Safety at TOMCAT

In case of any emergencies on PSI premises, dial 3333 immediately from any PSI phone (or +41 56 310 3333 from external telephones) to reach the PSI emergency response team.

Also please make sure you know how to behave correctly in case of emergencies and alarms at PSI.

The safety of users and staff has the highest priority for the Paul Scherrer Institut (PSI) in designing and conducting research and experiments. Therefore, we diligently adhere to the safety first principle:

"No work we do is so important that it needs to be done without assuring the proper safety measures."

PSI strictly requires that users and staff comply with all the institute's safety rules and regulations while working on the premises. It is your responsibility to follow the PSI general safety instructions to protect yourself and others.

All TOMCAT staff and PSI safety personnel have the authority and duty to enforce safe working conditions. As such, they are authorized and required to STOP your experiments immediately if conditions are deemed unsafe. Experiments may potentially be resumed if the safety of the setup can be improved and proven to be adequate. Note, however, that willful non-compliance with any safety instructions or orders from PSI staff will result in the immediate termination of an experiments.

General PSI safety guidelines and information are available on the Safety webpage of the User Office. Please read this information carefully and share it with everyone on your team.

For TOMCAT-related safety questions, please consult with your local contact or contact the TOMCAT safety officer directly:

TOMCAT safety officer email phone number
Christian Schlepütz +41 56 310 40 95

Before arriving at PSI, all users are required to complete a brief online safety training that covers general safety issues related to working at PSI. Additionally, everyone coming to PSI has to confirm notice of the PSI regulation "Usage and Monitoring of IT Resources at PSI" when requesting the badge and dosimeter in the DUO system.

At the beginning of your experiments, this general training is complemented by a mandatory on-site safety training and TOMCAT beamline orientation that will point out specific details about the operation and safety features and emergency equipment present at the TOMCAT beamline. This beamline orientation will be administered by your TOMCAT local contact and is required for all members of external user groups. Prior to conducting experiments at TOMCAT, the PI or leading researcher of each user group must also complete and sign the facility’s safety declaration form.

Printed copies of the beamline orientation and the safety declaration form are available at the TOMCAT beamline.

The small sample preparation lab at TOMCAT is equipped with the basic tools and equipment necessary to prepare samples and to mount them on holders. As such, it is not a fully equipped chemical laboratory!

Separate tools are provided for work with either normal samples (blue boxes), or any biological samples (green boxes). Please always use the appropriate equipment and make sure they do not get mixed up.

Please keep the work area clean at all times and follow the posted instructions. After your experiments, clean up all work areas and remove all of your own equipment. Wipe down the work area with normal lab alcohol (70%) and leave the place in such as state as you would like to find it in when you arrive for your own experiments.

A large fridge and freezer unit is available for sample and chemicals storage in the sample preparation lab. All items entering the fridge must be thoroughly labelled according to the instructions on the fridge (sample labels are available on the right side of the fridge). Unlabelled items can and will be disposed of at any time without further notice. However, users are absolutely required to remove all of their samples, chemicals, and waste upon the conclusion of their experiments.

Note that this fridge is strictly for sample storage - Never store any food or drinks in this fridge!

Users requiring dedicated space for chemical work can apply for access to the chemical laboratory (WSLA/028) through the DUO proposal system. Consult the chemistry lab user manual carefully before beginning any work and make sure you follow the outlined rules and procedures carefully. Note that the chemistry laboratory is a shared user space.

Snacks and drinks can be consumed in the beamline’s control and compute rooms. However, it is strongly recommended to use the SLS break room or the TimeOut facilities for the consumption of larger meals. According to SLS regulations, the consumption of alcoholic beverages at the beamlines is not permitted!

Also note that food/drinks and samples/chemicals have to be kept strictly separat. Therefore, no food or drinks are allowed in the sample preparation lab and the experimental hutch. Vice versa, no samples or chemical can be used in the control room and compute lab.

As a courtesy, TOMCAT provides a small food fridge in the compute lab, where users can store snacks and drinks for the duration of their experiments. Please label all of your fridge items and remove them from the food fridge and clean the fridge upon your departure. Never store any food in the sample fridge!

Note that the experimental hutch is a radiation-controlled zone, and it is therefore absolutely forbidden to bring any food or drinks into the hutch!

TOMCAT offers the possibility to work with different types of equipment or samples that potentially pose additional hazards beyond what is to be expected in standard experiments. In such cases, experiments need to be even more carefully planned and additional safety measures may need to be taken.

These additional safety issues must already be declared upon proposal submission. We strongly encourage users to contact beamline personnel well in advance of submitting a proposal and again before performing actual experiments to ensure that all necessary permissions and safety measures are in place.

Note that experiments are only allowed to begin once all required approvals are present, the safety training has been completed, and all safety measures are in place.

Electrical Installations

Users are not permitted to conduct any work on low, medium or high-voltage electrical installations
(> 25V AC / > 60V DC or > 2.0 A) at PSI. Only trained and authorized PSI personnel must perform such work.

Custom electrical equipment (> 25V AC / > 60V DC or > 2.0 A) brought to the beamline must either be certified according to European or equivalent standards (e.g.: CE certification) or be inspected and approved by an electrical safety inspector from PSI before being used at the beamline. Please discuss this with your local contact well in advance of the beamtime to make sure the criteria for safe operation of electrical equipment can be met by your experiment.

Work involving chemicals

When chemicals are used to prepare samples or as a part of the actual measurements, special care must be taken. Consult the General directive for activities involving chemicals at PSI for further information and guidelines.

Always label all containers containing any form of chemicals at the beamline, even if they are only used as temporary storage. Make sure that you have up to date safety data sheets (SDS, formerly also know as MSDS) available for all of your chemical substances, along with the required standard operation procedures (SOP) and the necessary safety equipment. Always use the proper PPE (personal protection equipment, e.g.: gloves, etc.) when handling chemicals. Potentially dangerous work should never be performed alone. Also prepare for your experiments by carefully noting the locations of emergency equipment (chemical shower, eye wash solution, etc.).

Depending on the chemical processes required, the sample preparation lab at TOMCAT and the laminar flow hood available in the mechanics and laser testing lab adjacent to the beamline might not be sufficiently secure and well equipped to carry out the work. Instead, users should request access to the shared user chemistry laboratory of SLS. To do so, check the corresponding box ("I intend to use the SLS chemistry laboratory WSLA/028") when applying for your badge and dosimeter through the DUO system prior to your arrival at PSI. Consult the chemistry lab user manual for further information on its usage rules and the available equipment.


The use of lasers poses potential safety risks. For information and official regulations on the use of lasers at PSI, please consult the General directive for activities involving lasers at PSI.

Always wear laser safety goggles when necessary!

TOMCAT laser furnace

TOMCAT features a dedicated infrared laser furnace for sample heating, powered by two 150 W infrared class 4 lasers, which is routinely available for user operation. If you request to use this device, please contact a beamline staff for more information and to coordinate the necessary procedures for the laser use.

Special safety instructions are required before using these lasers, and all members of the experimental team are required to read and sign a liability waiver.

User-owned laser systems

User-owned laser systems can be used at TOMCAT, provided they meet the necessary safety criteria and the operation adheres to established standard operation procedures. The required safety approval steps depend on the type of laser to be used:

Class 1 and class 2 lasers

Class 1 and 2 lasers are deemed to be safe for work at PSI, and no special safety precautions are required. These systems can be used for user experiments without further issues.

Class 3B and class 4 lasers

Class 3B and 4 lasers will require special safety approval and dedicated interlock systems to be integrated at the beamline. Contact beamline personnel well in advance of planning experiments to initiate the necessary safety work and approval processes for these types of lasers.

Again, special safety instructions are required before using these lasers, and all members of the experimental team are required to sign a liability waiver.

Biological samples

Pathogenic and genetically modified materials

The TOMCAT beamline is equipped with all necessary safety measures and equipment (laminar flow hood, personal protective equipment (PPE), and cleaning agents) to conduct experiments on biological samples covered under the biosafety level 1 and 2 categories (BSL-1, BSL-2).

Users conducting experiments with pathogenic and genetically modified samples must indicate this already in the proposal and are required to contact TOMCAT staff (usually the local contact) well in advance of the experiments to make sure all necessary safety measures can be put in place before the experiments.

More information and guidelines for working with biological samples are provided in the Safety concept for activities involving pathogenic and genetically modified organisms at the Paul Scherrer Institute.

In vivo experiments

Experiments involving invertebrates or vertebrates, either in vivo or post mortem, require special attention and very careful preparation. It is essential that you contact beamline personnel well in advance when planning such experiments to discuss all relevant issues (experiment feasibility, ethical considerations, import/export restrictions, permits, housing at the beamline, etc.) ahead of proposal submission. Keep in mind that a significant amount of additional paperwork may be required and take the response time of local and foreign authorities into account when applying for documents and permits.

Important Note: The beamtime allocated by the PRC for experiments involving live specimens will only be definitively scheduled for TOMCAT beamtime after all of the necessary permits are in place and have been approved. If the experiments have not yet been fully approved by the time we schedule the upcoming beamtime cycle, the allocated shifts may be postponed to a next cycle, contingent on the necessary approvals. We therefore strongly recommend to have all required permits ready at proposal submission time to avoid delays in obtaining beamtime at TOMCAT.


Special rules and regulations govern the use of nanomaterials at PSI. Please consult the General directive for activities involving Nanomaterials at PSI for further information, and discuss potential hazards with your beamline local contact.

Radioactive samples

At present, TOMCAT is not equipped to conduct experiments with radioactive samples. This situation can be potentially re-evaluated if a solid scientific case for it can be presented, but at the moment this is not actively pursued. Contact beamline management if you have a use case that convincingly demonstrates that the current policy should be re-evaluated.