commissioning electron cooler on 300 kv...
TRANSCRIPT
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.