Proceedings of the 10th Annual Meeting of Particle Accelerator Society of Japan (August 3-5, 2013, Nagoya, Japan) ATF STATUS REPORT 2012ĴĢ ħ#, A), ATF »ƥGh_kpJgn
Nobuhiro Terunuma#, A), ATF International CollaborationA)
KEK, High Energy Accelerator Research Organization

AbstractAccelerator Test Facility (ATF) in KEK is a research center for studies on issues concerning the injector, damping
ring, and beam delivery system for the ILC. The ATF damping ring reduces the vertical emittance of the beam down to4 pm·rad. ATF2 is a final-focus test beam line that aims to focus the low emittance beam from the ATF damping ring toa vertical size of about 37 nm and to demonstrate the nanometer level beam stability, using numerous advanced beamdiagnostics and feedback tools. The beam size smaller than 70 nm at the ATF2 focal point was confirmed by December
2012 following the efforts to cure the multipole errors, wake field effects and the repeatability of the beam size
measurement. The equipments for the beam position stabilization in the nano meter level have been installed in July
2013. The studies both on a small beam toward the 37 nm beam and a nanometer position stabilization are continued.

ŀ&¨ !9ƑÜ'ſ´Ŭÿ= figure 2 &ňATF2 žľ"(ƀž 7àƀoƘ¶&Ů9/"
KEK & 9 ATFƳŒ Ɣ·Ƅưŵũƴ"( » ƥ ŀ &  ° " Ų  !  9  à ƀ Č (2006~8) #»ƥiV?Gh@Op(ILC)žľ [1]%$Ôď' Ɣ· commissioning Č(2009~10)&(ĨÆ 7Ç'ŅŎ"êŹ#:9ZpcžĮôų 6+Zpcèô Ŭ ſ:õ!9ŵũ'őr=řŀ&
ų'ƞĿ=Ų!9ATF (ajPXnPZpc Ɨ2!2011 Ü(ƪı&69Ě#'æ'é
ļñ=Ų
photocathode RF gun  1.3GeV S-band ą ē'2&ZpcÐư'ĈƟÇ% éąƉĀ'2&Ç'ŅŎŬ ſ:!9
LinacBbQNnLZpc&Äü9On[nF'æ(õĘ·&êŹ%dnRUnL
ē3×%
inF7&'Zpc=Ľ ILC ĊŞªĎJ[2]
%8ċ¦"'İ¼7ZpcƘƎ
9Ɩ&7LRc'ƞĿƄư=Ų
ATF2 Zpch@nƦt!İ¼9äð&ŊŲ!
8İ¼Ąÿ'ĕñ:!9(Figure 1)
ī×#!Ĺ:!9ZpcƘƎČƟ&ơ!0
ATF "'ÇØ&Ĭ9ŅŎƞĿ[3]&(MoU &¿[4]»ƥGh_kpJgn şŨ:! 8 » :)ÈÌƢļ'ÿ3Ã ! 8&3Ã!
Æ'ÈÌ 6+ŅŎĘƠ 7Ç'ŅŎŬ ř ĥĿ%°ŅŎ Ų<:!9

1.

Figure 1: Layout of the ATF.
____________________________________________#nobuhiro.terunuma@kek.jp- 377 -

Proceedings of the 10th Annual Meeting of Particle Accelerator Society of Japan (August 3-5, 2013, Nagoya, Japan)

Figure 3: ATF2 beamline (Final Focus System).

Figure 2: The numbers of visited researchers.

2.

R&D



ATF "Ų<:!9ŅŎƞĿ(ÇŌÇĖ&<9
't"3iV?Gh@OpĊŞªĎ(final focus)JLRc'ôųƞĿ]lFhc(ATF2) ĊzƬ"8ĨÆ 7'¨ Ŭ'Ç :&¨ !
9ZpcĈƟ( ATF2 & 50Ʋ:Æ& 50Ʋ
=¿č#!ƛ® R&D 'ƗùĶģ&ë!
ƉĀ!92.1½łĂ± 37 nm 'ĔÖZpcƞĿ

ATF2 žľ& 9œq'Łė(½łĂ± 37nm 'ĔÖZpc'ƚñ"9ATF2 Zpch@nFigure 4: Schematic configulation of the nano-meter( ILC Ċ Ş ª Ď Z p c h @ n # °  ƀ ž (energybeam size monitorscaled)"8ATF2 "' 37 nm ( ILC "' 6 nm &Ńã9
ATF2 "'îŴŐĲƳIPƴ'ZpcH@MĮÏ(kpIpÛĪŧ=#'Gn]Snþw=Ľ
9 (IPBSM, Figure 4)ÛĪ9kpIp'}ÙŻ
"ÛĪŧ'[QP ġ/8:&ë!ZpcH@M'ĮÏŗº ġ/9ATF2 ' IPBSM "( 3 ŌƯ'}ÙŻepT 9Ċ'}ÙŻepT"'ĮÏ( 2 μm ŋÞ 7É/8&Ů9/"( 5μm 'Dp_nm@f&69ZpcH@M'ĮÏoZpcƉĀ Ų<:9œ{'}ÙŻepT"'Į
Ï&Ŋ92&( 300 nm s'ZpcH@M/"Ţ7%:)%7%7&ĊŞ'}ÙŻepT
&Ŋ92&( 90 nm &ƚ%:)%7%
ZpcH@MeVNp' commissioning #ĔÖZpc'ƉĀ |&ĩËĶģ=ŸƧ&!
 t" 2012 Ü 2 ċ&2!œ 2 'epT
Figure 5: Beam size monitor at ATF2-IP"'ĮÏ&ŊŲ165 nm 'ZpcH@M=ņƆćÜÞ'¥ƳÅČĚƴ('k^j"'
Zpc'÷9ů 7Ė% Optics 'ĒƂ=Ų łťLRpK'ş"}ÙŻ=è9ýƕ Ų<ƱęŇÁBhp'ƃ Ɨ0'Óŕ= 2012 Ü :(Figure 5):7&6811 ċ'ƘƎƞæ('ÅČĚČƟt&Ų!9/:/"' ZpcƉĀoĮÏ"'Ĺì Èýµ:}ÙŻèĘĕ"(3 'epT"'bhpƉĀ Zpch@n'ĺż 68ĩƗ>'t"
ķő&%! 7¸ƎLRpK'Ĺì 7 ZpcH@M& 9âZpcƩĦËì ņƆ´Ʈ ļ4%$šĐŀ&}ÙŻƉĀ&ĈƟ :ZpcâÞ=:/"' 1/5~1/10 &Ńã
9#Ž ´Ʈ ƪı"7&Mk
9 1x109 electrons/bunch ŋÞ&s!ƉĀ=Ɨ2
*$%!#38¸ƎLRpK=ßĚ šĐ2012 Ü 12 ċ&2!ĊŞ'}ÙepT"'- 378 -Proceedings of the 10th Annual Meeting of Particle Accelerator Society of Japan (August 3-5, 2013, Nagoya, Japan)

P 7ũíÀ=áæŤ'XnPŪ'ũ=Ŷě9 Intra-train feedback ôų(FONT)'ƞĿ
ATF =Ľ!Ɨ27:!9
ATF "(On[nFinF 7 154 ns ƟƤ"«8:Ʒ'XnP=Ľ!92012 Ü 6
ċ/"(«8Zpch@n& stripline kicker #stripline BPM 'ş0¯<&69 feedback system(Figure 7)=ĕŘ!Ƅư Ų<:!Ċ'XnPũĒ 7œƶXnP=Ŷě9/"& 133ns "'ëŔ=ÐĹũKQNp= 1/5
7 1/3/"ī9#&ñ!9(Figure 8)

Figure 6: Evaluated beam size at the ATF2 IP.
Gn]Sn­=Ē½łZpcH@M 70 nm
ŋÞs"9# ņƆ:'æZpc
ƩĦËì'Ɖđ(wakefield %$ƴ=Ɨ2!9
2013 Ü 3 ċ' run "ĮÏ:ZpcH@M'Ú= Figure 6 &ňIPBSM 'ĮÏ"(ŚţƇÙ(ZpcH@M=ÈŖ9& Ľ9'"Ð
ƥ'Zpc(:768Ö#ĺż:!9ZpcƉĀ'ƅŝ(vĞ'À²=¨Ĵ: [5] Figure 8: Position jitter suppression by FONT.
:7'ĔÖZpcŅŎƞĿ&ƥ!inF 7
Ɠ7:!9Zpc'Ä¢=Ö¡ êŹ2012 Ü 11 ċ 7(ƞĿ'Áò=îŴŐĲ&Ŋ"ĻÂĭÞ&Ɗ¹9inF³Ɲ'Ä£' ~æyÏ:!9 nm k^j"'ÐƂÐư'24ƍƙ%$ Ä<9:=in 2&yƄư=É2ATF "' nm k^jF'³Ĥÿ=ƉĀ9#"ī!9:& è'2&( Cavity BPM = êŹ 9ƀ!(űĞ'À²=¨Ĵ:[6]
ũ:! Cavity BPM ( 1 ¬"8żŭƒĠ'2&ŷ :Č¾'3'" 154 ns ƟƤ'XnP&Ó!(­ƨ ¤"% yATF2 žľ"'œƶ'Łė(ĔÖZpc'ũ=Ƅư#!­= feedback board &JLnm k^j"ÍÏ£9#"9ILC "'Rc'ĺż=ĩ2!#;"9:(ZpcH@M'Ƶ/Ʒ"9 2 nm =Łė#!9
2013 Ü 6 ċ/"Ť7:
ILC 'Zpc( 1 ms 8Ċ3XnPÿ ÇC]żŭ 2 nm 'ÇXnPĽ BPM #' readout ¸Jgn"ś 2600 'XnP 366 ns ƟƤ"ŴŐƋ'ƞĿ( KNUƳƫ»ƴ'õ"Ɨ27:!
Ĳ&Ɠ7:!9Ý÷¢%$Zpc=wŹ¹(ă& Low-Q ¾' BPM (ƞĿ:! 8:=:&ĝ-!58"8XnP(GYpkĽ!ç7:9Ðƥ'Zpc­=Ľ!ƱżŭnS&÷¢!9#ź%9"ƭ'Xn

2.2 UWdpSj"'ZpcũèFigure 7: Configuration of the intra-train feedback.

Figure 9: Cavity BPM on piezo mover- 379 -

Proceedings of the 10th Annual Meeting of Particle Accelerator Society of Japan (August 3-5, 2013, Nagoya, Japan)'2' readout ¸Ƌ'ƞĿ Ɨ27:Ĺ¼2
On[nFinF"'BbQNnLĮÏ( lasernm 'ïÞ=źƐ29Ķð&9 čÐư=Ų wire, X-SR monitor, SR interferometer %$'ZpcH% 7~æ3ƞĿ Ť3'#ū !9@MeVNp"Ų<:!ÿÜ( real timeUWdpSj"'ZpcũèÐư"(' "ZpcƉĀ& 9 X-SRu&Ľ7:!9
BPM = 3 Ľ92 "Zpcƍƙ=ƈ0 Ĺ¼ ATF2 "êŹ#:9BbQNnLƳ½łĂ±
Ĝ8' BPM 'Əě=Ų BPM 'ŃÓũƉĀ4 " 10 pm ŋÞƴ,(ĝƏŀÑĆ&ƉĀ:!9ïÞŶě%$'2&ũƉĀLRpK3êŹ"  % 72 pm 'BbQNnLZpc#
9ńŏPAnXp3ŷ #%8BPM H`pS ƞĿŁė 8'2&(kpIp#ƩÊZpŚ#q" LALƳ\hnLƴ õãFigure 9 c'łûþw=Ľ9 laser wire "'ņƆ êŹ(  î Ŵ Ő Ĳ (IP)' ń ŏ P A n X p & Ŝ 2 9  ' #%910 Ü.$ 7inF&ƀũ:!
Cavity BPM "9BPM
IP =ö16 &rĦ& laser wire ( 2-mirror system "8ƉĀ&(ĵŦ2 Ƴóq£:!9ƴ#sĦ&Ƶƛũ Šư êŹ"ƑÜ"(.#>$ƘĽ:!%:::piezo mover 'r&ũ :!9 ĔťŅŎ& 9 4-mirror system 'Ð
ƞĿ: BPM readout ¸Ƌ& !ũż Ľ£=ƌ/ laser wire 3 4-mirror system #!ƀŭ 2 nm 'ƱïÞƀÏ"( BPM 'O@UbQEkn žƳFigure 11):9##%82012 Ü&ŷ =K 5 μm #ÖƳAttenuator =Ľ!ïÞ=s Îx!9~Ü'Å&inF,'Õ=Ų [7] :)O@UbQEknK=ÈÃ4#("9ƴpiezo mover ( 1 nm 'ũè"±150 μm'¢ ŗº 9BPM ­=ź% 7Zpc#'?h@dnS=ƒƐ>"Ų# ƜŹ"9ċ 7 ċ& IP ,'ş0Ɛ0 Ų<: ē'
2kpIpèŚ=«8ÆāńŏPAn
X p = ƀ ũ   ' t & BPM J L R c ø   (Figure 10)ńŏğÒƄư©+ piezo mover '¢ Ƅ
ư3ĳzÎx! 8Ĺ¼( IPBSM kpIp'
ũƉĀ ē=Ų!9Figure 11: New 4-mirror optical cavity for the DR. An
electron beam goes from top to bottom and thecollision point is middle of the two concave mirrors.

3.

Figure 10: ATF2 IP. Cavity BPM were installed in thevacuum chamber. Closed flanges will be replaced by
the viewports for lasers.
2.3 kpIpŰōŵũƞĿĔƣƩÊįƞĿ'2'Ĕ γ ť'ļñŅŎOn[nFinF"Ų<:!9kpIpŰōŵ
ũ"Ď'âÞ=Ʊ2ƩÊZpc#ŴŐ!
Ĕť=ç92011 Üŉ&kpIpŰōŵũ= 2mirror optical cavity 7 4-mirror &693'&Äĉ:&68kpIpŰō'2'bhpè'ƁÑÞ r 8šĐ#!ƱŰōĸ=ÍÏ&ÐĹ9#&ñ!92012 Ü(ƩÊZpc
#'°ČJLRc'ƱÞ£&Ʀt!«8ş>"
8~ÜÞ'ñĐ=Čå

ćÜ( ATF2 žľ'œqŁė"9 37 nm ĔÖZpc'ÐĹ&ƦtÜ"ƱŇÁBhp'ÓŕZpcH@MeVNp'ýµ%$'¡'šĐ½łĂ±ZpcH@M( 65 nm s"9#=ņƆ"âZpcƩĦËì'´Ʈ(ā%ƜŹ%Rpa#!ũ =Ų
8#§¹=úĠÓŕ!
œ{'Łė"9UWdpSjk^j"'Zpc ũ  è ô ų ' ƞ Ŀ " (  BPM  mover  7 &feedback ¸Ƌ%$'Ƅư Ɨ0:7=ţ¯!
ATF2 îŴŐĲ&ş0Ɛ0 Ɨ27:!9Łėƚñ&(ĈƟ êŹ#ū 9 ~Ü'ŉ 7ő
r&È&Čå
[1] ILC RDR, ILC-REPORT-2007-001.
[2] P. Bambade et al., Phys. Rev. ST-AB 13, 042801 (2010).
[3] N. Terunuma et al., Proceedings of PAC11, NY (2011).
[4] http://atf.kek.jp/twiki/bin/view/Main/ATFIntroduction[5] K. Kubo and T. Okugi, č Ɣ·ÌSAOTP1[6] T. Naito, č Ɣ·Ì, SAP081[7] A. Rawankar, č Ɣ·Ì, SAP103- 380 -