1. Beam Delivery System Deepa Angal-Kalinin, Hitoshi Yamamoto, Andrei Seryi for BDS Area review video meeting March 28, 2006

2. 28 Mar 06 2 Agenda & questions suggested by RDR management Optics and layout status (35') [Optics, general layout, technical systems, etc] CF&S for BDS (15') [alcoves, tunnel size, access shafts, IR halls, etc] Options for cost reduction (15') [# of tunnels, system length, energy upgrade, # of Irs, etc] Operations & reliability issues (10') [beam losses, dumps, diagnostics, tuning etc] What are the design criteria that have driven your choices? What performance overheads are included in the design? Are their outstanding (cost-relevant) design choices? Is all the cost-relevant information available to the TS groups? What is the status of the TS groups (with respect to the BDS)? Are there identified 'costing bottlenecks'? Can you foresee cost saving modifications, and what would their performance impact be?

3. 28 Mar 06 3 Baseline layout 20mrad IR and 2mrad IR Two longitudinally separated IPs, two independent collider halls for two experiments Entry to entry: ~5.5km (grid size: 100m * 5m) Shafts & service tunnel not shown

4. 28 Mar 06 4 Details of layouts and corresponding optics EFF1 EDL1 spoilers survive 2 bunches undisrupted beam size does not destroy beam dump window without rastering. Rastering to avoid boiling of water

5. 28 Mar 06 5 to tune-up dump EBSY EBSYD EIRT2 EIRT1 EFF1 EFF2 to IP MPS betatron collimators skew correction 4-wire 2D  diagnostics Energy diag. chicane kicker, septum polarimeter chicane betatron collimation High bandwidth horiz. bending system EBSY Updated optics (ILC2006a). August-October 2005 optics put together. No change with respect to what is described in BCD, except: –new: sacrificial MPS betatron collimation at the entrance –some length (diag.; kicker) increased (according to BCD) Still working on EBSY& EBSYD and will have new version soon 1um beam at laser wires

6. 28 Mar 06 6 EIRT1 EIRT2 EFF1 EFF2 to IP betatron collimation energy collimation energy spectrometer EIRT2 ISR in 11mrad bend:

7. 28 Mar 06 7 Layouts with captions (fragment of EFF2 & PDL2) http://www-project.slac.stanford.edu/ilc/acceldev/beamdelivery/rdr/components/bds_layout_feb10_06.pdf grid dx=100m tail folding octupoles crab cavity in 2mrad sextupoles absorbers muon wall

8. 28 Mar 06 8 EFF1 EFF2PFF2 EDL2 EDL1PDL1 PDL2 tail folding octupoles aberration correction section final transformer disruption beam capture E and polarization diagnostics EDL2 E and polarization diagnostics Length needed to provide ~3m separation of the dump from incoming beamline

9. 28 Mar 06 9 ebds0_survey.tape EBSYD ebds1_survey.tape EBSY EIRT1 EFF1 EDL1 ebds2_survey.tape EIRT2 EFF2 EDL2 pbds0_survey.tape PBSYD pbds1_survey.tape PBSY PIRT1 PFF1 PDL1 pbds2_survey.tape PIRT2 PFF2 PDL2 Optics organization Optics ILC2006a: http://www.slac.stanford.edu/~mdw/ILC/Beam_Delivery/2006a/ http://www.slac.stanford.edu/~mdw/ILC/Beam_Delivery/2006a/ The MAD optics files: Survey files: Sub-beamlines: ebds0.mad ebds1.mad ebds2.mad pbds0.mad pbds1.mad pbds2.mad

10. 28 Mar 06 10 EBSY (Electron Beam Switch Yard)  BEGIN: exit of last ELIN2 cryomodule  MPS betatron collimation  skew correction section  4-laser wire 2D  diagnostic section with trajectory feedback  energy diagnostic chicane (with MPS energy collimator)  END: entrance of first extraction bend magnet (kicker) EBSYD (Electron Beam Switch Yard to Dump)  BEGIN: entrance of first extraction bend magnet (kicker)  Bend (kicker) for slow (fast) extraction  septum  high bandwidth horizontal bend system  vertical bending system  beam sweeping system  tune-up dump  END: entrance of tune-up dump window EIRT1 (Electron Interaction Region Transport to ir 1)  BEGIN: entrance of first EBSY extraction bend magnet (kicker)  matching section  stretch (for longitudinal interaction region separation)  polarimeter chicane  END: exit of last polarimeter chicane bend magnet Functional description EFF1 (Electron Final Focus 1)  BEGIN: exit of last EIRT1 polarimeter chicane bend magnet  primary betatron collimation section  primary energy collimation section  energy spectrometer chicane  tail folding octupoles  aberration correction section  final transformer  final doublet  END: IP1 (20 mrad crossing angle) EDL1 (Electron Dump Line 1)  BEGIN: IP1 (20 mrad crossing angle)  disrupted beam capture  energy spectrometer chicane  polarimeter chicane  collimation  rastering and final drift to dump  END: dump window

11. 28 Mar 06 11 Tables of elements (example) Aperture is as seen by beam, vacuum chamber thickness not included SC magnets indicated by “SC” in eng. type column Beam energy in tables is 250GeV. Magnets and PS should work for 500GeV Additional description required for kickers, septa, IR magnets Optics has info where movers are. It needs to be transferred to tables. http://www-project.slac.stanford.edu/ilc/acceldev/beamdelivery/rdr/components/

12. 28 Mar 06 12 Counts of elements in subsystems Red numbers indicate possible inconsistencies that need to be fixed

13. 28 Mar 06 13 Tech specs being prepared http://www-project.slac.stanford.edu/ilc/acceldev/beamdelivery/rdr/ ILC BDS Area. Materials for RDR Layouts, apertures, tables of components, etc. Layouts, apertures, tables of components, etc. (tentative) UPDATED Feb 11, 2006 BDS Optics filesBDS Optics files (tentative) UPDATED Feb 11, 2006 Technical specs for feasibility study and cost estimations 2mrad IR Final Doublet Posted Feb 22 Crab cavity system Posted Feb 26 to come: Collimators (spoilers, absorbers, PCs) Beam dumps Muon walls 20/(14)mrad FD2mrad IR Final DoubletCrab cavity system … etc http://www.linearcollider.org/wiki/doku.php?id=rdr:rdr_as:rdr_as_home

14. 28 Mar 06 14 Tech systems progress Well developed communication and started work with Tech.Syst. & Glob.sys –Magnets –Instrumentation –Installations –Controls –Conv. facility Need to be improving –Vacuum –Dumps & collimators Mid April : plan to have phone/video meeting with Tech.systems to discuss their first cost estimates

15. 28 Mar 06 15

16. 28 Mar 06 16 Technical system Magnets tech system: –Meetings at Fermilab and consequent visit of John Tompkins and Vladimir Kashikhin to SLAC on March 2-3 –Discuss cost estimations, design of magnets, movers, etc. –Issues identified that need further work or definition in BDS low field magnet – design, field quality, etc. stringing rules for 500GeV CM –going down in energy by switching strings off Need guidance on both Max Energy and also Min Energy from Exec.Comm. – should we assume 91GeV CM to 250 GeV CM for 1 st stage? Missing bend strategy is being developed (50% or less installed at 500GeV) –IR magnets Fermilab focused on 2mrad IR magnets, BNL is working on 14/20mrad IR, Saclay will hopefully also consider 2mrad IR magnets –Met and discuss this further with Sugahara-san at Bangalore

17. 28 Mar 06 17 At 500GeV CM will install 50% or even less number of bends to cut cost. These bends need to be installed after the energy upgrade. Bends will be split and arranged in strings so that decreasing the energy much below the nominal 500GeV CM will be done by switching off the strings. Splitting bends (12m presently) will be determined by the energy range (should we assume 91GeV – 500GeV CM?) – by 5 to 2.4m? Example shows one of possible configuration in the FF part (Y.Nosochkov) Missing bend strategy at 500GeV CM

18. 28 Mar 06 18 14(20)mrad, BNL

19. 28 Mar 06 19 QD0 SD0 QF1 SF1 Q,S,QEXF1 Disrupted beam & Sync radiations Beamstrahlung Incoming beam 60 m Shared Large Aperture Magnets Rutherford cable SC quad and sextupole pocket coil quad 2mrad IR: Fermi and possibly Saclay will look on feasibility and cost estimates

20. 28 Mar 06 20 Muon walls BCD: two walls, 9m and 18m per branch, to reduce muon flux to less than 10muons/200bunches if collimate 0.001 of the beam Predictions of halo ~1e-6 - 1e-5 Min one 5m wall needed for PPS Approach: consider installing single 5m wall, space in tunnel for full set The 5m wall allow to collimate 2e-5 before reaching 10  /200bunches Before the CCR can be considered => –ask Accel. Phys. Tech. System to evaluate predictions of halo population –ask Installation Tech. System to evaluate possibility to install additional wall if muon rate will exceed the limit –ask MDI panel to evaluate the 10  /200bunches detector tolerance No magnetic wall 5 m wall at S = -321m 18 m wall at S = -321m 250 GeV beam Lew Keller Muon Momenta from PC-3 Hitting 6.5 m Detector

21. 28 Mar 06 21 Technical system (contd.) Accel. Phys. tech system: –Video mtg on Feb 24. Defined urgent Acc. phys. questions from BDS Vacuum chamber material (Cu, Al, SS, wakes etc), tens of M$ difference Prediction of halo population (collimate 1E-5 instead of 0.001?)  ~tens of M$ for muon walls Evaluate BDS vacuum requirements (~10nTorr to ~50nTor w.r.to e-cloud in e+ branch, etc) Evaluate  and  E/E of the beam with large  and E errors Evaluate effect of HOMs and LOMs of the crab cavity on the beam –Discussed this with Daniel Schulte e.g. Daniel asked to find resources in BDS group to investigate the issue of material for vacuum chamber –plan to study if SLAC ARDA can do this

22. 28 Mar 06 22 Technical system (contd. 2) Beam dumps and collimators tech system: –Meeting at DESY on Feb.16 devoted to beam dump design with participation of DESY, UK and SLAC colleagues, and with video link to SLAC. –Review design of water beam dump and its cost estimate Cost differences of earlier estimates are understood much better –Cost of dump vessel itself or plumbing and cooling systems are not very different in DESY and SLAC early cost estimates. Civil construction gives most of the difference. Decommissioning cost. »DO NOT include decommissioning cost??? »DOE or other rules may require us to consider plan for decommissioning? There are still questions of maintenance, approval, etc, that need to be carefully addressed For r&d, the window remains the most important item –Tech.System is just starting the work – may be a concern –Collimators system – need a fresh design look as well. Tech.system requests help in collimation system design

23. 28 Mar 06 23 Picture of beam dump from NLC 1999 study ILC Beam dump design based on design of MW dumps established at SLAC in sixties by D.Walz Adjusted design for 18MW Working with collaborating labs (UK) on eng. design and cost estimate for RDR Collimators: experience in design of survivable and renewable spoilers Plan survivable spoilers for ILC, will build renewable for LHC (experience may then be applied to ILC) Collimators (spoilers, absorbers). Spoiler: ~1r.l. of Cu, and Cu plated Be to min wakes Beam dumps & collimators

24. 28 Mar 06 24 Beam dumps and collimations Full power dumps (18MW) (6) –Removing tune-up dumps will be considered Photon (~1-3?MW) dumps (2) May consider reducing power of tune-up dumps when cost will be provided by Tech. system –(if cost would be weak function of power, such change may not make sense) Fixed aperture protection collimators (~60) Adjustable spoilers and absorbers (~60) Passive devices to limit betatron aperture

25. 28 Mar 06 25 Technical system (contd. 3) Instrumentation & controls tech system: –Following discussions at Fermilab, will look at the list of instrumentation in BDS and include what is missing (still to be done) –Based on Excel spreadsheets of BDS elements, the list of controls requirements was generated by ANL colleagues Number of DAQ channels, cables, etc. Started detailed discussion of these lists –Discussed with John Carwardine and Marc Ross at Bangalore –Discussed with Marc Ross & Grahame Blair last week at KEK –Added into BDS instrumentation (Marc Ross, Feb. RDR mtg) Imagers profile/SR/XSR (2/0/4) LOLA cold (4) to measure sz and y/x/E – z correlations

26. 28 Mar 06 26 Model of 3.9GHz deflecting (crab) cavity designed by Fermilab Collaboration is being formed to work on ILC crab cavity systems: Fermilab, Daresbury, SLAC, … The 3.9GHz deflecting cavity designed at Fermilab. Several simplified models have been manufactured. Complete design with all couplers exist now. Design is being verified with various tools including parallel codes (see next page), and then a prototype will be built. The phase stabilization system is being designed. L.Bellantoni, et al HFSS Mesh from FNAL SLAC Model Meshing is next K.Ko, Z.Li, et al

27. 28 Mar 06 27 Vacuum system Total length ~12km, ~30% in bends with SR losses Vacuum requirements ~10nTorr in ~0.5km within IP (based on beam-gas scattering), and ~50nTor (tbc) elsewhere Fast valves, optical windows, … Apertures shown in Fig. => (region of crotches show “oscillation”, special design attention required)

28. 28 Mar 06 28 Vacuum system (contd.) Material choice is not finalized (cost driver) –Cu, Al and SS considered for NLC. Finally, SS was costed in 1999. –TESLA design: SS chamber with Cu plated bellows and ports to reduce wakes Asked Accel.Physics Tech.System to evaluate effect of wakes in BDS, define requirements on conductivity and other parameters of vacuum chamber SS vacuum chamber concerns: –may affect field quality in magnets (  >1, experience of KEK-B) – to be evaluated –SR losses in bends areas at 1TeV CM: up to several kW/m in some chicanes and septa => may require copper and/or antechamber Information on NLC and TESLA vacuum chamber design: http://www-project.slac.stanford.edu/ilc/acceldev/beamdelivery/rdr/docs/vacuum_intro.html

29. 28 Mar 06 29 Conv. facility: Transverse space Beamline approximately 1m from the floor Min 1m from the wall (beamline is curved) Space for low energy positrons Space for optional tune-up line to the main dump on the same side (if decide later to include it into design) 1m Low E e+

30. 28 Mar 06 30 Shafts and path of access in BDS Locations of beamlines: Close to external walls, to allow access from IR halls without crossing the extraction lines The service tunnel in the linac should be moved to the side of larger angle IR Shafts: maximum number Where this shaft is located and can it provide access to all three branches? Low E e+

31. 28 Mar 06 31 Baseline layout 20mrad IR and 2mrad IR Grid size: 100m * 5m (Beamline is not placed near external walls, as suggested above) Shafts and places for power supplies not specified

32. 28 Mar 06 32 Max number of shafts in BDS (8) Shafts near all full power dumps, IR halls and “Y”s.

33. 28 Mar 06 33 Additional tunnels for power supplies 1) Extend linac service tunnels to BDS for ~500m to house power supplies and beam diagnostics lasers 2) Connect two collider halls by an accessible tunnel to place power supplies service tunnel

34. 28 Mar 06 34 Min number of shafts in BDS (2 large and 1 small) Two large shafts for detectors and one small shaft

35. 28 Mar 06 35 Issues of no service tunnel in BDS Long cables: up to 1.5km Power supply rating is likely to double for cables Cable plant cost is noticeable (still seems smaller than service tunnel) Temperature stability in tunnel is very serious issue: –cables will probably dissipate several MW(?): i.e. several hundred W/m => cables need to be placed in water cooled enclosure (?) to provide the needed temperature stability T stability is to be defined. In NLC specified  2  C/24hr and  0.25 ºC/1hr, however, this appear not stable enough. Would like to have  0.5  C/24hr and  0.1 ºC/1hr Laser transport up to several hundred meters may be needed (vacuum pipe) – probably feasible (cost) BPM performance with long cables

36. 28 Mar 06 36 Issues of min shafts Installation, access, maintenance of beam dumps and other equipment Min number of shafts may be mitigated by a full length service tunnel In general, decision of #shafts and service tunnel should come from consideration on space needed, access and installation needed requested by Tech. Systems. In many cases such consideration haven’t started yet

37. 28 Mar 06 37 CF BDS layouts: example of e+ transport options e+ tunnel F.Asiri, C.Corvin, et al. suggested baseline solution abandoned version

38. 28 Mar 06 38 IR hall sizes GLD: 72m x 32m x 40m [Snowmass data] SiD: 48m x 18m x 30m [SiD Collab. Mtg. 16-17 December 2005] Large range (3.5 times in volume) Assumptions for RDR: Largest size –also weight of detector, crane, etc.

39. 28 Mar 06 39 Discussed in details in LCWS06/MDI panel Upgrade from e+e- to  and back to e+e- –assume that 25mrad is needed for  to attain its max potential –reversibility of upgrade may be essential e.g. e+e- run =>  run => E upgrade and next e+e- run –consider concept for 20mrad or 14mrad IR upgrade –The suggested upgrade scenarios were accepted as a guideline: need to write a corresponding description for BCD For single IR, if two detectors are planned, then push-pull is needed –discussion started of the technical requirements that need to be solved to enable push-pull with rapid switch over time –Anything else than the baseline two IRs has met very strong resistance of detector/physics community at LCWS06 Updates on losses and radiation levels in 20mrad and 2mrad extraction lines –SR from disrupted beam is important

40. 28 Mar 06 40 20mr IR

41. 28 Mar 06 41 See notes on next page 20mr => 25mr

42. 28 Mar 06 42 Upgrade of 20mr to  25mr and back Install bend after energy collimator of modify E-coll bend to create additional 2.5mrad –Will need to study if this affects collimation efficiency and whether this is an issue for  Pink area show tunnels that need to be built for  in the upgrade or from start Detector and IP moved by about 1.8m, FF elements moved Build new ~0.25km gas dump followed by water dump for  ( next slide ) in a new tunnel, do not dismantle either the water dump for e+e- or extraction line If the  beam dump and new tunnel need to be much longer, the positron transfer tunnel should go above the projected path of  dump In back conversion  to e+e-, move FF beamline and detector back, continue to use e+e- water dump.

43. 28 Mar 06 43 Assumed this dump for  (feasibility to be studied)

44. 28 Mar 06 44 14mr => 25mr additional angle is 5.5mrad and detector need to move by about 4.2m

45. 28 Mar 06 45 Upgrade of 14mr to  25mr and back Additional comments Tunnel in FF area may need to be wider The gg dump is in separate tunnel – may ease radiation issues and upgrade back to e+e-

46. 28 Mar 06 46 Discussion of requirements to enable push-pull Detailed discussion happened on MDI panel/LCWS side (presented by Tom Markiewicz) –Technically, rapid (1-2 day every ~3month) switch may require Detailed engineering for push-pull from inception Part of Final Doublet carried with detector during move Break point in optics with double valves & cold warm transitions Sufficient embedded steel in the floor Reference alignment network in the hall to monitor detector and floor deformation; jacks under detector minimize detector deformation during move. Vertex and tracker may be on its own independent alignment system Detector is self shielded and no shielding wall SC solenoid of detector may need to stay cold and energized etc. Single IR (even with push pull) met strong resistance at LCWS06. It was strongly suggested that any such change go through ILCSC

47. 28 Mar 06 47 Radiation Loads in 20-mrad Extraction Line Dynamic heat loads up to 500 W/m Power density above quench limit Peak dose in coils up to 270 MGy/yr 2-mrad x-ing: 0.76 MW synch rad loss

48. 28 Mar 06 48 Approach suggested by DCB: focus on cost drivers “Decision” cost drivers –One or two IRs –Max energy (design for 250GeV/beam or 500GeV/beam) –Independent or single collider hall –Push pull detector or not, etc. “Components” cost drivers: –tunnels (~12km of beamlines), shafts and halls –vacuum system –magnets (large count) –muon walls (material cost) –IR regions (unique and complex) –beam dumps (CF cost)

49. 28 Mar 06 49 Possible cost saving strategies Need to know the costs to understand which strategies to implement Singe IR. Resistance from physics/detector community will be high. Plan to organize WBS in such a way that would be able to cost one IR or another (removing cost of bends and stretches not needed for single IR) If the design of single IR would need to be chosen, unlikely it would be 2 or 20mrad, but more likely something in between

50. 28 Mar 06 50 Discussion of WBS organization Plan to organize in such a way to allow easy evaluation of either of IRs E.g., larger xing IR would include –BDS_Larger_Xing –BDS_Common CF need to go to BDS (Numbers arbitrary)

51. 28 Mar 06 51 Other possible cost saving strategies Need to know the costs to understand which strategies to implement Install only fraction (half) of bends at 500GeV CM stage –this will increase difficulty and cost of the energy upgrade Design all quads as consisting from two halves and install only one half at 500 GeV CM –same difficulty with upgrade; also double movers & BPMs? Replace high power tune-up dumps with low power –do not consider additional beamline from BDS entrance to main dump –reduce band-path and shorten tune-up extraction line Consider staging construction and installation of muon walls (e.g. start with min 5m wall). Install more if muon rate is too high –May be difficult to install the wall in operational tunnel –Consider alternative muon spoilers Undisrupted beam size at dump window - rely not on drift but more on rastering - shorten extraction lines (MPS)

52. 28 Mar 06 52 Length and energy ILC BDS presently designed for up to 1TeV and assume that geometry (angle of bends) do not need to be decreased in energy upgrade. (Assume we do change FD in upgrade) If we would assume decrease of bend angles at the energy upgrade to 1TeV, then the BDS would have larger overhead and can go to E somewhat higher than 1TeV without much dilution If assumed this change of geometry strategy, and limit E to 1TeV CM, can say that BDS is longer than needed Even though FF and energy collimation could be shortened (if limit E strictly to 1TeV CM), with two IPs the limit is in transverse distance between detectors, i.e. the sum of crossing angles A radical way to attempt to reduce cost but keep two IRs may be to shorten ff and E-coll by ~500m per side, increase sum of crossing angles to ~35mrad, and use single IR hall –BDS entry to entry will be ~4.5km or a bit less –Length of beamlines and vac. chamber reduced by (also shorten extraction lines) by ~3km

53. 28 Mar 06 53 ILCFF9 (current BDS for 20mrad IR) vs beam energy with 1TeV nominal emittances and IP beta and zero energy spread. Without change of FD at higher energy. No change of bend angles.

54. 28 Mar 06 54 Bends are OK until 500GeV/beam, at that E there is a minor growth 500GeV/beam

55. 28 Mar 06 55 FD is OK until 250GeV/beam, after that assume it is replaced

56. 28 Mar 06 56 Backup slides

57. 28 Mar 06 57 IR design and Radiation safety design criteria Started the work on “ILC radiation guidance document” –beam containment policies and devices, conditions for occupancy –For IR region, in particular, defines Normal operation: dose less than 0.05 mrem/hr (integrated less than 0.1 rem in a year with 2000 hr/year) –This number 0.05mrem/hr is ten times less than what was discussed at Fermilab RDR meeting. Reason: to allow non-rad workers. Accidents: dose less than 25rem/hr and integrated less than 0.1 rem for 36MW of maximum credible incident (MCI) The team initially included N.Mokhov, D.Cossairt, L.Keller, S.Rokni, A.Fasso The document sent for discussion to colleagues from CERN, DESY, KEK, SLAC, Fermilab: –Alberto Fasso, Lewis Keller, Nikolai Mokhov, Sayed Rokni, Tom Himel, Nobuhiro Terunuma, Eckhard Elsen, Hideo Hirayama, Syuichi Ban, Hans Menzel, Norbert Tesch, Albrecht Leuschner, Andrei Seryi

58. 28 Mar 06 58 Updates on IR radiation safety design Considered cases –non self-shielding detector, with shielding wall in the hall –self-shielding detector Loss of the beam inside detector loss of the beam in the drift in the pacman loss of the beam near tunnel entry to the hall These study allow to define –thickness and distance to the shielding wall, or –thickness of packman, –design of the “tunnel plug” –design of instrumented “muon gaps” in the detector

59. 28 Mar 06 59 IR & radiation safety 1) Hall with shielding wall For 36MW MCI, the concrete wall at 10m from beamline should be ~3.1m Wall 18MW loss on Cu target 9r.l \at s=-8m. No Pacman, no detector. Concrete wall at 10m. Dose rate in mrem/hr. 25 rem/hr 10m Alberto Fasso et al

60. 28 Mar 06 60 2) Self-shielding detector color scale is different in two cases 18MW on Cu target 9r.l at s=-8m Pacman 0.5m iron and 2m concrete 18MW on Cu target 9r.l at s=-8m Pacman 1.2m iron and 2.5m concrete 18MW at s=-8m: Packman dose at pacman external wall dose at r=7m Fe: 0.5m, Concrete:2m 120rem/hr (r=3.5m) 23rem/hr Fe: 1.2m, Concrete: 2.5m 0.65rem/hr (r=4.7m) 0.23rem/hr A proper pacman can reduce dose below 25rem/hr Desired thickness is in between of these two cases

61. 28 Mar 06 61 Muon gaps 18MW loss on a Cu target (9r.l) placed at s=-8m Pacman is 0.5m iron and 2m concrete With muon chambers (with gap ~5cm) Dose rate shown is in mrem/hr

62. 28 Mar 06 62 Self-shielding (cont.) Illustrate two designs os the “tunnel plug” In the first one there is not enough overlap of shielding in the tunnel- hall transition next iteration of design show satisfactory performance Proper “tunnel plug” can be designed 0.5-0.7m of Fe for last 5m of tunnel; 0.5m transverse Fe shielding in Pacman Iron color scale is different in two cases

63. 28 Mar 06 63 Preliminary conclusions from all cases Self-shielding detectors –issue of gaps (muon chambers) need to be solved –entrance of tunnel should be covered by iron as well –distance helps (fencing out the working detector) –if issue of gaps can be solved, ~3m pacman is needed to meet 25rem/hr MCI requirement –accurate model of detector is very important –studies will continue Non self shielding detector –concrete wall at 10m from beamline should be ~3.1m