HES-HKS & KaoS meeting Toshi Gogami 27/June/2012

Contents SPL Magnetic field change by the effect of ENGE iron SPL + ENGE GEANT4 The Helmholtz coil for bucking coil test

B y on the line (Around SPL) Line coordinatesX [cm]Y [cm]Z[cm] Minimum Maximum Saw B y on the line

Setup 1.SPL + ENGE(OFF) 2.SPL + ENGE(ON) 3.Only SPL 4.SPL(8% up) + ENGE(OFF) SPL + ENGE model SPL model ON : current on OFF : current off SPL is ON all the time

Setup 1.SPL + ENGE(OFF) 2.SPL + ENGE(ON) 3.Only SPL 4.SPL(8% up) + ENGE(OFF) SPL + ENGE model SPL model ON : current on OFF : current off SPL is ON all the time Comparison Set1 & Set2  Effect of leaked field from ENGE Set1 & Set3  Effect of ENGE iron Set1 & Set3 & Set4  How much we can recover the effect from the ENGE iron after increased current on SPL by 8%

Results

Comparison 1 (Set1 and Set2) ~ 10 G reduction in SPL The effect is larger as closer to ENGE  Small effect Closer to ENGE SPL Subtraction SPL

Comparison 2 (Set1 and Set3) Up to ~ 0.3 T difference Became 80 ~ 95% in SPL  Need to increase current for SPL to send beam to the beam dump Closer to ENGE SPL Subtraction (Set1 – Set3) / Set3 * Ratio SPL Due to meshing 80 ~ 95%

Comparison 3 (Set1, Set3 and Set4) Recovered by <~5 % in SPL  But hard to say it is good enough to send beam to the beam dump. Closer to ENGE SPL Subtraction (Set1 – Set3,4) / Set3,4 * Ratio SPL Set1 – Set4 Set1 – Set3 Set1 – Set4 Set1 – Set3

Summary of SPL+ENGE TOSCA calculation SPL field – Leakage field effect is ~10 G level in SPL. – Effect from ENGE iron SPL field is no more uniform. Very large ( up to ~0.3T difference from only SPL model)  It is hard to find optimal current of SPL for sending beam to beam dump only by seeing B y in SPL.  Need to see beam tracks in TOSCA and/or GEAMT4  What about the field clamp effect ??

SPL + ENGE GEANT4 Major update – Added Field map (SPL+ENGE combined, SPL 8% up) Virtual detectors – VD3 : before EDC – VD4 : after EDC – VD5 : after SS (1cm away from SS back face) – Modified Trigger Sieve slit Output tree Distribution : spherical uniform Number of events : 300 p e : 0.27 ± 0.1 GeV/c θ : 0.1 ± 0.05 rad φ : 1.57 ± 1.5 rad

Sieve slit pattern (1) Distribution : spherical uniform Number of events : 154k Sieve Slit : ON p e : 0.29 ± 0.1 GeV/c θ : 0.1 ± 0.05 rad φ : ± rad VD0 VD5 At VD0 SPL ENGE

Sieve slit pattern (2) Will be compared to real data !!! x’ vs. y’ at the targetx vs. x’ at the reference plane

Helmholtz coil for the bucking coil test Central magnetic field Uniformity

By and uniformity from Chiba’s master thesis

TOSCA calculation of current vs. B y

Consistent with Chiba measurement

TOSCA calculation of uniformity Consistent with Chiba measurement

Summary and To do Summary – TOSCA calculation 8% up for SPL – GEANT4 SS pattern can be seen. To do – TOSCA calculation Field clamp Beam to beam dump – GEANT 4 code of SPL + ENGE Compare to real data – Matrix tuning (Beginning of June - ) mtune – Cross sections of Λ,Σ 0 and 12 Λ B g.s. Efficiencies (Trigger, Tracking, DAQ, K + selection, Burned effects, absorption, decay….)

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TOSCA calculation of current vs. B y Consistent with Chiba measurement