Table 1 Preliminary key parameters of FCC-ee IR as evolved from the CDR paramters, for scenarios with 4 IPs [5]

Circumference (km)

90.659

Crossing angle at IP (mrad)

30

\({\ell ^{*}}\) (m)

2.2

SR power/beam (MW)

50

Beam energy (GeV)

45.6

80

120

182.5

Luminosity/IP (10³⁴ cm⁻²s⁻¹)

140

19.4

7.26

1.25

\(\beta _{x}^{*}\) (m)

0.11

0.2

0.3

1

\(\beta _{y}^{*}\) (mm)

0.7

1.0

1.0

1.6

\(\epsilon _{x} \) (nm)

0.71

2.16

0.64

1.469

\(\epsilon _{y} \) (pm)

1.40

4.32

1.29

2.98

Beam current (mA)

1270

135

26.7

5.0

Bunch number/beam (#)

15880

880

248

40

Bunch length by SR/BS (mm)

5.60/12.7

3.55/8.01

3.34/6.00

1.94/2.74

En. Spread \(\sigma _{\delta}\) (SR) [%]

0.039

0.069

0.103

0.157

En. Spread \(\sigma _{\delta}\) (BS) [%]

0.089

0.154

0.185

0.221