<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">The UBC Departmental Doctoral Oral Examination<font face="Times New Roman"> for <b>Mathew Smith</b></font><b> </b>is set for<b> Friday, April 4th at 2:00 pm in Hennings 318.<br><br></b></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Research Supervisors:<br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "> Dr. Jens Dilling<br> Dr. Kirk Madison<br><br>Committee Members:<br> Dr. Stan Yen</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "> Dr. John Ng</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font-family: 'Lucida Grande'; font-style: normal; font-variant: normal; font-weight: normal; font-size: 14px; line-height: normal; min-height: 17px; "> <br><b>Thesis Title:</b> A Mass Measurement of the Short-lived Halo Nucleus 11Li with the TITAN Penning Trap Spectrometer<font face="Arial" size="3"><span style="font-size: 12px; "><b><br><br><br></b></span></font><font face="Arial" size="3"><span style="font-size: 12px; "></span></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><b>ABSTRACT</b></div><br>New measurements of the masses of the isotopes 8,9,11Li were made using <br>the recently commissioned TITAN Penning trap mass spectrometer at TRI- <br>UMF. The measurement of halo nucleus 11Li represents a new standard in <br>Penning trap mass spectrometry, as it is the shortest lived, t1/2 = 8.8 ms, <br>isotope ever weighed using this technique. Low energy, E = 20 keV , beams <br>of these radioactive isotopes were produced using the ISAC facility. These <br>were subsequently cooled and bunched using a square-wave-driven Radio- <br>Frequency Quadrupole (RFQ) ion guide, which was filled with hydrogen <br>gas. The cooled ion bunches were then passed into a Penning trap where <br>the mass measurements were made. <br><br>A description of the RFQ in the ISAC hall is given along with some <br>results from the commissioning of the device. A new set of harmonic decel- <br>eration optics is presented which have been successfully used to inject ions <br>into the RFQ. Cooling of lithium ions with high DC efficiencies of 20%, in <br>helium, and 40%, in hydrogen are shown. Extraction of extremely short <br>ion bunches, 30 ns FWHM, is also demonstrated. Storage times for stable <br>lithium ions in helium and hydrogen were investigated. It was found that <br>lithium ions could be cooled in hydrogen for up to 30 ms without significant <br>losses whereas cooling in helium lead to exponential losses with a half-life of <br>5.7(1) ms. <br><br>The TITAN Penning trap is described and the 8,9,11Li data presented. <br>Final values for the mass excess ∆(8 Li) = 20945.70(38) keV , ∆(9 Li) = <br>24954.80(60) keV and ∆(11 Li) = 40728.1(12) keV are obtained. The 9,11Li <br>results are then used to obtain a new value for two neutron separation energy <br>of 11 Li, S2n = 369.3(1.3) keV . This agrees with the recent measurement from <br>the MISTRAL spectrometer, 376(5) keV at the two sigma level, but shows <br>over three standard deviations from the most recent atomic mass evaluation, <br>300(20) keV .<div apple-content-edited="true"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><br class="Apple-interchange-newline"></span><br class="Apple-interchange-newline"></div></span> </div><br></body></html>