development of the neutron counters for the Spin dipole resonance Kazuhiro Ishikawa

Our group experiment test experiment for the newly developed the neutron counters to measure the spin dipole resonance (SDR reaction). Simulation for the neutron counters by the Geant4 My research thesis

フローチャート n 検出 ↑ d *singlet → p-n ↑ ( d, d* singlet ) ( d, d* singlet )↑ （ 、 ) (spin dipole resonance) （ 、 ) (spin dipole resonance)↑ Super nova (cooling mechanism)

The condition of Supernova's explosion and the cooling velocity of neutron star is determined by the neutrino. The condition of Supernova's explosion and the cooling velocity of neutron star is determined by the neutrino. Mainly μ-neutrino and τ-neutrino is emitted by these reaction Mainly μ-neutrino and τ-neutrino is emitted by these reaction If we detect their neutrino, we can get the important information of Supernova. If we detect their neutrino, we can get the important information of Supernova. μ- neutrino and the τ- neutrino. SDR is used to detect the μ- neutrino and the τ- neutrino.

We observe μ-neutrino τ-through by using the spin dipole resonance (SDR) reaction. We measure γ- decay on the 16O. SDR research is not made progress so much. We must firstly establish the probe SDR excited. We substitute the deuteron for the neutrino,d(, )d* singlet.

What is the SDR reaction? Next state is J+=0-or 1- or 2-. SDR reaction change ΔS ＝１ and ΔL ＝１ and ΔT ＝１ compared initial state. Excited 16O* decay into 15N or 15O emitting γ- ray. (particle threshold 15N=10.2Mev,15O=7.3Mev)

How to select the d + → d*singlet + (d*singlet is ). state exhausts 85% of the cross section under 0.5Mev in the p-n relative energy.

To obtain the SDR cross-section (d*singlet,p-n) →Energy spectrum of relative energy E → select of

Example in the (d,pn)

The purpose of simulating a new neutron counter. resolution to be reached resolution to be reached angular resolution energy resolution angular resolution energy resolution We need almost the same performance neutron counter as the proton detector. We simulate the neutron counter by using geant4. proton detector resolution at the smart Optimization of detector dimensions to detect 1S0 state.

Definition of geometry sincilator definition bc408 density 1.032g/cm refraction rate 1.58 H/C Total volume(6 planes×5 layers ） 60cm×15cm×60cm

Included in the scintilator Interaction definition Interaction definition γ photoelectric effect, compton scattering pair production pair production multiple scattering, ionisation ｌｏｓｓ multiple scattering, ionisation ｌｏｓｓ ｂｒｅｍｓｓｔｒａｈｌｕｎｇａｎｎｉｈｉｌａｔ ｉｏｎ ｂｒｅｍｓｓｔｒａｈｌｕｎｇａｎｎｉｈｉｌａｔ ｉｏｎ p elastic scattering,inelastic scattering ionisation loss,multiple scattering ionisation loss,multiple scattering n elastic scattering, inelastic scattering neutron capture neutron capture d,α, ion elastic scattering, ionisation, multiple - scattering scattering

Result of simulation Energy loss Energy loss ↓ 135MeV neutron beam

time information time information Resolution(0.4ns) is caused by thickness of scintilator. ↓ 135MeV neutron beam

efficiency efficiency

energy calculated from TOF Resolution is 0.4MeV

The 7Li(p,n)7Be test experiment obtain the efficiency in the new neutron counter. obtain the energy resolution on the target. Beam source is.

Experiment institution ＲＡＲＦ

smart First focal plane(F1) Second focal Plane(F2) Magnetic elements QQD QQDQD First order resolving power Mean orbit radius 2.4 m 2.4 m Maximum magnetic field 1.5 T 1.5 T Typical Angular resolution 5-25 mrad 3 mrad

Experimental result 7Li(p,n)7be Resolution is 2.6MeV.

efficiency

To develop the excellent neutron counter We must multiple sincilator to increase efficiency. We must remove more the γ-ray and th e particle ….d,p etc. We must improve the beam quality.