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SUMMARY:Proposal for VEPP-4M beam energy measurement using magnetic spectr
 ometer with Compton calibration and photon detector
DTSTART;VALUE=DATE-TIME:20170228T100000Z
DTEND;VALUE=DATE-TIME:20170228T110000Z
DTSTAMP;VALUE=DATE-TIME:20260717T164725Z
UID:indico-contribution-1680@indico.inp.nsk.su
DESCRIPTION:Speakers: Viacheslav Kaminskiy (Budker Institute of Nuclear Ph
 ysics SB RAS)\nA method for circular e$^-$/e$^+$ accelerator beam energy m
 easurement is proposed. Coordinate of an electron (or positron) in a focus
 sing magnetic spectrometer built in a circular accelerator depends on its 
 energy $E$\, spectrometer parameters $A$\, $B$\, and circulating beam ener
 gy $E_0$: $X = A E_0 / E + B$. To define parameter $A$\, Compton backscatt
 ering with two wavelengths can be applied\, which produces two scattered e
 lectron energies strictly coupled with the beam energy. Parameter $B$ is d
 efined using coordinate detector for Compton backscattered photons. This d
 etector should be calibrated in the coordinate frame of the spectrometer e
 lectron detector using precisely measured beam energy or precision geometr
 y measurements. Thus\, the beam energy can be defined with expected uncert
 ainty better than $10^{-4}$.\nBuilt-in focussing magnetic spectrometer is 
 an essential part of VEPP-4M collider\, it is intended for two-photon proc
 esses study at KEDR detector. It has Compton calibration system with two l
 asers. Also photons scattered from interaction point can be registered by 
 coordinate detector. Thus\, the the technique proposed could be implemente
 d here with minimum efforts\, test of the technique is planned with the pr
 esent equipment. To measure VEPP-4M beam energy in whole energy range 1.5-
 5.0 GeV (which is essential for future precision experiments at KEDR detec
 tor in $\\Upsilon$ mesons energy range) the installation needs an extra eq
 uipment and optimisation\, they are also planned after the test.\n\nhttps:
 //indico.inp.nsk.su/event/8/contributions/1680/
LOCATION:Budker Institute of Nuclear Physics
URL:https://indico.inp.nsk.su/event/8/contributions/1680/
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