Also, the quadrupole calibrations were changed: Up to now the quadrupole iron lenths had been used for the optics, but the effective length is larger than the iron by approx. one aperture radius (30 mm) . Actually it varies with current, adding 31 mm at low current and 26 mm at 140 Amps to the iron length. Therefore all quad lengths in the lattice files have been increased by 30 mm, the optics was re-designed and the calibrations which were for integrated gradient anyway were adjusted accordingely.
A new feature coming with F6T is a local tune variation over the 5L straight: With constraints for betas and alfas at the ends of 5L, the quadrupoles QLG-04/05, QLH-04/05 and QFT-1/2 are varied to adjust both tunes within a range of +/-0.06. Parabolic fits to the matching results give for each quads five parameters to set its current for a local tune change dQx, dQy:
dI = A*dQx + B*dQy + C*dQx2 + D*dQx*dQy + E*dQy2
This plot (PS) shows the quadrupole currents as function of tune shifts (top to bottom: data, fit, difference), and the coefficients are given in the snap file. (Basically, the tuning could include QFT3 for maintaining alpha_y=0 in the radiator center, but this would allow only a small tuning range.)
This optics is in operation from January to April 2006, until the FEMTO chicane will be installed.
| Circumference [m] | 288.000 |
| Working Point Qx / Qy | 20.43 / 8.72 |
| Natural chromaticities | -67.3 / -21.0 |
| Corrected chromaticities | +5 / +5 |
| Momentum compaction factor | 6.56E-4 |
| Horizontal emittance at 2.4 GeV [nm rad] | 4.96 |
| rms relative energy spread at 2.4 GeV | 8.56E-4 |
| Energy loss per turn (no IDs) [keV] | 519 (incl. Femto U19) |
| Short straight: Beta_x / Beta_y / Disp [m] | 1.38 / 1.00 / 0.00 |
| Medium straight: Beta_x / Beta_y / Disp [m] | 2.26 / 2.50 / 0.00 |
| Long straight: Beta_x / Beta_y / Disp [m] | 4.52 / 5.00 / 0.00 |
| FEMTO radiator: Beta_x / Beta_y / Disp [m] | 8.94 / 0.51 / 0.00 (alfa_x = -2) |
| Maximum values: Beta_x / Beta_y / Disp [m] | 23.1 / 23.7 / 0.35 |
F6T snap file (ARIMA-OPTIC_prod_F6T_060123.snap) for upload to control system
F6T Lattice file composed from database as input for TRACY
F6T listing of beta functions (TRACY)