The search for and registration of the superweak angular ground motions JINR: J. Budagov, M. Lyablin., G. Shirkov. CERN: J-Ch. Gayde, D. Mergelkuhl

The principle of construction of the registration device to measure the seismic slope of the Earth’s surface. θ ψ Laser QPR Original direction of the reflected beam Base Cuvette with a liquid The surface of the liquid in case of horizontal basis with tilt base Direction the reflected beam after tilt base Main principle : use reflected laser beam from horizontal surface liquid

Experimental set-up L-laser QPr-quadrant photodiode O,O1,O2- bases C О1 О2 Sensor S О SM CF 50 cm L-laser QPr-quadrant photodiode O,O1,O2- bases SM-semitransparent mirror C-calibration screw CF- collimator with changeable focus frequency internal of 10-4Hz÷1Hz The achieved inclinometer angular precision is 5 10-9 rad

The inclinometer tests The angular component of the Earth quake The Earth quake in Siberia on February 26, 2011 Average amplitude of quake in Siberia was 6.5 units The distance to Geneva (on the Earth surface) was determined: L=6160km Calculation time of Earth quake begin Tcalc=6h 21 min in Siberia (world time) practically coincides with the published Tpub=6h 17min (world time) Amplitude angular oscillations consisted 2 10-6 rad

Earth surface single oscillation. The observation of an earth surface “single inclination” effect Amplitude consisted few μrad

Earth surface oscillations of an industrial noise origin Industrial origin noise: high activity of auto– traffic, works in the neighboring (with our set-up) Lab room, people movement close to detecting set-up etc.

Calculation sigma value angular ground motion from industrial noise Amplitude consisted in work period 0.3 μrad Amplitude consisted In dinner time 0.04 μrad

Measurement deformation value concrete floor Concrete floor inclination due to man presence in 3 meters distance from the experimental set-up Amplitude consisted 0.3μrad

The microseismic peak observation by ground angular motion The seismogram of an earth surface angular oscillation at the “microseismic peak” frequency

Fourier analyses oscillation at the “microseismic peak” Amplitude Earth surface oscillation at the “microseismic peak” frequency consist 0.03μrad with frequency fd=0.13Hz Inclinometer sensitivity estimate on the level of ≈5·10-9 rad

The long experimental setups space location stability and an earth surface angular oscillations θmp Linear accelerator-collider Experimental Hall The Earth surface fixed time picture: surface deformation induced by the standing waves originated by the interference of “microseicmic peak” Line of horizon The accelerator-collider positioning on the earth surface deformed by the microseismic peak wave Different accelerator parts are inclined relative to the ”basic” horizontal line and consequently particle beams going through the focusing elements leave them with some angular spread θmp relative to the nominal. As a result it leads to random motion position focus es accelerators If we can stabilize the angular movements of the accelerator with an accuracy of 10-9nrad we will be able to stabilize position its focuses to within 50 nm

Conclusion The ground motion was studied by the detection of an earth surface angular oscillation. Instrumentally method is based on the conceptually new design laser inclinometer using the reflecting surface liquid, as a space stable (horizontal) reference level. The achieved inclinometer measurement precision was experimentally proved to be ≈5·10-9 rad. The achieved laser inclinometer sensitivity was proved by observation (in Geneva) of: Ground 2µrad oscillation caused by the Siberian earth quake (6160 km); Single 1÷2 µrad oscillation of origin to be studied; Industrial origin noise of about 10-7 rad amplitude; Microseismic peak for the first time recognized as a ground ≈ 10-8rad angular oscillation at 0.13Hz frequency. The last observed effect if properly “compensated” by adequate instrumental method could give significant colliders luminosity increase by reduction of beams intersection area to about 50µ level (an estimate) due to some suppression of the lateral focus effect. The instrument of this sort may happen to be useful for modern high precision research equipment stabilization, for example, of large telescope to reach an extreme resolution with them.