6/11/2019 Setting up a very low noise continuous vibration monitoring system and evaluating the measurements. ENRIS2019, 16-18 June 2019 1 Acknowledgements Dorien van der AA, project manager 2015-2018 H.L. Offerhaus, chairholder E.H. Ruiter, maintenance G.J Roelofs, head MESA+ Nanolab ENRIS2019, 16-18 June 2019 2 1
6/11/2019 Motivation An increasing number of instruments require a “quiet” floor • Real time web page (“can I blame it on the floor”). • Checking equipment susceptibility for vibrations. • Identifying noise sources (construction work, traffic, machines, people,…. • Check if building contractors works “quiet”. • Check equipment for anomalies (worn bearings). ENRIS2019, 16-18 June 2019 3 Nanolab Overview Offices Labs, VC-D VC-G Labs Facilities & Technical Area Clean- Room Cleanroom, VC-D VC-G ENRIS2019, 16-18 June 2019 4 2
6/11/2019 Nanolab cross section Plenum VC-G labs Plenum Cleanroom Technical area VC-G labs Cleanroom Basement crawlspace ENRIS2019, 16-18 June 2019 5 Nanolab construction, schematic drawing ENRIS2019, 16-18 June 2019 6 3
6/11/2019 Hardware (commercially available) ENRIS2019, 16-18 June 2019 7 Measurement setup Web server, Optional: control, Second sensor for: Redundancy, (HP elitebook) Excluding locally Power supply + induced vibrations, filtering Noise source Identification, Data-acq. NI Validating the USB-6341 (BNC) sensors by “coherent transfers”. Sensor CME-6211 3-axial, 60s – 50Hz http://r-sensors.ru/ ENRIS2019, 16-18 June 2019 8 4
6/11/2019 Location sensors ENRIS2019, 16-18 June 2019 9 Molecular Electronic Transducer https://en.wikipedia.org/wiki/Molecular_electronic_transducers Anode: 3 I − → I 3 − + 2 e − Cathode: − + 2 e − → 3 I − I 3 ENRIS2019, 16-18 June 2019 10 5
6/11/2019 CME-6211 noise spectral density Lowest noise Acceleration geophones Power Spectral Density [10Log(m 2 /sec 4 )/Hz] Our sensor Lowest earth background Units can be hard noise, NLNM to interpret seconds ENRIS2019, 16-18 June 2019 11 Software (NOT commercially available) Measurement, real time Post processing ENRIS2019, 16-18 June 2019 12 6
6/11/2019 What timeframe to measure? Ability to detect peak disturbances Shorter is better Ability to cover the VC-range (1-80 Hz) 1 Hz is minimum Highest grade floor = VC-G, v < 0.78 μ m/s, next: VC-F, 1.6 μ m/s, VC-E, 3.2 μm/s, ….., until VC -A. Vibration Criterion (VC) is velocity power spectral density (rms) integrated over one third octave bands from 1 Hz to 80 Hz. The maximum value in the VC-curve defines the VC class. For more information see: Vibration transfers to measure the performance of vibration isolated platforms on site using background noise excitation , F. B. Segerink, J. P. Korterik, and H. L. Offerhaus, REVIEW OF SCIENTIFIC INSTRUMENTS 82 , 065111 (2011). ENRIS2019, 16-18 June 2019 13 What to show on the real time screen? Narrowing down the data-amount! Peak disturbances are most important. Each timeframe ( 1 s) is converted to 1 number called “ trillingsgetal ”, defined as the peak VC value in all directions relative to the VC-G level. Our reference VC-G level will be depicted by a green line. ENRIS2019, 16-18 June 2019 14 7
6/11/2019 Measurement web page http://utwks61920.roaming.utwente.nl:8000/CMEmain02.html ENRIS2019, 16-18 June 2019 15 High pass filtering, Barkan formula ENRIS2019, 16-18 June 2019 16 8
6/11/2019 Post processing software Data is only valuable when processed! 1. Time slices within one file (~1 hour) 2. VC terts bands vs time over long time (~1 month) ENRIS2019, 16-18 June 2019 17 Evaluating measurements What did we learn so far (4 years)? ENRIS2019, 16-18 June 2019 18 9
6/11/2019 Traffic and height differences cantine ENRIS2019, 16-18 June 2019 19 Traffic and height differences “ trillingsgetal ” = 9.2 Conclusion: Height differences add very significant to floor vibrations! ENRIS2019, 16-18 June 2019 20 10
6/11/2019 Traffic and height differences problem solved! ENRIS2019, 16-18 June 2019 21 Separated floors A well known concept, hardly ever quantified… Coherent transfer measurement setup. Excitation: background noise. Coherent transfer Sensor 2 Sensor 1 Noisy floor Isolated floor Floor separation ENRIS2019, 16-18 June 2019 22 11
6/11/2019 Post processing software VC-terts bands over long time 26 days of measurements, VC-terts-band versus time, starting Friday February 15, 2019. North- Time trace interval length = 32768 points (rms), Hamming window. South Many East- peaks West Vertical, Offset, Z sensor noise. 12
6/11/2019 Increasing the frequency to the next terts band Lower offset, sensor noise. Earthquake Equador Mw 7.5 13
6/11/2019 Earthquakes show at very low frequencies No more offset, some background signal comes up. Background increases, origin still unknown. Not wind-speed related. 14
6/11/2019 Background, typically between 0.1 and 0.3 Hz. Background at maximum. 15
6/11/2019 Background gradually decreasing Background gradually decreasing 16
6/11/2019 Both background and earthquake gradually disappear at higher frequencies. Just below 1 Hz there is not much happening. 17
6/11/2019 Still not much happening. Still very quiet 18
6/11/2019 Approaching 1 Hz, a daily pattern starts to appear. Weekends and working days show up 19
6/11/2019 Weekends and working days show mostly in the x-y direction Weekends and working days, z-direction is joining 20
6/11/2019 Weekends and working days, z-direction dominates Weekends and working days impact at maximum 21
6/11/2019 Weekends and working days gradually decreasing Weekends and working days decreasing more. 22
6/11/2019 Weekends and working days gradually decreasing further. The z-direction shows extra signal, related to the air handling system. 23
6/11/2019 Air conditioning and distribution, dominant in z-direction, increases. Air conditioning and distribution, dominant in z-direction around 10 Hz 24
6/11/2019 Air conditioning and distribution, rapidly decreasing above 10 Hz Local construction work 25
6/11/2019 Local construction work No high amplitudes at higher frequencies 26
6/11/2019 No high amplitudes at higher frequencies No high amplitudes at higher frequencies 27
6/11/2019 Upper limit detector = 50 Hz Zooming in on the Equador earthquake, Mw 7.5, 9783 km from the Nanolab. 28
6/11/2019 Zooming in on the earthquake. Adjusting the z-scale 29
6/11/2019 Zooming in more. And more 30
6/11/2019 43 minutes Zooming in on a typical working day, Tuesday February 26, 2019. 31
6/11/2019 Tuesday February 26, 2019, 00:00h – 24:00 h. Well below VC-G, Well below VC-G Mainly human induced vibrations restricted access until 22:00h. Curiosity: Tuesday February 26, 2019, peaks at very low frequency, around 09:00h, Predominantly in the East-West direction, not in the z-direction. 32
6/11/2019 Zooming in on the peaks at very low frequency. From observation it showed that the truck for cantine 6 min. supplies parks near the sensor for unloading. Lab tilted back Lab tilted Post processing software Time slices 33
6/11/2019 Time signal post processing, 1 hour 9 minutes data file with earthquake event. 60 seconds Pre shocks suddenly appear. 34
6/11/2019 Further following the time line… The big one! 150 s 35
6/11/2019 End of post processing software demo “noticeable events” (last part of the talk) Noise increase triggers maintenance Monday Tuesday Wednesday Sunday June 25, 2017, 10 Hz terts band Start excess noise 12.7 Hz terts band ENRIS2019, 16-18 June 2019 72 36
6/11/2019 Negotiating construction work VC-G ENRIS2019, 16-18 June 2019 73 Asphalt milling at ~1 km, not negotiable… VC-G ENRIS2019, 16-18 June 2019 74 37
6/11/2019 Storm batters Nanolab and Carré S2 S1 ENRIS2019, 16-18 June 2019 75 Storm batters Nanolab and Carré ENRIS2019, 16-18 June 2019 76 38
6/11/2019 King’s -Day podium FC Twente 400 m ENRIS2019, 16-18 June 2019 77 King’s -Day VC-G ENRIS2019, 16-18 June 2019 78 39
6/11/2019 GOALS in the Golsch Veste VC-G ENRIS2019, 16-18 June 2019 79 Wrapping up: Impact of vibrational disturbances Generic I. Damage to equipment and sample tip crash in UHV vacuum STM (2-3 weeks time loss) groups II. Damage to sample only e-beam write errors, TEM imaging, FIB milling, Heidelberg mask writer error III. Failed experiments most imaging applications (SEM, TEM, AFM), pulsed laser deposition IV. Not susceptable for vibrations most of the equipment has low floor vibration demands, cleaning, sputtering, etching, spinning,….. ENRIS2019, 16-18 June 2019 80 40
6/11/2019 Thank you for your attention. ENRIS2019, 16-18 June 2019 81 Extra slides ENRIS2019, 16-18 June 2019 82 41
6/11/2019 Carré air handling machines Top floor (5 th ) Sensor position ENRIS2019, 16-18 June 2019 83 Carré 5 th floor and basement ENRIS2019, 16-18 June 2019 84 42
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