commissioning electron cooler on 300 kv...

Commissioning electron cooleron 300 kVECOOL05

E.Behtenev, V.Bocharov, V.Bubley, M.Vedenev, R.Voskoboinikov, A.Goncharov, Yu.Evtushenko, N.Zapiatkin, M.Zakhvatkin, A.Ivanov,

V.Kokoulin, V.Kolmogorov, M.Kondaurov, S.Konstantinov, G.Krainov, V.Kozak, A.Kruchkov, E.Kuper, A.Medvedko,

L.Mironenko, V.Panasiuk,V.Parkhomchuk, V.Reva, A.Skrinsky, B.Smirnov, B.Skarbo,

B.Sukhina, K.Shrainer, BINP, Novosibirsk, RussiaYang X.D, Zhao H.W, Li J, Lu W, Mao L J, Wang Z X, Yan H B,

Zhang W, Zhang J H, IMP, Lanzhou, China

EC-300 1-high voltage line, 2-collector magnet shilding, 3-collector, 4-de accelerator tube, 5-magnet filed coils, 6-electrostatic bending, 7-toroidal coils, 8-coils cooling section, 9-high voltage vessel, 10-magnet yoke, 11- Ti pumping, 13-gun solenoid coils, 14-gun solenoid yoke, 15-acceleration tube, 16-electron gun, 17-concentrator of magnet field of electron gun, 18- high voltage terminal, 19-ion pump, 20- dipole corrector

Electron cooler EC-300300 kV at Novosibirsk

EC-300at IMP

6.05.2004after commisioning

withmaximal

voltage 250 kVcurrent 3 A 1A*150

kV24 hours run

Problems of pollution of electrostatic plate- 2 weeks training at BINP from 5 kV

to 25 kVno problems at IMP ???

0 5 10 15 20 250

5

10

15

20

25

30

35pr

essu

re T

orr/

10-1

1cu

rren

t µA

voltage (kV)

pressure Torr/10-11

29/05/2003current µ Apressure 13/05/2003 current

0 20 40 60 80 1000

50

100

150

200

250

300T, K

t, hours

Vacuum (bake)

At time of commissioning at IMP at moment of initial beam with energy 50 kVstrong outgasing with preassure >3E-9 Torr

After backing electron beam with energy 50 keV wasused for final clearing vacuum chamber. Initial vacuum 2E-9 Torr and for beam 0.25A the sameoscillations at pickup electrodes was found. After fewhours training vacuum pressure go to 5E-10 Torr andoscillations disappear for current >1 A. The thresholdelectron current change inverse proportional vacuumpressure.

3 4 5 6 70,0

0,2

0,4

0,6

0,8

1,0

1,2

p, torrI, A

t, hours

10-11

1x10-10

1x10-9

Vacuum with electron beam

Speck of dust atvacuum chambermelt by electron beam

0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,60,0

0,5

1,0

1,5

2,0

2,5ra

diat

ion

(R

em/s

ec)

J , Аe

Radiation for different electron current (260 kV)

180 200 220 240 260 2800

5

10

15

20

25

30

35

40ra

diat

ion

,R

em/(s

ecm

A)

E , keVe

.

Radiation at 1 m from collector at gap magnetsystem

Problems high voltage

0 50 100 150 200 250 3000,00

0,05

0,10

0,15

0,20 SF6 1.7 atm air 1 atm

high

vol

tage

PS

curr

ent (

mA)

cooler voltage (kV)

0 50 100 150 200 2500

0.5

1

1.5

high voltage (kV)

curr

ent (

mA

)

1.442

4 10 4−×

Gk 25,

239.6420 Gk 26,−

Corona happened at 240 kV with slow increasing to 1.5 mAafter this for 150 kV high corona current withslow decreasing at time. SF6 with water? Drying help!.For stable operation should used clearing SF6 gas system.

initial

Coronaon!Down to low

voltage

•Commissioning with electron beam both coolers was successful •Electrostatic bending means: low noise, better vacuum.•High perveanse electron beam with hollow beam will help •optimized cooling and decreased losses ion beam by recombination•Pancake design of magnet system showed reasonable accuracy•Gas isolation should calculated with more maximal voltage +30% •(for not perfect gas)!•Resistive damper at collector PS for operation with current more 1 A. •High level oscillations without this damping resistor. •Important to have commissioning with electron beam before •using at ion ring.

ConclusionElectron cooler was commissioning and operation at Novosibirsk and Lanzow with beam currentup to 3 A voltage with beam up to 275 kV, vacuumless 5E-11 Torr with electron beam 1 A.