The beamline
The source of beamline X10SA is fed from an in-vacuum undulator of 19 mm period length (U19). The beam size at the source at an energy of 12.4 keV is 202 μm x 18 μm (FWHM), its divergence is 135 μrad x 25 μrad (FWHM).
A double-crystal Si(111) monochromator determines the energy within a range from 6 keV to 20 keV. Horizontal focusing is provided with the sagittal bender (the second monochromator crystal). A mirror afterwards provides the vertical focusing.
In the exposure box, a system of
- beam position monitor
- H/V slits ("tertiaries")
- filter wheels
- flux monitor
- H/V slits ("quarternaries")
ensures beam shape, position and flux monitoring and optimization.
The focal point (sample position) is at 25.60 m from the source, and currently the focal spot size is 74 μm x 17 μm without any limiting aperture employed.
Between exposure box and sample, a system of variable apertures and a collimator are mounted to further shape and limit the beam and minimize air scatter.
Currently, 3 apertures can be selected:
The given relative flux refers to the flux in ph/s measured in the exposure box which is shown on the beamline panel.
- 150 μm diameter (beamsize = 74 μm x 15 μm, flux reduced to 99 %)
- 30 μm diameter (beamsize = 24 μm x 12 μm, flux reduced to 30 %)
- 10 μm diameter (beamsize = 15 μm x 7 μm, flux reduced to 5 %)
(measurements of February 2016)
Programs and User GUIs at the beamline
Login
When you start your experiment, log in at console 1 (x10sa-cons-11) which is the "data collection station".
Log in is possible only with you e-account (such as e10xxx) and the corresponding password which you should have ready. In general, it is sent via email to the PI or main proposer of the experiment. (If you forgot or lost the email or your boss forgot or ... ask your local contact. They might change/re-set the password for you.)
- login at x10sa-cons-1 and start the programs described below
- login at x10sa-user-1, the data processing terminal server and ssh into the computing nodes (x10sa-cn-111 to x10sa-cn-132) for processing
- login to the media station (located in the small room next to the control room) and organize your backup
Startup programs
Startup the following programs (from the User Launcher Menu, left top bar) : Note: if you "lost" the launcher, you can re-gain it from the panel bar or type "launcher" in a terminal.
- DA+, THE data collection GUI
- start the SERVER
- start the GUI
- BOTH !
- for information (about the communication between detector and daq server) watch the server output messages
- start the automated data processing ADP
- Albula - the diffraction image viewer
- Note: also the MAD software - for the Fluorescence detector - is started and operated from the DA+ GUI
Prepare and start experiment
- mount a test loop of your default length
- centre it - and check whether cryo is ok, i.e., the sample is in the laminar flow
- take a test shot and check whether all is ok for you
Note: the first exposures with the detectors after an energy change take longer because of the internal detector calibration procedure.
Measurements
- select the wavelength(s) appropriate for your experiment(s)
- it makes sense to group nearby wavelengths if possible
- change of energy from the x10sa-cons-2 workstation (left side)
- in the IDL session enter
- IDL> sete, energy with energy given in keV, alternatively, use
- IDL> sete, wavelength, /wave , with wavelength in Ångstroem
- check and process your data as soon as possible!
- the data are immediately stored on Data10/, the user data space
- process on x10sa-cn-111
- you might want to use the automated data reduction and processing tool
- or any of your favourite data processing and analysis programs (e.g., xds, or use the xds-gui)
- for serial crystallography and merging of small-range data sets on a grid/mesh you might want to use the CY+ GUI
Measurements with the KETEK fluorescence detector
Fluorescence detector, SAD/MAD
Special setups / non-standard experiments / room temperature measurements
- room temperature measurements
- a special rt kit (holders and capillaries) is available on request
- in DA+, choose the required cryo stream setting
- spectroscopy (inquire with the SpectroTeam)
- UV/VIS
- Raman
- ask the beamline scientists or your loco if you have questions about a specific measurement
Vertical alignment
Within the DA+ "Expert" environment, the beam position can be set/updated. HOWEVER, this in general at least requires an update of the aperture positions and, even more important, of the diffractometer (rotation axis) position.
Beam alignment for Experts
Alarms and Emergencies
- Oxygen sensor alarm:
- first: lamp in hutch blinking
- IMPORTANT:
- interrupt your experiment
- open the doors for venting
- confirm/quit the alarm asap afterward (blue button within the rack on the outer left side of the hutch entrance)
- if NOT, the fire brigade will show up and finish your experiment
- second: acoustic signal
- no chance to avoid meeting the local fire brigade any more
- first: lamp in hutch blinking
Some quick fixes
- FE shutter closed
- reset the FE shutter at the OPTICS hutch outside
- close door/open shutter
- maybe also reset the Exp Hutch shutter (photon shutter alarm button red?)
- beamline state dropped into maintenance mode
- from Expert Launcher
- MX Common Tools --> ESCAPE toolbar
- goto Sample Exchange Mode
- Token lost? (may happen to DA+/Ketek Gui, CATS...)
- in a terminal type
caput X10SA-APP-TOKEN:SET ""
(NOT blank, EMPTY!)
- in a terminal type
- No flux on sample anymore (and no shutter closing)
- check whether a filter wheel got stuck
- open the filter wheel application from the expert launcher
- move the filters successively to find a hanging one, watch the flux