HES-HKS & KaoS meeting
Toshi Gogami
Contents
Energy loss simulation by HES,HKS and POSI
1. POSI for beam energy loss– Harver foil is already implemented in this code.– Implemented Raster newly.
2. HKS, HES for K+ and e’ energy loss– Transplant harver foil into these code from POSI.
• バグだし(HES、 HKS)変数の定義の間違え・・・昔からあるようだが。。(POSI)Rasterを入れる際のバグ… .etc
• New ver. GEANT では動かない問題 (HES,HKS)コンストラクターの引数の数、順番G4ThreeVector…..etc日本で解決済
Beam Energy Loss study
Used Geant4 simulation code “Modified POSI”Water ( + harver ) target in the display
Virtual Detector
TargetGeneration point(Uniform in z-direction)
SIMULATION
Momentum distribution
Incident beam
After target
H2O (500mg/cm2)+ Harver
Determination of the value of energy loss
This edge is the peak value which is derived by the fitting results
EDGE
31 keV
Boron , 56.1 mg/cm2
Water target with Harver foils
EDGE
371 keV
Harver foil effect Water
water
Foil
Simulation ResultsTarget < 5 MeV < 1 MeV < 0.5 MeV Kawama Toshi7Li184 mg/cm2
160137165
141121157
133115149
133133151
10389118
9Be188.1 mg/cm2
161141170
140122159
132115150
177 (Chen)177138
10590124
10B56.1 mg/cm2
554855
474052
453950
454552
312737
12C112.5 mg/cm2
11197111
9482105
8977100
9089103
665877
52Cr154 mg/cm2
151140127
113101117
10493112
939499
797188
Water + Harver500 mg/cm2
552555547
429434468
251257254
439*1.6442*1.6487*1.6
371373408
Polyethylene450.8 mg/cm2
500436530
406362454
240241244
436*0.8440*0.8502*0.8
349296416
Unit : keV
Energy Loss scan
• CH2 energy loss ± 20%– How does it effect on the Missing mass– To be reported next week
Λ cross section from water target
Λ cross section from water target
Sensitive Nonlinear Iterative Peak (SNIP) clipping algorithm
References:C. G Ryan et al.: SNIP, a statistics-sensitive background treatment for the quantitative analysis of PIXE spectra in geoscience applications. NIM, B34 (1988), 396-402.M. Morháč, J. Kliman, V. Matoušek, M. Veselský, I. Turzo: Background elimination methods for multidimensional gamma-ray spectra. NIM, A401 (1997) 113-132.D. D. Burgess, R. J. Tervo: Background estimation for gamma-ray spectroscopy. NIM 214 (1983), 431-434.
New Cut efficiency estimation(WC for demonstration)
Real distributionProbability density function (PDF)Imitation dataCut efficiency
K+
p
Nor
mal
ized
N.P
.E
Mass square [GeV/c2]2
Mass square
Mass square [GeV/c2]2
Nor
mal
ized
N.P
.E Water target
Normalized N.P.E
Normalized N.P.E
Mas
s squ
are
[GeV
/c2 ]2 Water target
Seems working well.
Summary and To do• Summary– Energy loss are estimated
• Smaller than those of Kawama-san• Seeing effect on missing mass when the energy loss is changed ±
20%.– Now cut efficiency estimation method ( KID )
• On progress
• To do– Λ cross section from H2O before leaving Germany.– Matrix tuning
• Better cut• Water • TSpectrum Background subtraction• Definition of chi-square
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