Temperature Regulation for High-Precision Mass Measurements at ISOLTRAP Elizabeth Wingfield, Florida State, Tallahassee Advisor: Alexander Herlert

E. Wingfield August 10, 2006 UM REU Final Presentation Motivation for Precise Mass Measurements Courtesy: A. Herlert Nuclear Physics nuclear binding energies, Q-values shell closures, pairing, deformation, halos, isomers test of nuclear models and formulae  m/m  1·10 -7 Astrophysics nuclear synthesis r- and rp-process  m/m  1·10 -7 Weak Interaction symmetry tests CVC hypothesis  m/m  1·10 -8

E. Wingfield August 10, 2006 UM REU Final Presentation ISOLTRAP Setup buncher preparation trap precision trap

E. Wingfield August 10, 2006 UM REU Final Presentation Measurement Principles Three independent motions in a penning trap Cyclotron frequency Resonance Spectrum of 85 Rb

E. Wingfield August 10, 2006 UM REU Final Presentation ISOLTRAP Measurements Data from: G. Audi et al., Nucl. Phys. A 729 (2003) 3 Masses measured with ISOLTRAP: before 2002 since 2002

E. Wingfield August 10, 2006 UM REU Final Presentation Reducing Systematic Error Stabilizing the magnetic field  Pressure of the He recovery line  Center bore temperature Figure: Cyclotron frequencies compared to center bore temperature

E. Wingfield August 10, 2006 UM REU Final Presentation Temperature Regulation Setup PID Regulation  Proportional: Controls the gain with respect to the error (error = Set point – process variable) u p = K e(t)  Integral: Looks into the past, the error is integrated over a period of time to reduce oscillations of a P-controlled system u I = K/T i [e i (t-T s ) + T s e(t-T s )]  Derivative: Looks into the “future”, controls the response to a change in a system by measuring the slope of the error u D = KT d /T s [e f (t) - e f (t-T s )]

E. Wingfield August 10, 2006 UM REU Final Presentation Prior Temperature Regulation Performance

E. Wingfield August 10, 2006 UM REU Final Presentation Current Temperature Regulation Performance P: 400 I: D: 2000 Upper limit: 30 W Lower limit: 0W

E. Wingfield August 10, 2006 UM REU Final Presentation LabView Update Previous LabView program was re-examined Changes:  Calculation of output value more correctly follows the text-book mathematics  Filter was added to reduce high-frequency noise  A more logical test of the power-range Figure: LabView Block Diagram

E. Wingfield August 10, 2006 UM REU Final Presentation Ziegler-Nichols Step Response Method for PID Tuning Applied Power (W)KTiTi TdTd Table: Ziegler-Nichols Step-Response Analysis Didn’t Work!

E. Wingfield August 10, 2006 UM REU Final Presentation Many Thanks To: Alexander Herlert and the ISOLTRAP group CERN University of Michigan  Jeremy Herr  Dr. Jean Krisch  Dr. Homer Neal National Science Foundation Ford

E. Wingfield August 10, 2006 UM REU Final Presentation Questions?