In the ESR picture below, the decay of beam is very fast initially for few minutes and then the decay is constant. But why does it decay for first few minutes ?

beam: 205Tl81+ (no scraping , Al ~1g/cm2)
energy: 400 MeV/u
storage time: 0 hr
S2: 0/35 mm
s6: -20/7

purpose: data with TARGET ON

Detector position (CsISiPHOS):  out of the ring
Detector position (MWPC):  -60 mm

run start at 22:11,  run0308.lmd 
file running: 0339.lmd

_______________________________________________________________________________

time when accumulation starts: 17:56
time when storage starts: 18:28
time when storage ends: 18:28
I_cooler during storage time: -1 mA

I_cooler =  177 mA


I_SIS: 1.75e9      
ESR particles after stacking: 1.4e6 (offset 3.5e5)
Number of stackings: ~65 (was set to 80 but stacking broke down after ~65)  
Target ON density: 4.05e12 
Target on time for measurement: 10 mins (by event mode)      
time spend at manipulation 13 : 2 mins
(i.e. time for which electron cooler is on after gas jet)  



NTCAp file:
SC_2020-04-03_22-12-50
\IQ_2020-04-03_22-13-48
IQ rate: 8 MS/s
(saved in drive : O)

copy and repeat the above (below the line) for every storage time measurement

beam: 205Tl81+ (no scraping , Al ~1g/cm2)
energy: 400 MeV/u
storage time: 0.5 hr
S2: 0/35 mm
s6: -20/7

purpose: data with TARGET ON

Detector position (CsISiPHOS):  out of the ring
Detector position (MWPC):  -60 mm

run start at 22:11,  run0308.lmd 
file running: 0324.lmd

_______________________________________________________________________________

time when accumulation starts: 15:35
time when storage starts: 16:05
time when storage ends: 16:35
I_cooler during storage time: -1 mA

I_cooler =  177 mA


I_SIS: 1.25e9      
ESR particles after stacking: 1.8e6 (offset 3.6e5)
Number of stackings: ~80  
Target ON density: 4.08e12 
Target on time for measurement: 10 mins (by event mode)      
time spend at manipulation 13 : 3 mins
(i.e. time for which electron cooler is on after gas jet)  



NTCAp file:
SC_2020-04-03_22-12-50
\IQ_2020-04-03_22-13-48
IQ rate: 8 MS/s
(saved in drive : O)

copy and repeat the above (below the line) for every storage time measurement

beam: 205Tl81+ (no scraping , Al ~1g/cm2)
energy: 400 MeV/u
storage time: 10 hr
S2: 0/35 mm
s6: -20/7

purpose: data with TARGET ON

Detector position (CsISiPHOS):  out of the ring
Detector position (MWPC):  -60 mm

run start at 20:21,  run0540.lmd 
file running: 0558.lmd

_______________________________________________________________________________

time when accumulation starts: 08:21
time when storage starts: 09:27
time when storage ends: 19:27
I_cooler during storage time: -1 mA (20 mA)

I_cooler = 180 mA  


I_SIS: 1.8e9      
ESR particles after stacking: 3.1e6 (offset 4e5)
Number of stackings:  200 
Target ON density: 4.15e12 
Target on time for measurement: 10 mins (by event mode)      
time spend at manipulation 13 : 10 mins
(i.e. time for which electron cooler is on after gas jet) 



I_ESR (10:34): 2.78e6
I_ESR (11:07): 2.53e6
I_ESR (12:07): 2.2e6
I_ESR (13:43): 1.7e6
I_ESR (14:00): 1.6E6
I_ESR (14:43): 1.5e6
I_ESR (15:24): 1.43e6
I_ESR (16:19): 1.3e6
I_ESR (17:03): I.IIIeVI
I_ESR (18:20): 1.15e6 (frozen screen) 
I_ESR (18:50): 9.5e5
I_ESR (19:27): 8.5e5




NTCAp file:
SC_2020-04-06_00-59-46
\IQ_2020-04-06_00-59-38
IQ rate: 8 MS/s
(saved in drive : O)

copy and repeat the above (below the line) for every storage time measurement/

Schottky pictures from the 10 hour measurement gas target, including the time before gas target.

203Tl80+ impurity is removed by moving scrapper inside ESR.
Only 220Hg79+ is left now

Below in the schottky spectrum, on left is 203Tl80+ contamination, in middel is 200Hg79+ contamination and on right most is 205Tl81+.
These contaminations cannot be seen on CsISiPHOS but can only be seen on schottky.
The goal now is to get rid of these contaminations by putting slits.

Because the electron cooler was not switched on during beam accumulation in the previous measurement, we repeat this measurement again.
(In the picture below, it can be seen that the beam cooled. On right most is the Tl beam and rest are the contaminants.)

beam: 205Tl81+ (no scraping)
energy: 400 MeV/u
storage time: 2 hrs

purpose: data with TARGET ON

Detector position (CsISiPHOS):  out of the ring
Detector position (MWPC):       mm

run start at 08:46 , first file: run290.lmd
file running:   run290.lmd


time when accumulation starts: 09:06
time when storage starts:  09:16
time when storage ends:  10:59
I_cooler during storage time: 10 mA

I_cooler =  __ mA


I_SIS: 1.7e9      
ESR particles after stacking: 1e6
Number of stacking: 20
Target ON density:   3.9e12 atoms/cm2
Target on time:  11:00
Target off time: 11:10
Target on time for measurement: 10 
mins (by local mode)       


NTCAp file:
SC_2020-04-02_07-10-40
\IQ_2020-04-02_07-11-48
IQ rate: 8 MS/s
(saved in drive : p)

copy and repeat the above (below the 
line) for every storage time 
measurement

The beam in ESR was lost suddenly at ~22:20 due to a power supply failure of the quadrupoles.

Update (~20:40): Failure was resolved and new stacking started.

Thanks to Sergey and Markus, stacking of primary H-like 206Pb81+ beam in ESR is achieved.

The stacking of the primary beam was established. There is continuous cooling on the injection orbit by stochastic cooling and by electron cooling on the stack orbit. (Time controlled operation of stochastic cooling could not be achieved due to controls issues). After stchastic cooling on the injection orbit the rf system decelerates the beam by 1.5 % in momentum and at the lower momentum electron cooling keeps the beam. The DC trafo shows accumulation of 10 injections of primary low intensity Pb81+ beam. Losses during the accumulation seems to be small.

The limit of the leakage current for all Si pads was increased from 1500 nA to 5000nA and 
leakage current was recorded for different Bias Voltages (32V, 35V, 40V, 45V, 50V, 55V 
and 60V).
Since, I_leakage remains < 3 uA for 60 V, it is decided to increase the Bias Voltage for 
all the Si-pads from 32 V to 60 V.
For DSSD and CsI, bias voltages remains same (-50V and -160V respectively).

Since last night, the signals from the p-side of all the Si pads were seen as negative on picoscope.
The signals from DSSSD, all n-sides of Si pads and CsI were positive which all are in MSCF-5.
Thus, I and RuiJiu, changed the polarity jumpers of MSCF 1,2,3 and 4(all the four jumpers inside the mentioned MSCF) and now hope to see positive signals from the p-side of all the Si pads.

Cross-section for capture and ionisation of 206Pb81+ with H2 gas jet target are calculated using GLOBAL code.
The ionisation (on CsISiPHOS) and capture (on MWPC) trigger rates are calculated for 206Pb81+ beam with 10^6 particles revolving in ESR ~2 MHz frequency with H2 gas jet target density ~ 10^14 particles/cm3.

By changing the tune to Qx=2.33, Qy=2.36 the momentum acceptance was significantly improved. A variation of the cooler voltage of 10300 V was possible without beam loss. That corresponds to a momentum acceptance of 2.7 %. That should provide good conditions for longitudinal stacking.

Thanks to the ESR team !