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<p style="margin-top:0; margin-bottom:0"><font size="2"><span style="font-size:11pt"><span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont">Jefferson Lab's Graduate Student and Post-Doc Association Wiki:</span><br>
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</span><a href="https://gspda.jlab.org/wiki/index.php/Main_Page" target="_blank" rel="noopener noreferrer" id="LPlnk78984" previewremoved="true"><span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont">https://gspda.jlab.org/wiki/index.php/Main_Page</span></a><br>
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<span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont"> Please RSVP to: patient@jlab.org by COB on April 15, 2019</span><br>
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<span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont"> Wednesday, April 17, 2019</span><br>
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<span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont"> ***F113***</span><br>
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<span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont"> 12:00-1:00 pm</span><br>
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<div><span> <span style="font-size:11pt"> "Development of a 300 KV DC High Voltage</span></span><span style="font-size:11pt"> Photogun and Beam Based Studies of
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<div><span style="font-size:11pt"> Alkali Antimonide Photocathodes"</span><font size="2"><span style="font-size:11pt"><span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont"></span></span></font><br>
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<span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont"> Yan Wang
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<span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont"> Jefferson Lab</span><br>
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<span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont"></span><span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont">Abst</span><span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont"></span><span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont">ract:</span></span></font></div>
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<font size="2"><span style="font-size:11pt"><span style="font-size:12pt; font-family:Times New Roman,Times,serif,serif,EmojiFont"></span></span></font><span>A compact DC high voltage photogun with inverted-insulator geometry<span style="font-size:11pt"></span>
was designed, built, and operated reliably at 300 kV bias voltage using alkali-antimonide photocathodes. This photogun will provide a magnetized electron beam for the future Jefferson Lab Electron-Ion Collider (JLEIC) cooler. This research describes key electrostatic
design features of the photogun and evaluates the performance of the in-house fabricated photocathodes and the quality of the electron beams. The thermal emittance of the electron beam was measured with various conditions: different gun bias voltages, different
laser spot sizes, and photocathodes with different substrate materials. It has been hypothesized that the photocathode surface roughness affects the quality of the photocathodes and the electron beam produced, which is directly related to the thickness of the
antimony layer of the photocathode. This effect was studied experimentally for both the beam emittance and photocathode quantum efficiency lifetime, and the measurements indicate that the beam emittance is largely independent of the antimony layer thickness,
and the lifetime benefits from a thick layer. This presentation presents a summary of the good performance of the photogun, a remarkable quantum efficiency lifetime of the photocathodes, and a low emittance of the electron beam.</span><br>
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