I.V. Arkhangelskaja(a),A.I.Arkhangelskiy(a),E.N.Chasovikov(a),

A.M. Galper(a,b), M.D. Kheymits(a), A.E. Murchenko(a), Y.T. Yurkin(a)

a) National Research Nuclear University MEPhI (Moscow Engineering Physics Institute)

b) Lebedev Physical Institute, Russian Academy of Sciences

Gamma-quanta onboard identification in the

GAMMA-400 experiment using the counting and

triggers signals formation system

Three apertures provide events registration both from upper and lateral directions.

the main aperture triggers:gamma-quanta – special matrix includedTOF (S1,S2), Ech2 (S1,S2), Bsh, EeEch1(ACtop, AClat), Ebsh (ACtop, AClat)energy estimation EchN(S3,S4)

the main aperture triggers:electrons/positrons – special matrix includedTOF (S1,S2), Bsh, Ech1 (S1,S2), EeCC1, EeEch1(ACtop, AClat), Ebsh (ACtop, AClat)energy estimation EchN(S3,S4)

the main aperture triggers:nucleus – special matrix includedTOF (S1,S2), EchN (S1,S2), BshE, EpEchN(ACtop, AClat), BshE (ACtop, AClat)energy estimation EchN(S3,S4)

signals types used in triggers:amplitude analysis1) Ech1 – singly charged particle energy deposition 2) EchN – multiply charged particle energy deposition 3) Ech2 – double charged particle energy deposition4) BshE - back splash energy deposition5) Ee - electrons energy deposition6) Ep - protons energy depositionarrival time analysis7) TOF – particle direction up-down8) BshT – back splashsignals 1-2 - detectors ACtop, AClat, S1,S2,S3,S4 signal 4,8 - detectors ACtop, AClat signals 3, 7 – detectors S1,S2signals 5, 6 – detectors S3,S4 additional signals from CC1: EеСС1 - registration of e-/e+ EpСС1 - registration of p

Simplified scheme of special matrix for definition whether particle is neutral or charged for events inside of the main aperture.

The detectors registered particle energy deposition marked by colors, the black letter marked

devices sampled accordingly special matrix, the gray letter shown other detectors.

Simplified scheme of special matrix for definition whether particle is neutral or charged for events outside of the main aperture.

The detectors registered particle energy deposition marked by colors, the black letter marked

devices sampled accordingly special matrix, the gray letter shown other detectors.

Direct energy deposition in double layers ACtop for 100 GeV γ-quanta with backsplash subtraction using temporal analysis (area marked (1)

contains ~60% of events with energy deposition less than 1 keV in both ACtop layers)

Direct energy deposition in double layers ACtop for 3 GeV γ-quanta with backsplash subtraction using temporal analysis (area marked (2)

contains ~70% of events with energy deposition less than 1 keV in both ACtop layers)

Direct energy deposition in double layers ACtop for relativistic protons (grey) and electrons (black) used for thresholds definition.

Direct energy deposition in double layers ACtop for 3 GeV protons used for thresholds definition.

signals types used in triggers:amplitude analysis1) Ech1 – singly charged particle energy deposition 2) EchN – multiply charged particle energy deposition 4) BshE - back splash energy deposition5) Ee - electrons energy deposition6) Ep - protons energy depositionsignals 1-2 - detectors S2,S3,S4 signal 4 - detector S2signals 5, 6 – detectors S3,S4additional signals from CC1: EеСС1 - registration of e-/e+ EpСС1 - registration of pparticle CC1 – particle pass through one of layersadditional aperture triggers:gamma-quanta – special matrix included: particleCC1, EeCC1(2-3),Ech1 (S2,S3), BshE (S2), Eeenergy estimation EchN(S3,S4)electrons/positrons - special matrix included: particleCC1, EeCC1(1-2)Ech1 (S2) Ech1 (S3), Ebsh (S2), Eeenergy estimation EchN(S3,S4)

nucleus – special matrix included: particleCC1, EeCC1(1-2), EchN (S2), Ech1 (S3), BshE (S2),Epenergy estimation EchN(S3,S4)

signals types used in triggers:amplitude analysis

1) Ech1 – singly charged particle energy deposition

2) EchN – multiply charged particle energy deposition

4) BshE - back splash energy deposition5) Ee - electrons energy deposition6) Ep - protons energy deposition

signals 1-2 - detectors S2,S3,S4, LD signal 4 - detectos S2,S3,S4, LD

signals 5, 6 – detectors S2,S3,S4, LDadditional signals from CC2:

EеСС2 - registration of e-/e+ EpСС2 - registration of p

particle CC2_1, particle CC2_2 – particle pass through first, second and

forth perimeter layerslateral aperture triggers:

gammas – special matrix included: particleCC2, EeCC2,Ech1 (S2,S3,S4, LD),

BshE (S2,S3,S4, LD), Ee energy estimation EchN(S2,S3,S4,LD)

electrons/positrons - special matrix included: particleCC2, EeCC2, Ech1(LD), Ebsh

(S2,S3,S4,LD), Ee energy estimation nucleus – special matrix included: particleCC2,

Ee(LD),EchN(LD),Ech1(S3),BshE(S2,S3,S4,LD),Epenergy estimation EchN(S2,S3,S4,LD)

Energy band Energy resolution Angular resolution

0.1-0.25 GeV from ~30% up to ~15% from ~5о up to ~1.5о

0.25 – 1 GeV from ~15% up to ~9% from ~1.5о up to ~0.6о

1 – 10 GeV from ~9% up to ~2.7% from ~0.6о up to ~0.12о

10-102 GeV from ~2.7% up to 2% from ~0.12о up to ~0.02о

> 102 GeV 2% <0.02о

Conclusion: the main aperture characteristics

Conclusion: the additional and lateral apertures characteristics

Aperture type Energy band Energy resolution Angular resolution

Additional

1-10 MeV from 3% up to 2% ~5о

10-102 MeV 2% ~4о

0.1-1 GeV 2%from ~4о up to ~1о

(provides by strips in CC1)

> 1 GeV 2%~0.7о(provides by strips in CC1 and shower axis

registration in CC2)

Lateral

0.2-1 MeV from ~9% up to ~3%

Only for transient events ~5о

1-5 MeV ~3% Only for transient events ~10о

> 10 MeV ~2% -