j-parc での yn 相互作用の研究 東北大学理学研究科 三輪浩司. contents physics...
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J-PARCでの YN相互作用の研究
東北大学理学研究科三輪浩司
Contents Physics background
YN interaction Scattering experiment , spectroscopy
Past experiments of YN scattering What did we learn?. What should we improve?
Experiment at J-PARC LH2, Fast IIT, Scifi-MPPC
R&D of Scifi-MPPC Performance for MIP, proton
e+ beam test @ LNS proton beam test @ CYRIC
Outlook Trigger, Multi-channel readout
Nuclear force
r
egV
rmc
What is the origin?
Color magnetic interaction
ij
jijiji
s ssFFmm
AHH ))((0
meson exchange picture
NN interaction
interaction
Isospin 3/2Spin 1
Quark Pauli effectStrong repulsive force
More exchange mesons• K• K*,
To SU(3) flavor symmetry
Baryon-Baryon interaction
NN interaction special aspect of BB i
nteraction BB interaction
Effect of new quark Different aspect of u,
d quarks N
exchange is forbidden.
N (S,T)=(1,3/2) quark Pauli effect
S=0 NN(T=1) S=-1 N(T=3/2) N-N(T=1/2) S=-2 (T=2) N--(T=1) N--(T=0)S=-3 (T=3/2) - (T=1/2)S=-4 (T=1)
S=0 NN(T=0)S=-1 N-N(T=1/2)S=-2 N-(T=1)S=-3 (T=3/2)
S=-1 N(T=3/2)S=-2 N--(T=1)S=-3 - (T=1/2)S=-4 (T=0) S=-1 N-N(T=1/2) S=-2 N-(T=1) N--(T=0)S=-3 - (T=1/2)
S=-1 N-N(T=1/2) S=-2 N-(T=1) N(T=0)S=-3 - (T=1/2)
S=-2 N--(T=0)
Experimental investigation of YN interaction
2body interaction pp, np scattering deuteron
Tensor force
Spin dependent force Structure of Nuclei
Large LS force Polarized pp, np scatter
ing
2body interaction Bubble chamber Poor data
SU(3) framework
Spin dependent force Structure of Hypernulei
1950
NN interaction
YN interaction
npnp pppp pp p0p
p+p pp p0n pn
At J-PARC!70
90×
YN scattering observables
Precise measurement Model selection
Meson exchange model Quark model
RGM-F
NSC
HC-D
HC-F p scattering
N(N)=N(beam)/10000 More Hyperon beam
More fast imaging
YN scattering experiment at KEK
Important parameter Production of
1cm Scifi (CH) (from free proton) 1M/spill beam KURAMA spectrometer acceptance
(, ) 1.8mb 9 / spill (, ) 0.5mb 2 / spill
Scattering of
Mean flight legth ~ 1.3cm (p) ~ 10mb (assumption) 1600 1 p scattering
Production target 2cm CH2 + 2cm CH
Free proton 54
Quasi free 118
Important parameter2
(, )
(, )
1M/spill 10M/spill
5M/spill 50M/spill 500M/spill 5000M/spill
172/spill 1720/spill 17200/spill 172000/spill
p scat 0.1/spill 1/spill 10/spill 100/spill
We need Fast Imaging deviceWe need high quality trigger
@ 1M K
R&D works for fast imaging Ieiri
High-Speed Image Delay Tube Image duration
Electron drift
J.K. Ahn LH2 target (No Imaging)
Detect all state particle with spectrometer
Miwa Scifi-MPPC readout
Fast imaging + spectrometer
Read out system of SCIFI using MPPC’s Multi-Pixel Photon Counter (MPPC)
New Si photo-diode consisted of multipixel of Avalanche Photo Diode (APD) operating in Geiger Mode
100 ~ 1600 pixels of APD in MPPC Output signal is the sum of each pixel
Characteristics Fast time response ( < 10ns)
It can operate in the high beam intensity
Large gain (105106) Possible to detect 1 photon
Operation at the magnetic field IIT can not work at the magnetic field
Can we use this detector for hyperon scattering experiment using a high intensity beam ?
1mm
1mm
At J-PARC 1st target is p scattering production via (, ) reaction using a 1.1GeV/c K-
beam Forward spectrometer+ Cylindrical spectrometer
Concept of whole experimental setup
Zoom up
To be studied
MIP Light yield Enough
efficiency
Slow proton Dynamic range Range analysis Total energy
deposit
p
p
Performance check for MIP
LNS-Tohoku, test beam line
With 450MeV Positron beam
2007/Jan
20ch MPPC readout
Performance for MIP particle Prototype of Scifi-MPPC
system Readout of 20ch MPPC e+ beam
1mmx1mm Fiber 20 ch
Scinti. Fiber
MPPC
Connection between Fiber and MPPC
MPPC
Fiber
Photon number for MIP Identification of beam
Required hits of upstream and downstream fibers
Required these hits two photon
Check the photon number
Performance for proton
Tohoku Univ. CYRIC
80MeV proton beam
2008/June
50ch readout
Purpose of this experiment Response of Scifi-MPPC system for proton
Light yield Momentum resolution from Range Radiation hardness
Momentum range of proton in YN scattering exp.
Total 0~1.2GeV/c Stop in Scifi 0~0.4GeV/c This momentum range is accessible in CYRIC (80MeV proton)
Experimental setup Primary Proton beam
Ekin = 77.52 MeV 1~5nA
Secondary proton beam pp scattering (11~42MeV)
Primary target CH2
30, 100, 300 m
Fiber bundle 5segment x 10 layer 1mmx1mm
Vacuum chamber 10-3 Pa
77.52MeV p
pp’
Trigger counter12cm from targetEntrance 3mm
Fiber 5segment x 10layer20cm from target
Data List
(deg) trigger
’(deg) fiber
Ekin(MeV)
Range (mm)
23 67 11.3 1
27 63 14.3 2
30.5 58.5 18.8 4
35.5 55 23 5
38 52 27.4 7.3
39.5 49.5 30.0 8
45 45 34.7 11
50 40 42.1 16
CH2 targetp
p
Scifi
Trigger counter
p beam 77MeV
Angle scan
pp scattering
Momentum selected proton beam to Scifi
Signal of proton
Raw signal Proton ~250mV 1p.e. ~4mV
Dynamic range (400pixel) 1p.e. (1pixel) ~ 10ch 34MeV proton ~ 120pixel Stopping proton ~ 300pixel
Trigger selection Proton OK Stopping proton OK
MIP
reg
ion
Proton stop
Proton pass through
~250mV
(single photon ~ 4mV)
40ns
Stop layer and Total energy depositStop layer Total energy
Trigger possibility Identify of scattering proton
Total Energy deposit 1 scattering / 100 cut events ( >22MeV)
Number of particle + each energy deposit
p
Detect 3 particles with counter
2 particles Counter1 stopping particle Energy deposit
Multi-channel readout Total channel of MPPC
~5000 ch We have to serialize the readout (like SSD). Serializing chip Flash ADC
Requirement of serialize Fast time response
10MHz Trigger generation
Chip VA chip? (slow?) APV25 (50ns peaking time)
Summary We want to reveal new aspects of B.B. interaction
N, N, N We need high intensity beam
~10MHz, ~ 100MHz We have to develop high speed imaging device
Fast image delay tube MPPC readout
MPPC readout MIP
mean photon number ~6 photon Proton
Dynamic range is enough. Works well as range counter. Stopping proton can be triggered easily.
Further works Trigger possibility Multi-channel read out
Typical image (Ekin=30MeV)
YN scattering experiment at KEK Scintillation fiber and IIT-
CCD KEK-PS E289, E452 p, p, p elastic scattering Feasibility of SCIFI active
target
reaction Event number
E289
p 31
p 30
p ----
E452 p 113
ProblemIIT-CCD is slowThere are overlaps of image @ beam intensity > 300kHzDetection of all particles in the final state is difficult
Experimental investigation of YN interaction Hyperon-Nucleon Scattering
Difficult due to short lifetime of hyperon Poor data compared to NN scattering
Structure of hypernuclei High resolution magnetic spectrometer Gamma-ray spectroscopy using Ge detector
Problem Derive two body force from complex many body s
ystem N interaction, N interaction ?
npnp pppp pp p0p
p+p pp p0n pn
大きさについて
Advantage of detecting all particles in the final state
Remove the quasi free scattering SCIFI consists of CH Quasi-free scattering with proton in carbon nuclei should
be separated from the scattering with free proton.
Scattered p + from
n from
p
Scat’ : Momentum Scat’ angle
Proton: Mom, AnglePrediction
Proton: Mom, Angle
Measurement
MeasurementConsistency checkRemove quasi free
Momentumproton(GeV/c) (degree)
Free proton
Quasi free scattering
Photon number for MIP
Mean photon number ~6 photon Efficiency ( > 2 photon) ~ 95%
Mean photon number
> 1photon
> 2photon
Operation in Magnetic Field
Photon number with magnetic field Photon number Gain
e+ beam
Magnet
FiberB Field
Do NOT change due to the magnetic field
We can use this Scifi-MPPC system as an imaging detectorinside the magnetic spectrometer