The novel room concept

Central to the design of our light microscopy facility rooms was a meticulous assessment of the anticipated heat generation, the projected number of instrumentation and users, and the most stringent room requirements dictated by the intended instrumentation (i.e., a temperature stability of +/- 1°C and a floor vibration of less than 12.5 μm/s). To mitigate the heat production in the microscope rooms, we allocated space in the adjoining corridors to accommodate most of the heat-generating equipment. By implementing heavy-duty equipment shelves at the walls in the corridors directly adjacent to the microscope setups, and connecting them to the microscopes through strategically positioned windows and cable openings, we effectively minimized heat buildup within the primary laboratory space. The corridors are cooled by high-capacity conditioning cabinets.

The air conditioning of the rooms was based on the concept of exchanging the room air with fresh air that was only slightly, about 1 °C, cooler than the desired set temperature (22 °C). This was achieved by a large forced air-cooling device with up to 50x room volume air changes per hour during periods of heightened heat generation. To prevent drafts which negatively affect system stability and user comfort, large textile-based ductwork distribution systems were used (Figure 1).

Moreover, our efforts to reduce the impact of vibration artifacts were multifaceted, entailing the installation of conditioning cabinets and forced air-cooling devices on specialized anti-vibration mats and spring feet mounts. Recognizing the role of internal elements within the microscope setup as potential sources of vibration, we strategically housed these components in adjacent custom designed 19” racks, effectively isolating their vibrations from the main instrument. We designed the 19” racks with six individual power circuits, each with six power sockets and gas valves for all necessary gaseous media (Figure 2). To supply the racks with electrical power and media, they were connected to electricity and all media via sockets, which are placed on the walls close to the ceiling.

An additional source of vibration is the walls of the microscope rooms. For example, when heavy doors are closed, they induce vibrations in the walls. To eliminate this source of vibration, lightweight doors were used that do not close automatically. To ensure that the doors would close automatically, as required by the local fire prevention concept we created an entrance room. The entrance room is slightly depressurized compared to both the adjacent microscope rooms and the rest of the building. It also served as a dust sink minimizing the amount of dust entering the microscope rooms.

To prove the effectiveness of the facility concept, we monitored and documented the temperature during microscope use in multiple positions per room. Our findings indicated a temperature variance of less than 0.5°C from the designated target temperature across various locations within the facility. Our large rooms showed less variation (0.04°C +/- 0.07°C, maximum 0.8°C) than the small rooms (0.3 °C +/- 0.2 °C, maximum 0.9 °C). In addition, comprehensive floor vibration measurements, conducted under full operational conditions of the air conditioning system, revealed a mean effective (RMS) vibration velocity of 5.9 +/- 2.5 μm/s, validating the efficacy of our vibration reduction strategies. Notably, our assessment of noise levels within the microscope rooms underscored the remarkably quiet environment maintained, registering at approximately 45 dB.