HOME ESR EXPERIMENTS LABS etc
E121 E127 E132 E125 E143 laser_cooling_2021 E142 Ê128 E146 E0052 E0018 E0028
  proton-capture on 118Te, Page 14 of 29  Not logged in ELOG logo
Entry  Sat May 22 16:29:07 2021, Laszlo et al., General, coolers are back, 2021 
we can measure again.

(please write a detailed description if needed)
Entry  Wed Jul 14 14:46:05 2021, Jan, Sophia, Detectors, collimator geometry, 2021 10x
We have measured the collimator geometry. The annotations of the variables can be found in the attached sketch

90° Detector GEM1800 Distance[mm]
A2.4
B10.05
C2.1
D35.025
145° Detector GEM3000 Distance[mm]
A2.15
B10.05
C5.025
D35
35° Detetektor GLP-2000 Distance[mm]
A2.1
B10.05
C0
D13
Entry  Sat Mar 21 22:57:28 2020, Laszlo, Jan, DAQ, changing cables of the Xray 90 and 145,  
Energy signals of 90 and 145 degree detector have been checked and exchanged
They were connected to the wrong ADC channel.

Now 
E_Xray2 and t_Xray2 should belong to 90 degree
E_Xray3 and t_Xray3 belong to 145 degree
Entry  Sat May 29 13:43:39 2021, Tino, Rene, Yuri, Laszlo, Markus, Runs, change of settings, 2021 
from now on, everal beam setting will be different. We could not get the beam back to were it was before. When the scraper was pulled back by 2 cm, the loe/energy beam was visible again via cap. 
Schottky. However, no x-rays could be observerved during the target-on phase. 

Hence the interpretation:

beam position has change at least a few mm, at most 2 cm. 

Will now try to get a new overlap with target and need to adjust the detector position too.

All online - Si spectra are cleared.
Entry  Thu Apr 29 20:32:52 2021, Jan Glorius, Calibration, calibration sources, 2021 
We use the following list of sources for calibration of the Xray detectors:

- 210Pb [40.1 kBq (4%), 01.10.2020 12:00 UTC] SpecSheet

- 241Am_low [40.5 kBq (3%), 01.10.2020 12:00 UTC] SpecSheet

- 241Am_high [389 kBq (3%), 01.10.2020 12:00 UTC] SpecSheet

- 133Ba_low [40.8 kBq (3%), 01.10.2020 12:00 UTC] SpecSheet

- 133Ba_high [404 kBq (3%), 01.10.2020 12:00 UTC] SpecSheet
Entry  Thu Jan 23 16:35:47 2020, Laszlo, DAQ, cable documentation,  cable_documentation_e127.pdfcable_documentation_e127.ods
 
Entry  Fri Feb 21 09:39:40 2020, Laszlo, DAQ, cable documentation,  cable_documentation_e127.pdfcable_documentation_e127.ods
 
Entry  Wed Mar 11 14:33:44 2020, Laszlo, General, beam time manual,  E127_experimental_manual.pdfmanual.odt
Here you can find the digital version of the E127 beam time manual.
Entry  Mon Apr 6 23:00:51 2020, Laszlo, Calibration, beam energies for 124Xe and 118Te measurements,  SP54120040623030.pdf
"The e- cooler settings were the same for the 124Xe and 118Te beams" - Sergey --> speed of the ions is the same --> same MeV/u

E_beam = 10.0606MeV/u

The uncertainty on the cooloer values should be asked from Markus/Regina
Entry  Thu Jul 8 14:07:19 2021, Jan, Calibration, beam energies, 2021 CodeCogsEqn.pngCodeCogsEqn(1).png
Table of ion energies calculated from cooler parameters

nominal energyV_set V_meas I_set E_ion E_Error
6 MeV/u 3460.5 V 3364 V 50 mA 6.042 MeV/u YY keV/u
7 MeV/u 4008.3 V 3913 V 50 mA 7.049 MeV/u YY keV/u


Here is how the calculation works:

1. Find the voltage and current set values that were active during the measurement cycle.

2. These are only SetValues. For the current this is fine, but for the voltage you have to subtract an offset. This offset comes from the power supply and changes over time. It is measured regularly and the present offset you have to inquire with the ESR/cooler crew. For our beam time E127b in 2021 the offset is:

V_offset = -95 +/- ?? V (only for E127b)

The uncertainty has still to be discussed.

3. The space charge of the electron beam reduces the effective voltage seen by the electrons and thus reduces their energy. You have to calculate the space charge potential Phi_0 on the beam axis using the following formular:



using R_tube = 10cm and R_e-beam = 2,54 cm and all constants, you arrive at the ESR specific equation:



4. Now calculate effective Voltage and electron energy:

V_eff = V_set + V_offset + Phi_0

This time we measured the effective voltage for each energy, so we can actually use this values (V_meas) instead of V_set + V_offset.

E_e = e * V_eff

5. With E_e you can now calculate the ion energy by using the definition of the Lorentzfactor gamma:

gamma - 1 = E_kin/(m_0 * c^2)

In equilibrium, the left side of the equation is equal for both, electrons and ions in the cooler, leading to:

E_ion = E_el * M_ion/M_el

which gives the total energy of the ions.

NOTE:
In principle, this should be an iterative calculation, since the potential depends on beta and is then used to calulate beta or ion energy. But in practice a single iteration is precise enough, if beta was a good estimate.
Entry  Thu May 20 17:31:50 2021, Jan, Laszlo, Beatriz, General, beam & target alignement, 2021 
beam and target alignement was checked by looking at the Xray rates. Best case when:
Target bump (position) SC 9: -18.5mm

(We were aiming to keep the particles in the beam at a const. level when target switched ON)
pos   bdt
-21   800
-20   1000
-19   1300
-18   1300
-17   1000
-16   500
Entry  Thu Aug 29 10:02:22 2019, Jan, Detectors, bakeout at ESR setup,  T_set_bakeout.png
The bakeout for our detector setup has started on the evening of 27.08.2019 
We have a temperature sensor in the vacuum next to the detector.
The goal is to maximize bakeout temperature, while not going above 125°C at the detector/sensor.

Here is a daily protocol of temperatures and vacuum pressure
T_12 is the set value of the 1st and 2nd controller device
T_34 is the set value of the 3rd and 4th controller device 
T_56 is the set value of the 5th and 6th controller device
T_sens is the temperature measured by the sensor close to the detector

day   date        P_setup    T_sens  T_12   T_34   T_56   comment
1     tue 28.08.  1e-6 mbar  ~100°   ~120°  ~120°  ~120°  carefull start
2     wed 29.08.  3e-7 mbar  ~121°   ~180°  ~150°  ~150°  T_sens reached ~126° during NEG-pump conditioning
3     thu 30.08.  6e-7 mbar  ~124°   ~185   ~150°  ~175°  readjusted T_56, outgassing a bit increased
7     mon 02.09.  5e-9 mbar   ~80°                        during cooldown
9     wed 04.09.  2e-10mbar   ~30°                        after cooldown, NexTorr Pump active     
Entry  Mon Mar 23 07:56:51 2020, Laszlo, General, Yuri made magick and we operate again,  
DSSSD was moved out (HV switched off)
also the scraper was mistakenly moved.

Now we move everything back to its original position

We leave the scraper still in the "scraping position" in order to collect more data.
Soon we should switch to "without sctraper mode"
Entry  Sun Mar 22 19:49:12 2020, Michael, Laszlo, Yuri, , Yuri is still tuning FRS,  
We filled the Xray detectors.
Yuri is sill tuning FRS for primary beam.
Entry  Wed May 26 14:28:23 2021, Jan, Analysis, Xrays from 118Te & 124Xe, 2021 xray90_124Xe_118Te.png
Attached is a plot of the uncalibrated energy spectra taken with the 90 degree xray detector for 118Te (red) and 124Xe (blue).
Shown is the region covering the K-alpha and K-REC peaks.

Calculating the ratios (Te/Xe) for K_alpha and K-REC energies from theory one gets:

K_alpha (theory): 0.9236  
K-REC   (theory): 0.9308

Without energy calibration we get the following ratio (using channel numbers):

K_alpha (exp): 0.9293  
K-REC   (exp): 0.9344

Taking into account that the channel numbers are not calibrated, the agreement is still very good.

In summary we can be sure that we have 118Te stored at 7AMeV.
Entry  Fri Mar 20 16:58:02 2020, Jan, DAQ, Xray2 & Xray3 cabling,  
We found that Xray2 and Xray3 the cabling is not consistent:

90 degree detector 
> E_Xray2 for energy
> t_Xray3 for times

145 degree detector
> E_Xray3 for energy
> t_Xray2 for timing

35 degree detector
> E_Xray1
> t_Xray1

We can run like this, but should be aware of it!
Entry  Tue May 4 14:34:51 2021, Jan Glorius, Detectors, Xray weight control induces signals, 2021 
When the readout/control of the det. weight control via serial connection is active, there is a clear signal induced in the Xray detectors for each command sent.

The solution for now is, that we activate weight control NOT DURING MEASUREMENT!
Entry  Sun May 16 11:54:12 2021, Jan Glorius, Calibration, Xray performance in lab, 2021 
These are the current Xray detector performances in the lab using data from run0046

det DAQ ch threshold resolution @ 60keV
GEM1800 xray1 5keV 495eV
GLP2000 xray2 5keV 430eV
GEM3000 xray3 7keV 525eV
Entry  Fri Apr 30 10:55:34 2021, Jan Glorius, DAQ, Xray multi-triggers - blocking gate, 2021 
From the CFD of Xray1 (90deg) we get multiple trigger signals every ~5sec for unknown reasons. 
No hint from the preamp signals.

The solution now is to have an extended blocking gate active in the trlo-config of node 2.
There is now a trigger_stretch of 2500ns for all Xray triggers:

trig_stretch(1)  = 2500ns;
trig_stretch(2)  = 2500ns;
trig_stretch(3)  = 2500ns;

This prevents the multiple triggers to reach the lmu (before_dt scalers)
However, this will also lead to a very small loss of good signal triggers that overlay within 2.5 us.

This has to be taken into account for deadtime determination.
Entry  Mon May 3 14:55:44 2021, Jan Glorius, Calibration, Xray energy calib. table, 2021 
Here is the table of energy calibration lines from Am241 for all Xray detectors for several measurements.
Also the linear fit parameters [ E(ch) = A*ch + B ] are given at the bottom of the table.

E [keV] xray90 (GEM1800) xray35 (GLP) xray145 (GEM3000)
lab (28.04.21) lab (04.05.21) lab (11.05.21)
59.54 2402.45 ch 2399.07 ch 2423.24 ch
26.34 1107.38 ch 1116.65 ch 1127.94 ch
13.95 624.33 ch 638.38 ch 645.39 ch
slope A 0.0256387 keV/ch 0.0258923 keV/ch 0.0256408 keV/ch
offset B -2.05477 keV -2.57638 keV -2.59114 keV
ELOG V3.1.5-fc6679b