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1 liter (2 kg) COUPP Bubble Chamber In NuMI tunnel University of Chicago Indiana University, South Bend at at Fermilab Fermilab � Fermilab test site � ~300 m.w.e. �
<4=&>$??@1&)4#A?10%B & !" � #$%&'()$%&')(*$++'+(,-./0(1'(2-++31/'" � Multi ton chambers were built in the 50’s- 80’s. � • � 4" � 56('783)36&(*'6.(-9($:$3/$1/'()$%&')(6.8/'3" � No liquid that has been tested seriously has failed to work as a bubble chamber liquid (Glaser, 1960). � Most common: Hydrogen, Propane � • � But also “Heavy Liquids”: Xe, Ne, CF 3 Br, CH 3 I, and CCl 2 F 2 . � • � Good targets for both spin- dependent and spin-independent scattering. � • � Possible to “swap” liquids to check suspicious signals. � • � ;"(<$8=&%-.60+(0.'()-('6:3%-6*'6)$/(&$**$($60(1')$($8)3:3)>(8$6(1'( +.22%'++'0(1>(%.6636&($)(/-,(2%'++.%'"( • � Bubble nucleation depends on dE/dx, which is low for electrons, high for nuclear recoils �
0?@0A(B3+8%3*36$)3-6(36(<.11/'(CD$*1'%+ & • � Energy to make bubble must be deposited inside critical radius, which depends on vapor pressure, chamber operating pressure and surface tension � ( Seitz, 1954) . � 2 � R C = ~ 100 nm C"=D53#@E& P P � vapor external • � We adjust the temperature and pressure to make R c large compared to a nuclear recoil length (<100 nm at 10 keV) and small compared to electron recoils (>1 micron) �
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-&6=D53#@&)*+,,&FG1." & Two views of same bubble (cameras offset by 90˚): -&<HI,&5."10#3"5'.& 2'$@/&D0'/$31&#&%5.J@1& ?$??@1&C.'&"0#3K%&'0& A$@"5D@1%E& -DD1#0#.31&'(&#&?$??@1& 3#$%1%&"41&34#A?10&"'& ?1&"05JJ101/&?=&5A#J1& D0'31%%5.J&%'("2#01L& >$??@1&D'%5"5'.%& A1#%$01/&5.&"4011& /5A1.%5'.%&(0'A&%"101'& 3#A10#&G512%&
Neutron and Gamma Calibrations • � &M1$"0'.&%3#""105.J&/#"#&C 7NO -AP>1E&5%&21@@P/1%305?1/&?=&%"#./#0/&!15"Q&?$??@1& .$3@1#"5'.&"41'0=&25"4&"41&#%%$AD"5'.&'(&#&%4#0D&1.10J=&"401%4'@/L& • � &FRD'%$01&"'&45J4P5."1.%5"=&J#AA#&%'$031%&/1A'.%"0#"1%&5.%1.%5"5G5"=&"'&?1"#&#./& J#AA#&?#3KJ0'$./%L& GD%'+D-/0( E'3)F( 1.11/'( 6.8/'$)3-6(( *-0'/ &
E2$)3$/(B3+)%31.)3-6(-9(E36&/'(<.11/'+ & <#@@&FG1."%S&.'"&#& ?#3KJ0'$./T&?$"&"41=& >$@K&1G1."%S& 01/$31&'$0&@5G1&"5A1&/$1& 5./5%"5.J$5%4#?@1& (0'A&<HI,& "'&"41&.11/&"'&/13'AD01%%& #("102#0/%T&D0'45?5"5G1&('0& 5."10#3"5'.%&'.&#.& @#0J10&34#A?10%L&& 1G1."P?=P1G1."&?#%5%L&& & U&V88;/#=& U&78P&O88& &1G1."%;/#=&&&
5/2D$(H$%)38/'(<$8=&%-.60+ & • � Alpha decay produces monoenergetic, low energy nuclear recoils. � For example, consider 210 Po-> 206 Pb: � E R = 101 keV � E � = 5.407 MeV � � � 206 Pb � • � The recoiling nucleus will nucleate a bubble in any chamber that is sensitive to the lower energy (~10 keV) recoils expected from WIMP scattering. � • � The 238 U and 232 Th decay series include many alpha emitters, including radon ( 222 Rn) and its daughters. � • � Radon is highly soluble in bubble chamber liquids. �
W#"#&(0'A&788X&Y$.& • � W#"#&(0'A&D01%%$01&%3#.&#"&"2'&"1AD10#"$01%L& • � Z5"&"'&#@D4#%&[&<HI,%& F.10J=&6401%4'@/&& H.&\1]& Y#/'.&& ?#3KJ0'$./ & Solid lines: Expected WIMP response for � � SD(p) =3 pb
)*+,,S&Z50%"&Y1%$@"%& <1&4#G1&3'AD1"5"5G1&%1.%5"5G5"=&('0&%D5.P/1D1./1."&<HI,PD0'"'.&%3#""105.JT& • � /1%D5"1&45J4&0#/'.&?#3KJ0'$./&5.&788^P788:&0$.%&'(&7PKJ&34#A?10L& !D5.P/1D1./1." & !D5.P5./1D1./1." & !"#$%"$&'()*+'*((,*(-'./0012 L&
7PKJ&)4#A?10&788_&W#"# & *@/&)4#A?10&W1%5J.& ` � (I$0-6(&%'$)/>(%'0.8'0(1>(%'2/$8'*'6)(-9( Viton � J3)-6((KL%36&+(,3)D(*')$/(+'$/+"( rubber � ` � (M'(1'&36()-(+''(1$8=&%-.60+(9%-*(8-+*38L O-ring � %$>(8-36830'6)(6'.)%-6+ & metal � radon � NV&/1J011%&)& bellows � water � J#AA#% & volume � #@D4#%&[& .1$"0'.%& [&<HI,%&CBE & quartz � CF 3 I � vessel � sensitive � Volume � 20-100 � Radon � decays/day � )'%A53&0#=& 3'5.35/1." &
N.$%)F(H.%3)> & ` � &)$001."&0#"1&'(&2#@@&1G1."%&C8L_;3A 7 P/#=E&3#.&?1&1RD@#5.1/&?=&N7&DDA&3'."#A5.#"5'.& '(&a$#0"Q&?=&+0#.5$A&[&/#$J4"10%&C.#"$0#@&bFP7ON&a$#0"QEL& ` � &645%&3#$%1%&#&UV8c&/1#/&"5A1&/$1&"'&3'AD01%%5'.&D105'/%&?1"211.&1G1."%&5.&7PKJ& 34#A?10d&2'$@/&?1&D0'45?5"5G1&('0&@#0J10&/1"13"'0%L& ` � &*$0&.1210&%A#@@&/1"13"'0%&#./&"41&X8PKJ&34#A?10&$%1&@'210P#3"5G5"=&%=."41"53&a$#0"QL& Material � Uranium [ppt] � 7PKJ&34#A?10T& 42,000 (0.8 /cm 2 -day) � Natural (GE-214) � ,$?@5%41/&01%$@"% Heraeus Suprasil synthetic � 21* � 78PKJ&34#A?10& (20 kg chamber) � 61%"%&$./102#=& Covalent T-6040 synthetic � < 100 � X8PKJ&34#A?10&5..10& G1%%1@&D0'3$01/L& (60 kg chamber) � -G#5@#?@1&5.&%5Q1%&$D&"'& Corning synthetic � 260* � ^88&KJ& Dynasil synthetic � 226* � * EXO compilation of Kvartzsteklo synthetic � 17* � quartz activity St. Gobain Spectrosil � < 4.6* � measurements [Arxiv 0709.4524.v1]
X8P\J&)4#A?10&)'.%"0$3"5'.& Z5.#@&1@13"0'D'@5%41/&5..10& G1%%1@&"'D& ,0'"'"=D1&H..10&]1%%1@& *$"10&,01%%$01&]1%%1@& Z5.#@&($%1/&%5@53#&G1%%1@&&
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M1R"&!"1D%& 78&KJ& 34#A?10& • � YfW&3'."5.$5.J&25"4&%A#@@&34#A?10%& – � a$#0"Q&D$05"=T&3'."0'@&%341A1%T&D4'"'J0#D4=T& #3'$%"53&%1.%'0&"134.'@'J=L& • � X8PKJ&34#A?10&5%&01#/=&"'&"$0.&'.L& – � ,01@5A5.#0=&1.J5.1105.J&0$.&#?'G1& J0'$./& – � Z50%"&D4=%53%&0$.&5.&%4#@@'2&Z10A5@#?& "$..1@& • � b'#@&5%&"'&?05.J&@1G1@&'(&0#/5'D$05"=&$D& "'&%'@#0&.1$"05.'&%"#./#0/%L& – � >'01R5.'& ~ &8L8O&#@D4#&1G1."%;KJP/#=& • � !1.%5"5G5"=&25@@&?1&&@5A5"1/&?=&.1$"0'.& ?#3KJ0'$./&#"&@1G1@&'(&8LO;KJP/#=&25"4& 2#"10&)101.K'G&A$'.&G1"'d&&7PV&'0/10& '(&A#J.5"$/1&5.301#%1&'G10&D$?@5%41/& %1.%5"5G5"=L& – � !"$/=5.J&$./10J0'$./&%5"1&5%%$1%g& !'$/#.&'0&!.'@#?L&
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