. This avoids any beam into XTD9, resolved the interlock problem and allows the machine to continue SASE tuning.

4) We don't know what had blocked the beam not only to 2 but actually to 1 bunch / train (no traces of problems in Big Brother).

Goal: Analyze and quantify the mispositioning of the new 4mm-aperture behind the undulator

Positions in tunnel:

• ABSP4.2422.SA2 = ABSP4.CELL37.SA2 L_z position 2422.558m
• Last closed undulator for this test is cell16 at 2294m (at end of segment) = SR radiation source point
• IMGTR = 2576m (BT=181.1m, PD=582.0m).
• IMGSR = 2586m (BT=191.6m, PD=591.5m).
• IMGFEL = 2637m (BT=242.0m, PD=642,8m).
• Sequence: end-of-cell16 -- ABSP4 -

Measurements:

• IMGTR : dX=15.15-8.25=6.9mm. dY=17-9.8=7.2mm. Aperture shadow mean diameter = 7.1mm
• IMGSR : Aperture shadow mean diameter = ca. 8.5 mm
• IMGFEL : Aperture shadow mean diameter = 9.0 mm.
  The handover cross is at dy = +1.0mm (up) and dx = -2.6mm (left) relative to the apparent center of the aperture shadow.

Comments to the screenshots:

• The handover cross on the IMGFEL cannot be seen simultaneously with the weak SR background because it has the color scaled to high intensity beam.
• The FEL beam spot is almost perfectly centered on the handover cross.

Calculations:

Conclusions:

The 4mm aperture is misplaced by 0.97mm (x) and 0.37mm (y).
It should be moved dx = -0.97mm and dy = 0.37mm, or the FEL has to be made on a different trajectory.

Problem: Beam operation in SASE2 is prohibited by SEPS / MPS
Origin of problem: HED-CRL3
(this was already an issue during the past weekend)

HED (Karen) today realigned CRL3 and brought the lenses into the safe OUT state, see entry https://in.xfel.eu/elog/OPERATION-2023/2
In karabo then everything seemed find, SEPS switches all green / OUT, see ATT#1.
Nevertheless, in DOOCS the signal safety_HED_CRL_OPT was still red, see ATT#2.

The MPS safety_HED_CRL_OPT signal from the Beckhoff HED PLC was missing.
Onsite investigation by EEE (Leandro and Bernard) revealed that the Beckhoff crate BKF000476 was offline (switched off).
Switching the crate ON fixed the missing signal problem.

Presumably crate BKF00476 was not powered back on since after the planned power-cut in December 2022,
and because it is not part of PLC EtherCAT loop, the Nagios system didn't inform EEE about the crate status.

Result: Problem solved, beam operation in SASE2 can resume normally.

CRL3 arm 2, 5 and 9 were mecanically religned to the V groove and retracted to some y position.

The y motor position was recalibrated by moving the motor to the lower limit switch, moving it up by 0.5 mm and then recalibrating the motor and encoder position to the former software limit position.

In that down position, the x range was tested by moving into the limit switches:

arm 2 x -1.213 to 0.824

arm 5 x -1.22 to 1.73

arm 9 x -0.32 to 2.256

The x limit switches were not changed and also the motor x axis were not recalibrated.

After that the x and y motors were moved to the x and y out position as stored in the CRL3 MDL. In that position, it was confirmed that all SEPS interlocks are triggered.

CRL3 is thus set-up for the SEPS testing, that will take place on the 24th of January.

I started the upstream XGMs in XTD2, XTD1, and XTD10.