MiniGrail: Difference between revisions
m fmt headline levels (to start with "==", WP Check Wikipedia check #7 |
Expanded content; attempted to address templates. |
||
| Line 1: | Line 1: | ||
'''MiniGRAIL''' is an instrument that is designed to detect [[gravitational wave]]s. The MiniGRAIL is the first such detector to use a spherical design. It is located at [[Leiden University]] in the [[Netherlands]]. The project is being managed by the [[Kamerlingh Onnes Laboratory]].<ref name="cqg20">{{cite journal |
|||
{{Unreferenced|date=July 2007}} |
|||
| author=de Waard, A, | coauthors=''et al''. |
|||
{{Confusing|date=July 2007}} |
|||
| title=MiniGRAIL, the first spherical detector |
|||
| year=2003 | journal=Classical and Quantum Gravity |
|||
| volume=20 | pages=S143–S151 |
|||
| doi=10.1088/0264-9381/20/10/317 }}</ref> A team from the Department of Theoretical Physics of the [[University of Geneva]], [[Switzerland]], is also heavily involved. |
|||
Gravitational waves are a type of radiation that is emitted by objects that have mass and are undergoing acceleration. The strongest sources of gravitational waves are expected to be [[compact object]]s such as [[neutron star]]s and [[black hole]]s. This detector may be able to detect certain types of instabilities in rotating single and binary neutron stars, and the merger of small black holes or neutron stars.<ref name="Houwelingen02">{{cite web |
|||
'''MiniGRAIL''' is the world's first spherical [[gravitational wave]] detector, based at [[Leiden University]], the [[Netherlands]]. The [[Kamerlingh Onnes Laboratory]] is managing the project. A team from the Department of Theoretical Physics of the [[University of Geneva]], [[Switzerland]], is also heavily involved. |
|||
| first=Jeroen | last=Van Houwelingen | date=2002-06-24 |
|||
| title=Development of a superconducting thin-film Nb-coil for use in the MiniGRAIL transducers |
|||
| publisher=Leiden University | pages=1–17 |
|||
| url=http://www.minigrail.nl/Student/Jeroen-report.pdf |
|||
| accessdate=2009-09-16 }}</ref> When gravitation waves with frequencies around 3,000 Hz pass through the MiniGRAIL ball, it will vibrate with displacements on the order of 10<sup>-20</sup> m.<ref>{{cite web |
|||
| first=Eppo | last=Bruins |
|||
| title=‘Listen, two black holes are clashing!’ |
|||
| date=2004-11-26 | publisher=innovations-report |
|||
| url=http://www.innovations-report.com/html/reports/physics_astronomy/report-36884.html |
|||
| accessdate=2009-09-16 }}</ref> For comparison, the cross-section of a single [[proton]] (the nucleus of a [[hydrogen]] [[atom]]), is 10<sup>-15</sup> m (1 fm).<ref>{{cite book |
|||
| first=Kenneth William | last=Ford | year=2005 |
|||
| title=The quantum world: quantum physics for everyone |
|||
| page=11 | publisher=Harvard University Press |
|||
| isbn=067401832X }}</ref> |
|||
A spherical design has the benefit of being able to detect gravitational waves arriving from any direction, and it is sensitive to polarization.<ref name="prd76">{{cite journal |
|||
The MiniGRAIL detector is a cryogenic 68 cm diameter spherical [[gravitational wave]] antenna made of CuAl(6%) alloy with a mass of 1400 kg, a resonance frequency of 2.9 kHz and a bandwidth around 230 Hz, possibly higher. The quantum-limited strain sensitivity ''dL''/''L'' would be on the order of 4×10<sup>-21</sup>. The antenna will operate at a temperature of 20 mK. Another similar detector is being built in [[São Paulo]], which will strongly increase the chances of detection by looking at coincidences. The sources being aimed at are, for instance, non-axisymmetric instabilities in rotating single and binary [[neutron stars]], small [[black hole]] or [[neutron star]] mergers. |
|||
| last=Gottardi | first=L. | month=November | year=2007 |
|||
| title=Sensitivity of the spherical gravitational wave detector MiniGRAIL operating at 5K |
|||
| journal=Physical Review D | volume=76 | issue=10 |
|||
| pages=102005.1–102005.10 |
|||
| doi=10.1103/PhysRevD.76.102005 }}</ref> The detector was intended to operate at a temperature of 20 mK.<ref name="cqg20" /> The original antenna for the MiniGRAIL detector was a 68 cm diameter sphere made of an alloy of copper with 6% aluminum. This sphere had a mass of 1,150 kg and resonated at a frequency of 3,250 Hz. It was isolated from vibration by seven 140 kg masses. The [[bandwidth]] of the detector was expected to be ±230 Hz.<ref name="Houwelingen02" /> |
|||
During the casting of the sphere, a crack appeared that reduced the quality to unacceptable levels. It was replaced by a 68 cm sphere with a mass of 1,300 kg. This was manufactured by ItalBronze in Brazil. The larger mass lowered the resonant frequencies by about 200 Hz.<ref>{{cite journal |
|||
| author=de Waard, A. | coautmors=''et al''. |
|||
| title=MiniGRAIL progress report 2004 |
|||
| journal=Classical and Quantum Gravity | volume=22 |
|||
| pages=S215–S219 | doi=10.1088/0264-9381/22/10/012 }}</ref> The sphere is suspended from stainless steel cables to which springs and masses are attached to dampen vibrations. Cooling is accomplished using a [[dilution refrigerator]].<ref>{{cite journal |
|||
| author=de Waard, A. | coauthors=''et al''. |
|||
| title=Cooling down MiniGRAIL to milli-Kelvin temperatures |
|||
| journal=Classical and Quantum Gravity | volume=21 |
|||
| issue=5 | pages=S465–S471 | year=2004 | month=March |
|||
| doi=10.1088/0264-9381/21/5/012 }}</ref> |
|||
Tests at temperatures of 5 K showed the detector to have a peak strain sensitivity of {{nowrap|1.5 × 10<sup>-20</sup> Hz<sup>-½</sup>}} at a frequency of 2942.9 Hz. Over a bandwidth of 30 Hz, the strain sensitivity was more than {{nowrap|5 × 10<sup>-20</sup> Hz<sup>-½</sup>}}. This sensitivity is expected to improve by an order of magnitude when the instrument is operating at 50 mK.<ref name="prd76"/> |
|||
A similar detector named "Mario Schenberg" is being built in [[São Paulo]], which will strongly increase the chances of detection by looking at coincidences.<ref>{{cite journal |
|||
| author=Frajuca, Carlos | coauthors=''et al''. |
|||
| title=Resonant transducers for spherical gravitational wave detectors | month=December |
|||
| journal=Brazilian Journal of Physics | volume=35 |
|||
| issue=4b | year=2005 | pages=1201–1203 |
|||
| doi=10.1590/S0103-97332005000700050 }}</ref> |
|||
==References== |
|||
{{reflist|2}} |
|||
==External links== |
==External links== |
||
Revision as of 17:42, 16 September 2009
MiniGRAIL is an instrument that is designed to detect gravitational waves. The MiniGRAIL is the first such detector to use a spherical design. It is located at Leiden University in the Netherlands. The project is being managed by the Kamerlingh Onnes Laboratory.[1] A team from the Department of Theoretical Physics of the University of Geneva, Switzerland, is also heavily involved.
Gravitational waves are a type of radiation that is emitted by objects that have mass and are undergoing acceleration. The strongest sources of gravitational waves are expected to be compact objects such as neutron stars and black holes. This detector may be able to detect certain types of instabilities in rotating single and binary neutron stars, and the merger of small black holes or neutron stars.[2] When gravitation waves with frequencies around 3,000 Hz pass through the MiniGRAIL ball, it will vibrate with displacements on the order of 10-20 m.[3] For comparison, the cross-section of a single proton (the nucleus of a hydrogen atom), is 10-15 m (1 fm).[4]
A spherical design has the benefit of being able to detect gravitational waves arriving from any direction, and it is sensitive to polarization.[5] The detector was intended to operate at a temperature of 20 mK.[1] The original antenna for the MiniGRAIL detector was a 68 cm diameter sphere made of an alloy of copper with 6% aluminum. This sphere had a mass of 1,150 kg and resonated at a frequency of 3,250 Hz. It was isolated from vibration by seven 140 kg masses. The bandwidth of the detector was expected to be ±230 Hz.[2]
During the casting of the sphere, a crack appeared that reduced the quality to unacceptable levels. It was replaced by a 68 cm sphere with a mass of 1,300 kg. This was manufactured by ItalBronze in Brazil. The larger mass lowered the resonant frequencies by about 200 Hz.[6] The sphere is suspended from stainless steel cables to which springs and masses are attached to dampen vibrations. Cooling is accomplished using a dilution refrigerator.[7]
Tests at temperatures of 5 K showed the detector to have a peak strain sensitivity of 1.5 × 10-20 Hz-½ at a frequency of 2942.9 Hz. Over a bandwidth of 30 Hz, the strain sensitivity was more than 5 × 10-20 Hz-½. This sensitivity is expected to improve by an order of magnitude when the instrument is operating at 50 mK.[5]
A similar detector named "Mario Schenberg" is being built in São Paulo, which will strongly increase the chances of detection by looking at coincidences.[8]
References
- ^ a b de Waard, A, (2003). "MiniGRAIL, the first spherical detector". Classical and Quantum Gravity. 20: S143–S151. doi:10.1088/0264-9381/20/10/317.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help)CS1 maint: extra punctuation (link) CS1 maint: multiple names: authors list (link) - ^ a b Van Houwelingen, Jeroen (2002-06-24). "Development of a superconducting thin-film Nb-coil for use in the MiniGRAIL transducers" (PDF). Leiden University. pp. 1–17. Retrieved 2009-09-16.
- ^ Bruins, Eppo (2004-11-26). "'Listen, two black holes are clashing!'". innovations-report. Retrieved 2009-09-16.
- ^ Ford, Kenneth William (2005). The quantum world: quantum physics for everyone. Harvard University Press. p. 11. ISBN 067401832X.
- ^ a b Gottardi, L. (2007). "Sensitivity of the spherical gravitational wave detector MiniGRAIL operating at 5K". Physical Review D. 76 (10): 102005.1–102005.10. doi:10.1103/PhysRevD.76.102005.
{{cite journal}}: Unknown parameter|month=ignored (help) - ^ de Waard, A. "MiniGRAIL progress report 2004". Classical and Quantum Gravity. 22: S215–S219. doi:10.1088/0264-9381/22/10/012.
{{cite journal}}: Unknown parameter|coautmors=ignored (help) - ^ de Waard, A. (2004). "Cooling down MiniGRAIL to milli-Kelvin temperatures". Classical and Quantum Gravity. 21 (5): S465–S471. doi:10.1088/0264-9381/21/5/012.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help); Unknown parameter|month=ignored (help) - ^ Frajuca, Carlos (2005). "Resonant transducers for spherical gravitational wave detectors". Brazilian Journal of Physics. 35 (4b): 1201–1203. doi:10.1590/S0103-97332005000700050.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help); Unknown parameter|month=ignored (help)