The New Labs

Progress status report as of 24 March 2019

HDR is the firm UC San Diego hired in 2017 to design the laboratories, in progress as of March 24th 2019.

Specifications:

Parameter Target Status
Temperature+/- 0.1 F
fixed air supply T
+/- 0.06 F reported 🙂
 +/- 0.5 F
across the lab at optical table height
Potentially not achievable due to insufficient airflow,
fan coil running at full speed. Not quite a spec, more of a hope.
 +/- 0.1 F
inside optical table enclosures
+/- 0.06 F reported 🙂
 (all CFD verified with model heatloads) 
Humidity+/- 5 % RH  Work in progress
Cooling 60+ kW (air + water) To be tested
Air qualityISO 7 cleanroom lab yet to be cleaned
Acoustic
63Hz – 8kHz
NC-30 Currently inside canopies
~50 dBA, ~70 dBC
EM/RF
near DC – 10 kHz
<<1mG pk to pk ~ 0.6 mG at 60 Hz pk to pk
(elevator drives a 0.4 mG signal)
Vibrations, floorVC-E  Better 🙂
almost VC-F @ table for ultrastable laser cavity
   

The new labs were meant to feature a displacement system where laminar diffusers cover the walls and provide a slow massive flow of temperature and humidity stabilized air (+/- 0.1 F, +/- 5% RH). Each table will also be covered by laminar flow difussers with air of the same specs. This ultrastable conditions guarantee minimal downtime due to drift in optics, optomechanics and lasers, which is a common problem in state-of-the-art experiments with ultracold atoms in engineered optical potentials. In addition, the EMI/RF specs of the labs guaranteed much less than 1mG peak-to-peak fluctuations, which will help in achieving a few orders of magnitude lower fluctuations at the atoms location.

The airflow and temperature stability across the room including heat loads has been modeled using CFD (Computational Fluid Dynamics) by Fluid Dynamics Solutions Inc. Based on this model several improvements will be implemented 😉

Pictures of the labs as of March 2019.


Current labs

Temperature+/- 0.2 F average, measured at return, several F across room, occasional spikes lasting up to a few hours
see sample data below
 +/- 0.1 F at laminar flow diffusers (independent units)
Humidity10 % RH pk to pk continuously oscillating every 5 min. due to cyclic operation of dehumidifier, drifts of >10 % RH
see sample data below
Cooling30+ kW (air + water)
Air qualityHEPA filter after fan coil
Acoustic65 dBA (fan coil and dehumidifier in room)
EM/RF (near DC – 10 kHz)5 mG pk to pk
Vibrations, floor500 μm/s (third floor)
   

Current labs sample performance (11-17 March 2019)

Temperature plot (left)
blue: supply air
black: return air (target stability)
other colors: inside canopies
The chiller was down on 14 March 2019, resulting in excessive heat. Humidity on other days is typical of dry/humid days (15-16/11-13 March)