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T-489: Induced Activity and Residual Dose Rates. Johannes Bauer for T-489 experimenters prepared 3/19/2007. Irradiation Experiment in Endstation A Spring 2007. Motivation. Monte Carlo Simulations for Design of New Facilities Simulation of residual activity improved in last years - PowerPoint PPT Presentation
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T-489: Induced Activity and Residual Dose Rates
Irradiation Experiment in Endstation A Spring 2007
Johannes Bauerfor T-489 experimenters
prepared 3/19/2007
3/19/2007 2
Motivation
Monte Carlo Simulations for Design of New Facilities• Simulation of residual activity improved in last years• Better-controlled experiments needed for benchmark
tests
CERN Involvement: • Four collaborators from CERN• Two years ago similar experiment at CERN with hadron
beam• SLAC experiment complimentary with electron beam
3/19/2007 3
Experimental Setup
Beam • Primary beam 28.5 GeV at 20 W average (up to 100 W
temporarily), ~ 2x109 e-/pulse at 1 to 10 Hz (not exceeding 100 W)
• Compatible with PEP2 and BABAR• Beams delivered to dedicated copper dump • Need to know absolute beam power to ~5%
Equipment
• Use of existing wire scanner 3WS1 and standard roller screens for beam monitoring and alignment
• Use of existing toroids to measure current
Infrastructure• Just standard beam delivery
3/19/2007 4
Samples at DumpInstallation in beam line inside shielding tunnelof ESA
Regularly controlledaccess to remove and replace samples
Measurements of samples in Bldg.24
3/19/2007 5
Schedule
Installation Official schedule: Mon/Tue April 2/3, 2007
(earlier if access to ESA possible)
Beam Starting Wed April 4, 2007 for 5 to 7 days
(earlier if beams available)
3/19/2007 6
Radiation Hazards
Concrete in ESAAlready irradiated
T-489 does not add much: < 0.01 mrem/h
Equipment in ESAAlso very little: ~ 0.13 mrem/h
Dump
1 mrem/h at 30 cm distance off dump surface13 mrem/h on contact
Values for 100 hours cooling time
3/19/2007 7
Radiation Hazards (cont)
Worst case radiation dose according to simulation, 4 days, 20 W, 15 min cooling time:
contact 30 cm
Dump 2000 mrem/h
130 mrem/h
sample(worst case stainless steel )
2 mrem/h 0.02 mrem/h
Dump’s 30 cm dose rate: 70 mrem/h after 30 min cooling time 50 mrem/h after 1 hour cooling time 20 mrem/h after 10 hours cooling time
3/19/2007 8
Radiation Hazards (cont)
Exposure during sample exchange (4 days of 20 W, 15 min cool-down):
Task Dose rate Time Dose
Approaching dump
1 mrem/h 1 minute 0.017 mrem
Exchanging sample
130 mrem/h
20 seconds
0.72 mrem
Leaving dump 1 mrem/h 1 minutes
0.017 mrem
Total 0.76 mremTraining and rehearsals will be required
Radiological postings and procedures worked out with RPFO