Report on Stanford Superconductive Monopole Detectors
Since January, 1983 we have been operating a three loop superconducting detector with a signal to noise ratio of 100 for the direct detection of Dirac magnetic charges.1 Its sensing area averaged over solid angle is nearly 500 cm2 for double coincidence events. To date, the data contain no candidate events and set an upper flux limit of 2 × 10−11 cm−2 s−1 sr−1 at 90% C.L., 70 times lower than that suggested by the single candidate event2 seen on the prototype single loop detector. If supermassive magnetic monopoles exist they are rare and the need for cost-efficient larger area superconductive detectors is evident if we are to push forward a definitive search in the cosmic rays. Superconducting loop detectors can be constructed with 1 to 10 m2 planar areas coupled to a single SQUID while achieving a signal to noise ratio of 10 for the detection of a Dirac magnetic charge. A 100 m2 sensing area array of such detectors, which would reach the Parker flux bound in one year of operation, can be built at a cost comparable to that of typical high energy experiments. It remains quite possible that a monopole particle flux significantly higher than the Parker bound exists within our galaxy. In this paper the most recent results from low noise operation of the three loop detector are presented. Also discussed are our plans to build a larger fixed loop detector with a sensing area of 1.5 m2. It is designed as a prototype for a future yet larger 100 m2 array.
KeywordsMagnetic Charge Magnetic Monopole Candidate Event Magnetic Field Change Loop Detector
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- R. Farouki, S.L. Shapiro and I. Wasserman, Astrophys. J. (in press), contains detailed computer simulations of self-consistent galactic monopole halo models.Google Scholar
- 7.For reference see paper by C.G. Callan in this volume.Google Scholar
- 8.For reference see paper by J.A. Harvey in this volume.Google Scholar
- 11.B. Cabrera, Magnetic Monopoles, eds. R.A. Carrigan and W.P. Trower (Plenum Publishing Corp., 1983), p. 175.Google Scholar
- 12.B. Cabrera, R. Gardner and R. King, submitted to Phys. Rev.D.Google Scholar
- 14.S. Boughn, Ph. D. Thesis, Stanford University, 1975 (unpublished).Google Scholar