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THE ESS LINAC HS_2011_11_23 Mohammad Eshraqi 8 December 2011 2
ESS • Power: 5 MW • Energy: 2.5 GeV • Current: 50 mA • Repetition rate: 14 Hz • Duty cycle: 4% • Ions: p 3 M. Eshraqi | 8-December-2011 | SLHiPP -CERN
ESS LINAC HS_2011_11_23 352.21 MHz 704.42 MHz 2.1 m 5 m 1.0 m 19 m 75 m 117 m 200 m 100 m Target Low β High β Source LEBT RFQ MEBT DTL Spokes HEBT & Upgrade 75 keV 3 MeV 50 MeV 191 MeV 653 MeV 2500 MeV β g Energy (MeV) No. of Modules No. of Cavities Temp (K) Cryo Length (m) Source 0.075 1 0 – ~300 – LEBT 0.075 – 0 – ~300 – 3 1 1 – ~300 – RFQ 3 – 2 – ~300 – MEBT 50 3 3 – ~300 – DTL Spoke 191 18 2 × 18 0.46 β opt ~2 3.67 Low β 653 16 4 × 16 0.70 ~2 6.80 High β 2500 14 8 × 14 0.92 ~2 13.81 2500 HEBT – 0 – ~300 – M. Eshraqi | 8-December-2011 | SLHiPP - CERN 4
CRYOMODULE ������������� ������ ����������� ������ ��� ��� ��� ���������� ��� ��� ��� ��� ��� ������������ ������� �������� ���������� ��� ��� ��� ������������� ��� ��� ��� ��� ��� ��� ��� L period = L cryo + 500 mm ��������� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� For exact lengths visit: http://esss.se/linac/Parameters/pdf/Cryomodules%20Spoke.pdf http://esss.se/linac/Parameters/pdf/Cryomodules%20Low%20beta.pdf http://esss.se/linac/Parameters/pdf/Cryomodules%20High%20beta.pdf M. Eshraqi | 8-December-2011 | SLHiPP - CERN 5
CRYOMODULE ? ������������� ������ ����������� ������ ��� ��� ��� ���������� ��� ��� ��� ��� ��� ������������ ������� �������� ���������� ��� ��� ��� ������������� ��� ��� ��� ��� ��� ��� ��� L period = L cryo + 500 mm ��������� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� Warm quads? Could save ~30 m in length M. Eshraqi | 8-December-2011 | SLHiPP - CERN 6
PHASE ADVANCE M. Eshraqi | 8-December-2011 | SLHiPP - CERN 7
RESONANCES M. Eshraqi | 8-December-2011 | SLHiPP - CERN 8
ENVELOPES M. Eshraqi | 8-December-2011 | SLHiPP - CERN 9
DENSITY M. Eshraqi | 8-December-2011 | SLHiPP - CERN 10
EMITTANCE M. Eshraqi | 8-December-2011 | SLHiPP - CERN 11
EMITTANCE M. Eshraqi | 8-December-2011 | SLHiPP - CERN 12
AVE. PHASE ADVANCE M. Eshraqi | 8-December-2011 | SLHiPP - CERN 13
DTL II M. Eshraqi | 8-December-2011 | SLHiPP - CERN 14
A REMEDY? 26 90 DTL W out DTL k 0l out 4 24 Spokes W in 85 Spokes k 0l in DTL Spokes-6 22 80 20 5 W out (MeV) 75 18 k 0l ( ° /m) DTL-5 70 16 Spokes-5 5 1 3 7 14 65 9 Spokes-4 12 60 DTL-4 11 10 Spokes Spokes-3 55 8 Spokes-2 50 6 0 5 10 15 20 25 30 35 45 55 65 75 85 95 105 115 125 135 145 155 L (m) W(MeV) Courtesy of James Stovall Reducing the number of spoke cavities/cryomodule from 3 to 2 increased the k ol to ~18 deg/m. M. Eshraqi | 8-December-2011 | SLHiPP - CERN 15
QUAD ERROR FODO Δ x = Δ y = 0.1 mm, Δ G= 0.5% Δε x = 25±12 Δε y = 20±10 Δε z = 34±18 M. Eshraqi | 8-December-2011 | SLHiPP - CERN 16
QUAD ERROR FODO M. Eshraqi | 8-December-2011 | SLHiPP - CERN 17
CAVITY MISALIGNMENT Δ x = Δ y = 0.5 mm Δε x = 0.42±0.26 Δε y = 0.16±0.18 Δε z = 0.28±0.27 M. Eshraqi | 8-December-2011 | SLHiPP - CERN 18
CAVITY MISALIGNMENT M. Eshraqi | 8-December-2011 | SLHiPP - CERN 19
QUAD ERROR FFDD Δ x = Δ y = 0.1 mm, Δ G= 0.5% Δε x = 22±11 Δε y = 20±9 Δε z = 34±18 M. Eshraqi | 8-December-2011 | SLHiPP - CERN 20
QUAD ERROR FFDD FFDD FFDD M. Eshraqi | 8-December-2011 | SLHiPP - CERN 21
BRANCHING 352.21 MHz 704.42 MHz 2.1 m 5 m 1.0 m 19 m 75 m 117 m 200 m 100 m Target Low β High β Source LEBT RFQ MEBT DTL Spokes HEBT & Upgrade 75 keV 3 MeV 50 MeV 191 MeV 653 MeV 2500 MeV A 2.4 m, 1 T dipole is enough to divert the beam by 32 deg at 650 MeV, plus 2.7 m or , 2.16 m for the quadrupoles. Leaving one period respects the periodicity and provides space to extract the beam using NC dipoles. M. Eshraqi | 8-December-2011 | SLHiPP - CERN 22
SUMMARY AND FURTHER STUDIES The discontinuity in the average phase advance causes emittance increase in transition between RFQ-MEBT, MEBT-DTL, and DTL-Spoke. The current baseline uses a FoDo lattice in the DTL, however, an FFDD lattice would cause less losses in the spokes in cases of errors. Alignment precision of 0.1 mm and 0.5% gradient error results in losses within the limit in the FFDD DTL. Quad error in the SC linac is left to be studied, although the same error as in DTL caused no extra losses in SC linac. M. Eshraqi | 8-December-2011 | SLHiPP - CERN 23
THANK YOU! M. Eshraqi | 8-December-2011 | SLHiPP - CERN 24
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POWER PER CAVITY #!!!" +!!" *!!" )!!" !"#$%&'$%&()*+,-&./01& (!!" '!!" &!!" %!!" $!!" ,"-./0"123.45" ,"-./0"637"849:" #!!" ,"-;/0"<=>?"849:" !" !" '!" #!!" #'!" $!!" $'!" %!!" %'!" &!!" !"2+3"4&.51& M. Eshraqi | 8-December-2011 | SLHiPP - CERN 26
PHASES M. Eshraqi | 8-December-2011 | SLHiPP - CERN 27
INTEGRATED GRADIENT M. Eshraqi | 8-December-2011 | SLHiPP - CERN 28
FIELD AND TTF IN SPOKE "#$% !",!# !"+!# "$$% !"*!# !")!# #$% !"(!# +,-.%/0''1% -./0# $% 23445-%/("'1% 12334/# $% $&'% $&(% $&)% $&*% "% "&'% 267%/0$81% !"'!# 156# !"&!# !#$% !"%!# !"$$% !"$!# !"!!# !"#$% !"&$# !"&)# !"'$# !"')# !"($# !"()# !")$# M. Eshraqi | 8-December-2011 | SLHiPP - CERN 29
DTL The DTL is designed by Michele Comunian • The DTL is designed, for the moment, as one RF tank and there are 2 different focusing schemes used, FFDD and FoDo. • Each of these designs have two settings for the gradients, one “Constant Gradient” and one “equipartitioned”. M. Eshraqi | 8-December-2011 | SLHiPP - CERN 30
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