First test of hybrid target Status of the experiment at KEKB for - PowerPoint PPT Presentation

First test of hybrid target Status of the experiment at KEKB for the hybrid targets Junji Urakawa instead of T.Takahashi KEK Positron Workshop Durham 28 October 2009

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300Hz generation for ILC

Hybrid Target for the ILC 1 mm 8 mm 10 GeV • KEKB LINAC – E(beam) : 8GeV – Bunch Charge: ~nC – Repetition : up to 50Hz (may limited by radiation safety ) Good place for the test (except for muti-bunch operation )

experimental site KEKB LINAC Switch yard e+ source

Set up Site Looking up from Down stream

A TEST at KEKB LINAC JFY2009 1 To Demonstrate • positron yield with the hybrid system • heat reduction by hybrid target w/ a real beam (angular divergence, alignment) and crystal (mosicity),,, JFY2010~ 2. Detail investigation toward the positron source • momentum distribution, • angular distribution of e+

Status and Preliminary results of first beam test September 21 – 23 2009 All results shown in the following slides are preliminary

Setup 8GeV e- 1mm Sweeping Magnet amorphous W Analyzing magnet W crystal 0.96T 0.75m 0.4 mm 5 ~ 20MeV 8 mm

Around the magnet Shielding lead bricks 15 φ hole in the lead shielding γ s All charged particles are dumped here when the Sweeping magnet ON

Data Acquisition Counting room Beam Area ADC e+ detector e+ PM Beam current Gate e- motor Controller Goniometers to Align Crystal

Background conditions ANA. mag ANA. mag set to 20 MeV set to 20 MeV e- Sweep Sweep mag mag Crystal W 0.4mm No Crystal No Amorphous off Aligned Amorphous W background e+ of the least yield condition Signal is well separated from background even with thin converter ADC counts

Rocking curve 0.4mm sweep e mag rot. in vertical plain ( ) 2 ( ) 2 θ − θ θ − θ positron yield (arb. unit) − − 2 2 ( ) 2 σ 2 σ θ = + + f Ae Be Const 1 2 2.27 0.06 σ = ± 1 4.86 0.2 σ = ± 2 144.4 1.1 = ± const Well fitted by two Gaussians angle of crystal w.r.t. beam (mr) Channeling + CB? Narrower component is still x 4 wider than the critical angle

Rocking curve 0.4mm sweep e mag ( ) 2 ( ) 2 θ − θ θ − θ positron yield (arb. unit) − − 2 2 ( ) 2 σ 2 σ θ = + + f Ae Be Const 1 2 σ = 2.07 ± 0.04 1 5.3 0.2 σ = ± 2 141 1 = ± const angle of crystal w.r.t. beam (mr)

data looks likes.. amorphous amorpous amorphous 8mm 8mm 0.4mm Cr not aligned Cr aligned Wa 0.4mm Cr aligned Cr off aligned number of counts /bin BG ADC counts

After BG substraction 1.2 1.9 amorphous amorpous 8mm 8mm Cr not aligned Cr aligned amorphous number of counts /bin 0.4mm Wa 0.4mm Cr aligned Cr off aligned ADC counts

sweeping magnet OFF 1.07 amorphous amorpous 8mm 8mm Cr not aligned number of counts /bin Cr aligned No Crystal Amorpous 8mm ADC counts

Momentum dist. e+ yield P [MeV/C]

Data was taken under various conditons Crystal amorphous Sweep mag Ana mag NO NO on 20MeV aligned 0.4mm on 20MeV not alinged 0.4mm on 20MeV not alinged NO on 20MeV aligned 8mm on 20MeV not alinged 8mm on 20MeV not alinged NO on 20MeV aligned NO on 20MeV off NO on 20MeV aligned 8mm off 20MeV not alinged 8mm off 20MeV aligned NO off 20MeV not alinged NO off 20MeV off 8mm off 20MeV NO NO off 20MeV on 8mm on 15MeV 〃 8mm on 10MeV 〃 8mm on 5MeV

Summray • Set up works ! – Very small backgound – DAQ seems good enough • already have – many to be analyzed – worth to compare with simulation – some quantitative results in this workshop • Hope temperature data in next run (Jan. 2010)

Background conditions ANA. mag ANA. mag set to 20 MeV set to 20 MeV e- Sweep Sweep mag mag Crystal No Crystal No Amorphous No Amorphous off Aligned background e+ of the least yield condition Signal is well separated from background even with NO converter ADC counts