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In the framework of the development of a new linac for carbon ion therapy, this article describes the design of a compact 750 MHz radio frequency quadrupole (RFQ) with trapezoidal vanes. A new semianalytic approach to design the trapezoidal-vane RFQ is introduced together with the relevant beam dynamics properties. The RFQ is split into two decoupled rf cavities, both of which make use of a novel dipole detuning technique by means of length adjustment. The splitting is described both from the rf and the beam dynamics point of view. The paper concludes with the rf design of the full structure, including maximum surface field and thermal studies. High-frequency linear accelerators are very suitable for carbon ion therapy, thanks to the reduced operational costs and the high beam quality with respect to synchrotrons, which are presently the only available technology for this application. In the framework of the development of a new linac for carbon ion therapy, this article describes the design of a compact 750 MHz Radio Frequency Quadrupole (RFQ) with trapezoidal vanes. A new semi-analytic approach to design the trapezoidal-vane RFQ is introduced together with the relevant beam dynamics properties. The RFQ is split into two decoupled rf cavities, both of which make use of a novel dipole detuning technique by means of length adjustment. The splitting is described both from the rf and the beam dynamics point of view. The paper concludes with the rf design of the full structure, including maximum surface field and thermal studies. Bencini, Vittorio; Pommerenke, Hermann W.; Grudiev, Alexej; Lombardi, Alessandra M." /> <meta name="keywords" content="CERN Document Server, WebSearch, CERN Document Server" /> <script type="text/javascript" src="https://cds.cern.ch/js/jquery.min.js"></script>  <link rel="stylesheet" href="https://cds.cern.ch/img/webnews.css" type="text/css" />  <script type="text/javascript" src="https://cds.cern.ch/js/webnews.js?v=20131009"></script> <meta property="fb:app_id" content="137353533001720"/> <script type="text/x-mathjax-config"> MathJax.Hub.Config({ tex2jax: {inlineMath: [['$','$']], processEscapes: true}, showProcessingMessages: false, messageStyle: "none" }); </script> <script src="/MathJax/MathJax.js?config=TeX-AMS_CHTML" type="text/javascript"> </script>  <meta content="APS : 750 MHz radio frequency quadrupole with trapezoidal vanes for carbon ion therapy" name="citation_title" /> <meta content="Bencini, Vittorio" name="citation_author" /> <meta content="Pommerenke, Hermann W." name="citation_author" /> <meta content="Lombardi, Alessandra M." name="citation_author" /> <meta content="Grudiev, Alexej" name="citation_author" /> <meta content="10.1103/PhysRevAccelBeams.23.122003" name="citation_doi" /> <meta content="Phys. 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In the framework of the development of a new linac for carbon ion therapy, this article describes the design of a compact 750 MHz radio frequency quadrupole (RFQ) with trapezoidal vanes. A new semianalytic approach to design the trapezoidal-vane RFQ is introduced together with the relevant beam dynamics properties. The RFQ is split into two decoupled rf cavities, both of which make use of a novel dipole detuning technique by means of length adjustment. The splitting is described both from the rf and the beam dynamics point of view. The paper concludes with the rf design of the full structure, including maximum surface field and thermal studies." property="og:description" /> <meta content="High-frequency linear accelerators are very suitable for carbon ion therapy, thanks to the reduced operational costs and the high beam quality with respect to synchrotrons, which are presently the only available technology for this application. In the framework of the development of a new linac for carbon ion therapy, this article describes the design of a compact 750 MHz Radio Frequency Quadrupole (RFQ) with trapezoidal vanes. A new semi-analytic approach to design the trapezoidal-vane RFQ is introduced together with the relevant beam dynamics properties. The RFQ is split into two decoupled rf cavities, both of which make use of a novel dipole detuning technique by means of length adjustment. The splitting is described both from the rf and the beam dynamics point of view. The paper concludes with the rf design of the full structure, including maximum surface field and thermal studies." property="og:description" />  <meta content="summary" name="twitter:card" /> <style></style> </head> <body class="CERN32Document32Server search" lang="en">  <div id="cern-toolbar"> <h1><a href="http://cern.ch" title="CERN">CERN <span>Accelerating science</span></a></h1> <ul> <li class="cern-accountlinks"><a class="cern-account" href="https://cds.cern.ch/youraccount/login?ln=en&referer=https%3A//cds.cern.ch/record/2751417/plots" title="Sign in to your CERN account">Sign in</a></li> <li><a class="cern-directory" href="http://cern.ch/directory" title="Search CERN resources and browse the directory">Directory</a></li> </ul> </div>   <div role="banner" class="clearfix" id="header"> <div class="header-inner inner"> <hgroup class="clearfix"> <h2 id="site-name"> <a rel="home" title="Home" href="/"><span>CERN Document Server</span></a> </h2> <h3 id="site-slogan">Access articles, reports and multimedia content in HEP</h3> </hgroup> <div role="navigation" id="main-navigation" class="cdsmenu"> <h2 class="element-invisible">Main menu</h2><ul class="links inline clearfix"> <li class="menu-386 first active-trail"><a class="active-trail" href="https://cds.cern.ch/?ln=en">Search</a></li> <li class="menu-444 "><a class="" title="" href="https://cds.cern.ch/submit?ln=en">Submit</a></li> <li class="menu-426 "><a class="" href="https://cds.cern.ch/help/?ln=en">Help</a></li> <li class="leaf hassubcdsmenu"> <a hreflang="en" class="header" href="https://cds.cern.ch/youraccount/display?ln=en">Personalize</a> <ul class="subsubcdsmenu"><li><a href="https://cds.cern.ch/youralerts/list?ln=en">Your alerts</a></li><li><a href="https://cds.cern.ch/yourbaskets/display?ln=en">Your baskets</a></li><li><a href="https://cds.cern.ch/yourcomments?ln=en">Your comments</a></li><li><a href="https://cds.cern.ch/youralerts/display?ln=en">Your searches</a></li></ul></li> </ul> </div> </div> </div>  <table class="navtrailbox"> <tr> <td class="navtrailboxbody"> <a href="/?ln=en" class="navtrail">Home</a> > <a class="navtrail" href="/record/2751417">750 MHz radio frequency quadrupole with trapezoidal vanes for carbon ion therapy</a> > Plots </td> </tr> </table> </div> <div class="pagebody"><div class="pagebodystripemiddle"> <div class="detailedrecordbox"> <div class="detailedrecordtabs"> <div> <ul class="detailedrecordtabs"><li class="first"><a href="/record/2751417/?ln=en">Information </a></li><li class=""><a href="/record/2751417/files?ln=en">Files </a></li></ul> <div id="tabsSpacer" style="clear:both;height:0px"> </div></div> </div> <div class="detailedrecordboxcontent"> <div class="top-left-folded"></div> <div class="top-right-folded"></div> <div class="inside">  <div id="detailedrecordshortreminder"> <div id="clip"> </div> <div id="HB"> <strong><a href="/record/2751417?ln=en">750 MHz radio frequency quadrupole with trapezoidal vanes for carbon ion therapy</a></strong> - <a href="/search?f=author&p=Bencini%2C%20Vittorio&ln=en">Bencini, Vittorio</a> <em>et al</em> - arXiv:2007.10739 </div> </div> <div style="clear:both;height:1px"> </div> <table width="95%" style="display: inline;"><tr><td width="66%"><a name="0" href="https://cds.cern.ch/record/2751417/files/cavity_both_rfqs.png"><img src="https://cds.cern.ch/record/2751417/files/cavity_both_rfqs.png" width="95%"/></a></td><td width="33%"> Preliminary CAD model of the two Carbon-RFQ cavities RFQ1 and RFQ2. Each cavity consists of four individually brazed modules and features four input power couplers, 12~vacuum pumping ports, as well as 32~slug tuners.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="1" href="https://cds.cern.ch/record/2751417/files/v_aperure_scan.png"><img src="https://cds.cern.ch/record/2751417/files/v_aperure_scan.png" width="95%"/></a></td><td width="33%"> Maximum surface field as a function of vane voltage and input aperture for different RFQ designs.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="2" href="https://cds.cern.ch/record/2751417/files/smooth.png"><img src="https://cds.cern.ch/record/2751417/files/smooth.png" width="95%"/></a></td><td width="33%"> Analytic function used to describe the modulation along the gentle buncher. $m_0$ and $m_1$ are the initial and final values of $m(z)$, $z_0$ shifts the function along z, $r$ defines the slope of the ramp.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="3" href="https://cds.cern.ch/record/2751417/files/rfq_params_ht.png"><img src="https://cds.cern.ch/record/2751417/files/rfq_params_ht.png" width="95%"/></a></td><td width="33%"> Modulation, synchronous phase, and minimum aperture of the high transmission RFQ are plotted for the two final energies of \SI{2.5}{\mega\eV\per\atomicmassunit} (solid line) and \SI{5}{\mega\eV\per\atomicmassunit} (dashed line).</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="4" href="https://cds.cern.ch/record/2751417/files/acceptance.png"><img src="https://cds.cern.ch/record/2751417/files/acceptance.png" width="95%"/></a></td><td width="33%"> Longitudinal acceptance for high transmission with (blue) and compact (red) RFQ.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="5" href="https://cds.cern.ch/record/2751417/files/rfq_params_c.png"><img src="https://cds.cern.ch/record/2751417/files/rfq_params_c.png" width="95%"/></a></td><td width="33%"> Modulation, synchronous phase, and minimum aperture of the compact RFQ are plotted for the two final energies of 2.5 MeV/u (continuous line) and 5 MeV/u (dashed line).</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="6" href="https://cds.cern.ch/record/2751417/files/trapezoidal_electrode.png"><img src="https://cds.cern.ch/record/2751417/files/trapezoidal_electrode.png" width="95%"/></a></td><td width="33%"> Geometry and simulated electric potential of a trapezoidal RFQ cell.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="7" href="https://cds.cern.ch/record/2751417/files/trapezoidal_Ez.png"><img src="https://cds.cern.ch/record/2751417/files/trapezoidal_Ez.png" width="95%"/></a></td><td width="33%"> :</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="8" href="https://cds.cern.ch/record/2751417/files/trapezoidal_efficiency.png"><img src="https://cds.cern.ch/record/2751417/files/trapezoidal_efficiency.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="9" href="https://cds.cern.ch/record/2751417/files/field_enhancement_gap10.png"><img src="https://cds.cern.ch/record/2751417/files/field_enhancement_gap10.png" width="95%"/></a></td><td width="33%"> : $g/L=0.62$</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="10" href="https://cds.cern.ch/record/2751417/files/field_enhancement_gap06.png"><img src="https://cds.cern.ch/record/2751417/files/field_enhancement_gap06.png" width="95%"/></a></td><td width="33%"> : $g/L=0.20$</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="11" href="https://cds.cern.ch/record/2751417/files/field_enhancement_gap04.png"><img src="https://cds.cern.ch/record/2751417/files/field_enhancement_gap04.png" width="95%"/></a></td><td width="33%"> : Surface electric field in a trapezoidal cell, shown for varying gap lengths~$g/L$~\protect\subref{fig:field_enhancement_gap1,0}--\protect\subref{fig:field_enhancement_gap0,2}, and \protect\subref{fig:field_enhancement_legend}~legend.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="12" href="https://cds.cern.ch/record/2751417/files/field_enhancement_gap02.png"><img src="https://cds.cern.ch/record/2751417/files/field_enhancement_gap02.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="13" href="https://cds.cern.ch/record/2751417/files/field_enhancement_colorbar.png"><img src="https://cds.cern.ch/record/2751417/files/field_enhancement_colorbar.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="14" href="https://cds.cern.ch/record/2751417/files/trapezoidal_16pot_fit.png"><img src="https://cds.cern.ch/record/2751417/files/trapezoidal_16pot_fit.png" width="95%"/></a></td><td width="33%"> Approximation of the electric field simulated in \textsc{comsol} (black dashed line) on the beam axis of a trapezoidal cell by the potential function with increasing number of terms.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="15" href="https://cds.cern.ch/record/2751417/files/trapezoidal_mpole_scatter_A_0_1.png"><img src="https://cds.cern.ch/record/2751417/files/trapezoidal_mpole_scatter_A_0_1.png" width="95%"/></a></td><td width="33%"> :</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="16" href="https://cds.cern.ch/record/2751417/files/trapezoidal_mpole_scatter_A_1_0.png"><img src="https://cds.cern.ch/record/2751417/files/trapezoidal_mpole_scatter_A_1_0.png" width="95%"/></a></td><td width="33%"> :</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="17" href="https://cds.cern.ch/record/2751417/files/trapezoidal_mpole_scatter_A_5_0.png"><img src="https://cds.cern.ch/record/2751417/files/trapezoidal_mpole_scatter_A_5_0.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="18" href="https://cds.cern.ch/record/2751417/files/trapezoidal_mpole_scatter_FE.png"><img src="https://cds.cern.ch/record/2751417/files/trapezoidal_mpole_scatter_FE.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="19" href="https://cds.cern.ch/record/2751417/files/vane_parameters_trapezoidal.png"><img src="https://cds.cern.ch/record/2751417/files/vane_parameters_trapezoidal.png" width="95%"/></a></td><td width="33%"> Beam dynamics parameters of the Carbon-RFQ with trapezoidal vanes.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="20" href="https://cds.cern.ch/record/2751417/files/vane_comparison.png"><img src="https://cds.cern.ch/record/2751417/files/vane_comparison.png" width="95%"/></a></td><td width="33%"> Comparison between standard-vane RFQ, trapezoidal-vane RFQ, and a design employing purely sinusoidal vanes, for the same final energy of \SI{5}{\mega\eV\per\atomicmassunit}. Parameters are shown as functions of the position~$z$, while~$V_0$, $r_0$, and $\varrho$ are constant and equal in all designs. The gap length~$g$ is a free parameter for the trapezoidal design, but equals the cell length in the other designs.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="21" href="https://cds.cern.ch/record/2751417/files/phasespace_2term_8pot.png"><img src="https://cds.cern.ch/record/2751417/files/phasespace_2term_8pot.png" width="95%"/></a></td><td width="33%"> : standard vanes, \textsc{comsol} FEM map</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="22" href="https://cds.cern.ch/record/2751417/files/phasespace_2term_comsol.png"><img src="https://cds.cern.ch/record/2751417/files/phasespace_2term_comsol.png" width="95%"/></a></td><td width="33%"> : trapezoidal vanes, \textsc{comsol} FEM map</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="23" href="https://cds.cern.ch/record/2751417/files/phasespace_trapezoidal_16pot.png"><img src="https://cds.cern.ch/record/2751417/files/phasespace_trapezoidal_16pot.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="24" href="https://cds.cern.ch/record/2751417/files/phasespace_trapezoidal_comsol.png"><img src="https://cds.cern.ch/record/2751417/files/phasespace_trapezoidal_comsol.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="25" href="https://cds.cern.ch/record/2751417/files/enveloperms_2term.png"><img src="https://cds.cern.ch/record/2751417/files/enveloperms_2term.png" width="95%"/></a></td><td width="33%"> : trapezoidal vanes</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="26" href="https://cds.cern.ch/record/2751417/files/enveloperms_trapezoidal.png"><img src="https://cds.cern.ch/record/2751417/files/enveloperms_trapezoidal.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="27" href="https://cds.cern.ch/record/2751417/files/lost_particles.png"><img src="https://cds.cern.ch/record/2751417/files/lost_particles.png" width="95%"/></a></td><td width="33%"> Energy distribution of the particles lost during the particle tracking through the FEM field map of both designs.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="28" href="https://cds.cern.ch/record/2751417/files/tlm_2wire_with_ends.png"><img src="https://cds.cern.ch/record/2751417/files/tlm_2wire_with_ends.png" width="95%"/></a></td><td width="33%"> Transmission line model of the symmetric four-vane RFQ cavity with ends, valid for both quadrupole and dipole modes.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="29" href="https://cds.cern.ch/record/2751417/files/spectrum_rfq1.png"><img src="https://cds.cern.ch/record/2751417/files/spectrum_rfq1.png" width="95%"/></a></td><td width="33%"> : RFQ2</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="30" href="https://cds.cern.ch/record/2751417/files/spectrum_rfq2.png"><img src="https://cds.cern.ch/record/2751417/files/spectrum_rfq2.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="31" href="https://cds.cern.ch/record/2751417/files/vane_section_drift.png"><img src="https://cds.cern.ch/record/2751417/files/vane_section_drift.png" width="95%"/></a></td><td width="33%"> Field map of the lattice used to transfer the beam from the last accelerating cell of RFQ1 to the first accelerating cell of RFQ2. After the transition cells~(TC), the vanes are extended by the quadrupole cells QC1 and QC2, whose lengths is chosen such that the envelope oscillation in RFQ2 is minimal.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="32" href="https://cds.cern.ch/record/2751417/files/section_drift_matching_x.png"><img src="https://cds.cern.ch/record/2751417/files/section_drift_matching_x.png" width="95%"/></a></td><td width="33%"> :</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="33" href="https://cds.cern.ch/record/2751417/files/section_drift_matching_y.png"><img src="https://cds.cern.ch/record/2751417/files/section_drift_matching_y.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="34" href="https://cds.cern.ch/record/2751417/files/enveloperms_rematch.png"><img src="https://cds.cern.ch/record/2751417/files/enveloperms_rematch.png" width="95%"/></a></td><td width="33%"> Beam envelopes of the Carbon-RFQ split into two cavities before and after the rematch.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="35" href="https://cds.cern.ch/record/2751417/files/cavity_2d_geometry.png"><img src="https://cds.cern.ch/record/2751417/files/cavity_2d_geometry.png" width="95%"/></a></td><td width="33%"> Quadrant of the Carbon-RFQ cavity cross section with restrictions to the optimization highlighted in red.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="36" href="https://cds.cern.ch/record/2751417/files/cells_rf_parameters.png"><img src="https://cds.cern.ch/record/2751417/files/cells_rf_parameters.png" width="95%"/></a></td><td width="33%"> Rf parameters along the RFQ derived from simulation of of individual cells. The vertical lines indicate the approximate dimensions of the $2\times 4$~RFQ modules (inter-cavity drift is neglected).</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="37" href="https://cds.cern.ch/record/2751417/files/cavity_2d_E.png"><img src="https://cds.cern.ch/record/2751417/files/cavity_2d_E.png" width="95%"/></a></td><td width="33%"> :</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="38" href="https://cds.cern.ch/record/2751417/files/cavity_2d_H.png"><img src="https://cds.cern.ch/record/2751417/files/cavity_2d_H.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="39" href="https://cds.cern.ch/record/2751417/files/Emax_buncher_sameScale.png"><img src="https://cds.cern.ch/record/2751417/files/Emax_buncher_sameScale.png" width="95%"/></a></td><td width="33%"> :</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="40" href="https://cds.cern.ch/record/2751417/files/Emax_acc_sameScale.png"><img src="https://cds.cern.ch/record/2751417/files/Emax_acc_sameScale.png" width="95%"/></a></td><td width="33%"> :</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="41" href="https://cds.cern.ch/record/2751417/files/Emax_gap_in_buncher.png"><img src="https://cds.cern.ch/record/2751417/files/Emax_gap_in_buncher.png" width="95%"/></a></td><td width="33%"> : Surface electric field in normal cells of bunching section~\protect\subref{fig:Emax_buncher} and accelerating section~\protect\subref{fig:Emax_acc}, as well as in cells interrupted by the inter-module gap in bunching section~\protect\subref{fig:Emax_gap_in_buncher} and accelerating section~\protect\subref{fig:Emax_gap_in_acc}, and \protect\subref{fig:Emax_legend}~legend.</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="42" href="https://cds.cern.ch/record/2751417/files/Emax_gap_in_acc.png"><img src="https://cds.cern.ch/record/2751417/files/Emax_gap_in_acc.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="43" href="https://cds.cern.ch/record/2751417/files/Emax_colorbar.png"><img src="https://cds.cern.ch/record/2751417/files/Emax_colorbar.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="44" href="https://cds.cern.ch/record/2751417/files/tuner_H.png"><img src="https://cds.cern.ch/record/2751417/files/tuner_H.png" width="95%"/></a></td><td width="33%"> :</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="45" href="https://cds.cern.ch/record/2751417/files/vac_H.png"><img src="https://cds.cern.ch/record/2751417/files/vac_H.png" width="95%"/></a></td><td width="33%"> :</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="46" href="https://cds.cern.ch/record/2751417/files/coupler_H.png"><img src="https://cds.cern.ch/record/2751417/files/coupler_H.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="47" href="https://cds.cern.ch/record/2751417/files/coupler_H_colorbar.png"><img src="https://cds.cern.ch/record/2751417/files/coupler_H_colorbar.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="48" href="https://cds.cern.ch/record/2751417/files/thermal_df_over_dc.png"><img src="https://cds.cern.ch/record/2751417/files/thermal_df_over_dc.png" width="95%"/></a></td><td width="33%"> Resonance frequency shift~$\Delta f$ of the RFQ cavity subject to heat-induced deformation as a function of duty cycle~$d$ and cooling water temperature $T_\text{w}$ for the cases of one and two cooling channels per vane. At nominal operation, the heating is compensated by reducing $T_\text{w}$ by \SI{1}{\kelvin}~($\star$).</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="49" href="https://cds.cern.ch/record/2751417/files/thermal_octant_temp.png"><img src="https://cds.cern.ch/record/2751417/files/thermal_octant_temp.png" width="95%"/></a></td><td width="33%"> :</td></tr></table><table width="95%" style="display: inline;"><tr><td width="66%"><a name="50" href="https://cds.cern.ch/record/2751417/files/thermal_octant_deform.png"><img src="https://cds.cern.ch/record/2751417/files/thermal_octant_deform.png" width="95%"/></a></td><td width="33%"> : Caption not extracted</td></tr></table><br /><br /> <div class="bottom-left-folded"></div> <div class="bottom-right-folded" style="text-align:right;padding-bottom:2px;"> <span class="moreinfo" style="margin-right:10px;"><a href="/search?ln=en&p=recid%3A2751417&rm=wrd" class="moreinfo">Similar records</a></span></div> </div> </div> </div> <br/> </div></div> <footer id="footer" class="pagefooter clearfix">  <div class="pagefooterstripeleft"> CERN Document Server :: <a class="footer" href="https://cds.cern.ch/?ln=en">Search</a> :: <a class="footer" href="https://cds.cern.ch/submit?ln=en">Submit</a> :: <a class="footer" href="https://cds.cern.ch/youraccount/display?ln=en">Personalize</a> :: <a class="footer" href="https://cds.cern.ch/help/?ln=en">Help</a> :: <a class="footer" href="https://cern.service-now.com/service-portal?id=privacy_policy&se=CDS-Service" target="_blank">Privacy Notice</a> :: <a class="footer" href="https://repository.cern/content-policy" target="_blank">Content Policy</a> :: <a class="footer" href="https://repository.cern/terms" target="_blank">Terms and Conditions</a> <br /> Powered by <a class="footer" href="http://invenio-software.org/">Invenio</a> <br /> Maintained by <a class="footer" href="https://cern.service-now.com/service-portal?id=service_element&name=CDS-Service">CDS Service</a> - Need help? 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