Magnus Marklund , Rikard Gebart , David Fletcher Introduction
1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration...
-
date post
15-Jan-2016 -
Category
Documents
-
view
214 -
download
0
Transcript of 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration...
![Page 1: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/1.jpg)
1
Downstream scraping and detector sizes
Rikard SandströmUniversity of Geneva
MICE collaboration meeting2007-02-24 CERN
![Page 2: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/2.jpg)
2
Introduction
• Study A– Full phase space beam approach.– Radial positions measured at
• cryostat end• thick iron shield surfaces• TOF2• thin iron shield surfaces• calorimeter layer 0 surfaces• calorimeter center and end.
• Study B– Matched beam approach.
• 140 MeV/c, 200 MeV/c
– Radial positions measured at same z as in Study A.
![Page 3: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/3.jpg)
3
Setup, study A
• Geometry:– MICE stage6, with updated positions and iron shields.
• Iron shields not physically present in simulation, but using Virtual detectors at their surfaces.
– Now with cryostats physically present.– Empty absorbers.
• Field:– Holger’s empty channel, beta 42 cm, 200 MeV/c
field. http://mice.iit.edu/software/bfield/holger/FieldMaps24-01-07/CoilconfigWangNMRironshield200MeVbeta42emptychannel.g4mice
– RF field OFF
• Beam:– The same “full phase space beam” as was used
before.
![Page 4: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/4.jpg)
4There are no good events going through the cryostat!
![Page 5: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/5.jpg)
5
![Page 6: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/6.jpg)
6
![Page 7: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/7.jpg)
7
![Page 8: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/8.jpg)
8
Outside calorimeter (air)
![Page 9: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/9.jpg)
9
Again…The large radius events are all low momentum,Hence, setting a minimum → pz fixing maximum rho !
![Page 10: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/10.jpg)
10
Setup, study B
• Geometry:– MICE stage6, with updated positions and iron shields.
• Iron shields not physically present in simulation, but using Virtual detectors at their surfaces.
– Now with cryostats physically present.– 4.2 mm diffuser for 140 MeV/c, 7.6 mm diffuser for 200
MeV/c.– Empty absorbers.
• Field:– Holger’s empty channel, beta 42 cm, 140 MeV/c and
200 MeV/c fields respectively. http://mice.iit.edu/software/bfield/holger/FieldMaps24-01-07/CoilconfigWangNMRironshield140MeVbeta42emptychannel.g4mice
– RF field OFF.• Beam:
– Matched 140 MeV/c beam.
![Page 11: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/11.jpg)
11
Matched 200 MeV/c, thick shield
![Page 12: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/12.jpg)
12
Matched 200 MeV/c, TOF2
![Page 13: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/13.jpg)
13
Matched 200 MeV/c, thin shield
![Page 14: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/14.jpg)
14
Matched 200 MeV/c, EMCal0
Outside calorimeter (air)
![Page 15: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/15.jpg)
15
This beam uses the same field map as the full phase space beam, hence the same dependency on momentum
![Page 16: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/16.jpg)
16
Matched 140 MeV/c, thick shield
![Page 17: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/17.jpg)
17
Matched 140 MeV/c, TOF2
![Page 18: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/18.jpg)
18
Matched 140 MeV/c, thin shield
![Page 19: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/19.jpg)
19
Matched 140 MeV/c, EMCal0
Few muons make it through the preshower layer.
![Page 20: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/20.jpg)
20
Same tendency as before, but shifted w.r.t. pz
due to different field map.
![Page 21: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/21.jpg)
21
Emittance
• Typically it is the high amplitude particles which are missing the detectors.– High bias on emittance measurement.
• However, MICE will measure change of emittance!– If no change of emittance between upstream and
downstream, losing events does not affect the change of emittance measurement.
• This simulation contains no RF field, and empty absorbers, so bias on change of emittance as a function of TOF2 radius not meaningful here.– Instead, quoting bias on emittance measurement.
![Page 22: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/22.jpg)
22
Emittance
• Using no field approximation at TOF2 exit to calculate emittances:– ε = sqrt(x
2px2-xpx
2)/m
pz [MeV/c] εx εy
140 6.596 6.618
200 6.923 6.955
pz [MeV/c] R [cm] dεx/ εx dεy/ εy
140 42 -0.70 ppm -0.80 ppm
200 30 -0.63 ppm -0.80 ppm
• Requiring dε/ ε < 1 ppm, gives minimum radiuses
• Typically 1 ppm is at radius where 0.1 ppm is lost.
![Page 23: 1 Downstream scraping and detector sizes Rikard Sandström University of Geneva MICE collaboration meeting 2007-02-24 CERN.](https://reader036.fdocuments.in/reader036/viewer/2022062518/56649d445503460f94a206b1/html5/thumbnails/23.jpg)
23
Conclusions
• The cryostat is no longer an issue.• Setting TOF2 radius to
– 25 cm, start losing events pz<225 MeV/c– 30 cm, start losing events pz<169 MeV/c– 35 cm, start losing events pz<129 MeV/c
• According to no field approximation, minimum radius of TOF2 should be 42 cm to achieve dε/ ε < 1 ppm.– 30 cm for 200 MeV/c settings.– Usually 0.1 ppm loss radially is barely acceptable.