Beam Dump System. Guangrui Li. CEPC-SppC Study Group Meeting, 08 Apr. 2016, Institute of High Energy Physics, Beijing

Transcription

1 Beam Dum System Guangrui Li CEPC-SC Study Grou Meeting, 08 Ar. 2016, Institute of High Energy Physics, Beijing

2 Outline Brief review of injec-on and extrac-on system LHC beam dum system design Energy deosi-on Thermal analysis Off-normal oera-ng Ugrade to SC/FCC

3 Brief review of LHC injection system LHC orbit H 12 mrad LHC orbit Kicker (V) Q5 Setum (H) 0.39 mrad V 1.24 mrad

4 Brief review of LHC extraction system

5 Brief review of LHC extraction system Fast-Pulsed Dilu-on Magnets(MKB)

6 Brief review of LHC extraction system Beam Dum Absorber Block TDE Polycrystalline Grahite(PG) Ø b, beam at 7 TeV during 20 years 1.73 g/cm 3 Ø 80% energy(428mj) is absorbed every dum Ø Otimized design to avoid thermal and mechanical degradation Ø ~900 tons radiation shielding blocks Ø Filling the dum with an inert gas ermanently to avoid grahite from fire

7 Dum system design Related areas Ø Particle shower simulation Ø Ø Ø Heat transfer analyses Structural deformation and stress analyses Other cascade simulations The design should define Ø Some critical arameters Ø Ø Ø Ø Ø Otimal choice of materials Size and alignment of various comonents Tye and erformance of cooling systems Rules of beam abort reetition Safety recautions

8 LHC beam dum system design Energy deosition Ø 80%(428 MJ) energy is absorbed for 30 cm radius and 700 cm deth

9 LHC beam dum system design Energy deosition distribution(one roton)

10 LHC beam dum system design Energy deosition with swee Ø Direct MC simulation is too time consuming, the energy deosition is achieved by suerimosing the distribution of single roton Ø Temerature rise is estimated by resolving the equation

11 LHC beam dum system design Thermal analysis Ø Time-deendent nonlinear thermal analysis Ø Nonlinear is due to larger temerature range Ø Long transient state of heat transfer, beam imact(<0.1ms), cooling rocess(a few hours)

12 LHC beam dum system design Finite element model Al frame Radiation shielding Grahite core Water-cooled Al base late

13 LHC beam dum system design Temerature rise in grahite and Al frame Ø Maximum temerature rise below 1200 in grahite Ø Maximum temerature rise below 150 in Al frame

14 LHC beam dum system design Temerature rise in grahite and Al frame Ø Several seconds are required to cool the hottest region below 1000 (No cooling system is effective in such a short time) Ø More than 3h are necessary to bring temerature below 50

15 LHC beam dum system design Reetitive beam aborts Ø At nominal intensity, beam can seemingly be dumed without cooling for eriods longer than 3 h Ø No ractical cooling system can reare the dum 7 TeV beam at ultimate or nominal intensity as frequently as once er hour Ø After 6 cycles, the thermal steady state is almost reached in grahite, the situation is different in Al frame

16 LHC beam dum system design Reetitive beam aborts Ø In order not to exceed 150 in Al frame, the eriod should be longer than 2.5 h at nominal intensity and longer than 12.5 h at ultimate intensity Ø Without cooling, the eriod should multilied by at least a factor 2

17 LHC beam dum system design Off-normal oerating condition Ø Abnormal dilution(most dangerous!), may cause core erforation and structural break-down Ø Loss of vacuum, oxidation begins on grahite at 450, on flexible grahite at 550

18 LHC beam dum system design Ugrade to SC/FCC Ø Peak energy density increases by a factor ~30 Ø Entire dum needs to be longer to sufficiently absorb showers

19 LHC beam dum system design Ugrade to SC/FCC Ø Linear swee to estimate eak energy density Ø Distance of 2 mm between bunches should kee eak temerature below 2000 Ø For bunches, the swee length would be 21.2 m

20 Summary Ø The erformance of dum system is imortant for the running mode of whole system Ø Dum design involves many different subjects, collaboration is necessary Ø Ugrading LHC s dum system for SC/FCC seems feasible, but need more careful and elaborated study

21 Thanks!