Status of Radiation Protection Studies for the Linac4 beam dumps Joachim Vollaire DGS/RP
Outline List of beam dumps for L4 commissioning and operation Shielding for12 MeV beam dump Shielding and strategy for 50 – 100 MeV dump Status of main dump shielding analysis (160 MeV) Status of LBS/LBE dumps shielding analysis Conclusions EDMS L4 BCC meeting # 31, 24/22/2011
List of beam dumps for Linac4 EDMS L4 BCC meeting # 31, 24/22/20113 Temporary beam dumps for commissioning at different energies (12 MeV, 50 MeV and 100 MeV) Main dump shielding with new layout and operational scenario (160 MeV) LBS and LBE dumps (160 MeV) in the L4 transfer line (commissioning and measurements)
12 MeV beam dumps EDMS L4 BCC meeting # 31, 24/22/20114 12 MeV beam (proton instead of H - ) Average current 6.5 A (4.05x10 13 p.s -1 ) Operational scenario (4 weeks A (4.06e13 pps) Beam
Residual dose rate 12 MeV beam dump EDMS L4 BCC meeting # 31, 24/22/ mn cooling time 1h cooling time1day cooling time
50 MeV – 100 MeV beam dump EDMS L4 BCC meeting # 31, 24/22/20116 Re-location of the beam dump from the 50 MeV to the 100 MeV area Move the dump with part of its shielding to limit personnel exposure Best shielding material : lowest residual dose rate and activation of the surrounding structures Operational scenario: 1 Month of 800 W/1.6 kW for 50 / 100 MeV
Geometry and studied configurations (I) EDMS L4 BCC meeting # 31, 24/22/20117 Shielding on a “Table” Concrete bricks below the table (prevent tunnel activation) Shielding on table would move with the dump…
Geometry and studied configurations (II) EDMS L4 BCC meeting # 31, 24/22/20118 Steel (iron) good for high energy neutrons Borated poly. (5 %) high thermal neutron capture cross section Marble low activation, “shield” the shielding Shielding 1Shielding 2Shielding 3 Configuration 1SteelConcreteMarble Configuration 2SteelBorated Poly.Marble Configuration 3Concrete Marble Configuration 4SteelConcrete Configuration 5Borated Poly. Marble Configuration 6Steel Marble Configuration 7SteelMarble
Neutron spectra out of the shielding EDMS L4 BCC meeting # 31, 24/22/20119 Configuration 2 leads to the lowest number of neutrons escaping the shielding To confirm it is a good shielding looking at residual dose rate around the beam dump
Example residual dose rate (8 h cooling) EDMS S1S2S3 C.1SSCOMB C.2SSBPMB C.3CO MB C.4SSCO C.5BP MB C.6SS MB C7SSMB Configuration 1Configuration 2 Configuration 3Configuration 4 50 MeV commissioning
Example residual dose rate (8 h cooling) EDMS Meeting, Date11 S1S2S3 C.1SSCOMB C.2SSBPMB C.3CO MB C.4SSCO C.5BP MB C.6SS MB C7SSMB Configuration 5Configuration 6 Configuration 7 50 MeV commissioning
Example residual dose rate (1 Week cooling) EDMS Meeting, Date12 S1S2S3 C.1SSCOMB C.2SSBPMB C.3CO MB C.4SSCO C.5BP MB C.6SS MB C7SSMB Configuration 1Configuration 2 Configuration 3Configuration 4 50 MeV commissioning
Example residual dose rate (1 Week cooling) EDMS L4 BCC meeting # 31, 24/22/ S1S2S3 C.1SSCOMB C.2SSBPMB C.3CO MB C.4SSCO C.5BP MB C.6SS MB C7SSMB Configuration 5Configuration 6 Configuration 7 50 MeV commissioning
Example residual dose rate (8 h cooling) EDMS L4 BCC meeting # 31, 24/22/ S1S2S3 C.1SSCOMB C.2SSBPMB C.3CO MB C.4SSCO C.5BP MB C.6SS MB C7SSMB Configuration 1 Horizontal cut Configuration 2 Horizontal cut Configuration 3 Horizontal cut Configuration 4 Horizontal cut 50 MeV commissioning
Example residual dose rate (8 h cooling) EDMS L4 BCC meeting # 31, 24/22/ S1S2S3 C.1SSCOMB C.2SSBPMB C.3CO MB C.4SSCO C.5BP MB C.6SS MB C7SSMB Configuration 5 Horizontal cut Configuration 6 Horizontal cut Configuration 7 Horizontal cut 50 MeV commissioning
Residual dose rate profile (1 day – 1 week) EDMS L4 BCC meeting # 31, 24/22/201116
Residual dose rate profile (1 day – 1 week) EDMS L4 BCC meeting # 31, 24/22/201117
Conclusions on shielding comparison EDMS L4 BCC meeting # 31, 24/22/ Configuration 2 best combination for short cooling times Weight ~ 5000 kg
Examples of use of Borated Poly and marble EDMS L4 BCC meeting # 31, 24/22/201119
Dose rate during transport EDMS L4 BCC meeting # 31, 24/22/ Low after week of cooling. Quick disconnection + shielding (lead) to “plug” the opening in the shielding
Dose rate after 100 MeV run EDMS L4 BCC meeting # 31, 24/22/ MeV + 1 week CT 1 50 MeV + 1 week CT
Status of main dump study EDMS L4 BCC meeting # 31, 24/22/ New operational scenario and core design New fellow since 01/10/2011 (Jan Blaha) working on dump shielding CoreCore + shielding (SS/BP/MB)
Some preliminary results available EDMS L4 BCC meeting # 31, 24/22/201123
Contact with RP colleagues in JPARC EDMS L4 BCC meeting # 31, 24/22/ M. Vretenar Chamonix
Status of LBE/LBS beam dumps EDMS L4 BCC meeting # 31, 24/22/ Gallery and adjacent building Access from Booster side Work carried out by H. Richter
Prompt dose calculations EDMS L4 BCC meeting # 31, 24/22/201126
Residual dose rate calculation and optimization EDMS L4 BCC meeting # 31, 24/22/ Residual H*(10)-rate [µSv/h] after commissioning ( 1h ) No optimization1 m deep dumpMarble plate Report being written
Conclusions EDMS L4 BCC meeting # 31, 24/22/ Good progress for the commissioning dumps (12 / 50 / 100 MeV) Main dump shielding still to be specified (assuming 1 core for the entire lifetime of the facility for the time being ?) LBS dump study being documented. LBE study to be performed….