!!!reac&on!and!decay!studies!with!an!! ac&ve5target!time
TRANSCRIPT
Reac&on and Decay Studies with an Ac&ve-‐Target Time Projec&on Chamber.
I. The pAT-‐TPC at TwinSol.
II. Resonant α-‐scaAering from 6He.
III. Resonant α-‐scaAering from 10Be.
IV. Fusion of 10Be + 40Ar.
V. Direct α-‐decay of the Hoyle State.
VI. Future Work: Resonant α-‐scaAering from 10C.
VII. Modifica&ons to TwinSol.
Beam line Adapter
Gate valve
Bellows
α source Mul7-‐channel plate device
Interface with the TwinSol beam line
1.5 m Dependex
4”
Stopper Collimator
Comparison with Theory*
*Y. Kanada-‐En’yo and T. Suhara (Asymmetric Molecular Dynamics)
(I): Present Work. (II) Previous Data on Posi&ve-‐Parity States.
Hoyle-‐State α-‐Decay via 12B and 12N β-‐Decay
2H(11B,12B)p 3He(10B,12N)n
12B (5+) 12N (7+)
Implant: 4ms Delay: 2ms Count: 4ms Delay: 2ms
DDE: Direct Equal Energy DDΦ: Direct Equal Phase Space DDL: Direct Linear 3α
(18) M. Freer et al., Phys. Rev. C 49, R1751 (1994). 12C(12C,12C*) @ 4.83 MeV/A ~2,000 events
(17) Ad. R. Raduta et al., Phys. LeH. B 705, 65 (2011). 12C(40Ca,12C*) @ 25 MeV/A ~1000 events
(19) J. Manfredi et al., Phys. Rev. C 85, 037603 (2012). 9Be,12C(10C,12C*) @ 10.7 MeV/A ~4000 events
(20) O.S. Kirsebom et al., Phys. Rev. LeH. 108, 202501 (2012). 11B(3He,d) 12C* @ 2.83 MeV/A ~5000 events
(21) T. K. Rana et al., Phys. Rev. C 88, 021601(R) (2013). 12C(α,α’) 12C* @ 15 MeV/A ~20,000 events
(Pres.) M. Itoh et al., Phys. Rev. LeH. 113, 102501 (2014). 12C(12C,12C*) @ 9.17 MeV/A ~21,000 events
(Useful Refs.) C. Aa. Diget, et al., Nucl. Phys. A760, 3 (2005). 12B β-‐decay to the 10 MeV state in 12C M. Freer and H.O.U. Fynbo, Progress in Par^cle and Nuclear Physics 78, 1 (2014).
a) A$proton$track.$$The$center$of$the$image$$$$$$$$$$$is$suppressed$due$to$lower$bias$on$the$$$$$$$$$$$central$rings$where$the$beam$track$is.$$$
b) A$carbon$track.$$On$this$and$the$other$images,$$$$$$$delta$rays$from$the$heavily>ionizing$beam$$can$$$$$$be$seen$extending$beyond$the$central$region.$
c)$$A$three>body$event.$ d)$A$mulA>parAcle$event?$
1H(124Sn,1H) at ANL
Hoyle Sequen&al Decay
A “Golden” Event: This event is simple because: in only one quadrant, in the middle ( no odd-‐even staggering ) and oriented ~ perpendicular to the pad plane (no change in odd-‐ even staggering).
Monte-‐Carlo Simula^on
BEAMS (all are 3-‐5 MeV/A max, except 3H at 7 MeV/A max) 3H, 6He, 8Li (Typically at 106 -‐ 107 per second). 7Be, 8B,10Be,10C,12B,17F (Typically at 105 -‐ 106 per second). 12N,18Ne (Typically at 103 -‐ 104 per second). 11C, 13N, 15,19O, 18,20F (“Easy” to make but so far unused). 14,20O,21F,19Ne,22,24Na,22Mg,25,26,28Al,26,27,31Si,29P,33,34,36,38Cl,34,35Ar (The above are “hard” to make or untested).
TwinSol Radioac&ve Beams
The energy resolu&on of the beams is typically from 0.5-‐1 MeV FWHM and the angular resolu&on ranges from 4° to 1° depending on the loca&on of the focus. The corresponding beam-‐spot sizes are typically 5-‐25 mm FWHM. Experiments are typically 1-‐2 weeks in length. Scheduling occurs two months ahead of &me, so a high-‐priority experiment can be approved and carried out within as liAle as three months. Typically, 5-‐6 experiments are approved per year. Recent work on (d,n) reac&ons in inverse kinema&cs, and experiments using the prototype ac&ve-‐target TPC (pAT-‐TPC) developed at Michigan State University, require that the detectors be placed far from the originally-‐designed focus of TwinSol, at a point where the beam spot size is up to 25 mm in diameter. As a result, we are currently inves&ga&ng the addi&on of a third solenoid or other modifica&ons to produce 5-‐mm-‐diameter beam spots at this distant focus.
TwinSol Beam Parameters and Opera&ons
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0distance from target [m]
0.00
0.05
0.10
0.15
0.20
0.25
radi
us [m
]
University of Michigan - University of Notre Dame SolenoidI1: 29.5,I2: 20.8 Amps. File: 12NTi.dat
0.0 2.0 4.0 6.0 8.0 10.0distance from target [m]
0.00
0.05
0.10
0.15
0.20
0.25
radi
us [m
]
University of Michigan - University of Notre Dame SolenoidI1: 20.5,I2: 12.5 Amps. File: 12NTi.dat
Standard Configura&on Solenoids Shined
Improving the Beam Quality
New “TwinSolers” at ND: Dan Bardayan, Tan Ahn, Maxime Brodeur