Shutdown Constraints and Radiation and Activation effects

ECFA - Aix Les Bains21.10.2014

S. Bally, O. Beltramello, I. Bergstrom, N. De Bortoli, H.Vincke, K. Zabrzycki

Reassessment of the scaling factors for ATLAS following to the new luminosity profile...

Scale factor between the doses measured at LS1 and LS3/LS4/LS5 shutdowns ...Estimations are performed using the current ATLAS detector configuration

Updated Luminosity Profile (L. Rossi, O. Bruning, M. Lamont July 2014)

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Maximum ratio #/LS1

1 week 4 weeks 6 weeks 8 weeks 16 weeks 1 year

LS2 1.9 1.9 1.9 2.0 2.3 2.7

LS3 2.9 2.9 3.0 3.1 3.3 4.0

LS4 (1118 fb-1) 10.9 11.9 12.6 13.2 14.8 17.0

LS5 (1868 fb-1) 11.0 12.1 12.8 13.4 16.1 21.0

3000 fb-1 11.0 11.9 12.5 13.5 16.3 21.4

Maximum ratio #/LS1

1 week 4 weeks 6 weeks 8 weeks 16 weeks 1 year

LS4 (1281 fb-1) 15.1 15.7 16.2 16.7 18.2 20.5

LS5 (2181 fb-1) 15.1 15.9 16.4 16.9 19.4 25.2

3000 fb-1 15.1 15.9 16.5 17.1 20.7 27.1

4000 fb-1 15.1 15.9 16.4 17.5 21.1 27.7

Nominal luminosity

Maximum luminosity

(Based on average res. dose rate R<100 cm)ATLAS Scaling Factors – maximum

Estimation of the scaling factors: In general :

Short cooling times are dominated by short-lived radio nuclides dose rate reflects the interaction rate (peak luminosity)

Long cooling times are dominated by longer-lived radio nuclides dose rate reflects roughly the integrated luminosity

For both cases, it depends strongly on the material and therefore on the produced radionuclides

Between LS1 and LS2 / LS3/ LS4 /LS5 shutdowns – cooling time 4 months:

For a longer cooling time, the scaling factor is increasing

Scale factor:

ATLAS Scaling factor (at 4 months)

LS2 versus LS1 2.5

LS3 versus LS1 4

LS4 versus LS1 15 (nom. Lumi) / 20 (max lumi)

LS5 versus LS1 15 (nom. Lumi) / 20 (max lumi)

3000fb-1 / 4000fb-1 15 (nom. Lumi) / 20 (max lumi)

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ATLAS Dose rates profile – LS3 – LS4

40

250 50

10

250

1000

50

250

LS3

TASBarrel Cal./ End Cap Cal. I/F

1 year

4 weeks

LS3

LS4 LS4

1 year

4 weeks

TASBarrel Cal./ End Cap Cal. I/F

TASBarrel Cal./ End Cap Cal. I/F TASBarrel Cal./End Cap Cal. I/F

1 year

4 weeks 1 year

4 weeks

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ATLAS Scaling factors profile – LS3

TAS

VA & VT, Alu instead of SS

Scaling factors decreased due to change of material for beam pipes …. ALARA

Effect of pilling up of long-lived isotopes at long cooling time

ACTIWIZ Software for ALARA

ActiWiz software (http://actiwiz.web.cern.ch) allows to quickly quantify radiological hazard of material implemented into CERN’s accelerator environment.

optimize dose to personnel and minimize the production of radioactive waste.

Present situation 69 elements and most common metals and construction materials were processed first version of a catalogue for CERN accelerators(LINAC4, BOOSTER, PS, SPS & LHC radiation environments)

Future update • Adaptation of the code to the LHC experiments • Flexibility to efficiently extend ActiWiz for new radiation fields & future facilities• Efficiently conduct waste characterization + analysis for arbitrary radiation

fields• Available end of 2015

ALARA in progress in ATLAS .. To prepare for future shutdowns

Change of the Beam pipes from stainless steel to Aluminum at LS1, Motorization of the beam pipe VT support,

Remote handling VJ installation tool, etc ….

EDUSAFE gamma imaging camera – 1st prototype ready

Impact of the new regulations on ATLAS zoning (waste and operational)

A revision of the radioactive zoning performed for ATLAS taking into account the Exemption limits (in Bq/kg) currently under revision in Europe.

Operational zoning for various cooling times. Waste zoning calculated for 100 days (ref. L. Ulrici)

Need to assess the detailed impact of the regulation change for all CERN activities: new storage areas, impact on waste management, need of new radioactive workshops ?

“Old” ATLAS Waste Zoning “New” ATLAS Waste Zoning

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CMS Simulations

Same irradiation profile (max luminosity) as for ATLAS SimulationsNB: Cooling times quoted represent the time since proton operation (does not included heavy ion run)

Different geometry models used depending on shutdown configurationLS1Simulation with a Run 1 FLUKA model (Stainless Steel Central conical

beampipe, no YE4 disks)LS2 & LS3Simulations with a Run 2 FLUKA model (Aluminum Central conical beam

pipe, with YE4 disks)LS3 results based on assumption that remaining beam pipe up

to TAS isnot changed from Stainless Steel to Aluminum in LS2

LS4 and ‘3000 fb-1 ’Simulations with Phase 2 FLUKA model (Aluminum beam pipe, extended

TAS and other phase 2 upgrades).‘New’ components such as Aluminum forward beam pipe , TAS, Endcapdetectors are exposed to Run 1, 2, 3 irradiation in FLUKA Simulations

Conservative estimate of long-lived nuclides. How conservative

depends on saturation effects.

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CMS dose rate (LS1, 2, 3, 4, 3000/fb) profiles after 4 weeks cooling

HL-LHC Maximal luminosity

LS1

LS2

LS3

v.3.0.3.0, v.3.7.3.0, v.3.8.1.0,Ida Bergstrom (DGS/RP)

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Maximum ratio of dose rates #/LS1

1 week 4 weeks 6 weeks 8 weeks 16 weeks 1 year

LS2 2.0 2.0 2.1 2.2 2.5 3.4

LS3 3.1 3.2 3.3 3.4 3.8 5.0

LS4 (1281 fb-1) 17 18 18 19 20 26

3000 fb-1 17 18 18 19 23 34

CMS (Maximum luminosity for HL-LHC)

(Based on average res. dose rate R<100 cm)CMS Scaling factors – maximum

For Comparison: ATLAS (Maximum luminosity for HL-LHC)Maximum ratio of dose rates LS#/LS1

1 week 4 weeks 6 weeks 8 weeks 16 weeks 1 year

LS2 1.9 1.9 1.9 2.0 2.3 2.7

LS3 2.9 2.9 3.0 3.1 3.3 4.0

LS4 (1281 fb-1) 15 16 16 17 18 21

3000 fb-1 15 16 16 17 21 27

CMS results consistent with ATLAS The small difference in maximum scaling factors are possibly due to bulky

material at various points along the beam line (see next slides)

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CMS Scaling factor profile – LS3

Central conical beam pipe Al instead of SS

TAS

Pb, Al Preshower & support cone

Al EE back plate inserts/support plate

Stainless Steel back flange & support below ME1/1

Stainless Steel Interface Plate

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Between LS1 and LS2 / LS3/ LS4 /LS5 shutdowns – cooling time 4 months:

For a longer cooling time, the scaling factor is increasing

CMS Scaling factor (at 4 months)

LS2 versus LS1 2.5

LS3 versus LS1 4

LS4 versus LS1 20 (max lumi)

LS5 versus LS1 20 (max lumi)

3000fb-1 / 4000fb-1 20 (max lumi)

CMS Dose rates profile – LS3 CMS Dose rates profile – LS4 (Maximum Luminosity)

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CMS comparison between calculations and measurements for LS1

Preliminary benchmark between calculation and measurement has shown similar results (same order of magnitude).Require defined work method and post-treatment analysis.In-situ measurements are done in several “opening/maintenance” configurations

Example:3.2 m Flange

10.7 m Flange 5 uSv/h (40 cm; 1 y)

5 uSv/h (40 cm; 6 mon)

14 uSv/h (40 cm; 6 mon)

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ALARA in progress in CMS... To prepare for future shutdowns

Radiation ShieldingWorking group set up (Beam pipe flanges shielding and Inner detector region shielding manufactured)

Material ChoiceChange of the Beam pipes from stainless steel to Aluminum at

LS2

Working MethodJob preparation (writing or updating procedure), optimization

(job and dose planning) and follow-up (control and “retour d’experience”) is essential (learning curve)

Requires sufficient resources (time and manpower) well before the intervention starts.

Opening (maintenance) ScenariosBRIL project set up (specific FLUKA simulation prepared, 2-step computation method)

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Impact of the new regulations on CMS zoning (waste and operational)

New zoning simulations (with updated parameters) have to be performed before releasing the new definition of the radioactive zoning of CMS.

Requirements for:- radioactive material storage areas (quantities)- waste management (quantities, waste sorting, logistics, transport, cleaning activities)

and needs for- radioactive workshops (destructive activities)

shall be re-assessed accordingly.

Thank you to BRIL project team contributions (A. Dabrowski, M. Guthoff, S. Mallows)

Conclusions

New scaling factors for ATLAS and CMS from the updated luminosity profileFor LS2 shutdown, we expect UX15 and UX55 classified as Supervised Radiation

areas except some regions like Inner Detector or Forward shielding which will become Limited Stay areas

For ALICE and LHCb, the dose rates are not expected to change between Run 2 and Run1, they will remain Supervised Radiation areas

ALARA is an essential and natural part of CERN culture: all LHC experiments have a strong ALARA policy and have started implementation during LS1.

Activiz code is being upgraded currently, and will be ready end 2015 to cope with LHC experiments requirements.

The impact of the new radioactive material Exemption Limits is currently being assessed: waste material quantities, radioactive workshops, storage areas.

A working group is currently being set up to analyze these issues