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Building MACS *. Collin Broholm Johns Hopkins University and NIST Center for Neutron Research. Goals of the MACS project Status of the design Engineering resources for MACS. * Project Supported by the National Science Foundation. Scientific program for MACS.
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Building MACS* Collin Broholm Johns Hopkins University and NIST Center for Neutron Research • Goals of the MACS project • Status of the design • Engineering resources for MACS * Project Supported by the National Science Foundation
Scientific program for MACS • Dynamic correlations in nano-scale magnets • Magnetic order in organic metals • Quantum phase transitions versus pressure • Mixed phases in quantum spin systems • Spin and charge polarons in oxides • Weak broken symmetry phases
Technical Goals for MACS project • Maximize instrumental efficiency • Worlds most intense monochromatic cold neutron beam • Maximize solid angle and efficiency of detection system • Taylor energy band probed to scientific problem • Minimize instrumental background • From fast neutrons • From non-sample scattering • User-Friendly instrument • Reliable functional hardware • Streamline experimental process • Reliable software for planning, execution, and analysis
NCNR Liquid Hydrogen cold source MACS Beam New cold source to be installed in 2002 will double flux
Overview of MACS Cryogenic filters: PG, Be, and BeO Variable beam aperture and monitor Sample positioning system focusing super-mirror guide Cooled filters: PG, sapphire, Be Four Radial Collimators to change E-resolution Variable incident beam aperture to change Q-resolution Doubly focusing monochromator Multi-channel monochromatic detection system Design by C. Brocker, C. Wrenn, and M. Murbach
Monte Carlo Simulation of MACS Y. Qiu and C. Broholm to be published (2002)
Timeline for MACS - resources • 1993 Discussions about the possibility of a “sub-thermal” TAS on NG0 • 1994 Analytical calculations show efficacy of double focusing at NG0 • Initiate JHU/NIST project to develop conceptual design • 1998 Top level specification for monochromator completed • JHU/NIST project starts to develop Monochromator • 2000 Christoph Brocker starts engineering design • NIST-NSF-JHU agreement to fund MACS • 2001 JHU Instrument development group involved • 2002 Assistant engineer on board to help Christoph Brocker • 2004 MACS Post doctoral fellow to start • 2005 July: MACS complete and assembled at NIST • 2006 January: MACS User program starts • 2006 August: MACS project complete
January 2002 Status of MACS Top level specification completed Joe Orndorff of JHU IDG completed Phase A study Conceptual design completed, Rober Barkhauser of JHU IDG working on Phase A study Completed Conceptual design completed. Gregg Scharfstein of JHU IDG working on Phase A study of double analyzer mechanism NCNR design available Euro-collimators working on design of collimators Tom Reeves of JHU IDG working on Phase A study Design by C. Brocker, C. Wrenn, and M. Murbach
1428 cm2 MACS monochromator Electronic rack
MACS monochromator passes optical test defocused focused Blade 4 Remaining 20 blades
Multiplexing crystal analyzer system Design by C. Brocker
One of twenty channels “TAS” detector Collimator 1 Energy integrating Detector 8o vertically focusing Analyzer crystals BeO filter Be filter PG filter Design by C. Brocker Collimator 2
Conceptual design for cryogenic filters Neutron absorbing spacers 8” BeO 4” Be 2” PG
Key personnel building MACS Collin Broholm JHU PI Jeff Lynn NCNR Co-PI Paul Brand NCNR Engineering manager Christoph Brocker NCNR Lead M-engineer Interviewing JHU MACS M-Engineer Joe Orndorff JHU Assisting E-engineer Gregg Scharfstein JHU Assisting M-engineer Tom Reeves JHU Assisting E-engineer Robert Barkhauser JHU Assisting E-engineer Yiming Qiu JHU Graduate Assistant Undergraduates JHU U. G. Assistants
Summary • MACS will be a unique resource for probing dynamic correlations in condensed matter for • Can optimize range of energy transfer for experiment • Independent variation of Q and E resolution • Top level specifications have been established • Crucial monochromator successfully completed • Other important components are in conceptual design phase • Key personnel in place or being interviewed • On target for scientific commissioning 2005-6 and project completion in Fall 2006.