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Thanks Jay,
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<div>Cheers,<br>
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<p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt;"><span style="background-color: rgba(255, 255, 255, 0);">Alex<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt;"><span style="background-color: rgba(255, 255, 255, 0);">S. Alex Bogacz,<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt;"><span style="background-color: rgba(255, 255, 255, 0);">Accelerator Physics Group Leader<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt;"><span style="background-color: rgba(255, 255, 255, 0);">Center for Advanced Studies of Accelerators<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin: 0cm 0cm 0.0001pt;"><span style="background-color: rgba(255, 255, 255, 0);">Jefferson Lab<o:p></o:p></span></p>
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<div>Sent from my iPhone</div>
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<blockquote type="cite">On Jul 27, 2023, at 4:11 PM, Jay Benesch via PEPPo <peppo@jlab.org> wrote:<br>
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<div dir="ltr"><span>Wedge used to reduce momentum spread, as for muons. Something to think about for secondary electron/positron collection? I'll have to think some more about what wedge material would suit.</span><br>
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<span>https://www.nature.com/articles/s41567-023-02115-2</span><br>
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<span>In recent years, there has been a considerable push towards ultrahigh dose rates in proton therapy to effectively utilize motion mitigation strategies and potentially increase the sparing of healthy tissue through the so-called FLASH effect. However,
in cyclotron-based proton therapy facilities, it is difficult to reach ultrahigh dose rates for low-energy beams. The main reason for this lies in the large momentum spread that such beams have after reducing their energy to levels required for proton therapy,
incurring large losses in conventionally used momentum or energy selection slits. Here we propose momentum cooling by using a wedge in the energy selection system (instead of a slit) to reduce the momentum spread of the beam without introducing substantial
beam losses. We demonstrate this concept in our eye treatment beamline and obtain a factor of two higher transmission, which could eventually halve the treatment delivery time. Furthermore, we show that with a gantry design incorporating this feature, we can
achieve almost a factor of 100 higher transmission for a 70 MeV beam compared with conventional cyclotron-based facilities. This concept could enhance the potential of proton therapy by opening up possibilities of treating new indications and reducing the
cost.</span><br>
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