1 / 17

Superconducting Gravity Gradiometry

Superconducting Gravity Gradiometry. State of the Art. Superconducting Gravity Gradiometry. Present status Key technologies Conclusions. Present status: low-Tc. Maryland design (Paik et.al. 1996/2002) Noise level: 20 mE /  Hz (4 mE /  Hz) CMRR (lin.): 10 4. Oxford Instruments (2001)

rozene
Download Presentation

Superconducting Gravity Gradiometry

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SuperconductingGravity Gradiometry State of the Art Univeristy of Twente

  2. SuperconductingGravity Gradiometry • Present status • Key technologies • Conclusions Univeristy of Twente

  3. Present status: low-Tc Univeristy of Twente

  4. Maryland design (Paik et.al. 1996/2002) • Noise level: 20 mE /Hz (4 mE /Hz) • CMRR (lin.): 104 Univeristy of Twente

  5. Oxford Instruments (2001) • CMRR: 8104 (>106) • Noise level: 180 mE/Hz (?) (1 mE/Hz) Univeristy of Twente

  6. UWA (van Kann et.al. 2002) • Noise level: 0.5 E/Hz • CMRR (ang.): >104 (106) • CMRR (lin.): 109 (31010) Univeristy of Twente

  7. Gravitec (Veryaskin 2000) • Noise level: 3 E/Hz • CMRR: ? Univeristy of Twente

  8. Univ. Kharkov (verozub 1996) • Magnetic levitation of proof mass • Low intrinsic noise level… • Lateral stability… • Potential for miniaturization… F = 0 for I1 = 0. Univeristy of Twente

  9. High-Tc • High-Tc conceptual design study on basis of Maryland device1 • Predicted sensitivity • 4 mE/Hz @ 1 Hz and 77 K • 2.5 mE/Hz @ 0.1 Hz and 28 K 1 C.S. Jacobsen et. al., Conceptual Design of a Gravity Gradient sensor based on high Tc superconducting technology, ESA contract 9031/90/NL/PB CCN2 final report May 1995 Univeristy of Twente

  10. Key technologies: materials • Low-Tc • Nb @ 4 K • High-Tc • YBCO @ 77 K • Bi, Tl, Hg families • MgB2 • Tc of 39 K, operating temp. 35 K • Test masses • High quality Nb or Si Univeristy of Twente

  11. Key technologies: SQUIDS • Low-Tc • Nb: improved sensitivity • Well developed technology • High-Tc • YBCO: limited progress since 1995 • Lifetime: no significant improvement • Coupling coils: still difficult (T) • MgB2 • Research in full swing • At present no sophisticated junction technology • More work needed Univeristy of Twente

  12. Key technologies: levitation coils • Nb • Fulfils requirements • BSCCO • Joining still a problem • Tapes 0.2x5 mm2 (big) • Geometry: react after wind, limited strain • Other materials not suitable • MgB2 • First results wit powder in tube, but improvement in properties needed • Joints not yet realised Univeristy of Twente

  13. Key technologies: electronics • SQUID electronics for both low-Tc and high-Tc has improved in sensitivity and speed • Modulation techniques are available for improved signal to noise ratios at low frequencies Univeristy of Twente

  14. Key technologies: cooling1 • Cooler mass • 4K  100 kg • 35K  10 kg • 77K  1 kg Recent overview for cryocoolers in space: ISEC, 6-9 september 2005, Noordwijkerhout Univeristy of Twente

  15. Key technologies: cooling • Efficiency: Pin @ 0.3W • 2kW @ 4K • 20W @ 40K • 7W @ 77K Univeristy of Twente

  16. Key technologies: cooling • Mass vs. volume Univeristy of Twente

  17. Conclusions • Low-Tc: possible, size reduction possible, cooler has large mass and requires a lot of power • MgB2: research is underway, has to prove itself, cooling hast intermediate mass and power requirements • High-Tc: looks possible when several practical issues have been solved (maybe hybrid structure with MEMS), cooler has acceptable mass and power requirement Univeristy of Twente

More Related