CTF3

<h2 id="description-of-the-facility">Description of the facility</h2>

The facility implemented and demonstrated the feasibility of a scaled version of the <a href="/facts/Compact_Linear_Collider/6o8RWUFd">CLIC</a> Drive Beam: a 1.2 μs-long electron beam (bunched at 1.5 GHz, and with 4 A mean current) was generated and accelerated up to ~135 MeV in a ~80 m-long <a href="/facts/Linear_particle_accelerator/GIz6Uc4x">LINAC</a> by using fully loaded accelerating structures powered by ~40 MW, 3 GHz RF pulses.<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a> The beam was then going through a simplified version of the Drive Beam Recombination Complex (DBRC): a system composed of a delay loop and a combiner ring allowed to recombine different part of the incoming beam to finally produce a 140 ns-long train of bunches at 12 GHz and with mean current as high as 28 A.
A second electron beam of lower intensity (a few bunches of about 100 pC/bunch), called Probe Beam, was generated and accelerated up to 200 MeV in the so-called "Concept d’Accélerateur Linéaire pour Faisceau d’Electrons Sonde" (CALIFES) injector.<a class="footnote-ref" id="fnref:8" href="#fn:8">8</a> The main purpose of the Probe Beam was to emulate the main, colliding beam of CLIC.

<h2 id="experimental-program">Experimental program</h2>
The two electron beams produced at CTF3 were used to demonstrate the two-beam acceleration concept in the Two-Beam-Module installed into the CLEX experimental area: the Drive Beam was decelerated in special Power Extraction and Transfer Structures (PETS), and the power produced used to accelerate the Probe Beam with gradients as high as ~145 MeV/m.<a class="footnote-ref" id="fnref:9" href="#fn:9">9</a>
The facility served as test bed for other <a href="/facts/Compact_Linear_Collider/6o8RWUFd">CLIC</a> related R&D, for example:

<ul><li>Beam Loading effect on RF <a href="/facts/Electrical_breakdown/btrl0FPI">breakdown</a> rate.<a class="footnote-ref" id="fnref:10" href="#fn:10">10</a></li>
<li>Drive Beam deceleration efficiency studies.<a class="footnote-ref" id="fnref:11" href="#fn:11">11</a></li>
<li>Drive Beam phase stabilisation by using a novel <a href="/facts/Feed_forward_(control)/N2lyuRNm">feed-forward</a> system.<a class="footnote-ref" id="fnref:12" href="#fn:12">12</a></li></ul>
<h2 id="cern-linear-electron-accelerator-for-research">CERN Linear Electron Accelerator for Research</h2>

In December 2016, while CTF3 was ending its operation, it was decided to transform the Probe Beam in a new general purpose R&D facility under the name of CERN Linear Electron Accelerator for Research, or CLEAR.<a class="footnote-ref" id="fnref:13" href="#fn:13">13</a><a class="footnote-ref" id="fnref:14" href="#fn:14">14</a> The facility was launched in August 2017<a class="footnote-ref" id="fnref:15" href="#fn:15">15</a> and will operate, for now, until the end of 2030.
Thanks to its ease of operation and versatility, the Probe Beam was used also for activities not directly connected to <a href="/facts/Compact_Linear_Collider/6o8RWUFd">CLIC</a>. This triggered the interest of various communities, and a workshop was organised to discuss possible re-use of such a <a href="/facts/Beamline/vrfaEtFt">beamline</a>.<a class="footnote-ref" id="fnref:16" href="#fn:16">16</a><a class="footnote-ref" id="fnref:17" href="#fn:17">17</a>
CLEAR keeps providing testing capabilities for <a href="/facts/X_band/eMpD5T2r">X-band</a> accelerator technology, including <a href="/facts/Compact_Linear_Collider/6o8RWUFd">CLIC</a>, but it also allows to explore novel concepts as <a href="/facts/Plasma_acceleration/8AWHASED">plasma acceleration</a>, <a href="/facts/Terahertz_radiation/729QecPK">THz radiation</a> production. Furthermore, it provides electron irradiation capabilities to space and medical communities.<a class="footnote-ref" id="fnref:18" href="#fn:18">18</a>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">"CTF3 Design Report" (PDF). CERN Document Server. Retrieved 2018-07-30. <a href="https://cds.cern.ch/record/559331/files/ps-2002-008.pdf" target="_blank">https://cds.cern.ch/record/559331/files/ps-2002-008.pdf</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">Roberto, Corsini (May 2017). "Final Results From the Clic Test Facility (CTF3)". Proceedings of the 8th Int. Particle Accelerator Conf. IPAC2017. doi:10.18429/jacow-ipac2017-tuzb1. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">"Official CLEAR website". <a href="http://clear.web.cern.ch" target="_blank">http://clear.web.cern.ch</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">Gamba, D.; Corsini, R.; Curt, S.; Doebert, S.; Farabolini, W.; Mcmonagle, G.; Skowronski, P.K.; Tecker, F.; Zeeshan, S. (2018). "The CLEAR user facility at CERN". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 909: 480–483. Bibcode:2018NIMPA.909..480G. doi:10.1016/j.nima.2017.11.080. hdl:10852/63044. <a href="https://doi.org/10.1016%2Fj.nima.2017.11.080" target="_blank">https://doi.org/10.1016%2Fj.nima.2017.11.080</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">CERN Document Server | G. Geschonke and A. Ghigo (editors): CTF3 Design Report (2002) Retrieved on 31 July 2018 <a href="https://cds.cern.ch/record/559331" target="_blank">https://cds.cern.ch/record/559331</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">"CTF3 Design Report" (PDF). CERN Document Server. Retrieved 2018-07-30. <a href="https://cds.cern.ch/record/559331/files/ps-2002-008.pdf" target="_blank">https://cds.cern.ch/record/559331/files/ps-2002-008.pdf</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">Heinrich, Braun, Hans; Peter, Urschütz; Steffen, Döbert; Roberto, Corsini; A, Tecker, Frank; Erk, Jensen (2006-11-20). "Efficient long-pulse fully-loaded CTF3 linac operation". {{cite journal}}: Cite journal requires |journal= (help)CS1 maint: multiple names: authors list (link) <a href="https://cds.cern.ch/record/999488" target="_blank">https://cds.cern.ch/record/999488</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
<li id="fn:8">Navarro Quirante, Jose Luis; Corsini, Roberto; Grudiev, Alexej; Lefèvre, Thibaut; Mazzoni, Stefano; Pan, Rui; Tecker, Frank; Farabolini, Wilfrid; Peauger, Franck; Gamba, Davide; Khan, Muhammad Asif; Yaqub, Kashif; Ögren, Jim; Ruber, Roger; Vitoratou, Niki (1 December 2014). "CALIFES: A Multi-Purpose Electron Beam for Accelerator Technology Tests": MOPP030. {{cite journal}}: Cite journal requires |journal= (help) <a href="http://inspirehep.net/record/1363325" target="_blank">http://inspirehep.net/record/1363325</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">Ruber, R.; Ziemann, V.; Ekelöf, T.; Palaia, A.; Farabolini, W.; Corsini, R. (2013). "The CTF3 Two-beam Test Stand". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 729: 546–553. Bibcode:2013NIMPA.729..546R. doi:10.1016/j.nima.2013.07.055. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
<li id="fn:10">Tecker, Frank; Corsini, Roberto; Dayyani Kelisani, Mohsen; Döbert, Steffen; Grudiev, Alexej; Kononenko, Oleksiy; Lebet, Serge; Navarro Quirante, Jose Luis; Riddone, Germana (June 2013). "Experimental Study of the Effect of Beam Loading on RF Breakdown Rate in CLIC High-gradient Accelerating Structures": TUPME054. {{cite journal}}: Cite journal requires |journal= (help) <a href="http://inspirehep.net/record/1337158" target="_blank">http://inspirehep.net/record/1337158</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></li>
<li id="fn:11">Döbert, Steffen; Adli, Erik; Lillestøl, Reidar; Olvegård, Maja; Syratchev, Igor; Carrillo, David; Toral, Fernando; Faus-Golfe, Angeles; García-Garrigós, Juan (April 2011). "Commissioning Status of the Decelerator Test Beam Line in CTF3": MOP018. {{cite journal}}: Cite journal requires |journal= (help) <a href="http://inspirehep.net/record/1363717" target="_blank">http://inspirehep.net/record/1363717</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></li>
<li id="fn:12">Jack, Roberts; Alexandra, Andersson; Philip, Burrows; Glenn, Christian; Roberto, Corsini; Andrea, Ghigo; Fabio, Marcellini; Colin, Perry; Piotr, Skowroński (June 2016). "Demonstration of CLIC Level Phase Stability using a High Bandwidth, Low Latency Drive Beam Phase Feedforward System at the CLIC Test Facility CTF3". Proceedings of the 7th Int. Particle Accelerator Conf. IPAC2016. doi:10.18429/jacow-ipac2016-wepor006. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></li>
<li id="fn:13">"Official CLEAR website". <a href="http://clear.web.cern.ch" target="_blank">http://clear.web.cern.ch</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></li>
<li id="fn:14">Gamba, D.; Corsini, R.; Curt, S.; Doebert, S.; Farabolini, W.; Mcmonagle, G.; Skowronski, P.K.; Tecker, F.; Zeeshan, S. (2018). "The CLEAR user facility at CERN". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 909: 480–483. Bibcode:2018NIMPA.909..480G. doi:10.1016/j.nima.2017.11.080. hdl:10852/63044. <a href="https://doi.org/10.1016%2Fj.nima.2017.11.080" target="_blank">https://doi.org/10.1016%2Fj.nima.2017.11.080</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></li>
<li id="fn:15">"CLEAR prospects for accelerator research". CERN Courier. 2017-10-13. Retrieved 2023-03-16. <a href="https://cerncourier.com/a/clear-prospects-for-accelerator-research/" target="_blank">https://cerncourier.com/a/clear-prospects-for-accelerator-research/</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></li>
<li id="fn:16">"CALIFES Workshop 2016 (10-12 October 2016) · Indico". Indico. Retrieved 2018-01-04. <a href="https://indico.cern.ch/event/533052/" target="_blank">https://indico.cern.ch/event/533052/</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></li>
<li id="fn:17">Gamba, D.; Corsini, R.; Curt, S.; Doebert, S.; Farabolini, W.; Mcmonagle, G.; Skowronski, P.K.; Tecker, F.; Zeeshan, S. (2018). "The CLEAR user facility at CERN". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 909: 480–483. Bibcode:2018NIMPA.909..480G. doi:10.1016/j.nima.2017.11.080. hdl:10852/63044. <a href="https://doi.org/10.1016%2Fj.nima.2017.11.080" target="_blank">https://doi.org/10.1016%2Fj.nima.2017.11.080</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></li>
<li id="fn:18">"The CERN Linear Electron Accelerator for Research – CLEAR (30 November 2017) · Indico". Indico. Retrieved 2018-01-04. <a href="https://indico.cern.ch/event/681488/" target="_blank">https://indico.cern.ch/event/681488/</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></li>
</ol>

CTF3 open-in-new

CTF3