ID |
Date |
Author |
Category |
Subject |
4
|
Tue May 4 17:54:08 2021 |
Helmut Weick | Simulations | updated LISE file | This file really has the optics like used in the last ESR experiments.
Now the transmission is also a little bit better. |
5
|
Tue May 4 18:25:31 2021 |
Helmut Weick | Simulations | cutting of primary beam | The slits at TE4 and TE5 can be used to cut away the unwanted 78Kr beam (see pictures).
We do not want activation of the beamline. 78Kr35+ even has a chance of being injected. |
6
|
Tue May 4 21:49:04 2021 |
Helmut Weick | Simulations | cut Brho by scrapers | The dispersion from the production target into the ESR is not matched.
This is not good for momentum acceptance, but we anyway want to cut the acceptance.
Dispersion will oscillate with the tune of ESR. After 3 turns we expect a maximum dispersion.
The picture shows in red the dispersion curve for dp/p=0.1% and beam envelopes of 10 mm mrad.
So we can use scrapers in north or south arc to cut Brho. It should be done from both sides.
How much? Watch the intensity drop.
Best positions look at plot. Straight section outside for low Brho, arc outside for high Brho.
Could be EEXDS2HA and E02DSH (outside). |
8
|
Thu May 6 00:32:57 2021 |
Helmut Weick | Simulations | GICOSY file for TE beamline and ESR | This file has several options:
start in SIS, at TE3UF target or inside ESR, choose with GOTO LABEL (G L)after start system (S S).
Depending on the choice select different start beam parameters at top of file, others comment out.
There are also different optics setting with different quadrupoles:
- for TE beamline the standard and the mode by Hans for better focus on the target.
- for ESR a standard mode and variations of isochronous modes
also select by commenting in/out.
Input can be made also in units of K'L for fast import from parammodi, still by hand but with copy and paste.
One half of ESR is defined as a block, can be used more or less often (B I HALF ;) |
9
|
Thu May 6 13:26:56 2021 |
Helmut Weick | Detectors | TE5 profile grids do not work | There are several issues.
1. The stepper motor drive does not react from Device-Control, -> check controller in FRS Messhütte
2. They don't get a trigger, other grids in TE-line do -> check raw signals also in FRS Messhütte, ask Strahldiagnose
3. For less noise pockets of grids should be evacuated, but most likely the pump is still off or not even connected -> enter ESR and connect
Check also manual at https://web-docs.gsi.de/~weick/frs/current_grids.html
Below picture of no trigger shown in App. Usually it should say last trigger a few seconds ago and display some noise. |
10
|
Thu May 6 14:28:32 2021 |
Helmut Weick | Calibration | Be target thickness calibration -> 1839 mg/cm^2 | Injection was optimized before with Cu-40 mg/cm^2 stripper.
This reduces energy of 78Kr from 370 MeV/u -> 386.52 MeV/u.
To keep the same ESR injetion the SIS energy was raised with Be 10mm tatget.
For exactly 1850 mg/cm^2 a SIS-energy of 445.46 MeV/u would be needed. A scan of SIS energy resulted in 445.0 MeV/u as optimal.
This means target thickness is close to 1850 mg/cm^2, we can call it 1839 mg/cm^2. |
21
|
Fri May 7 01:07:27 2021 |
Helmut Weick | Analysis | maybe frequency ID | We think we see the frequency range of A/q=2.25 at 243.1 MHz.
This would correspond to L=108.2m and E=386.4 MeV/u (gamma_t = 1.3955) at h = 126.
Path length is a bit short, for L=108.4m it should be 370.6 MeV/u.
(later reanalysis shows the measured frequency corresponds to 108.38m, which is like expected)
We closed scrapers on arc outside and straight section outside to limit Brho from both sides.
GE02DS3HG = -35mm, GEEXDS2AH = -25mm
Expected frequencies see below: |
27
|
Fri May 7 03:44:55 2021 |
Helmut Weick | Accelerator | scraper optimisation | Opened TE4 slits again to +/-10mm.
Then we tried different scrapers:
in south arc outside: E02DS3HG, cuts at ~ -25mm, at -15mm gone, leave at -35mm.
on straight section: EEXDS2HA cuts at ~ -25mm, leave at -25mm.
EEXDS1HA, closing it to -25mm revealed a double peak structure with distance just like the wanted isomer (-2.2MHz at h=211).
But it is present on all intense peaks at the same distance, so it must be an artefact of a strange isochronicity curve.
Closing it to -15mm even had only the smaller lower frequency line survive.
But then it must be also possible to have only the stronger line. leave at -25mm
This worked with scraper in north arc E01DS_H which can cut from both sides.
The insie can ve iused to cut the lower Brho,
at -50mm still two peaks, at -45mm left peak almost gone, -40mm left peak gone but right still intense, leave at -40mm.
-> Lower Brho seems to be clearly related to lower frequency, higher Brho side is not so clearly related to frequency.
Measure in this setting, nice void at wanted frequency. But no isomers appear so far.
|
64
|
Sat May 8 01:33:25 2021 |
Helmut Weick | Simulations | frequency list for 70Se setting | EXCEL table with all possible fragments injected into ESR.
The path length in ESR, gamma_t and harmonic are adjusted to the 72Ge data.
Some lifetimes are limited but all intense lines are >30s in lab system.
There are two versions (for cooled beam with fixed v or uncooled (isochronous)
with fixed average Brho, take the second (grey) column.
For larger frequency shifts harmonics will overlap.
You can add more isomers. |
65
|
Sat May 8 01:43:23 2021 |
Helmut Weick | Accelerator | 70Se setting | If gamma_t = 1.3955 Tm stays, we will need Brho = 6.21902 Tm for 70Se.
The corresponding ESR Brho setting will be a bit shifted.
It then requires E-SIS = 446.55 MeV/u to get 70Se to this Brho and gamma_t.
For pre-drilling with 78Kr beam at same Brho use 416.70 MeV/u.
But we could also make a quick try without tuning before, just change all energies. |
76
|
Sat May 8 16:08:58 2021 |
Helmut Weick | Accelerator | beam position of Kr before ESR | Checked beam positions in beamline before ESR,
they all look the same as before, with direct Kr beam.
Compare with old elog entry #.
Also on Leuchttarget it is in the center like before. |
134
|
Thu Jun 24 22:05:11 2021 |
Helmut Weick | Accelerator | LISE files for 72Ge, 70Se, 52Mn settings | This is just a Brho selection by the ESR based on SIS-energy used,
energy-loss in target with calibrated thickness and momentum spread by the reaction (Goldhaber formula).
Production cross sections are by EPAX 3.1 |
85
|
Sun May 9 01:19:47 2021 |
Helmut, Sergey | Accelerator | scraper optmisation for 72Ge | To improve the isochronicity still in the 72Ge setting sextupoles and scrapers wer varies successfully.
1. E02DS_H -130 / 130mm - wide rect. peak
-30 / 130 - nothing
-35 / 130 - weak but broad
-70 / 130 - wider rect peak
-70 / 30 - two peaks
-70 / 10 - peak + small peak
-70 / 0 - peak + tiny peak
cannot move more than 0, back to
-70 / 50
2. E01DS_H: -130/130 - wide rectangular distribution
-40/130 - wide double structure
-35/130 - very weak, still double structure
some sectupole tuning
-40/0 - nothing
-50 / 0 - peak with right tail
cannot close outside more than 0 so try next scraper
3. E01DS3HG
-130 - peak with long right tail
-30 - nothing
-50 - peak with long right tail
-40 - weak peak with long right tail
==> no good scraper do not use
4. EEXDS2HA
-120 - peak with long right tail
-20 - peak with long right tail
0 - peak with less right tail
10 - small peak, no right tail
5 - smaller peak, no right tail
3 - smaller peak, with small right tail
8 - small peak no tail
==> good scraper use it (+8mm)
5. Try a bit more on E01DS_H
-55 / 0 - small peak no tail
-55 / 50 - same no loss in resolution
-55 /130 - same no loss in resolution
-65 /130 - same good peak, but higher intensity
-75 /130 - same good peak, but left tail
-65 /130 - same good peak, no tail
6. open E02DS_H to -130 / 130 no difference
7. again E01DS_H
-125 /130 - very wide left tail
-68 /130 - one peak
-72 /130 - one peak, samll left tail
-66 /130 - one peak, no tail
==> good scraper use it (-66mm)
8. check all other scrapers they are all open
also open TE4 slits to +/-20mm, no difference, back to +/-10 mm
9. bit more sextupole variation on the narrow line
===> only two scrapers used
picture shows result afterropimisation, the markers indicate the lines,
the left marker is for a +691 keV isomer.
|
80
|
Sat May 8 21:08:13 2021 |
Helmut, Sergey, Shahab, Wolfram, Yuri | Accelerator | optimisation of sextuples | The optimisation of sextuples is finished. Record a few files. |
86
|
Sun May 9 01:49:25 2021 |
Helmut, Sergey, Yuri | Accelerator | change to 52Mn |
It was done in steps:
isochronous 52Mn should come at Brho = 6.28239 Tm (gamma_t = 1.3955).
set ESR to m/q and E for 52Mn, 368.41 MeV/u
1.) predrilling 1st try
- set beamline to E, q for 52Mn and m = 51.9319 u by trim
- E-SIS = 422.1 MeV/u
but then not centred on profile grids, with thick Be target in
-15mm on TE4DGC also not on Lecuhttarget, not good
2.) pre-predrilling 2nd try
don't set beamline for 52Mn but define it as 78Kr, in trim mass back to 77.92 u.
insert Cu-40 mg/cm² and inject, just use dE = 1.5 MeV/u in stripper for SIS-energy (343.353 + 1.5) MeV/u
optimise a bit, then keep beamline energy set as 78Kr36+ beam the same.
3.) pre-drilling 422.1 MeV/u in SIS
insert Be target and optimise with kicker and septum angle,
energy also tried but back to old value, reache 6 - 7 % transmission
4.) change E-SIS to 440.7 MeV/u to get 52Mn in ESR at gamma_t |
138
|
Tue Jun 29 20:13:58 2021 |
Helmut, Sergey, Yuri | Accelerator | change to predrilling an 72Ge | After optimisation of sextupoles we found a scraper position which makes a narrow peak and keeps 20% of the injected beam.
GEEXDS2HA = +2.0 mm (out is +130mm)
GE01DS_HI = -75 mm (out is -130mm)
removed scrapers again for predrilling.
We agree on gamma_t = 1.3956, E/m = 368.50 MeV/u.
Then for 78Kr at Brho = 6.79675 Tm of isoc 72Ge
E-SIS = 466.63 MeV/u, assume target of 1815 mg/cm² Be
after target E/m = 393.024 MeV/u
In ESR-Modi set for same E/m but different m/q (m=72, Z=q=32)
Injection looks good like before with isochronous 78Kr we go directly to the next step
72Ge with E-SIS = 440.16 MeV/u to get 72Ge at gamma_t. |
110
|
Sun May 9 18:50:23 2021 |
Helmut, Wolfram, Yuri | Accelerator | changed to 70Se | 18:45 changed SIS, ESR setting for 70Se without predrilling blind change.
E-SIS = 446.55 MeV/u, is centerd as before on TE3UF target grid.
set beamline after taret as 78Kr 36+ E = 337.375 MeV/u
set ESR to A = 70, Z=34 at isochronous E/m + 0.8 MeV/u = 369.2 MeV/u
kicker delay unchanged
4 quadrupoles failed during the change, skip cycle and reset, they work again, (GE01QS0D, GE01QS1F, GE01QS2F, GE01QS4F)
Now many lines in Schottky.
also 2 corrector coils were off, on again, now good resolution. |
114
|
Sun May 9 21:29:26 2021 |
Helmut, Wolfram, Yuri | Accelerator | target TE3UF shift | We see a very strong line at the left end of spectrum, stronger than all other lines.
When we shift the target TE3UF_H from -35mm to -37mm it gete weaker, but -37mm is the end of drive.
In the other direction it becomes worse. At -25mm completely new peaks.
Also scan in Y direction TE3UF_V +25mm and +40mm give other fragments even very intense, while the old lines vanish.
So production happens in target frame.
Use -37mm, +37mm as best target position.
We run with TCap only for some time hoping there is somewhere a peak of 70Se
running from about 9:15 to about 22:00
We set scrapers in the previous optimum position |
115
|
Sun May 9 22:31:23 2021 |
Helmut, Wolfram, Yuri | Accelerator | change to 72Ge | we change back to 72Ge
just change SIS-energy E = 441.0 MeV/u
beamline energy after target E = 392.9 MeV/u
set ESR to A=72, Z=32 (72Ge)
--> good injection and resolution in ESR, at old frequencies |
116
|
Sun May 9 23:24:49 2021 |
Helmut, Wolfram, Yuri | Accelerator | scraper optmisation for 72Ge | We tried the scrapers a bit, because right of peak some background appeared.
The GE01DS_HI shows a strange effect,
normal -65mm gives good resolution, -30mm kills the beam, but even more in at -15 there is beam again.
We suppose the scraper is not massive but has an empty space behind it.
GE01DS_HA has no effect even at +0V.
Therefore, put I to -100mm and also use GE01DS3HG (from outside),set to -55mm.
Then also the straight section EEXDS2HA from + 8mm to +10mm (a bit more closed). |
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