Beam Delivery System

Deepa Angal-Kalinin, Hitoshi Yamamoto, Andrei Seryifor BDS Area

review video meetingMarch 28, 2006

28 Mar 062

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?

28 Mar 063

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

28 Mar 064

Details of layouts and corresponding optics

EFF1EDL1

spoilers survive 2 bunches

undisrupted beam size does not destroy beam dump window without rastering. Rastering to avoid boiling of water

28 Mar 065

to tune-up dump

EBSY

EBSYD

EIRT2EIRT1

EFF1

EFF2

EFF2

to IP

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

28 Mar 066

EIRT1

EIRT2

EFF1

EFF2

to IP

to IP

betatron collimation

energy collimation

energy spectrometer

EIRT2

ISR in 11mrad bend:610 10 m0

E 500 GeVbeam

x 12.9 %0

x

x

28 Mar 067

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 2mradsextupoles

absorbers

muon wall

28 Mar 068

EFF1

EFF2 PFF2

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

28 Mar 069

ebds0_survey.tape EBSYDebds1_survey.tape EBSY EIRT1 EFF1 EDL1ebds2_survey.tape EIRT2 EFF2 EDL2

pbds0_survey.tape PBSYD pbds1_survey.tape PBSY PIRT1 PFF1 PDL1pbds2_survey.tape PIRT2 PFF2 PDL2

Optics organization• Optics ILC2006a:

http://www.slac.stanford.edu/~mdw/ILC/Beam_Delivery/2006a/

• The MAD optics files:

• Survey files: Sub-beamlines:

ebds0.madebds1.madebds2.mad

pbds0.madpbds1.madpbds2.mad

28 Mar 0610

EBSY (Electron Beam Switch Yard)BEGIN: exit of last ELIN2 cryomoduleMPS betatron collimationskew 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) extractionseptumhigh bandwidth horizontal bend system vertical bending systembeam sweeping system tune-up dumpEND: entrance of tune-up dump window

EIRT1 (Electron Interaction Region Transport to ir 1)BEGIN: entrance of first EBSY extraction bend magnet (kicker)matching sectionstretch (for longitudinal interaction region separation)polarimeter chicaneEND: exit of last polarimeter chicane bend magnet

Functional descriptionEFF1 (Electron Final Focus 1)BEGIN: exit of last EIRT1 polarimeter chicane bend magnetprimary betatron collimation sectionprimary energy collimation sectionenergy spectrometer chicanetail folding octupolesaberration correction sectionfinal transformerfinal doubletEND: IP1 (20 mrad crossing angle)

EDL1 (Electron Dump Line 1)BEGIN: IP1 (20 mrad crossing angle)disrupted beam captureenergy spectrometer chicanepolarimeter chicanecollimationrastering and final drift to dumpEND: dump window

28 Mar 0611

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/

28 Mar 0612

Element / Subsys EBSYD EBSY EIRT1 EFF1 EDL1 PBSYD PBSY PIRT1 PFF1 PDL1 TOTALBEND 33 20 4 61 18 33 20 4 61 18 272KICKER & CORR 25 15 25 15 80QUAD 11 39 26 45 16 11 39 26 45 16 274SEXTUPOLE 8 5 8 5 26OCTUP 7 8 7 8 30BPM 26 0 0 120 0 26 0 0 120 0 292LASER WIRE 1 4 2 1 4 2 14COLLIM. (SP,AB,PC) 4 29 4 4 29 4 74BEAM DUMP 1 1 1 1 4MUON WALL 2 2 4CRAB CAVITY 1 1 2

Element / Subsys EIRT2 EFF2 EDL2 PIRT2 PFF2 PDL2 TOTALBEND 52 61 50 52 61 50 326KICKER & CORR 14 14 28QUAD 18 45 15 18 45 15 156SEXTUPOLE 5 4 5 4 18OCTUP 9 9 18BPM 3 78 0 3 78 0 162LASER WIRE 2 2 4COLLIM. (SP,AB,PC) 29 29 58BEAM DUMP 1 1 2MUON WALL 2 2 4CRAB CAVITY 1 1 2

Counts of elements in subsystems

• Red numbers indicate possible inconsistencies that need to be fixed

28 Mar 0613

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. (tentative) UPDATED Feb 11, 2006BDS 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 26to come:     Collimators (spoilers, absorbers, PCs)    Beam dumps    Muon walls    20/(14)mrad FD

… etc

http://www.linearcollider.org/wiki/doku.php?id=rdr:rdr_as:rdr_as_home

28 Mar 0614

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

28 Mar 0615

28 Mar 0616

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 1st 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

28 Mar 0617

• 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

28 Mar 0618

14(20)mrad, BNL

28 Mar 0619

QD0SD0 QF1

SF1 Q,S,QEXF1

Disrupted beam & Sync radiations

BeamstrahlungIncoming 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

28 Mar 0620

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 = -321m18 m wall at S = -321m

250 GeV beamLew Keller

Muon Momenta from PC-3 Hitting 6.5 m Detector

28 Mar 0621

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

28 Mar 0622

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

28 Mar 0623

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

28 Mar 0624

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

28 Mar 0625

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

28 Mar 0626

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 alHFSS Mesh from FNAL

SLAC ModelMeshing is next

K.Ko, Z.Li, et al

28 Mar 0627

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 Mar 0628

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

28 Mar 0629

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+

28 Mar 0630

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+

28 Mar 0631

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

28 Mar 0632

Max number of shafts in BDS (8)

• Shafts near all full power dumps, IR halls and “Y”s.

28 Mar 0633

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

28 Mar 0634

Min number of shafts in BDS (2 large and 1 small)

• Two large shafts for detectors and one small shaft

28 Mar 0635

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 2C/24hr and 0.25 ºC/1hr, however, this appear not stable enough. Would like to have 0.5C/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

28 Mar 0636

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

28 Mar 0637

CF BDS layouts: example of e+ transport options

e+ tunnel

F.Asiri, C.Corvin, et al.

suggested baseline solutionabandoned version

abandoned version

28 Mar 0638

-40 -35 -30 -25 -20 -15 -10 -5 0 5 10

01

23

45

67

89

10

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.

28 Mar 0639

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

28 Mar 0640

20mr IR

28 Mar 0641• See notes on next page

20mr => 25mr

28 Mar 0642

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.

28 Mar 0643

Assumed this dump for (feasibility to be studied)

28 Mar 0644

14mr => 25mr

• additional angle is 5.5mrad and detector need to move by about 4.2m

28 Mar 0645

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-

28 Mar 0646

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

28 Mar 0647

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

28 Mar 0648

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)

28 Mar 0649

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

28 Mar 0650

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)

28 Mar 0651

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)

28 Mar 0652

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

28 Mar 0653

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.

28 Mar 0654

• Bends are OK until 500GeV/beam, at that E there is a minor growth

500GeV/beam

28 Mar 0655

• FD is OK until 250GeV/beam, after that assume it is replaced

28 Mar 0656

Backup slides

28 Mar 0657

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

28 Mar 0658

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

28 Mar 0659

IR & radiation safety1) 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

28 Mar 0660

2) Self-shieldingdetector

color scale is different in two cases

18MW on Cu target 9r.l at s=-8mPacman 0.5m iron and 2m concrete

18MW on Cu target 9r.l at s=-8mPacman 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/hrFe: 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 ofthese two cases

28 Mar 0661

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

28 Mar 0662

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

28 Mar 0663

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