Polarization studies on CLIC (compact linear collider) beam delivery system


Thesis Type: Doctorate

Institution Of The Thesis: Bursa Uludağ University, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2018

Thesis Language: Turkish

Student: Ayşegül Uşun Simitçioğlu

Supervisor: ZERRİN KIRCA

Abstract:

The scaling factors of particles obtained at the interaction point by collision of polarized beams in linear colliders are increased by two or three times compared to colliders using non-polarized beams. Thus, the effective luminosity value obtained in collisions is increased. For this reason, it is planned that the Compact Linear Collider (CLIC) will operate with an electron beam polarization of 80% at the collision point of 3 TeV center of mass energy. Within the scope of this thesis, the polarization distribution of the electron beam travelling along the Beam Delivery System (BDS), which transports the electron-positron beams from the exit of the high energy linacs, focusing them to the sizes required to meet the CLIC luminosity goals and bringing them into collision, has been studied in detail with the BMAD program. A detailed understanding of the spin transport of electron beam in the BDS is mandatory to estimate how precise the longitudinal polarization at the interaction point. For CLIC, the envisaged precision for longitudinal polarization measurement of 80% at the collision point is expected to be 0.1%. For this reason, offsets have been applied to the CLIC electron beam and the different beamline elements aligned along the BDS. The effect of the 80% polarization value desired to be obtained at the collision point and the predicted polarization sensitivity was comprehensively obtained by means of the BMAD program.