Excel spreadsheet for the FEL settings is here.
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- Prepare the hutch for the shift (done 1h before the actual start time)
- open the grafana dashboards located here (requires UNIX login/pwd) to access beam owner, energies and coatings
- no gate valve in the trajectory
- check in the vacuum windows that no gate valves from the NEH to the MEC hutch are IN (red)
- it is ok that the DG2 STP 1 is IN
- it is ok that the GL window is IN in MEC
open the rolling status and confirm that no devices upstream the hutch obstructs the beam
Code Block language py theme RDark linenumbers true op.rs()insert yag3 to provide a photon terminator before TCC prior to send any beam in the hutch
Code Block language py theme RDark linenumbers true op.yag3.insert()- confirm that the chamber is loaded with targets and being pumped down to be ready at the start of the shift
- search the hutch but leave SH6 IN (you are not the beam owner yet)
- 15 min before the shift begins, call ACR at x2151 to check
- look at current ACR beam operator on shift here
- confirm photon energy
- confirm pulse energy
- confirm pulse duration
- confirm beam mode
- confirm multiplexing mode
- ask for an e-loss scan
- transition to beam ownership
- ACR calls you to confirm they are tweaking the beam for you
- confirm with ACR that MR1L0 and MR2L0 have the right coating following this page
- if moving the mirror yourself, then open MR1L0 and MR2L0 HOMS GUI located in the mechome > LCLS tab > HOMS overview button
- set the coatings to the appropriate material as a function fo the photon energy as per the page from above
- getting ready to accept the beam:
- close DG2 STP 1
- make sure the reference laser is out (check in the rolling status)
- confirm the target chamber is pumped down
- insert the Be window IN the beamline
- search H6 if not already searched
- remove SH6 OUT of the beamline
- beamline alignment
- ACR calls you to confirm beam is ready for alignment
force close the pulse picker to make sure it does not let the beam propagate to the hutch yet
Code Block language py theme RDark linenumbers true op.pp.close()- check MR1L3 mirror OUT (-6000) position (XCS mirror)
- check the XPP slits (slit1) are open (20mm, 20 mm) in the rolling status
- open the mirror settings located here
- confirm bending values for MR1L0 and MR2L0 (advanced)
insert YAG0
Code Block language py theme RDark linenumbers true op.yag0.insert()- confirm FEL beam is on the cross for the OUT position (undeflected beam)
- confirm the shape of the beam is round (advanced)
- set the MR1L4 coating as per this page
- insert MR1L4
- confirm FEL beam is on the cross for the IN position (deflected beam)
insert YAG1
Code Block language py theme RDark linenumbers true op.yag1.insert()remove YAG0
Code Block language py theme RDark linenumbers true op.yag0.remove()remove all Si attenuators (send full energy beam)
Code Block language py theme RDark linenumbers true op.SiT(1)open the pulse picker
Code Block language py theme RDark linenumbers true op.pp.open()- fine tune the pitch of MR1L4 to center the beam on YAG1
insert YAG3
Code Block language py theme RDark linenumbers true op.yag3.insert()- remove hutch Be CRL (Mechome > Beamline > Beamline CRL(hutch))
open slit 2
Code Block language py theme RDark linenumbers true op.slit2.move(5)remove YAG1
Code Block language py theme RDark linenumbers true op.yag1.remove()- fine tune the pitch of MR1L4 to center the beam on YAG3
- to adjust the height using the YAG3 red cross centered at (265, 282), call ACR, and for a 200 mic motion on the yag, ask them to move 200/4 mic up or down.
- you could set SiT(0.2) to not saturate the image
- you could set 10 images averaged to get a cleaner picture
- log the mirror settings in our table here
- confirm photon energy and lens stack to use and log the change of stack in the paper document for Be CRL log
- insert the Be lenses with these parameters
- set 1: 9 keV, 9 x 300 mic, f = 3.96 m, Y = 2.8816 mm
- set 2: 17 keV, 10 x 100 mic, f = 4.4243 m, Y = 29.52 mm
- set 3: 22 keV, 9 x 50 mic, f = 3.904 m, Y = ?
- once they are done tuning
- timing check
- turn off laser triggers
go to the titanium foil:
Code Block language py theme RDark linenumbers true op.ti()- move hutch CRL out
set slit4 to 400 mic:
Code Block language py theme RDark linenumbers true op.slit4.move(0.4)send full beam on titanium:
Code Block language py theme RDark linenumbers true op.SiT(1)set the EVR to 10 Hz settings:
Code Block language py theme RDark linenumbers true op.lpl_check_timing(rate='10Hz')- set vertical division to 10 mV/div on oscilloscope Lecroy 1
- once you see the signal of the X-rays, set 100 sweep to average the signal
- save it on memory 2
- set back sweeps to 1 on channel 2
- move target about 0.8-1 mm negative to target the Al frame
- turn on the LPL trigger on, event code 43 for 10Hz
- once you see the signal of the LPL, set 100 sweep to average the signal
move timing to overlap the LPL with the memory trace 2 using the python command
Code Block language py theme RDark linenumbers true op.nstiming.mvr(2e-9)to move the LPL 2 ns later than the FEL, but this is just an example! Move it (or not) by the necessary amount to overlap best the rising edges of the beams.
save the current value as our t0, using hte python command
Code Block language py theme RDark linenumbers true op.nstiming.save_t0()- once timed, set 100 sweep to average the signal and save the trace on memory 3
- take a screenshot and put it in the elog
- move back the hutch Be CRL
- set the slits back to data-taking move size
set the EVR to single shot settings:
Code Block language py theme RDark linenumbers true op.lpl_check_timing(rate='single')- set the scope Lecroy 1 channel 2 voltage/div to the maximum (1V/div) to be able to observe the shot on the diode and monitor the timing
- laser
select the laser pulse shape
Code Block language py theme RDark linenumbers true meclas.LPL.psmenu() L3to choose pulse shape : 8ns flat top, max 80J
start by optimizing the conversion efficiency
Code Block language py theme RDark linenumbers true meclas.LPL.SHG_opt()finish by optimizing the pulse shape
Code Block language py theme RDark linenumbers true meclas.LPL.psefc10Hz(numIterQ=150)
- detector
- confirm LPL event code is either 182 or 43 (precaution)
in python, set event sequencer to 120 Hz:
Code Block language py theme RDark linenumbers true op.x.start_seq(120)- aadd the detectors you want a pedestal for, remove any VISAR or slow cameras and allocate the DAQ
in a random DAQ terminal, execute
Code Block language bash theme RDark linenumbers true takepedsand follow instructions
after takepeds is done, execute
Code Block language bash theme RDark linenumbers true makepeds -r xxx -u yourusername -q milanowith xxx being the run number and yourusername being the user name of the person who extract the pedestal, then follow instructions
- shutdown the DAQ (don't need to 'restartdaq'), reallocate and confirm the pedestal has been applied
- alight Ge spectrometer
- check 4 Quads with calibrant sample (CeO2) for q range
- timing check
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Experts: click to hide code blocks ->
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Initial Spatial overlap between LPL, VISAR and X-rays
- This procedure assumes that
- the beamline is aligned up to yag3
- the slits are aligned to the beam
- the yag at TCC has been prealigned with the help of Questar 2 as well (for maximum accuracy) and the pin (the pin is used to measure the LPL spot size and set the plan of interaction)
Go to the yag at TCC
Toggle Cloak Cloak visible true pyRDarktrue - Remove the hutch Be CRL
Close slits 4 to 50 mic
Toggle Cloak Cloak visible true pyRDarktrue - Set a cross on Questar 1 screen and write down the X and Y positions in the preset spreadsheet of the experiment
Close the pulse picker and reinsert the Be CRL
Toggle Cloak Cloak visible true pyRDarktrue Move to the pinhole
Toggle Cloak Cloak visible true pyRDarktrue Tweak the position of the pinhole until it is centered on the cross
Toggle Cloak Cloak visible true pyRDarktrue Save the new pinhole position
Toggle Cloak Cloak visible true pyRDarktrue Move back to the yag
Toggle Cloak Cloak visible true pyRDarktrue - Send the VISAR laser with event code 43 and enable the trigger
- Confirm that the focus of the VISAR provides a sharp and round image on any VISAR cameras (Visar gige 1 and 2)
Tweak the focus of the visar position accordingly (50 mic steps is good enough)
Toggle Cloak Cloak visible true pyRDarktrue - Turn off the VISAR trigger
Prepare the system to check the front alignment of the drive lasers
Toggle Cloak Cloak visible true pyRDarktrue Check spatial overlap of the drive beams ABEF and GHIJ successively by centering the scattered signal on the cross of Questar 1 screen
Toggle Cloak Cloak visible true pyRDarktrue - Record each positions of the VISAR and drive lenses in the experiment spreadsheet
Initial Temporal overlap between LPL and X-rays
go to Ti sample
Toggle Cloak Cloak visible true pyRDarktrue - remove the Be CRL
open slit4 to 400 mic
Toggle Cloak Cloak visible true pyRDarktrue set full X-ray transmission
Toggle Cloak Cloak visible true pyRDarktrue open the pulse picker
Toggle Cloak Cloak visible true pyRDarktrue Open the TCC scope
Toggle Cloak Cloak visible true pyRDarktrue Set the EVR of the scope to 10Hz
Toggle Cloak Cloak visible true pyRDarktrue - Set channel 2 to 2 or 5 mV/div
- Confirm that the X-ray pulse is seen around 60 ns.
- Average over 100 sweep and save the trace on M2 (from C2)
- Set the sweep averaging back to 1
Close the pulse picker
Toggle Cloak Cloak visible true pyRDarktrue Insert the filter in front of Questar 1
Toggle Cloak Cloak visible true pyRDarktrue Set the laser pulse shape to the timing shape
Toggle Cloak Cloak visible true pyRDarktrue Send the 10Hz LPL (enable the trigger of the ns slicer) on target at full energy
Toggle Cloak Cloak visible true pyRDarktrue - Set the channel 2 to 10 mV/div
- Confirm you see a trace on C2
- Average over 100 sweep and save the trace on M3 (from C2)
- Set the sweep averaging back to 1
- Take a screenshot and post it to the elog
- Set the channel 2 to 1V/div
Set the scope to single shot trigger
Toggle Cloak Cloak visible true pyRDarktrue - Further fine timing can be done by using a LiF coated window
- Move to the appropriate target
- Confirm Be CRL are inserted in the beamline
Set the timing of the drive to 0
Toggle Cloak Cloak visible true pyRDarktrue Confirm that the streak window have zero offset in the window size requested
Toggle Cloak Cloak pyRDarktrue Take a single refence only shot to observe the change in reflectivity at the arrival time of the X-rays
Toggle Cloak Cloak visible true pyRDarktrue To double check, confirm timing at another step
Toggle Cloak Cloak visible true pyRDarktrue - Fine tune the timing is the X-ray trace is not where it is expected using the nstiming.mv function accordingly.
Check Spatial overlap between LPL, VISAR and X-rays on target
Start by moving to the desired target (refer to the python manual here for details on the arguments)
Toggle Cloak Cloak visible true pyRDarktrue
Continue by checking the alignment of the drive lasers
Set the system in a mode where the laser energy is minimum, the filter is removed from questar 1 and the trigger is enabled
Toggle Cloak Cloak visible true pyRDarktrue - Confirm you see a scattering signal close to the X-ray cross (342, 561)
Move the hexapod X axis to center the beams on the cross and produce a round scattering signal (steps of 50 mic is good)
Toggle Cloak Cloak visible true pyRDarktrue
- Continue by checking the alignment of the VISAR system
Adjust the VISAR Z axis to make sure the image is round and sharp (could be set to the value by using the right equation as well). Steps of 50 mic is good.
Toggle Cloak Cloak visible true pyRDarktrue Alternatively, move the Z value by exactly the thickness of the ablator + material of interest and add the change in position due to the visar window. To calculate the change use the following command
Toggle Cloak Cloak visible true pyRDarktrue
Take reference images with VISAR and/or X-rays
For 5 references with VISAR and X-rays (at 20% max)
Toggle Cloak Cloak visible true pyRDarktrue
Take a driven shot with the LPL
For a driven shot at full energy (lpl_ener=1.0), with X-rays arriving 5 ns later (timing=5.0e-9) at full intensity (xray_trans=1) use the following command
Toggle Cloak Cloak visible true pyRDarktrue