1. HERMES dipole magnet model for CBM CBM Collaboration Meeting September 25-28,2006 Pavel Akishin Elena Litvinenko Victor Ivanov LIT JINR, Dubna litvin@nf.jinr.ru

2. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 2 The available magnetic field maps… cbmroot/ AUG07 / FieldActive.root FieldMuonMagnet.root FieldMuonMagnet_small.root cbmroot / FEB 07 / FieldActive.root FieldAlligator.root FieldActive_Bs.root FieldDipole.root FieldHera.root FieldHeraP.root FieldHeraS.root FieldIron.root FieldMuonMagnet.root

3. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 3 … and the “Active” magnet geometry 1.8 m 4.24 m

4. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 4 … and the “MuonMagnet” geometry 1m 2.9 m MuonMagnet

5. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 5 The new addition to cbmroot magnets Input data – one A4 page with a schematical view and the basic parameters of the dipole magnet from the HERMES experiment at DESY Motivation – checking the chances to use the existing magnet for CBM

6. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 6 3D model for TOSCA calculations HERMES magnet model:

7. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 7 Field map “FieldHermes” for cbmroot

8. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 8

9. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 9 cbmroot geometry “magnet_hermes.geo”

10. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 10 0.7 m 1.9 m 2.1 m 1.75 m 1.12 m 25º 1.19 m Target (-11.7cm) Angular acceptance of the magnet Integral = 0.76 Tm Hermes

11. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 11 0.7 m 1.12 m Modification of the magnet geometry 1 m 1.41 m 1.61 m Hermes HermesE

12. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 12 The changes of the coil current geom: magnet_hermesmagnet_hermes_e.geo field map: Hermes HermesEn HermesE Nominal current: 1500A Number of coils: 2 Turns/coil: 440 1500A 1650 A 2 2 440 440

13. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 13 1 m 1.9 m 2.1 m 1.75 m 1.42 m 25º 1.51 m Target (-63.9 cm) Modified angular acceptance Last STS detector 1 m Integral = 0.79 Tm HermesE

14. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 14 The most significant field component |By| (z), x=y=0

15. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 15 |By| (z,y) x=0 for HERMES

16. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 16 Available Field Maps namesymmetry x,y ranges [cm] z range [cm]grid step Active1/8 [-150,150] [-300,300]1 cm MuonMagnet_small1/8[-150,150] [-250,250]1 cm MuonMagnet1/8[-150,150] [-450,450]2 cm Hermes->HermesE 1/4[-300,300] [-450,450]2 cm

17. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 17 Together with the existing field maps

18. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 18 Field Integrals along z axis (z1,z2) [Tm] FieldMap:(-50,50cm)(-50,100)(-50,200)(-100,100)(-200,200) Active 0.891.011.021.141.16 MuonMagnet 1.011.221.291.441.61 Hermes 0.961.181.241.481.63 HermesEn 0.740.941.031.191.39 HermesE 0.780.991.071.251.45

19. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 19 Existing maps: |By| (z,y) x=0

20. Volker Friese CBM Simulation Meeting 15. September 2006 20 And with “Hermes”: |By| (z,y) x=0

21. Elena Litvinenko CBM Collaboration Meeting 25-28 September 2007 21 The results HERMES magnet model is available The variant of the minimal magnet modification is proposed to improve the angular acceptance The files are available for the simulations : / u/litvinen/cbmroot/input/ FieldHermes.root FieldHermesEn.root FieldHermesE.root /u/litvinen/cbmroot/geometry/ magnet_hermes.geo magnet_hermes_e.geo -”-