1 Search for Magnetic Monopoles at the Relativistic Heavy Ion Collider (RHIC) Praveen Chaudhari *, Vasily Dzhordzhadze, Veljko Radeka, Margareta Rehak, Pavel Rehak, Sergio Rescia, Yannis Semertzidis, John Sondericker, and Peter Thieberger BNL PAC Meeting September 12, 2006 * Spokesperson

2 Outline Motivation Experimental Approach Monopole Detector Interaction with SQUIDs and Walls DAQ and Trigger Influence on STAR and PHENIX Future Developments Schedule and Costs

3 Maxwell equations (1873) Motivation Magnetic monopole terms Introducing magnetic monopole makes equations symmetric GUT (1974) requires monopoles

4 Dirac showed (1931) g = nħc/2e = (137/2) ne, n=1, 2, 3, … First strong scientific motivation to search for magnetic monopoles The defining property of a monopole Motivation (continued)

5 Two types of monopole searches: GUT and accelerator based GUT mass ~10 16 GeV - 10 TeV No evidence of GUT monopoles at the level of Parker Limit (~ cm -2 sr -1 s -1 ) No evidence in accelerator based search: Bradner and Isbell(1959)  2006 BNL experiment at AGS: Purcell et al.(1963) Motivation (continued)

6 Previous accelerator searches assumed mass, velocity, charge, or binding energy to nuclei: etch tracks, scintillators, ionization detectors, or capture in liquids and solids We propose to detect a monopole via its magnetic charge  use an inductive detector. Use superconducting coils and SQUID technology Monopole Detectors

7 Monopole Detector Setup Superconducting Shield LHe Dewar Superconducting Grid Silicon Detectors IR Baffle Biased Screen Heat Station Heat ShieldMu Metal Shield Trapezoidal Transition piece RHIC Beam tube Vacuum Valve 2 m Gradiometers

8 Monopole Detector Elements Silicon Detectors Gradiometers Superconducting Shield Vacuum Valve RHIC Beam Tube IR Baffle Biased Screen Heat Station Trapezoidal Transition Piece

9 Gradiometer Assembly Support Ring Silicon Gradiometer Coil SQUID Solder Tab 4K Cooling Ring

Gradiometer 10 Rejects “stray” B fields but has full sensitivity to monopole signal Built with superconductor on Si substrate (for cooling) Built in quadrants to reduce inductance and fit into 30cm diameter commercial Si wafers

Third Order Gradiometer 11 3 rd or 4 th order gradiometer coils are being investigated L 3rd ~2  H L 4th ~3  H 3 rd order gradiometer cancels polynomial terms up to 25 th degree to better than 1% 4 th order gradiometer cancels polynomial terms up to 75 th degree to better than 1% 150mm

Fourth Order Gradiometer Cancellation 12

Measurement time (  s) x u l F e s i o N 00 SQUID Noise 13 Time resolution ~1  s ~100  s measurement time needed to achieve 0.1   sensitivity

14 Geometry of Silicon Detectors

15 Central Au-Au collisions: at the location of SQUIDs less than 120 charged particles/sr. For a 10 μmX10 μm SQUID Josephson junction probability of a single incidence of ~ , and of coincident events of ~ Estimated secondary radiation from stainless cylinder walls is also negligible Interaction of Charged Particles with SQUIDs and Chamber Wall

16 Two types of trigger: monopole candidates and monitoring Monopole candidates: coincident signals from gradiometer and/or Silicon detectors Monitoring triggers: monitored detector clocked to RHIC Use RHIC luminosity monitors to obtain integrated luminosity DAQ and Trigger

17 Common vacuum with RHIC due to 35cmX5cm cut in the RHIC tube Provide electrical continuity by placing a grid across cut Mitigate possible but very unlikely vacuum disturbance to RHIC by placing a valve at the entrance to the monopole chamber Two additional vacuum valves on RHIC beam tube Influence on STAR and PHENIX

18 Observe credible monopole signal. Determine the mass of the monopole by carrying out a g/m experiment No credible signal but SQUID detectors perform satisfactorily, as demonstrated by a clear signal from magnetic pseudopole Approach LHC and/or ILC Future Developments

19 Schedule

20 Materials and supplies: 1. Detector cryostat and refrigeration system $330k 2. Magnetic detection system (gradiometers, SQUIDS, control and signal processing electronics) $190k 3. Silicon detector system $220k 4. Data Acquisition (DAQ) $80k ========= Subtotal: $820k + ($287k+ C-AD) Manpower: 1. S&P 2.5 FTE $650k 2. Other (designer and tech. specialists) 2 FTE $360k Subtotal: $1,010k ======== Project total: $1,830k + ($287k +C-AD) Cost

21 The counterpart to the quantized elementary charge is the magnetic monopole. No monopole has been detected so far Our proposed search is to measure the magnetic charge of a monopole Detector can be used in future higher energy accelerators: LHC and/or ILC Summary

22 Back-up Slides

23 Charged Particle Distribution

24 Secondary e Yield Angular Dependence

25 Secondary Electron Yield

26 Thermal Analysis of the SQ Grid

27 Second and Fourth order Gradiometer

28 Deformation and Stress of the Gradiometer

29 Vibration and Deformation of the Gradiometer

30 Second and Third Mode Vibration

31 First mode Supporting and Harmonic Excitation

32 First mode Supporting and Harmonic Vibration

33 ¼ of Shield

34 Shield with and without Hole

35 Increased acceptance Set-up