CBELSA/TAPS (????) ? Crystal Ball at MAMI, TAPS and A2 (?????) - PowerPoint PPT Presentation

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CBELSA/TAPS (????) ? Crystal Ball at MAMI, TAPS and A2 (?????)

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Title: CBELSA/TAPS (????) ? Crystal Ball at MAMI, TAPS and A2 (?????)


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????? ?????????? ???????????? CBELSA/TAPS (????)
? Crystal Ball at MAMI, TAPS and A2 (?????)

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????????? ????????????
CBELSA/TAPS (????)
?? ??????????? ???????? ??????
?.?. ????????, ?.?. ??????????, ?.?. ???????, ?.?
???????, ?.?. ?????????,
?.?. ???????, ?.?. ???????.
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?????????? - ELectron Stretcher Anlage (ELSA)
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????? ????????? CB-ELSA
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Well-established nucleon resonances
revisited by double-polarization measurements.
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Linearly polarized photons were produced by
scattering of a 3.3 GeV electron beam off a
diamond crystal, whereby maximal polarization of
65 at 950 MeV and 59 at 1150 MeV for second
data set where reached. The photons then hit a
butanol (C4H10O) target with longitudinally
polarized protons, with a mean proton
polarization of about 75. The butanol target was
replaced by a hydrogen or carbon target for
background studies and for normalization.
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Transparency ratio is the ratio of production
cross sections per nucleon in different nuclei
with respect to the elementary cross section on
the nucleon. The photoproduction cross section
A(g,h)A in nuclei is not proportional to A for
different nuclei, and the deviation from A
scaling can be related to the width of the
produced particle in the nucleus.
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Crystal Ball at MAMI, TAPS and A2 (?????)
?????????
???????????? ??
??????????? ???????? ??????
?.?.????????, ?.?.???????, ?.?.
?????????
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  • Crystal Ball
  • µ 233 MeV
  • p 240 MeV
  • K 341 MeV
  • p 425 MeV
  • TAPS
  • µ 165 MeV
  • p 180 MeV
  • K 280 MeV
  • p 360 MeV

Experimental Setup
  • Crystal Ball
  • 672 NaI crystals about 16 r.l.
  • Cover 94 solid angle
  • Angular resolution s(f) is 2-3 degree and s(T)
    is (2º-3º)/cos(T)
  • Energy resolution of about ?E/E0.02(EGeV)-0.36
  • TAPS
  • 366 BaF2 and 72 PbWO crystals
  • Time resolution 160 psec
  • Overall acceptance for EC calorimeter 97
  • PID
  • Barrel of 24, 4 mm thick plastic strips
  • Good time resolution
  • Proton identification using ??/?x
  • MWPC
  • Two-layers cylindrical chamber
  • Angular resolution 2-3 degrees
  • Minimum material in particular in forward
    direction

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Tagged Photon Beam
  • Maximum electron energy 1604 MeV
  • Maximum energy of tagged photons
  • 1453 MeV with the main tagger,
  • and up to 1548 MeV with the end-point tagger
  • Energy resolution 4 MeV in the main tagged
    ladder, 1 MeV resolution in the microscope

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