1. Elias Métral for the BLRWG (25 + 5 min, 21 slides)
BEAM LOSS AND RADIATION
IN THE PS & SPS
Elias Métral for the BLRWG ( min, 21 slides)
Beam Loss and Radiation Working Group (BLRWG) in 2005
High-intensity beams at CERN
Summary of the beam losses in LINAC2 / PSB / PS / SPS
Appendices (15 slides)
1: More details for the beam losses in the PS
2: More details for the beam losses in the transfer line PS-SPS
3: More details for the beam losses in the SPS
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

2. BEAM LOSS AND RADIATION WORKING GROUP (1/2)
Created at the beginning of 2005
Will end in ~ April 2006 after publication of a report (> 100 pages)
Members
G. Arduini (Chairman) for the SPS
C. Hill for the Linac
M. Benedikt for the PSB
M. Giovannozzi for the PS
E. Métral (Scientific secretary) for the PS
E. Shaposhnikova for the SPS
B. Goddard for the SPS
D. Forkel-Wirth for the Radioprotection
T. Otto for the Radioprotection
H. Vincke for the Radioprotection
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

3. BEAM LOSS AND RADIATION WORKING GROUP (2/2)
Mandate
Produce an inventory of the losses associated with operation, setting-up and machine studies in the PS and SPS Complex with high intensity beams (in particular CNGS beam) and of their radiological impact  Weighted losses
Define measures and upgrades aimed at reducing beam losses during machine operation. Quantify their impact on losses and on radiation …
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

4. HIGH-INTENSITY BEAMS AT CERN (1/7)
List of high-intensity beams considered
CNGS: pot/year GeV/c (SPS)
FT: pot/year GeV/c (SPS)
LHC: pot/year GeV/c (SPS)
nTOF: pot/year 20 GeV/c (PS)
AD: pot/year 26 GeV/c (PS)
ISOLDE: pot/year GeV/c (PSB)
Transmission efficiency (i.e. the ratio between the intensity at the LINAC2 source and at the target)
CNGS: 16 %
FT: 13 %
LHC: 12 %
nTOF: 19 %
AD: 18 %
ISOLDE: 20 %
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

5. CNGS beam
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

6. SFTPRO beam
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

7. LHC beam
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

8. nTOF beam
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

9. AD beam
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

10. ISOLDE beam
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

11. BEAM LOSSES IN LINAC2 / PSB / PS /SPS (1/11)
The yearly weighted losses are calculated by multiplying the expected yearly losses (in 1019 p) by the corresponding energy scaling factor*
 The maximum of the 2 criteria is given
For the total number of inelastic interactions caused by a beam loss. This proportionality is also valid for the total activation of massive objects hit by the beam, such as magnets
For dose equivalent rates behind a radiation shielding  Enters into consideration of the suitability of areas for permanent occupation and into the design of radiation shielding
* Radiological impact: Dose  Ek for Ek > 1 GeV (with Ek the kinetic energy)
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

12. BEAM LOSSES IN LINAC2 / PSB / PS /SPS (2/11)
SPS ramp
aft. trans.
PS extr.
SPS trans.
SPS inj.
SPS ramp
bef. trans.
SPS extr.
Transfer TT2-TT10
SPS Flat Bottom
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

13. BEAM LOSSES IN LINAC2 / PSB / PS /SPS (3/11)
Dump (TIDVG  Remaining beam in the SPS after slow extraction)
SPS extr.
Transfer to targets (splitters)
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

14. BEAM LOSSES IN LINAC2 / PSB / PS /SPS (4/11)
Scraping (at ~ 3.5 σ) to correctly enter into the transfer line and LHC
Transfer TT2-TT10
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

15. BEAM LOSSES IN LINAC2 / PSB / PS /SPS (5/11)
PS ramp
bef. trans.
PS extr.
PSB extr. + Transfer PSB-PS + PS inj.
PS trans.
PSB inj.
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

16. BEAM LOSSES IN LINAC2 / PSB / PS /SPS (6/11)
PS extr.
PSB inj.
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

17. BEAM LOSSES IN LINAC2 / PSB / PS /SPS (7/11)
PSB inj.
PSB extr.
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

18. BEAM LOSSES IN LINAC2 / PSB / PS /SPS (8/11)
Yearly radiological impact (Weighted losses in 1019 p/year) of the different physics / machine studies / setting-up operation modes. For each machine we summed all the contributions (shown in more detail in the previous plots) as given below
CNGS FT
LHC
nTOF AD
ISOLDE
Setting-up & MDs
LINAC2 (incl. transfer to PSB)
0.1
0.04
0.01
0.03
0.4 -
PSB
0.8
0.2
0.02
4.5
PS (incl. transfer from PSB and to SPS)
6.9
2.1
0.6
1.1
0.05 2
SPS (incl. extr. transfer lines) 16 53
2.6 12
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

19. BEAM LOSSES IN LINAC2 / PSB / PS /SPS (9/11)
300 μSv/year = Legal limit for the annual dose to the public
10 μSv/year = Limit for the annual dose delivered to public above which optimization is required
100 μSv/year = Limit for the annual dose delivered to personnel not professionally exposed above which optimization is required
2 μSv/day is the background noise at CERN (value subtracted from the total dose read by our RADOS badge)
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

20. BEAM LOSSES IN LINAC2 / PSB / PS /SPS (10/11)
The following main critical areas have been identified and are listed in order of importance, as a function of their impact on the public and on the personnel
1) PS bridge (SS07 to 11) and PS North and South Halls
 One of the weakest points of the PS shielding
2) TDC2/TCC2 area in the SPS
- The targets and the splitter magnets are located in this area  Losses on these components are unavoidable and for that reason this zone is highly radioactive. During beam operation the air in TDC2/TCC2 is re-circulated in a closed-loop in order to prevent the release of radioactive air
- An additional problem is the very high tritium concentration measured in the water collected in the retention pit DP540, presently exceeding the limit set by Swiss regulations
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

21. BEAM LOSSES IN LINAC2 / PSB / PS /SPS (11/11)
3) Air release points in Meyrin (in particular TT10)
 ~ 10 μSv/year expected for the public living close to the Meyrin site of CERN
4) Straight section SS31 in the PS
 During the CT (Continuous Transfer) extraction for the FT and CNGS beams to the SPS the beam is sliced horizontally by an electrostatic septum located in SS31. Typical losses at the septum after optimisation are close to 7%
5) ECA4 area in the SPS
 During CNGS and LHC operation, protons with a momentum of 400 and 450 GeV/c respectively will be extracted from the SPS into the TT40 transfer line. Particle losses occur during the extraction process as a result of the finite rise and fall times of the extraction kicker and of the presence of particles in the beam gap. Losses are particularly important for the CNGS beam because of the short gap (~1 μs)
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

22. APPENDIX 1: BEAM LOSSES IN THE PS (1/6)
TT2
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

23. CNGS beam Saturation at 255  Could be much higher Beam Loss Monitor
Transition
at ~ 5.2 GeV
Saturation at 255  Could be much higher
Detector = ACEM (Aluminum Cathod Electron Multiplier), placed at the beginning of the SS
Beam Loss Monitor
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

24. SFTPRO beam
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

25. LHC beam
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

26. nTOF beam
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

27. AD beam
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

28. APPENDIX 2: BEAM LOSSES IN TT2
SFTPRO & CNGS
LHC
TOF AD
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

29. APPENDIX 3: BEAM LOSSES IN THE SPS (1/8)
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

30. APPENDIX 3: BEAM LOSSES IN THE SPS (2/8)
CNGS beam
(2 batches from the PS)
New intensity record
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

31. APPENDIX 3: BEAM LOSSES IN THE SPS (3/8)
1 PS batch
# p
[1013 p]
Losses
[%]
FTA212
3.1
BFCT102834
3.06
~1.6
SPS INJ.
2.92
~4.6*
END FB
2.86 ~2
F. PORCH
5.53
~3.3
> TRANS.
5.39
~2.5
400 GeV/c
5.26
~2.4
EXT. ~1
Hot-spot at switching magnets
Mechanical aperture
RF + H scrap. at transition ?
Ghost bunches in the kicker gap
* Injection losses to be verified – calibration ( kinds of BCTs)
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

32. APPENDIX 4: BEAM LOSSES IN THE SPS (4/8)
Injection and flat-bottom losses
Vertical mechanical aperture of the machine: Limited in 2004 by the deformation of the Ti foil of the TIDVG (high energy beam dump absorber)
Extraction area in LSS6 and downstream ( )
Beam
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

33. APPENDIX 5: BEAM LOSSES IN THE SPS (5/8)
Tight vertical aperture  The alignment of the 5 CT-turns is critical
Vertical position
Courtesy of G. Arduini
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

34. APPENDIX 6: BEAM LOSSES IN THE SPS (6/8)
TRANSVERSE EMITTANCES : COMPARISON WITH 1997
(1σ,norm) in μm
PSB
(SEMG-BTM) PS
(FWS)
(SEMG-TT2)
SPS
(SEMG-TT10)
Oct H
12.7
16.6
4.6
10.1
11.6 V
7.8
8.3
7.5
6.9
6.4
Sept
11.4
13.1
9.3
3.3
8.5 8
6.8
8.0
9.1 5
4.3
inj
top CT
min
max CT
1 ~ p accelerated in the PSB (SL-MD Note 251)
2 ~ p accelerated in the PSB
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

35. APPENDIX 7: BEAM LOSSES IN THE SPS (7/8)
PS and SPS
vertical acceptances
Assuming a bi-Gaussian
 Pessimistic
Beam losses at PS injection [%]
Beam losses at SPS injection [%]
Vertical emittance from the PSB
Vertical emittance measured at SPS injection
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06

36. APPENDIX 8: BEAM LOSSES IN THE SPS (8/8) See Elena&Gianluigi’s talks
LHC beam
(4 batches from the PS)
See Elena&Gianluigi’s talks
Elias Métral, CERN-GSI bi-lateral working meeting on Collective Effects – Coordination of Theory and Experiments, GSI, 30-31/03/06