HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

1KEK

Crab Cavity:Refrigeration System
KEKB Crab Cavity R&D Group(presented by NAKAI Hirotaka)

KEKB Review Committee/20050221

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK2Overview• Refrigeration system at “Nikko”• Crab cavity sites in KEKB tunnel• D10 test stand for crab cavities

KEKB Review Committee/20050221

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK3Nikko Large Helium Ref. System• Built in 1988
• 8 kW at 4.4 K(refrigerationmode)• 1 420 L/h(liquefactionmode)

KEKB Review Committee/20050221

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK4Nikko Large Helium Ref. System

KEKB Review Committee/20050221

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

KEK

5Specifications• Cold box: 8 kW at 4.4 K with 5 turboexpanders• Helium compressors: 10 820 + 3 825
Nm3/h• Liquid helium storage vessel: 12 000 L• Medium pressure gas storage: 100 m3 x9 vessels• Liquid nitrogen storage vessel: 50 000 L
KEKB Review Committee/20050221

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK6Features• High efficiency with supercritical turboexpander• High temperature turbo-expander to saveliquid nitrogen• Liquid nitrogen circulation system for 80
K thermal shield• Inner 80 K charcoal filter for continuous &stable operation

KEKB Review Committee/20050221

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

7Refrigeration Control System

KEK

Ref. Control RoomOperator's Console #1

Operator's Console #3

Printer
PCPC

POC-3PC

LBPPC

Printerr IJP

Data High WayController

Refrigerator

MLC-1(DHW)
Controller
MLC-3Controller

Compres., Purifier
Cavities L2-L4Controller
MLC-2

MLC-5

Crab Cavity (HER)

Cavities R2-R4Cavity L6
Crab Cavity (LER)

D11Controller

LN2 Circul. Sys.
Cavity L6

MLC-4

D10
KEKB Review Committee/20050221

Controller
MLC-6

D10 Test Stand

S.C. Accel. Cav.
Crab cavity

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

KEK

8Configuration of TRISTAN• 32 superconducting accelerating cavitiesin 16 cryostats (2 cavities in 1 cryostat)• 8 cryostats at D10 tunnel (L1-L8) and 8
at D11 tunnel (R1-R8)• Cryogens (liquid helium and liquidnitrogen) distributed from “connectionports”to cryostats by transfer lines

KEKB Review Committee/20050221

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEKKEKB Review Committee/20050221

9Transfer Line

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEKKEKB Review Committee/20050221

10Sub Transfer Lines

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK

11Current Configuration in KEKB
• 8 s.c. acc. cavities in8 cryostats• 4 cryostats at D10
and 4 at D11• 4 “connection ports”
not in use at D10 andat D11 each• Heat load of s.c. acc.
cavities ˜ 3 kW

KEKB Review Committee/20050221

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION12KEKB Tunnel (Nikko)

KEK

Nikko Straight Section
LER

HER

D10

Crab Cavity
for HERKEKB Review Committee/20050221

D11

Crab Cavity
for LERNAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK13D10 Site

• L1 position ofconnection port• Downstream ofsuperconducting
acceleratingcavities

KEKB Review Committee/20050221

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

KEK14

Layout of Crab Cavities at Nikko

D10 Straight Section

Transfer LineConnection PortLER

e-Acc. Cavities

KEKB Review Committee/20050221

e+HER

Crab Cavity

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK15

D11 Site• R7 position ofconnection port
• Upstream of
wiggler magnets

KEKB Review Committee/20050221

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK16Crab Cavity at D11 Site

KEKB Review Committee/20050221

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

KEK17

D10 Test Stand• Horizontal measurement of crab cavities• Final cold test of crab cavities andcryostats• Measurement system for s.c. acc. cavities
can be used also for crab cavity
measurement• New pit for crab cavities because ofdifferent dimensions

KEKB Review Committee/20050221

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

KEK18

D10 Test Stand SchematicSub.
TRT

SCC
MonitorSub.
TRTSCC(Acc.)

5.2 x 2CrabCavity

SCC
V-TestShutter

KEKB Review Committee/20050221

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK19Summary• Refrigeration system has enough coolingpower to operate 2 crab cavities inaddition to 8 s.c. acc. cavities• Positions of crab cavities for HER and LER
in KEKB tunnel have been determined• Testing site of crab cavity in preparation
at D10 Test StandKEKB Review Committee/20050221

NAKAI Hirotaka