SCUs for the LCLS-II HXR FELP. Emma

July 8, 2014

Soft X-Ray (SXR) FEL for LCLS-II must cover 0.2-1.3 keV (4-GeV)Hard X-Ray (HXR) FEL for LCLS-II must cover 1-5 keV (4-GeV)SASE to 5 keV is just possible (with no margin)Self-seeding with PMU not possible beyond 4 keVRadiation dose at 1 MHz threatens PMU fields (DK/K ~ 0.01%)SCU can extend photon range toward 8 keV, and beyond, with much less sensitivity to radiation dose

L2-Linac L3-Linac

HXU

SXU

Sec. 21-30

LH BC1 BC2

BC3

D2

D10

m-wall

0.65 m0.93 m

2.50 mL1

“kicker”LTUH

LTUSLCLS-ILinac

Pe 120 kW

Pe 120 kW

Pe 250 kW Lu 145 m

PMUNbTi Nb3Sn

g = 5 mm

g = 4 mmg = 4 mm

E = 4.0 GeV (nominal)

145 m

lu = 25.6 mm, 18.4 mm, 16.8 mmK = 0.6-2.4, 1.1-3.0, 1.3-3.2B = 0.2-1.0 T, 0.6-1.8 T, 0.8-2.0 T

gex,y = 0.40 mmIpk = 1 kAsE = 500 keVb = 16 m20% Lu margin3.4-m seg’s1.0-m breaks1 und. missing1.5 keV low-lim.

magnetic gap is 2.3 mm larger than vac. gap, g

7.6 keV SASE~5 keV SASE6.8 keV

SASE

PMUNbTi Nb3Sng = 5 mm

g = 4 mmg = 4 mm

E = 4.2 GeV (stretch)

8.2 keV SASE145 m

~7 keV HXRSS limit

gex,y = 0.40 mmIpk = 1 kAsE = 500 keVb = 16 m20% Lu margin3.4-m seg’s1.0-m breaks1 und. missing1.65 keV low

magnetic gap is 2.3 mm larger than vac. gap, g

E = 4.8 GeV (20% upgrade)

10 keVSASE

PMUNbTi

Nb3Sn

g = 5 mm

g = 4 mm

g = 4 mm

145 m

8.3 keV HXRSS limit

magnetic gap is 2.3 mm larger than vac. gap, g

END

PMUNbTi Nb3Sn

g = 5 mm

g = 5 mmg = 5 mm

145 m

E = 4.0 GeV (nominal) – all 5-mm vac. gaps

lu = 25.6 mm, 19.2 mm, 17.6 mm

E = 4.2 GeV - all 5-mm vac. gaps

145 m

PMU NbTi Nb3Sng = 5 mmg = 5 mmg = 5 mm

lu = 25.6 mm, 19.2 mm, 17.6 mm

145 m

PMU NbTi

Nb3Sn

g = 5 mm

g = 5 mm

g = 5 mm

E = 4.8 GeV - all 5-mm vac. gaps

7.9 keV HXRSS limit

lu = 25.6 mm, 19.2 mm, 17.6 mm

145 m

NbTi

Nb3Sng = 4 mm

g = 4 mm

E = 3.4 GeV (drop 5 Cryo-Modules)

lu = 25.6 mm, 18.4 mm, 16.8 mm