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Message ID: 85     Entry time: Sun May 9 01:19:47 2021
Author: Helmut, Sergey 
Category: Accelerator 
Subject: 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.








 
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