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The Modular Neutron Array consists of 144 individual detector modules. Each module is based on a plastic [[scintillator]] measuring 10 cm by 10 cm by 200 cm. This scintillator bar is fitted with light guides on each end that direct the light into one [[photo-multiplier tube]] on each end. Each detector module is wrapped in a light-tight material, allowing the detector array to be arranged in different configurations.
In its original configuration, MoNA consisted of 9 vertical layers of 16 detectors stacked closely, having an active area of 2.0 m wide by 1.6 m tall. In its current arrangement (depicted in the adjacent image), it is stacked in four separate sections of 2, 2, 2, and 3 layers each, respectively, separated by spaces ranging from 0.5 to 0.8 meters. It measures both the position and time of neutron events with multiple-hit capability. The energy of a neutron is based on a time-of-flight measurement. This information together with the detected position of the neutron is used to construct the momentum vector of the neutrons.<ref>{{citation | last1=Luther | first1=B. | last2=Baumann | first2=T. | last3=Thoennessen | first3=M. | last4=Brown | first4=J. | last5=DeYoung | first5=P. | last6=Finck | first6=J. | last7=Hinnefeld | first7=J. | last8=Howes | first8=R. | last9=Kemper | first9=K. | last10=Pancella | first10=P. | last11=Peaslee | first11=G. | last12=Rogers | first12=W. | last13=Tabor | first13=S. | date=June 2003 | doi=10.1016/s0168-9002(03)01014-3 | issue=1–2 | journal=[[Nuclear Instruments and Methods in Physics Research
The detection efficiency of MoNA is maximized for the high-beam velocities that are available at the NSCL's Coupled Cyclotron Facility (CCF). For neutrons ranging from 50 to 250 [[MeV]] in energy, it is designed to have an efficiency of up to 70% and expands the possible coincidence experiments with neutrons to measurements which were previously not feasible. The detector is used in combination with the Sweeper magnet<ref>{{citation | last1=Zelevinsky | first1=V. | last2=Volya | first2=A. | editor1-last=Woehr | editor1-first=A. | editor2-last=Aprahamian | editor2-first=A. | contribution=Continuum Shell Model, Reactions and Giant Resonances | doi=10.1063/1.2187905 | pages=493–497 | publisher=[[American Institute of Physics]] | series=[[AIP Conference Proceedings]] | title=Capture Gamma-Ray Spectroscopy and Related Topics: 12th International Symposium, 4–9 September 2005, Notre Dame, Indiana | volume=819 | year=2006}}</ref><ref>{{citation | last1=Prestemon | first1=S. | last2=Bird | first2=M. D. | last3=Crook | first3=D. G. | last4=DeKamp | first4=J. C. | last5=Eyssa | first5=Y. M. | last6=Morris | first6=L. | last7=Thoennessen | first7=M. | last8=Zeller | first8=A. | date=March 2001 | doi=10.1109/77.920115 | issue=1 | journal=[[IEEE Transactions on Applied Superconductivity]] | pages=1721–1724 | title=Structural design and analysis of a compact sweeper magnet for nuclear physics | volume=11 | bibcode=2001ITAS...11.1721P | display-authors=3}}</ref><ref>{{citation | last1=Toth | first1=J. | last2=Bird | first2=M. D. | last3=Miller | first3=J. R. | last4=Prestemon | first4=S. | last5=DeKamp | first5=J. C. | last6=Morris | first6=L. | last7=Thoennessen | first7=M. | last8=Zeller | first8=A. | date=March 2002 | doi=10.1109/tasc.2002.1018415 | issue=1 | journal=[[IEEE Transactions on Applied Superconductivity]] | pages=341–344 | title=Final design of a compact sweeper magnet for nuclear physics | volume=12 | bibcode=2002ITAS...12..341T | display-authors=3}}</ref><ref>{{citation |last1=Bird |first1=M. D. |last2=Bole |first2=S. |last3=Gundlach |first3=S. |last4=Kenney |first4=S. |last5=Miller |first5=J. |last6=Toth |first6=J. |last7=Zeller |first7=A. |date=June 2004 |doi=10.1109/tasc.2004.829720 |issue=2 |journal=[[IEEE Transactions on Applied Superconductivity]] |pages=564–567 |title=Cryostat Design and Fabrication for the NHMFL/NSCL Sweeper Magnet |volume=14 |bibcode=2004ITAS...14..564B |s2cid=34670655 |display-authors=3}}</ref><ref>{{citation |last1=Bird |first1=M. D. |last2=Kenney |first2=S. J. |last3=Toth |first3=J. |last4=Weijers |first4=H. W. |last5=DeKamp |first5=J. C. |last6=Thoennessen |first6=M. |last7=Zeller |first7=A. F. |date=June 2005 |doi=10.1109/tasc.2005.849553 |issue=2 |journal=[[IEEE Transactions on Applied Superconductivity]] |pages=1252–1254 |title=System Testing and Installation of the NHMFL/NSCL Sweeper Magnet |volume=15 |bibcode=2005ITAS...15.1252B |s2cid=24997693 |display-authors=3}}</ref> and its focal plane detectors for charged particles.<ref>{{citation | first=N. | last=Frank | type=Ph.D. Thesis | title=Spectroscopy of Neutron Unbound States in Neutron Rich Oxygen Isotopes | publisher=[[Michigan State University]] | year=2006}}</ref> In addition, MoNA’s modular design allows it to be transported between experimental vaults and thus to be used in combination with the Sweeper magnet installed at the S800 magnet spectrograph.<ref>{{citation |last1=Bazin |first1=D. |last2=Caggiano |first2=J. A. |last3=Sherrill |first3=B. M. |last4=Yurkon |first4=J. |last5=Zeller |first5=A. |date=May 2003 |doi=10.1016/s0168-583x(02)02142-0 |journal=[[Nuclear Instruments and Methods in Physics Research Section B
== History ==
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*[[Westmont College]]
The proposals were funded by the NSF in the summer of 2001. Following the detailed design, the first modules of the detector array were delivered in the summer of 2002. During the following year all modules were assembled and tested by undergraduate students at their school,<ref>{{citation |last1=Howes |first1=R. H. |authorlink=Ruth Howes |last2=Baumann |first2=T. |last3=Thoennessen |first3=M. |last4=Brown |first4=J. |last5=DeYoung |first5=P. A. |last6=Finck |first6=J. |last7=Hinnefeld |first7=J. |last8=Kemper |first8=K. W. |last9=Luther |first9=B. |last10=Pancella |first10=P. V. |last11=Peaslee |first11=G. F. |last12=Rogers |first12=W. F. |last13=Tabor |first13=S. |date=February 2005 |doi=10.1119/1.1794758 |issue=2 |journal=[[American Journal of Physics]] |pages=122–126 |title=Fabrication of a modular neutron array: A collaborative approach to undergraduate research |volume=73 |bibcode=2005AmJPh..73..122H |display-authors=3}}</ref> and finally added to form the complete array at the NSCL.
The MoNA collaboration continued after the initial phase of construction and commissioning was concluded [MoNA], and is now using the detector array for experiments, giving a large number of undergraduate students from all collaborating schools the opportunity to take part in cutting-edge nuclear physics experiments at one of the world’s leading rare-isotope facilities. The research at the undergraduate institutions is funded by the NSF through several RUI (Research at Undergraduate Institutions) grants.
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