All users must have successfully completed the ESRF User Safety Training before carrying out any experiment at the Cryobench.


Before an experiment takes places at the Cryobench, all samples have to be reported via an A form to the safety group (i.e., the same procedure as on X-ray beamlines).

Only after validation by the safety group, the experiment may take place!


Aside from potentially harmful biological samples, the main hazards at the Cryobench lab are associated with the various lasers.

On the positive side, our lasers are (a) mostly guided through fibers and (b) focused onto the sample (which is inaccessible by the human eye) and highly divergent beyond their focal spot.

Nevertheless, some of the lasers at the cryobench are quite powerful and thereful potentially harmful. Therefore, it is absolutely necessary to comply with the following regulations:

  • Post the laser(s) that are currently in use on the door of the experimental hutch, together with the corresponing laser goggle code (A, B, or C) in case somebody needs to enter the hutch.
  • The "bypass mode" (see below) can only be used by authorized personnel who are aware of the associated dangers.
  • When inside the hutch, especially during alignment procedures, wear the appropriate laser safety googles!

Laser PSS

At the Cryobench, the lasers are powered via a PSS (Personal Safety System) which ensures that no harmful laser radiation can escape from the experimental hutch.

Groups of lasers

The lasers are divided into two groups:

  • "big" lasers: the Argon laser (under the optical table) and the three Raman lasers
  • "small" lasers: the other lasers (on the optical table and the HeNe laser underneath it)

Principles of Laser PSS

These two groups are treated differently by the PSS, as the PSS may break the power to the "small" lasers, while the "big" ones are permanently powered and the PSS controls shutters and interlocks to these lasers.

The reason behing this distinction is that the "small" lasers probably can survive a brutal shutdown of their electrical power, even though it should not happen too often. On the other hand, the "big" lasers are more sensitive in this respect (e.g., because they are actively cooled), and therefore abrupt power cuts have to be avoided under all cirdumstances.

Activation of Laser PSS

In order to be able to use lasers at the cryobench, the laser PSS has to be activated in a manner that is similar to the procedure for a PSS on an X-ray beamline:

  • Close the black curtain behind the door of the experimental hutch and attach it to the interlock above the door. (Do not rip the curtain when detaching it again from the interlock!)
  • Search the experimental hutch and confirm this by activating the search button at the rear end of the hutch (requires a special key).
  • Close the door of the experimental hutch.
  • Press the yellow button on the laser PSS box in the control room.

The laser PSS is now activated, the door to the hutch is locked, and the lasers are ready to be used.

Breaking any interlocks (e.g., forcefully opening the door, removing the curtain,...) results in shutdown of electrical power to the (small) lasers and should thus be avoided under all circumstances!

Shutdown of Laser PSS

In order to shutdown the laser PSS, press the red button on the laser PSS box in the control room.

Now the lasers are disabled, the door is unlocked, and the hutch can be safely entered.

Bypass mode

In some cases it is absolutely necessary to enter the experimental hutch while the lasers are operating. For such cases, the laser PSS offers a special "bypass mode" which allows to open the door of the experimental hutch for 20 seconds without interrupting the lasers.

  • Make sure to wear the appropriate laser safety googles.
  • Use the safety key to turn the lock on the laser PSS box in the control hutch.
  • For 20 seconds, a beeping sound is emitted. During this time, the door to the experimental hutch can be opened without shutting down the lasers.
  • Thus, quickly enter the hutch and make sure to close the door behind you.
  • Similarly, to leave the hutch without powering off the lasers, press the green button next to the door. Again, you have 20 seconds to leave the hutch and close the door.
  • Once more: When you are inside the hutch, do not open the door without pressing the green button first, since otherwise the lasers will lose power!
  • To shut down the laser PSS from inside the hutch, press the red button next to the door.

Liquid nitrogen

If you are working with liquid nitrogen, make sure to wear the appropriate safety gear (googles, gloves, closed shoes).