radiation. safety@isac saferib workshop cern, oct.30-nov.1, 2002

Radiation.Safety@ISAC

SAFERIB WorkshopCERN, Oct.30-Nov.1, 2002L. MoritzTRIUMF 4004 Wesbrook Mall Vancouver, B.C. [email protected]

OverviewShort description of ISACShielding (tools and verification)Activation (yields and distribution)Target handlingContamination controlExperience and plans for future

ISAC ParametersReference Design:

100 A of 500 MeV protons on 95 g cm-2 UC2Authorization:

100 A of 500 MeV protons on targetsZ 82Application for targets with Z > 82 in preparationOttawa

Targets (to September 2002)Test only

Targett (g cm -2)Max. Ip (A) Ipdt (Ah)CaO36.0

ISAC at TRIUMFhttp://www.triumf.ca/isac/is9-00-t.jpg

ISAC Experimental Hall

ISAC-II (2005)

ISAC Target Stations500 MeV ProtonsRIBInitial Installation:West Target StationInstallation 2002: East Target Station

ShieldingBulk Shielding: Point source, line-of-sight attenuation Complicated geometries: FLUKAVerification: MCNP, LCS

Point Source, Line-of-sight Attenuation of Prompt Radiation FieldNuclear interaction probabilityHigh-energy neutron yieldAngular dependenceExponential AttenuationGeometry factor

Parameters fn(Ep), h0, , Nuclear interaction probability, fnAngular dependence, Attenuationlength, Source term, h0m=0.8

Chart4

1.40.180.18

1.660.270.27

1.010.070.07

0.760.060.06

0.440.030.03

0.470.010.01

0.330.020.02

0.320.010.01

0.240.020.02

Incident proton energy (MeV)

Sheet1

2005.130.184.330.134.620.092001.40.1820088154

3004.590.184.080.053.820.093001.660.2730089145

4004.020.153.540.113.390.074001.010.0740095416

5003.580.143.20.122.990.075000.760.0650098214

6003.190.172.920.082.690.066000.440.0360010129

7002.970.172.720.112.490.087000.470.0170010315

8002.80.182.540.12.360.078000.330.0280010467

9002.70.142.510.082.30.069000.320.0190010585

10002.580.162.340.132.140.0910000.240.02100010867

Sheet1

00.180.1800.130.1300.090.09

00.180.1800.050.0500.090.09

00.150.1500.110.1100.070.07

00.140.1400.120.1200.070.07

00.170.1700.080.0800.060.06

00.170.1700.110.1100.080.08

00.180.1800.10.100.070.07

00.140.1400.080.0800.060.06

00.160.1600.130.1300.090.09

Al

Cu

Pb

Proton energy (MeV)

Angular relaxation parameter b

Sheet2

00.180.18

00.270.27

00.070.07

00.060.06

00.030.03

00.010.01

00.020.02

00.010.01

00.020.02

Proton energy (MeV)

h0 (pSv m2)

Sheet3

05454

04545

01616

01414

099

055

077

055

077

Proton energy (MeV)

Attenuation length (kg m2)

Chart2

5.130.180.184.330.130.134.620.090.09

4.590.180.184.080.050.053.820.090.09

4.020.150.153.540.110.113.390.070.07

3.580.140.143.20.120.122.990.070.07

3.190.170.172.920.080.082.690.060.06

2.970.170.172.720.110.112.490.080.08

2.80.180.182.540.10.12.360.070.07

2.70.140.142.510.080.082.30.060.06

2.580.160.162.340.130.132.140.090.09

Al

Cu

Pb

Incident proton energy (MeV)

Sheet1

2005.130.184.330.134.620.09

3004.590.184.080.053.820.09

4004.020.153.540.113.390.07

5003.580.143.20.122.990.07

6003.190.172.920.082.690.06

7002.970.172.720.112.490.08

8002.80.182.540.12.360.07

9002.70.142.510.082.30.06

10002.580.162.340.132.140.09

Sheet1

00.180.1800.130.1300.090.09

00.180.1800.050.0500.090.09

00.150.1500.110.1100.070.07

00.140.1400.120.1200.070.07

00.170.1700.080.0800.060.06

00.170.1700.110.1100.080.08

00.180.1800.10.100.070.07

00.140.1400.080.0800.060.06

00.160.1600.130.1300.090.09

Al

Cu

Pb

Proton energy (MeV)

Angular relaxation parameter b

Sheet2

Sheet3

Test: 500 MeV Proton Beam Stop1.8 m2.9 m

Chart1

00.00000001630.0000000306

0.0000000001-5.680.000000056

0.00000000020.0000000253-5.24

0.0000000006-4.680.0000000319

0.00000000140.0000000409-4.24

0.0000000057-3.530.0000000369

0.00000001010.0000000572-3.24

0.0000000311-2.680.0000000321

0.00000007540.0000000735-2.24

0.0000000421-2.530.0000000406

0.00000010190.0000000809-2.09

0.0000002299-1.680.0000004104

0.0000003078-1.530.0000002699

0.0000005340.000000163-1.24

0.00000070380.000000121-1.09

0.0000014334-0.680.000001713

0.0000018231-0.530.000001599

0.0000027960.000000409-0.24

0.00000341290.000000378-0.09

0.00000539720.320.000005087

0.00000616870.470.000006142

0.00000756510.000001140.76

0.00000817320.0000008090.91

0.00000917421.320.000009096

0.00000898180.000001881.76

0.00000925521.470.00001063

0.00000864540.000001211.91

0.00000726062.320.000008679

0.00000665612.470.00000863

0.00000545740.000001962.76

0.00000485490.0000009442.91

0.00000291883.470.000004822

0.00000183360.0000004863.91

0.00000095344.470.000002968

0.00000054910.0000003024.91

0.00000026235.470.000002992

0.00000014350.0000001625.91

0.00000006526.470.000000957

0.00000003460.0000001216.91

0.00000001527.470.0000004802

0.00000000790.0000000627.91

Formula

Snoopy

FLUKA

Horizontal distance (m)

Dose equivalent (pSv per proton)

Beam line 2A test (graphite target)

Moyer

Energy (MeV)=495h0 (pSv)=1.29fnuc=0.788l=0.42

Current (mA)=100m=0.73b=3.5

x

NUMBERxThetartH

1-1.00E+012.85E+001.01E+016.37E+001.64E-07

2-9.50E+002.84E+009.62E+006.07E+003.79E-072.8961.829

3-9.00E+002.82E+009.16E+005.78E+008.81E-07

4-8.50E+002.80E+008.70E+005.50E+002.06E-06

5-8.00E+002.78E+008.25E+005.21E+004.86E-06

6-7.50E+002.76E+007.80E+004.92E+001.15E-05

7-7.00E+002.74E+007.35E+004.64E+002.77E-05

8-6.50E+002.71E+006.91E+004.36E+006.69E-05

9-6.00E+002.68E+006.48E+004.09E+001.64E-04

10-5.50E+002.64E+006.05E+003.82E+004.04E-04

11-5.00E+002.60E+005.63E+003.55E+001.01E-03

12-4.50E+002.55E+005.22E+003.30E+002.57E-03

13-4.00E+002.50E+004.83E+003.05E+006.59E-03zthetartMoyer

14-3.50E+002.43E+004.45E+002.81E+001.72E-02-4.52.55E+005.22E+003.30E+002.57E-03

15-3.00E+002.36E+004.10E+002.59E+004.52E-02-3.52.43E+004.45E+002.81E+001.72E-02

16-2.50E+002.27E+003.77E+002.38E+001.20E-01-2.52.27E+003.77E+002.38E+001.20E-01

17-2.00E+002.16E+003.48E+002.20E+003.15E-01-1.52.03E+003.24E+002.04E+008.10E-01

18-1.50E+002.03E+003.24E+002.04E+008.10E-01-0.51.74E+002.94E+001.85E+004.41E+00

19-1.00E+001.89E+003.05E+001.93E+001.98E+000.51.41E+002.94E+001.85E+001.40E+01

20-5.00E-011.74E+002.94E+001.85E+004.41E+001.51.11E+003.24E+002.04E+002.08E+01

210.00E+001.57E+002.90E+001.83E+008.57E+002.58.76E-013.77E+002.38E+001.55E+01

225.00E-011.41E+002.94E+001.85E+001.40E+013.57.09E-014.45E+002.81E+007.17E+00

231.00E+001.25E+003.05E+001.93E+001.88E+014.55.88E-015.22E+003.30E+002.49E+00

241.50E+001.11E+003.24E+002.04E+002.08E+015.54.99E-016.05E+003.82E+007.31E-01

252.00E+009.83E-013.48E+002.20E+001.93E+016.54.32E-016.91E+004.36E+001.93E-01

262.50E+008.76E-013.77E+002.38E+001.55E+017.53.81E-017.80E+004.92E+004.80E-02

273.00E+007.85E-014.10E+002.59E+001.10E+018.53.39E-018.70E+005.50E+001.14E-02

283.50E+007.09E-014.45E+002.81E+007.17E+009.53.06E-019.62E+006.07E+002.66E-03

294.00E+006.44E-014.83E+003.05E+004.35E+00

304.50E+005.88E-015.22E+003.30E+002.49E+00

315.00E+005.40E-015.63E+003.55E+001.37E+00

325.50E+004.99E-016.05E+003.82E+007.31E-01

336.00E+004.64E-016.48E+004.09E+003.80E-01

346.50E+004.32E-016.91E+004.36E+001.93E-01

357.00E+004.05E-017.35E+004.64E+009.69E-02

367.50E+003.81E-017.80E+004.92E+004.80E-02

378.00E+003.59E-018.25E+005.21E+002.35E-02

388.50E+003.39E-018.70E+005.50E+001.14E-02

399.00E+003.22E-019.16E+005.78E+005.53E-03

409.50E+003.06E-019.62E+006.07E+002.66E-03

411.00E+012.91E-011.01E+016.37E+001.27E-03

421.05E+012.78E-011.05E+016.66E+006.06E-04

431.10E+012.66E-011.10E+016.95E+002.88E-04

441.15E+012.55E-011.15E+017.25E+001.37E-04

451.20E+012.45E-011.19E+017.54E+006.48E-05

461.25E+012.36E-011.24E+017.84E+003.06E-05

471.30E+012.27E-011.29E+018.13E+001.45E-05

481.35E+012.19E-011.33E+018.43E+006.82E-06

491.40E+012.11E-011.38E+018.73E+003.22E-06

501.45E+012.04E-011.43E+019.03E+001.52E-06

Point LossDistributed Loss

-4.52.95E-034.87E-03-4.52.00E-040.00E+00

-3.52.60E-021.73E-02-3.55.99E-037.68E-03

-2.56.96E-023.39E-02-2.53.21E-022.18E-02

-1.52.32E-016.35E-02-1.52.46E-016.17E-02

-0.51.82E+003.02E-01-0.59.90E-011.32E-01

0.55.47E+003.29E-010.53.47E+003.27E-01

1.59.70E+004.16E-011.55.22E+004.21E-01

2.51.03E+014.88E-012.55.45E+003.24E-01

3.56.56E+003.66E-013.54.27E+003.78E-01

4.54.05E+004.90E-014.53.06E+002.64E-01

5.51.87E+001.82E-015.52.19E+002.45E-01

6.51.14E+002.82E-016.51.19E+001.49E-01

7.56.80E-011.35E-017.58.19E-011.21E-01

8.52.68E-016.61E-028.56.81E-011.17E-01

9.52.05E-014.99E-029.55.18E-018.34E-02

&A

Page &P

Moyer

000.002565378

000.0171669012

000.1195373653

000.8095799363

004.4069924529

0014.0024626153

0020.7862871988

0015.4721503673

007.1736765039

002.4940467879

000.7309725398

000.1933076167

000.0479738274

000.0114355069

000.0026555591

Point Loss

Distributed Loss

Moyer


Dose equivalent rate (Sv/h)

Sheet2

00.00000001630.0000000306

0.0000000001-5.680.000000056

0.00000000020.0000000253-5.24

0.0000000006-4.680.0000000319

0.00000000140.0000000409-4.24

0.0000000057-3.530.0000000369

0.00000001010.0000000572-3.24

0.0000000311-2.680.0000000321

0.00000007540.0000000735-2.24

0.0000000421-2.530.0000000406

0.00000010190.0000000809-2.09

0.0000002299-1.680.0000004104

0.0000003078-1.530.0000002699

0.0000005340.000000163-1.24

0.00000070380.000000121-1.09

0.0000014334-0.680.000001713

0.0000018231-0.530.000001599

0.0000027960.000000409-0.24

0.00000341290.000000378-0.09

0.00000539720.320.000005087

0.00000616870.470.000006142

0.00000756510.000001140.76

0.00000817320.0000008090.91

0.00000917421.320.000009096

0.00000898180.000001881.76

0.00000925521.470.00001063

0.00000864540.000001211.91

0.00000726062.320.000008679

0.00000665612.470.00000863

0.00000545740.000001962.76

0.00000485490.0000009442.91

0.00000291883.470.000004822

0.00000183360.0000004863.91

0.00000095344.470.000002968

0.00000054910.0000003024.91

0.00000026235.470.000002992

0.00000014350.0000001625.91

0.00000006526.470.000000957

0.00000003460.0000001216.91

0.00000001527.470.0000004802

0.00000000790.0000000627.91

This paper

Snoopy

FLUKA




z(m)r(m)t(m)thetaMoyerFLUKAMeasured

-24.041.412.098.70E-07125-25.37E-078.20E-080.0000005564

-13.641.271.8493.48E-06430-11.74E-062.50E-070.0000019142

03.511.221.5711.11E-0540004.71E-063.40E-070.0000017806

13.641.271.2932.44E-0558019.13E-066.90E-070.0000025819

24.041.411.0523.29E-0570028.41E-064.50E-070.0000031161

34.612.350.8635.23E-0628032.66E-062.70E-070.0000012464

45.323.360.725.84E-078249.74E-073.13E-070.000000365

56.114.250.6117.80E-084551.37E-074.00E-080.0000002003

66.954.830.5292.02E-082563.63E-081.97E-080.0000001113

y(ft)y(m)r(m)t(m)h(meas)h(FLUKA)h(moyer)FLUKAMeasured

-15-4.5725.5813.7212040.0100.000000011400.0000000168

-13-3.9625.0943.0914857.59.60.00000006160.00000000630.0000000403

-11-3.3534.6352.252135151381210.00000054820.00000011590.0000001134

-9-2.7433.5721.90510001008963380.00000210890.00000075260.0000008399

-7-2.1343.8472.565185205733460.00000037770.00000048130.0000001554

-5-1.5243.5452.364300404111900.00000071780.00000034520.000000252

-3-0.9143.3292.2196005011492360.00000114960.00000096510.000000504

-1-0.3053.2152.1447005012893120.00000147360.00000108270.0000005879

10.3053.2152.1447205013373320.00000147360.0000011230.0000006047

30.9143.3292.2195204513143830.00000114960.00000110370.0000004368

51.5243.5452.364400408072870.00000071780.00000067780.000000336

72.1343.8472.5651702019486.30.00000037770.00000016290.0000001428

92.7434.2163.025100102101320.00000010520.00000017640.000000084

y(ft)y(m)rz(m)r(m)t(m)h(meas)FLUKAMeasured

-11-3.3534.1455.4294.935251.10513.415.70.00000000340.00000001132.10E-08

-9-2.7433.675.0754.511351.06922.415.80.00000001220.00000001882.94E-08

-7-2.1343.244.7734.09601.03529.819.70.00000004240.0000000255.04E-08

-5-1.5242.8754.5333.6271151.003158680.00000015830.00000013279.66E-08

-3-0.9142.6044.3663.0371900.97830762.70.0000007590.00000025791.60E-07

-1-0.3052.4574.282.9772750.9658061820.00000095350.0000006772.31E-07

10.3052.4574.282.9772800.9655621270.00000095350.0000004722.35E-07

30.9142.6044.3663.0372000.97843779.10.0000007590.0000003671.68E-07

51.5242.8754.5333.1531651.00340080.70.00000048940.0000003361.39E-07

72.1343.244.7733.321251.03513356.40.00000026520.00000011171.05E-07

92.7433.675.0753.667601.06962.337.80.00000009120.00000005235.04E-08

113.3534.1455.4293.923301.10514.317.60.00000003820.0000000122.52E-08

z(m)r(m)thetad

FormulaSnoopyFLUKA

-6.687.282.734.601.42E-111.63E-083.07E-08

-5.686.382.674.038.97E-115.60E-08

-5.245.992.643.782.05E-102.53E-08

-4.685.502.593.485.97E-103.19E-08

-4.245.132.543.241.40E-094.09E-08

-3.534.572.452.885.65E-093.69E-08

-3.244.352.412.741.01E-085.72E-08

-2.683.952.322.493.11E-083.21E-08

-2.243.662.232.317.54E-087.35E-08

-2.533.852.292.434.21E-084.06E-08

-2.093.572.202.261.02E-078.09E-08

-1.683.352.102.112.30E-074.10E-07

-1.533.282.062.073.08E-072.70E-07

-1.243.151.981.995.34E-071.63E-07

-1.093.091.931.957.04E-071.21E-07

-0.682.971.801.881.43E-061.71E-06

-0.532.941.751.861.82E-061.60E-06

-0.242.911.651.842.80E-064.09E-07

-0.092.901.601.833.41E-063.78E-07

0.322.911.461.845.40E-065.09E-06

0.472.931.411.856.17E-066.14E-06

0.762.991.311.897.57E-061.14E-06

0.913.041.271.928.17E-068.09E-07

1.323.181.142.019.17E-069.10E-06

1.763.391.022.148.98E-061.88E-06

1.473.251.102.059.26E-061.06E-05

1.913.470.992.198.65E-061.21E-06

2.323.710.902.347.26E-068.68E-06

2.473.810.862.406.66E-068.63E-06

2.764.000.812.535.46E-061.96E-06

2.914.110.782.594.85E-069.44E-07

3.474.520.702.852.92E-064.82E-06

3.914.870.643.071.83E-064.86E-07

4.475.330.573.369.53E-072.97E-06

4.915.700.533.605.49E-073.02E-07

5.476.190.493.912.62E-072.99E-06

5.916.580.464.161.44E-071.62E-07

6.477.090.424.486.52E-089.57E-07

6.917.490.404.733.46E-081.21E-07

7.478.010.375.061.52E-084.80E-07

7.918.420.355.327.92E-096.20E-08

0.000.000.00E+00

0.000.000.00E+00

0.000.000.00E+00

&A

Page &P

0.000000870500

0.000003478600

0.000011149600

0.000024352200

0.000032926100

0.000005226300

0.000000584500

0.00000007800

0.000000020200

Moyer

FLUKA

Measured



Beam line 4A test

000

000

000

000

000

000

000

000

000

000

000

000

000

Moyer

FLUKA

Measured

Transverse distance (m)


Beam line 1A test (lower)

0.00000000340.00000001130.000000021

0.00000001220.00000001880.0000000294

0.00000004240.0000000250.0000000504

0.00000015830.00000013270.0000000966

0.0000007590.00000025790.0000001596

0.00000095350.0000006770.000000231

0.00000095350.0000004720.0000002352

0.0000007590.0000003670.000000168

0.00000048940.0000003360.0000001386

0.00000026520.00000011170.000000105

0.00000009120.00000005230.0000000504

0.00000003820.0000000120.0000000252

Moyer

FLUKA

Measured

Transverse distance (m)


Beam line 1A test (upper)

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

Moyer

Snoopy

FLUKA




ISAC Target Shielding (Plan) SteelConcrete(low Na)Radioactive Ion beamSlitsCu Beam dumpTargetProton beamConcreteAA

ISAC Target/ion Source Shielding ion beamsteelsteelsteelconcreteconcrete & steelService space recycled steeltargetvacuum seals(Section AA)

Streaming Through Pre-separator MazeTarget: 50 g cm-2 UC2Ep = 500 MeVIp = 100 mA

Pre-separator MazeAdded shieldingBeforeAfter

ISAC Target Module

Target Module Service DuctsTarget/Ion Source

Streaming Through Target Vacuum Exhaust DuctsTarget: 50 g cm-2 UC2Ep = 500 MeVIp = 100 mApAirConcrete-steelsteel

Streaming Through DuctsConcrete-steelAir

Composition of Top Shield

Radiation Fields above TargetAndersson-Braun Measurement100 A on Mo Target Test

Activation

Experimental Cross-sectionsSilberberg & TsaoFLUKA, LAHET, MCNPXORIGEN

238U(p,x) Cross Section Comparison at 500 MeVLCSFLUKAExperimentalSilberberg & TsaoFissionSpallationPeripheral

Silberberg & Tsao (YIELDX)500 MeV Protons

FLUKA Simulation (500 MeV protons on UC2 target) 18 cm1.4 cmUC2 (5.076 g cm-3)67 mmUC2 (5.076 g cm-3)TaH2O27 mmpp

Yields: UC2 target (FLUKA simulation)18 cm1.4 cmUC2 (5.076 g cm-3)500 MeV p

ORIGEN (build-up and decay)Beam OnBeam Off

Chart2

5178000000000124500000000388400000001066000000010320000000101900000001019000000010190000000994300000025950000000025950000000025900000000022180000000038620000000386200000003862000000038370000000173500000001735000000036500000000378100000009149000000009838000000122900000001229000000075750000000108300000001204000000010830000000694000000019400000004267000000987700000000102400000017930000006323000000004867000000081100000032240000000105800000

8554000000000236500000000721400000002635000000026050000000259300000002593000000025930000000256800000002681000000002681000000002676000000002304000000006638000000066380000000663800000006613000000032730000000327300000006425000000064980000000118600000000018400000000188200000001882000000011380000000017990000000185700000001799000000011530000000389000000068410000009878000000002040000000326900000070200000000048670000000139400000040470000000240400000

107500000000003371000000001007000000004539000000045140000000450100000004501000000045010000000447600000002755000000002755000000002750000000002379000000008752000000087510000000875100000008727000000046380000000463800000008538000000085670000000126600000000025850000000228500000002285000000013300000000022310000000226000000002231000000014290000000583300000083930000009878000000003049000000448300000070970000000048680000000183800000042580000000378300000

121900000000004275000000001251000000006604000000065850000000657200000006572000000065720000000654700000002820000000002820000000002815000000002444000000001036000000001036000000001036000000001034000000005849000000058490000000101500000000101400000000128900000000032340000000257400000002574000000014260000000025330000000254900000002533000000016230000000776800000094780000009878000000004050000000548200000071060000000048680000000217600000043120000000516400000

1312000000000050870000000014610000000087120000000869800000008685000000086850000000868500000008661000000028770000000028770000000028720000000025000000000011590000000011590000000011590000000011570000000069230000000692300000001138000000001135000000001296000000000379900000002811000000028110000000147500000000277600000002785000000027750000000177800000009696000000103500000009878000000005044000000630400000071060000000048690000000243400000043250000000654600000

13730000000000581700000000164100000000107800000000107700000000107600000000107600000000107600000000107300000000292600000000292600000000292100000000254900000000125300000000125300000000125300000000125100000000787600000007876000000012320000000012270000000012980000000004290000000030230000000302300000001499000000002991000000029980000000299100000001916000000011620000000111200000009878000000006031000000698000000071070000000048690000000263100000043290000000792800000

14130000000000647300000000179500000000127600000000127500000000127400000000127400000000127400000000127200000000296900000000296900000000296400000000259200000000132500000000132500000000132500000000132300000000872100000008721000000013030000000012970000000012980000000004718000000032240000000322400000001511000000003193000000031990000000319300000002046000000013530000000118500000009878000000007011000000753700000071070000000048700000000278200000043300000000931000000

143900000000007062000000001927000000001461000000001461000000001460000000001460000000001460000000001457000000003006000000003006000000003001000000002629000000001380000000001380000000001380000000001378000000009471000000094700000000135900000000135100000000129900000000050900000000342000000003420000000015170000000033900000000339400000003389000000021710000000154400000001256000000098780000000079840000007995000000710700000000487000000002898000000433000000001069000000

14560000000000759100000000204000000000163200000000163300000000163100000000163100000000163100000000162900000000303800000000303800000000303300000000266200000000142300000000142200000000142200000000142000000000101400000000101400000000140100000000139300000000129900000000054140000000361200000003612000000015210000000035830000000358700000003582000000022950000000173300000001325000000098790000000089490000008372000000710700000000487100000002987000000433000000001207000000

14670000000000806700000000213700000000178800000000178900000000178800000000178800000000178800000000178500000000306700000000306700000000306200000000269000000000145500000000145500000000145500000000145300000000107300000000107300000000143400000000142400000000129900000000056960000000380300000003803000000015220000000037740000000377800000003773000000024170000000192300000001394000000098790000000099080000008682000000710700000000487100000003055000000433000000001345000000

14610000000000805900000000213400000000181700000000182100000000178600000000178600000000178600000000178600000000113600000000113600000000113600000000112100000000143000000000141000000000146000000000143000000000107100000000107100000000143000000000138100000000129000000000056880000000376400000003764000000015120000000037750000000376300000003773000000024180000000192300000001393000000089080000000099070000008665000000695200000000435200000003030000000427200000001346000000

1454000000000080510000000021310000000018170000000018210000000017870000000017870000000017860000000017870000000071830000000718300000007183000000071220000000142700000000138900000000145800000000142700000000107000000000107000000000142600000000136000000000127600000000056800000000375000000003750000000015010000000037750000000374900000003772000000024180000000192300000001393000000080330000000099060000008648000000680000000000388900000002983000000421400000001347000000

1436000000000080250000000021210000000017870000000017920000000017900000000017900000000017880000000017900000000056900000000569000000005690000000056870000000141500000000137500000000143900000000141500000000106600000000106600000000141400000000134600000000123000000000056560000000370700000003707000000014710000000037690000000370600000003763000000024150000000192300000001364000000058900000000099040000008597000000636500000000277500000002898000000404500000001349000000

1406000000000079820000000021050000000017880000000017930000000017940000000017940000000017930000000017940000000056230000000562300000005623000000056230000000139600000000136800000000141100000000139600000000106000000000106000000000139500000000133900000000115700000000056170000000363800000003638000000014210000000037470000000363700000003737000000024000000000192300000001349000000035120000000099010000008514000000570100000000158100000002875000000377800000001353000000

134700000000007897000000002073000000001796000000001801000000001801000000001801000000001801000000001801000000005545000000055450000000554500000005545000000013580000000013580000000012850000000013580000000010470000000010470000000013580000000013300000000010230000000005540000000035080000000350800000001327000000003667000000035070000000365300000002349000000019230000000131800000001249000000009894000000835000000045730000000051550000002853000000329600000001358000000

11840000000000764800000000197900000000181300000000181700000000181700000000181700000000181700000000181700000000531900000005319000000053190000000531900000001252000000001252000000001219000000001252000000001010000000001010000000001252000000001226000000007083000000005314000000031730000000317300000001079000000003388000000031730000000333400000002171000000019210000000121800000005732000000987200000078750000002360000000002214000002630000000218900000001370000000

9563000000000725000000000183200000000182300000000182800000000182800000000182800000000182800000000182800000000496200000004962000000049620000000496200000001094000000001094000000001094000000001094000000009514000000095140000000109400000000107100000000383700000000495700000002764000000027640000000765400000002893000000027640000000287900000001853000000019170000000104000000001568000009836000000714300000078400000000482800002297000000110700000001378000000

6234000000000651400000000157100000000179300000000179700000000179700000000179700000000179700000000179700000000431900000004319000000043190000000431900000008358000000083570000000835700000008358000000084390000000843900000008355000000081810000000112600000000431500000002300000000023000000000384900000002353000000022990000000235300000001507000000019100000000845700000010970000097650000005878000000864900000047600000175500000028280000001381000000

172700000000047260000000098990000000148800000000149200000000149200000000149200000000149200000000149200000000284800000002847000000028470000000284700000003761000000037610000000376100000003761000000058910000000589000000003760000000036820000000284300000028450000000193300000001933000000048950000001933000000019330000000193300000001238000000018880000000694600000076580000955300000032750000001161000047400000789800000472000001381000000

203300000000276900000000459400000008770000000087940000000879400000008794000000087940000000879400000001422000000014220000000142200000001422000000010300000000103000000001030000000010300000000323500000003235000000010300000000100800000006182000142100000001862000000018620000000157400000186200000001862000000018620000000119300000001852000000066920000004206000092110000001237000000189.847080000216300000514501380000000

u237

pa233

th227

tl207

bi211

rn219

po215

pb211

ra223

po214

rn218

ra222

th226

at217

bi213

pb209

fr221

pa234m

th234

ac225

po213

np239

u230

po216

rn220

u231

bi212

ra224

pb212

po212

th228

tl208

pa234

np235

ra225

pa232

ac228

tl209

np238

u232

Time (hours)

Activity (Bq)

Comparison

EOB10 days100 days1000 days

directtwostageratiodirecttwostageratiodirecttwostageratiodirecttwostageratio

u2371.47E+138.67E+121.691.41E+138.31E+121.699.56E+125.65E+121.692.03E+111.20E+111.69u237u2378.67E+128.31E+125.65E+121.20E+11

pa2338.07E+112.76E+112.927.98E+112.73E+112.927.25E+112.48E+112.922.77E+119.48E+102.92pa233pa2332.76E+112.73E+112.48E+119.48E+10

th2272.14E+114.54E+104.712.11E+114.47E+104.711.83E+113.89E+104.714.59E+109.74E+094.72th227th2274.54E+104.47E+103.89E+109.74E+09

tl2071.79E+113.56E+105.021.79E+113.58E+104.991.82E+113.70E+104.938.77E+101.84E+104.76tl207tl2073.56E+103.58E+103.70E+101.84E+10

bi2111.79E+113.57E+105.011.79E+113.59E+104.991.83E+113.71E+104.938.79E+101.85E+104.76bi211bi2113.57E+103.59E+103.71E+101.85E+10

rn2191.79E+113.57E+105.011.79E+113.59E+104.991.83E+113.71E+104.938.79E+101.85E+104.76rn219rn2193.57E+103.59E+103.71E+101.85E+10

po2151.79E+113.57E+105.011.79E+113.59E+104.991.83E+113.71E+104.938.79E+101.85E+104.76po215po2153.57E+103.59E+103.71E+101.85E+10

pb2111.79E+116.86E+102.611.79E+112.04E+108.811.83E+111.80E+1010.188.79E+105.15E+0917.09pb211po2146.86E+102.04E+101.80E+105.15E+09

ra2231.79E+113.57E+105.001.79E+113.59E+104.991.83E+113.71E+104.938.79E+101.85E+104.76ra223ra2233.57E+103.59E+103.71E+101.85E+10




at2171.46E+112.36E+106.151.40E+112.26E+106.181.09E+111.77E+106.191.03E+101.62E+096.34at217at2172.36E+102.26E+101.77E+101.62E+09


pb2091.46E+112.38E+106.101.41E+112.29E+106.161.09E+111.77E+106.191.03E+101.62E+096.34pb209pb2092.38E+102.29E+101.77E+101.62E+09

fr2211.45E+112.36E+106.151.40E+112.26E+106.181.09E+111.77E+106.191.03E+101.62E+096.34fr221fr2212.36E+102.26E+101.77E+101.62E+09

pa234m1.07E+112.74E+103.911.06E+112.71E+103.919.51E+102.43E+103.913.24E+108.27E+093.91pa234mpa234m2.74E+102.71E+102.43E+108.27E+09


ac2251.43E+112.32E+106.181.40E+112.26E+106.181.09E+111.77E+106.191.03E+101.62E+096.34ac225ac2252.32E+102.26E+101.77E+101.62E+09


np2391.30E+123.93E+120.331.16E+123.50E+120.333.84E+111.16E+120.336.18E+061.87E+070.33np239np2393.93E+123.50E+121.16E+121.87E+07







pb2123.77E+105.87E+096.433.74E+105.87E+096.372.88E+105.20E+095.541.86E+104.29E+094.35pb212pb2125.87E+095.87E+095.20E+094.29E+09











th2317.71E+105.88E+105.10E+092.69E+02

pb2113.57E+103.59E+103.71E+101.85E+10

po2143.07E+115.62E+104.96E+101.42E+10po214

ac2284.87E+101.58E+104.83E+074.71E+07ac228

u2371.691.691.691.69

pa2332.922.922.922.92

th2274.714.714.714.72

tl2075.024.994.934.76

bi2115.014.994.934.76

rn2195.014.994.934.76

po2155.014.994.934.76

pb2112.618.8110.1817.09

ra2235.004.994.934.76

rn2184.472.762.762.76

ra2224.472.762.762.76

th2264.122.762.762.76

at2176.156.186.196.34

bi2136.166.186.196.34

pb2096.106.166.196.34

fr2216.156.186.196.34

pa234m3.913.913.913.91

th2343.913.913.913.91

ac2256.186.186.196.34

po2136.156.176.196.34

np2390.330.330.330.33

u2302.762.762.762.76

po2166.416.255.424.35

rn2206.416.255.424.35

u2312.362.362.362.36

bi2126.436.385.544.35

ra2246.376.255.424.35

pb2126.436.375.544.35

po2126.436.385.544.35

th2284.354.354.354.34

tl2086.616.385.544.35

pa2342.682.683.583.91

np2352.052.052.052.05

ra2257.007.007.006.98

pa2322.912.912.912.91

tl2096.166.186.196.34

np2380.890.890.890.89

u2322.572.572.582.58

Direct

10020030040050060070080090010001001100210051010102010501100120015002000

u2375.18E+128.55E+121.08E+131.22E+131.31E+131.37E+131.41E+131.44E+131.46E+131.47E+131.46E+131.45E+131.44E+131.41E+131.35E+131.18E+139.56E+126.23E+121.73E+122.03E+11

pa2331.25E+112.37E+113.37E+114.28E+115.09E+115.82E+116.47E+117.06E+117.59E+118.07E+118.06E+118.05E+118.03E+117.98E+117.90E+117.65E+117.25E+116.51E+114.73E+112.77E+11

th2273.88E+107.21E+101.01E+111.25E+111.46E+111.64E+111.80E+111.93E+112.04E+112.14E+112.13E+112.13E+112.12E+112.11E+112.07E+111.98E+111.83E+111.57E+119.90E+104.59E+10

tl2071.07E+102.64E+104.54E+106.60E+108.71E+101.08E+111.28E+111.46E+111.63E+111.79E+111.82E+111.82E+111.79E+111.79E+111.80E+111.81E+111.82E+111.79E+111.49E+118.77E+10

bi2111.03E+102.61E+104.51E+106.59E+108.70E+101.08E+111.28E+111.46E+111.63E+111.79E+111.82E+111.82E+111.79E+111.79E+111.80E+111.82E+111.83E+111.80E+111.49E+118.79E+10

rn2191.02E+102.59E+104.50E+106.57E+108.69E+101.08E+111.27E+111.46E+111.63E+111.79E+111.79E+111.79E+111.79E+111.79E+111.80E+111.82E+111.83E+111.80E+111.49E+118.79E+10

po2151.02E+102.59E+104.50E+106.57E+108.69E+101.08E+111.27E+111.46E+111.63E+111.79E+111.79E+111.79E+111.79E+111.79E+111.80E+111.82E+111.83E+111.80E+111.49E+118.79E+10

pb2111.02E+102.59E+104.50E+106.57E+108.69E+101.08E+111.27E+111.46E+111.63E+111.79E+111.79E+111.79E+111.79E+111.79E+111.80E+111.82E+111.83E+111.80E+111.49E+118.79E+10

ra2239.94E+092.57E+104.48E+106.55E+108.66E+101.07E+111.27E+111.46E+111.63E+111.79E+111.79E+111.79E+111.79E+111.79E+111.80E+111.82E+111.83E+111.80E+111.49E+118.79E+10





at2173.86E+106.64E+108.75E+101.04E+111.16E+111.25E+111.33E+111.38E+111.42E+111.46E+111.43E+111.43E+111.42E+111.40E+111.36E+111.25E+111.09E+118.36E+103.76E+101.03E+10



fr2213.84E+106.61E+108.73E+101.03E+111.16E+111.25E+111.32E+111.38E+111.42E+111.45E+111.43E+111.43E+111.42E+111.40E+111.36E+111.25E+111.09E+118.36E+103.76E+101.03E+10

pa234m1.74E+103.27E+104.64E+105.85E+106.92E+107.88E+108.72E+109.47E+101.01E+111.07E+111.07E+111.07E+111.07E+111.06E+111.05E+111.01E+119.51E+108.44E+105.89E+103.24E+10


ac2253.65E+106.43E+108.54E+101.02E+111.14E+111.23E+111.30E+111.36E+111.40E+111.43E+111.43E+111.43E+111.41E+111.40E+111.36E+111.25E+111.09E+118.36E+103.76E+101.03E+10


np2399.15E+111.19E+121.27E+121.29E+121.30E+121.30E+121.30E+121.30E+121.30E+121.30E+121.29E+121.28E+121.23E+121.16E+121.02E+127.08E+113.84E+111.13E+112.84E+096.18E+06



















Direct

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u237

pa233

th227

tl207

bi211

rn219

po215

pb211

ra223

po214

rn218

ra222

th226

at217

bi213

pb209

fr221

pa234m

th234

ac225

po213

np239

u230

po216

rn220

u231

bi212

ra224

pb212

po212

th228

tl208

pa234

np235

ra225

pa232

ac228

tl209

np238

u232

Time (hours)

Activity (Bq)

Twostage

10020030040050060070080090010001001100210051010102010501100120015002000















pa234m4.44E+098.37E+091.19E+101.50E+101.77E+102.01E+102.23E+102.42E+102.59E+102.74E+102.74E+102.74E+102.73E+102.71E+102.68E+102.58E+102.43E+102.16E+101.51E+108.27E+09





fr2216.36E+091.09E+101.43E+101.69E+101.89E+102.04E+102.16E+102.24E+102.31E+102.36E+102.32E+102.31E+102.29E+102.26E+102.20E+102.03E+101.77E+101.35E+106.02E+091.62E+09

at2176.36E+091.09E+101.43E+101.69E+101.89E+102.04E+102.16E+102.24E+102.31E+102.36E+102.32E+102.31E+102.29E+102.26E+102.20E+102.03E+101.77E+101.35E+106.02E+091.62E+09




















Twostage

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u237

pa233

np239

th227

po214

ra222

rn218

th226

bi211

rn219

po215

ra223

pb211

tl207

pa234m

th234

u230

u231

pb209

fr221

at217

bi213

ac225

po213

po216

rn220

ra224

bi212

pb212

np235

th228

pa234

po212

tl208

np238

pa232

ra225

u232

tl209

th231

Time (hours)

Activity (Bq)

Decays Leading to 210Po210PoLong-livedNot in ORIGEN Library

Pu

Np

U

Pa

Th

Ac

Ra

Fr

Rn

At

Po

Bi

Pb

Tl

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

Atoms p-1

ISAC Target HandlingTarget Maintenance Hall

Maximum g-field Outside ITMH~10 Sv/h@ 1 m1 mSv/h

ISAC Target Servicing: HotCellsTarget storage pitHot CellsTarget storage pit

ISAC target hot cell roof docking mechanism

ISAC target being docked in hot cell

ISAC Hot Cells Before Installation of Windows

View Through ISAC Hot Cell Window

Contamination ControlVentilation SystemProduction of Radioactivity in AirTypical Release RatesProduction of Volatile RadioactivityVacuum Exhaust Handling

Ventilation SystemHot CellServiceRoomHot CellTargetServiceSpacePresep.CaveMassSeparatorRoomExperimentalHallServicesTarget Maintenance HallFanStandby FanAir pressure depressionrelative to outsideStack

Radioactivity Production in Air

Production in Pre-separator Vault(3000 hours per year, 100mA on 238UC2 target)

Production in Target Service Space(3000 hours per year, 100 A on 238UC2 target)

NuclideProduction rateRelease rate (s-1)(Bq a-1)(%DRL)3H 9.5x1041.8x1031.4x10-127Be2.2x1043.6x1043.0x10-911C4.6x1042.7x1083.0x10-613N1.1x1051.3x1091.2x10-515O4.8x1042.4x1091.6x10-541Ar3.6x1064.1x1095.5x10-5Total8.1x1091.1x10-4

Releases to Atmosphere (Gaseous, 2001)

IsotopeTotal Release (MBq)DRL (MBq)% of DRL127Xe3.41003.7 10108.8 10-941Ar+ +5.0 10-3

Production of VolatilesTargetHgI/XeRb/KrCl/ArNeb+volatiles

Vacuum Exhaust SystemHEPA filterCharcoal filterOperating storageLong-term storagePre-separatorMass-separatorTISExit modulesTPTPTPTPTPTPTPMPMPMPMPSecondaryPrimarySlits

Releases to Atmosphere (Particulates, 2001)

ExperienceContamination IssuesCollective Dose

One (!) Contamination Incident(June 2000)Target StationHot CellNb targetTa target12No contamination after step 1Uniform contamination after step 1No other significant contamination since June 2000

NuclideBq cm-283Rb0.1675Se0.0485Sr0.42169Yb0.03Total0.66

TRIUMF Collective DoseSo far ISAC has had no significant impact on TRIUMF collective doseStart of ISAC operation

Future PlansTask Force to pursue licensing for actinide targetsProposed test station to measure yields and transport properties of alpha-emittersProposed second proton beam line to feed second target station

Conceptual Design of Proposed Test Station

Storage/decay tank

Lucas cell

Vacuum pumping line

Vacuum chamber

Proton beam

Target

Heater power supply

Beam window

Double isolating valves (typical)

Collector plate

Vacuum pump

ISAC stands for Isotope Separator and Accelerator and is located at TRIUMF on the campus of the University of British Columbia in Vancouver, Canada. It is currently the most intense source of radioactive beams.This presentation consists of a very brief description of ISAC an illustration of some of the methods used to design the shielding and to estimate the radioactivity production. The methods devised for handling the irradiated targets and front end components an the design features that help to minimize the spread of loose radioactive material will also be described. Finally there will be a few remarks about our experience in operating the facility and our plans for the future.The reference design for ISAC required the capability to bombard a uranium target with a beam of 500 MeV protons at a maximum intensity of 100 A. The effort required to obtain a licence to operate such a facility was greater than anticipated as it coincided with a major change in the Canadian regulatory environment. Our current licence thus limits us to targets with atomic number less than or equal to 82. We are currently working on preparing an application to obtain a licence to bombard targets with atomic number greater than 82, specifically thorium and uranium targets.This table shows the radioactive ion beam production targets that have been bombarded so far. The second column gives the thickness, the third column the maximum beam intensity and the fourth column the integral of the beam intensity on each target. Only one target has been tested to maximum design intensity. This was a special target that was built for the test only and was not used to produce radioactive ion beam. Here is a three dimensional layout of the facility. The proton beam is brought from the TRIUMF 500 MeV cyclotron via an underground tunnel and impinges on one of two target stations. The target vacuum vessel is shown without the surrounding shielding. The target station is located within a heavily shielded Target Maintenance Hall that will be described in more detail later. The radioactive ion beam is analysed and then sent upward to experiments in the Experimental Hall. Here it may be sent either directly to low-energy experiments or accelerated tp approximately 1.5 MeV/u by a system consisting of an RFQ followed by a drift-tube linac.Here is a plan view of the ISAC Experimental Hall showing the most recent arrangement of low-energy experimental stations and the two high-energy experimental stations.We are currently constructing the second stage of ISAC (ISAC-II). This consists of a super-conducting linac to further accelerate the radioactive ion beam to an energy of between 9 and 16 MeV/u depending on ion mass. The accelerator will be located in a shielded vault primarily to allow the acceleration of high-intensity beams of stable ions.Here is a closer look at the ISAC target stations. The west station was installed first and has been in operation since December 1998. The installation of the second station is nearing completion and will see first beam before the end of this year. In principle it will be possible to operate one station while the other target station is undergoing maintenance.We next describe some of the methods used to design the shielding. For bulk shielding we use a point-source line-of-sight model that is basically a parametrization of Monte Carlo calculations. For complicated geometries we routinely use FLUKA but have verified some calculations using MCNP and LCS. This is the parametrization that we use. It looks a bit like the Moyer formula in that it has an inverse square dependence and an exponential attenuation and a similar angular and energy dependence. But all the parameters are energy dependent. We also multiply the source term by the nuclear interaction probability to account for the fact that at energies below about 1 GeV protons may range-out before participating in a nuclear interaction. This is illustrated in the next slide.The nuclear interaction probability is seen to vary greatly in the intermediate energy region, but is largely independent of material type. All the other parameters approach their Moyer values as the proton energy approaches 1 GeV. The exponent m in the power dependence on the energy is held constant a 0.8.We have verified this formula for a number of geometries and target materials. Here is the result of a typical measurement verifying the shielding for ISAC. A temporary graphite beam dump was installed in the proton beam transfer tunnel for this purpose. The geometry of the overhead shielding is indicated above the photo of the tunnel. The graph compares a FLUKA calculation and the formula (solid line). The agreement is of course very good, as the formula is really just a parametrization of FLUKA calculations. A measurement using an Andersson-Braun monitor is also shown in the graph. The monitor is seen to under-respond significantly near the maximum of the curve. If one folds the neutron spectra calculated using FLUKA with the monitor response one obtains very good agreement.This is a plan view of the shielding arrangement around one of the ISAC target/ion sources. There is more than 2 m of steel followed by low-sodium concrete and then ordinary concrete. This is a vertical section through the target station along the direction of the ion beam. The proton beam impinges on the target into the screen. The target/ion source and each of two sets of focusing electrodes and monitors are contained in modules suspended from massive steel shields. All radiation sensitive connections such as O-rings are made at the top of this shielding in service modules. The primary vacuum system pumps on the target and electrode modules. We expect that the inside of the primary vacuum will be heavily contaminated. The outer guard or secondary vacuum is expected to remain relatively clean of radioactive contamination.This shows a FLUKA calculation of the streaming from the target through the exit modules and the pre-separator cave and its entrance maze. The initial plan called for a rolling shielding door between the pre-separator cave and the high-resolution mass separator room. However, this was eventually abandoned in favour of a simpler maze. The mass separator room is not occupied during operation so that the objective of the maze is to prevent activation and radiation damage to components in the mass separator room. The radiation dose rate criterion was set at 1 mSv/h at the outside wall of the maze.These two plots show a vertical section along the ion beam through the pre-separator cave. A weak point in the shielding had been created by the cut-out left for the propose shielding door. For this reason and also to allow continued access to the pre-separator cave for maintenance, additional steel shielding was packed around the ion beam line and concrete blocks inserted beside the pre-separator magnet (over the objections of the beam physicists who would have liked to have continued access to the front end). A beam monitor located between the exit modules and the pre-separator magnet had to be re-designed so that it could be remotely handled.This is a photo of one of the target modules. It shows the copper-plated shielding plug and the aluminium containment box that contains the target and ion source. A remotely operated shutter closes the radioactive beam port during transport.The target module shielding (and also the shielding for the two exit modules) has a number of penetrations for services and for vacuum pumping. The service duct is straight because it is largely filled with high-voltage conductors, heater power cables and water cooling lines. Nevertheless we have used mycroy (a borated glass) as an insulator support to suppress streaming of low-energy neutrons. A more serious streaming problem is the vacuum exhaust chase. Note that it is off-set from the target position to avoid a direct line-of-sight from the target.This is a FLUKA simulation of the target module shielding that includes modeling of the service duct and the vacuum exhaust chase. What appears at first glance as streaming through the vacuum exhaust is in fact penetration through the shielding via the shortest line-of-sight.This is another view of the result of the simulation. In this case a vertical section along the ion beam axis. The proton beam direction is into the screen and again the weak point through the vacuum exhaust chase is evident. A number of options for the composition of the shielding plug above the target assembly target space were considered. The graph shows a comparison between the attenuation provided by a shielding plug made of standard concrete and that made of concrete that was made with an aggregate that consisted of steel punchings. The fraction of steel obtained was 50% by volume. The top 30 cm were standard concrete. This shows the result of a FLUKA simulation looking down on the target shielding plug. The position of the target is indicated by the red rectangle. The hot spot due to the vacuum chase is evident. The red numbers are measurements taken during the 100 A test on a Mo target. Because of the high iron content in the shielding these measurements taken with an Andersson-Braun monitor may be overestimating the neutron field. We are in the process of making neutron spectrum measurements on top of the shielding to calibrate these measurements.Now a few words about the problem of estimating the radioactivity production in the targets. Wherever estimates of the generation of specific nuclides is required we try to use experimental cross sections. For estimating integral quantities like total activity production and dose rates, this becomes cumbersome and we have generally used the semi-empirical cross section formulae of Silberberg and Tsao. For the purpose of trying to estimate the production of alpha-emitters and fission products from the bombardment of uranium and thorium we performed an extensive comparison between experimental values, the Silberberg and Tsao estimates and the results of Monte Carlo calculations FLUKA and LCS). Recently we have employed the ORIGEN code to estimate the build-up and decay of complex chains of radionuclides.These graphs are taken from a report prepared by Shiori Furihata on the comparison of measured cross sections taken from the literature and the results of various calculations. Wherever there are measurements the calculations agree quite well (for example the graph on the left, which shows the production of radioiodine). But where there is no data the calculations can diverge quite significantly. In the centre graph, showing the production of polonium, the result of the FLUKA calculation lies below the horizontal coordinate. For the production of francium there is on the other hand reasonable agreement. Generally, where data is available, the LCS calculations are in somewhat better agreement than the FLUKA calculations.The Silberberg and Tsao semi-empirical formulae do give a quick way of examining the general trend of the cross section curves. Shown here are cross section for 500 MeV protons on the various targets proposed for ISAC. These cross sections are shown as a function of atomic mass summed over atomic number. They clearly show the peak in curves due to fission for the heavier targets.Here are the results for a more detailed study of two types of uranium targets. The colours are coded to represent the production of nuclides per incident proton. That at the left is a so-called direct production target where the proton beam interact with the target material directly and the one on the right is a two-stage target where the proton beam bombards a water-cooled tantalum core that is surrounded by a uranium carbide blanket. The latter target enhances the production in the fission region relative to the direct reactions, presumably resulting in lower production of radio-toxic alpha-emitters. This is a close-up of the high-Z region of the chart of the nuclides showing the production of the alpha-emitting nuclides. One of the most worrisome is Po-210 because of the volatility and the half-life that is matched to the length of a typical target life-time.We have used the ORIGEN code to follow the complex decay chains in this region. Here is a typical example showing the build-up in a uranium target of the 40 most significant nuclides over a 1000 hour bombardment followed by a 1000 hour decay period. However, Po-210 does not appear in this graph. The reason is as follows:This is the same chart but it distinguishes between the nuclide that are included in the ORIGEN data library (solid colour) and those that are not included (dashed). It is evident that many decay paths that lead to Po-210 are not followed because the data libraries are not complete. We are in the process of updating the libraries so that all paths will be included.Now some practical matters. This is a view of the Target Maintenance Hall taken during commissioning. The view is from the target station towards the hot cells. A target module is being transported by the remotely operated crane. On the right is a cross section through the hall at the target position. A target or exit module weighs approximately 15 tonnes.For a maximally irradiated high-Z target the field at 1 m is expected to be ~10 Sv/h. If the average gamma-ray energy is 0.5 MeV then a target near one of the walls will result in a field of 1 Sv/h outside the concrete wall adjacent to the target. This avoids problems with having to evacuate the adjacent areas in the event a target should become stuck. The crane has many safety features: There are no electronic controls located on the crane; all wiring from sensors is brought back to the control room. All motors are doubled up so that in case one motor fails, the crane can still perform its complete function under load with just one motor. The lifting cable can be lifted from either end so that if one motor fails the target module can still be lifted through the entire range. Here is a simplified plan view and a section of the Target Maintenance Hall showing the relative arrangements of the target stations, the target storage silos and the hot cells used to service the target modules. The Target Hall is shielded by 120 cm of concrete on all sides to allow the movement of essentially bare targets without any radiological impact outside the Hall.This photo shows the hot cell roof and the mechanism for docking the target modules. Once docked the target module can be rotated through a full 360 degrees and raised and lowered through a range of nearly 2 m by the hot cell operator. This photo shows a target module being lowered into the hot cell during commissioning of the system. The drive motor that raises and lowers the target module is now installed as is the chain drive that rotates the mechanism.This is a view of the interior of the two hot cells. The scale is given by the ladders. The vertical slot at the left supports a dividing wall between the hot cells.This is a view through the lead glass window of one of the hot cells. The manipulators have been installed.Finally we will describe some of the contamination control measures that we have included in the design of the facility.This is a schematic diagram of the ISAC ventilation system. The building is divided into a number of zones. Shown are the air pressure depressions in each zone relative to the outside of the building and the direction of leakage of air between the zones. Primary HEPA filtration is supplied near the source; secondary HEPA filtration is supplied in the penthouse near the exhaust point. The secondary filters are DOP testable.

Exhaust is provided by two fans one of which is the duty fan and the other the stand-by fan. The fans are backed up by diesel power.One concern is the production of radioactivity in the air near the target.Two areas were examined: the service space above the target modules and the pre-separator cave. Neutron track length spectra averaged over these volumes were calculated using FLUKA and are shown at the right. Because of the predominantly iron shielding, the spectrum in the service space is much softer than that in the pre-separator cave. These spectra were folded with the production cross sections for nuclides typically produced in air.These are the results of the estimates. The release rates included is the delay during the transport to the exhaust point. The final column expresses these release rates as a percentage of the Derived Release Limit a Canadian regulatory concept. The Derived Release Limit is that amount of radioactivity released in a year that would lead to an equivalent dose of 1 mSv to the most exposed group in the public (the critical group). The same as the previous table, but for the Service Space above the target assembly.And these are the measured release for the most recent year available. The total of the positron and argon-41 releases is somewhat higher than estimated. This is probably because the air in the gap between the target vacuum vessel and the shielding was assumed to be stagnant. However, because no organic sealant can be used, it is likely that there is some leakage of this air into the adjacent space. The xenon-127 originates from inside the vacuum system.In fact there are many volatiles that can be produced from the targets that have been operating or are proposed. This figure shows the cross section curves for a number of targets and the atomic mass regions were volatiles are produced. Often the cross section maximum lies in the region of volatile production.As previously mentioned, the vacuum exhaust system is a two-stage system with an inner primary system that is expected to be highly contaminated and an outer secondary or guard vacuum that is expected to be relatively clean. The separation is not vacuum tight, as the separation has metal-to-metal joints. The systems are pumped separately and in order to avoid building up a large pressure differential they are protected by check valves. The exhaust is pumped into operating storage tanks that are buried in the concrete shielding because of high gamma fields from short lived radioactivities that build up quickly. These operating storage tanks can be emptied from time to time into a larger long-term storage tank that will contain low levels of long-lived species with higher radio-toxicity. The long-term storage tank can be sampled and assayed for radioactivity before release. The release point is filtered with both charcoal and HEPA filters. Here is a summary of the particulate releases for the year 2001. So far the release have been only a small fraction of the Derived Release Limit.Finally let me say a few words about our experience so far.The principle of having the two vacuum systems seems to have worked well as we have encountered very few incidents of contamination of the Target Maintenance Hall. The target and exit modules are generally very clean when they are removed from the vacuum vessel. The exception was one incident where an irradiated Nb target was removed from the target station and transported to the hot cell. No contamination was found after this target transfer. Subsequently a new Ta target was installed and the module transported back to the target station. After this transfer the entire target hall was uniformly contaminated at a low level. The contamination had spread over all walls, the ceiling and crane. At this point all transfers were stopped and extensive measurements made of air flows under different conditions. All measurements indicated that the ventilation system was functioning as it should under all possible module configurations. The cause of the spread of contamination was never established and has not occurred again.In this graph the total power in all extracted particle beams of all accelerators at TRIUMF is plotted as a function of time. (The power in kW has been multiplied by 20 to bring it into agreement with the same scale used for the collective dose). Superimposed is the collective dose for TRIUMF workers. During the initial learning curve the collective dose for all TRIUMF workers increased as the power in the accelerator beams was increased. Much development aimed specifically at reducing the dose to maintenance personnel after high intensity operation was carried out over time resulting in both enhanced reliability of the cyclotrons and improvements in the handling of radioactive components. These developments have been applied to the design of new cyclotrons installed at TRIUMF and elsewhere. As a result there has been a steady decline of the annual collective dose to TRIUMF personnel. At the same time several new facilities have been installed and production has continued to increase. The red arrow indicates the start of ISAC operation. There has been no appreciable impact of the ISAC operation on the collective dose.Presently we are [preparing an application for an amendment to our operating licence that would allow the bombardment of thorium and uranium targets. As part of this work we are proposing to install a test station on one of the unused beam lines at TRIUMF to study the production and transport through the vacuum system of alpha-emitters.There is also an unfunded proposal to install a second target station bombarded by a second simultaneously extracted proton beam from the 500 MeV cyclotron.

This sketch shows a conceptual layout of the test station. We invite interested parties to participate in the definition of the details of the design and what measurements should be performed.

radiation. safety@isac saferib workshop cern, oct.30-nov.1, 2002

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