Radiation Protection studies for the Linac4 / Linac2 interface Joachim Vollaire, DGS-RP 28/09/2015 Linac4 Coordination Meeting

Outline Status of RP studies and plan for the Linac2/Linac4 interface LBE beam dump (very preliminary)

RP studies and plan for the Linac2/Linac4 interface

Shielding Calculations Detailed FLUKA geometry of the area Considering permanent beam losses occurring between the vertical bending magnet and the BHZ20: 5 W in the bending magnets 1 W/m (10 W) distributed losses Much more than what has been considered for the Linac4 itself (overkill ?) Shielding implementation to limit the stray radiation levels due to the Linac4 operation in accessible areas: Building 363 Building 351 (Linac3) Outside

Sectorisation Current Linac2 envelop is becoming part of the Switch-Yard (baseline) New EISs for the Switch-Yard and no access to the new Switch-Yard sector with ion beam in the PS or in LEIR Considering new envelope to allow space for Linac(5 ?)…. ? ?

Layout

Building 363… in pictures

From 363 to 351

Inside the Linac2

Shielding element The “Chateau”: (top 1 m / thin side 50 cm / thick side 120 cm Include the “survey hole” and cable tray… Will block the current emergency exit of Linac2 Opening at the end of the Linac2 toward the switch-yard (currently filled with small blocks)

The “Wall” 1 m thick 6 m high Two half cylinder for cables (30 cm radius) Block the emergency exit from Linac4 New door facing the Linac4 door toward Linac2… Power cables to be re-routed (new opening)

The chicane(s) 80 cm thick concrete shield The “Chicanes” 80 cm thick – 180 cm side 170 cm opening to allow the passage of the BHZ20 (sufficient ?) To be validated by integration studies

FLUKA model 3 D view of the FLUKA geometry

Some FLUKA results (Horizontal view) Linac4 levelAmplifier gallery level Racks area level Beam losses : W ?

Vertical views

View perpendicular to the L2 beam (B351)

Possible sequence for the connection 1.Removal of L2 chicane (not needed for Linac4 operation) 2.Dismantling of Linac2 beam lines 3.Drilling of new door 4.New opening for cables 5.Re-routing cables and “grouping” remaining ones (services ?) & 5

Possible sequence for the connection 6.Chateau construction 7.Wall construction 8.Connection 9.Chicanes installation…

Others…. Infiltration on the Linac2 side, can something be done ? Removal of LT.STP.10 ? (not needed anymore…) Ventilation of the new area ? Air tightness with the PS enclosure…. Dismantling of wall close to the Linac2 dump (see next slide) ?

Possible dismantling of concrete blocks ? Most likely build for periods with beam parked on the beam dump (tbc)

LBE beam dump (very preliminary)

LBE beam dump pulse current and duty cycle spot size (mm x mm) duration Commissioning40 mA 400microsec 1.11 Hz (0.04%) 3 x 3~1month (6hour/day) PSB Operation40 mA 400microsec 1.11 Hz (0.04%) 3 x 3Occasionally LBS dump used only for ions

Possible shielding ? Main dump like not possible and not justified Test with the HST trolley shielding

Residual Dose rate at the end of commissioning Iron Borated concrete 8 hours cool down1 day cool down Horizontal view

Residual Dose rate at the end of commissioning Iron Borated concrete 8 hours cool down1 day cool down Vertical view

Residual Dose rate at the end of commissioning 8 hours cool down 1 day cool down Horizontal view 1 Week cool down Iron Borated concrete 1 month cool down 6 months cool down

Conclusions LBE Concrete of trolley not efficient Integration of iron shielding : Laterally 20 cm (min.) Back side 20 cm and 10 cm on front side Verification with integration studies and FLUKA