neutron and/or photon response of a tld-albedo personal...

P4 - TLD-albedo dosemeterWorkshop in Bologna July 14-17 2003

P4: 1QUADOSQUADOS

Neutron and/or photon response of a TLD-albedo personal dosemeter on

an ISO slab phantom

Problem P4

Rick J TannerNational Radiological Protection Board

Chilton, Didcot, Oxon OX11 0RQ, United Kingdom

Intercomparison on the Usageof Computational Codes in Radiation Dosimetry

Workshop in Bologna-Italy July 14 -17 2003


P4: 2QUADOSQUADOS

Albedo dosemeters

General features


P4: 3QUADOSQUADOS

Albedo dosemeters: I

• Original concept from UKAEA in the 1960’s

• More than 30 years later still one of the most commonly used personal dosemeters

• Basic principle relies on the detection of neutrons moderated in the body

• Sensitive volume shielded from direct neutrons

• Use capture reactions for detection

• Shield using material with large thermal neutron capture cross-section


P4: 4QUADOSQUADOS

Albedo dosemeters: II

• Albedo field has a strong thermalized component

• Capture reactions such as 6Li(n, t) or 10B(N, α) detect the backscattered field with good efficiency

• 6Li(n, t) is particularly useful because LiF is commonly used for thermoluminescence detectors (TLDs)

• Shield from incident thermals using boron-loaded plastic holder or cadmium

• Can add an unshielded element to give additional information on field hardness


P4: 5QUADOSQUADOS

Albedo dosemeters: III

• Natural lithium is 7.5% 6Li, 92.5% 7Li

• Typically β/γ TL-detectors 99.93% 7Li

• Typically neutron TL-detectors 95.6% 6Li

• Use four elements: two 7Li enriched to give the photon response and two 6Li enriched to give the neutron response

• Algorithm for dose equivalent involves subtraction of the low LET component and correction for field hardness


P4: 6QUADOSQUADOS

Important capture cross-sections (JEF-PC)

10-3 10-2 10-1 100 101 102 103 104 105 106 107

Neutron energy (eV)

10-3

10-2

10-1

100

101

102

103

104

105C

ross

-sect

ion

(barn

s) 6Li(n, t)

Cd(n, γ)

10B(n, α)


P4: 7QUADOSQUADOS

6Li cross-sections (JEF-PC)

10-3 10-2 10-1 100 101 102 103 104 105 106 107

Neutron energy (eV)

10-3

10-2

10-1

100

101

102

103

104C

ross

-sect

ion

(barn

s)

6Li(n, p)

Total

Elastic

6Li(n, t)


P4: 8QUADOSQUADOS

P4 Specification


P4: 9QUADOSQUADOS

Problem

• Model the photon response using the absorbed dose to the TL-material. Assume light output is proportional to dose.

• Model the neutron response by counting 6Li(n, t)αevents. Assume that the neutron response is proportional to the number of capture reactions.

• Calculate the fraction of the neutron and photon response that is due to backscatter


P4: 10QUADOSQUADOS

Irradiation conditions

• 30 cm x 30 cm plane parallel source located in a vacuum, incident normal to the front face of the phantom

• 30 cm x 30 cm x 15 cm ISO, water filled slab phantom (PMMA walls)

• Dosemeter mounted on the centre of the front face of the phantom


P4: 11QUADOSQUADOS

Dosemeter

Element 1 2 3 4x-offset -0.75 cm +0.75 cm -0.75 cm +0.75 cm

y-offset +1.75 cm +1.75 cm -1.75 cm -1.75 cm6Li (%) 95.6 0.07 95.6 0.077Li (%) 4.4 99.93 4.4 99.93

ρ (g cm-3) 2.54 2.64 2.54 2.64

Frontshielding

None none 4 mmboronloadedplastic plus1 mm Al

4 mmboronloadedplastic plus1 mm Al

Backshielding

2 mmboronloadedplastic

2 mmboronloadedplastic

none none


P4: 12QUADOSQUADOS

Dosemeter

Water

PMMA (Perspex)

Aluminium

LiF

Boron loaded CH2


P4: 13QUADOSQUADOS

Slices through dosemeter

back front

Aluminium 7LiF

Boron loaded CH2 6LiF


P4: 14QUADOSQUADOS

Author’s (normalization) solution: PHOTONS


P4: 15QUADOSQUADOS

General

• Implied kerma approximation

– Calculation in vacuum

– Need air column for secondary charged particle build up

– Variable depth because of ranges of secondaries

– Diameter of column?

– Electron transport will produce significant differences where the ranges of the electrons are significant

• Rapid calculation

– 33 keV main problem because of poor penetration

– Little need for variance reduction

– Generally very good agreement: refer to paper for results


P4: 16QUADOSQUADOS

Photon response: author

10 100 1000

Photon energy, Eγ (keV)

3

10

40

Resp

on

se (

MeV

g-1

)

E1: 6LiF, bare

E3: 6LiF, Hp(10)

E4: 7LiF, Hp(10)

E2: 7LiF, bare


P4: 17QUADOSQUADOS

Author’s (normalization) solution: NEUTRONS


P4: 18QUADOSQUADOS

Normalization solution: neutrons

• MCNP-4C

• F4 tally, track-length estimate of fluence with FM card - pure 6Li for tally only

• FM card: ρatom × V (i.e. atomic density of 6Li multiplied by the volume of the element)

• Relevant data in MCNP Table 60: atomic density needs to be multiplied by 0.5 × 6Li%

• ENDF/B-vi continuous cross-sections

• 40 cells, 41 surfaces, six materials

• S(α, β) for water, and used CH2 for polymers


P4: 19QUADOSQUADOS

Source neutrons (fixed CTME): analogue

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101

Neutron energy (MeV)

0

5

10

15

20S

ou

rce n

eu

tro

ns

(x1

06

)


P4: 20QUADOSQUADOS

Analogue, total response

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101

Neutron energy, En (MeV)

10-10

10-9

10-8

10-7

10-6

10-5

10-4

10-3

Resp

on

se p

er

sou

rce n

eu

tro

n

E1: 6LiF, direct

E3: 6LiF, albedo

E4: 7LiF, albedo

E2: 7LiF, direct


P4: 21QUADOSQUADOS

Analogue, backscatter

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101


10-11

10-10

10-9

10-8

10-7

10-6

10-5Fla

gg

ed

resp

on

se p

er

sou

rce n

E3: 6LiF, albedo

E1: 6LiF, direct

E4: 7LiF, albedo

E2: 7LiF, direct


P4: 22QUADOSQUADOS

Normalization solution: VR

• Main problem is to get thermal neutrons back from the phantom, through boron-loaded plastic to the TL-element

• Introduced extra cells in the vacuum and phantom to increase the response

• Used energy dependent weight windows to allow high-energy neutrons to pass through the phantom but increase the number of lower energy neutrons

• WWE:n = 100 meV, 10 eV, 1 keV, 1 MeV, 10 MeV


P4: 23QUADOSQUADOS

WWE, total response

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101


10-10

10-9

10-8

10-7

10-6

10-5

10-4

10-3

Resp

on

se p

er

sou

rce n

E1: 6LiF, direct

E3: 6LiF, albedo

E4: 7LiF, albedo

E2: 7LiF, direct


P4: 24QUADOSQUADOS

6Li(n, t) and Hp(10)/Φ

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101


10-10

10-9

10-8

10-7

10-6

10-5

10-4

10-3

Resp

on

se p

er

sou

rce n

6

10

30

60

100

300

600H

p (10

)/Φ

(pS

v cm

2)E2: 7LiF, direct

Hp(10)/Φ

E3: 6LiF, albedo

E1: 6LiF, direct

E4: 7LiF, albedo


P4: 25QUADOSQUADOS

Hp(10) response

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101


10-3

10-2

10-1

100

101

102

103

104

6Li(

n,

t) (µ S

v-1

)

E1: 6LiF, direct

E3: 6LiF, albedo

E4: 7LiF, albedo

E2: 7LiF, direct


P4: 26QUADOSQUADOS

Rdirect(6Li)/Ralbedo(6Li)

1.00E-01

1.00E+00

1.00E+01

2.53E-08 1.00E-06 1.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+00 1.00E+01 2.00E+01

Direct/Albedo

Neut

ron

Ene

rgy

(MeV

)


P4: 27QUADOSQUADOS

Backscatter: cell flagging for phantom

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101


10-10

10-9

10-8

10-7

10-6

10-5

10-4

Fla

gg

ed

resp

on

se p

er

sou

rce n

E3: 6LiF, albedo

E1: 6LiF, direct

E4: 7LiF, albedo

E2: 7LiF, direct


P4: 28QUADOSQUADOS

Backscatter, normalized (flagging)

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101


0

0.5

1.0

Fla

gg

ed

resp

on

se p

er

sou

rce n

E1: 6LiF, direct

E3: 6LiF, albedo

E4: 7LiF, albedo

E2: 7LiF, direct


P4: 29QUADOSQUADOS

Backscatter fraction (flagging)

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101


0

0.5

1.0

Fla

gg

ed

resp

on

se/

To

tal R

esp

on

se

E1: 6LiF, direct

E3: 6LiF, albedo

E4: 7LiF, albedo

E2: 7LiF, direct


P4: 30QUADOSQUADOS

BS fraction: flagging and voiding

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101


0

0.5

1.0

Back

scatt

er

resp

on

se f

ract

ion

E1: 6LiF, direct

E3: 6LiF, albedo

E4: 7LiF, albedo

E2: 7LiF, direct

Voided phantom


P4: 31QUADOSQUADOS

Participants’ solutions


P4: 32QUADOSQUADOS

Participants: codes

• 17 solutions

• 16 Monte Carlo

• 1 deterministic

• 15 participants transported photons

• 14 participants transported neutrons

• 13 solutions using MCNP family of codes

• 2 solutions using MCNPX

• One own code (photon only, but can transport n)

• One each TRIPOLI and PENELOPE


P4: 33QUADOSQUADOS

Participants: origin

• 13 solutions from Europe

• 11 from EU

– France 4

– UK 3

– Austria, Greece, Italy Portugal 1 each

• 2 from Eastern Europe

• 3 from the US

• 1 from South America


P4: 34QUADOSQUADOS

P4-A

• Comprehensive report

• Russian roulette to kill neutrons in the water

• Additional energy: 223 keV

– peak in the 6Li(n, t) cross-section

– shows as an increase in the response

– more visible as smaller backscatter fraction

• Careful inspection of cross-sections

• FM problem

• Tally all (n, t)


P4: 35QUADOSQUADOS

Normalized n response: P4-A

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101


0.4

1.0

4.0

10

Back

scatt

er

resp

on

se f

ract

ion

E1: 6LiF, direct

E3: 6LiF, albedo

E4: 7LiF, albedo

E2: 7LiF, direct


P4: 36QUADOSQUADOS

Normalized n response: P4-A. FM corrected

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101


0.5

1.0

5.0

10

No

rmalize

d r

esp

on

se

E1: 6LiF, direct

E3: 6LiF, albedo

E4: 7LiF, albedo

E2: 7LiF, direct

7Li(n, t)


P4: 37QUADOSQUADOS

High energy LiF cross-sections (JEF-PC)

1 2 3 4 5 7 10 20

Neutron energy (eV)

10-4

10-3

10-2

10-1

100C

ross

-sect

ion

(barn

s)

6Li

Target7Li 19F

(n, t)

(n, p)

(n, d)

(n, α)

Reaction

Q = +4.8 MeVQ = -3.4 MeV


P4: 38QUADOSQUADOS

Backscatter fraction: P4-A

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101


0

0.2

0.4

0.6

0.8

1.0

No

rmalize

d b

ack

scatt

er

fract

ion

E1: 6LiF, direct

E3: 6LiF, albedo

E4: 7LiF, albedo

E2: 7LiF, direct


P4: 39QUADOSQUADOS

With and without S(α, β) in PMMA: P4-A

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

1


0.8

0.9

1.0

1.1

S(α

, β )

: (W

ate

r &

PM

MA

)/W

ate

r

E1: 6LiF, direct

E3: 6LiF, albedo

E4: 7LiF, albedo

E2: 7LiF, direct


P4: 40QUADOSQUADOS

P4-B

• Thorough report

• Analogue solution

• In air not vacuum: source 2.5 cm from phantom (1.71 cm from front of holder)

• No 7Li(n, t) available, but subtracted 19F(n,t)

• Initial problem with FM card: neglected cell volume. Later corrected.

• Tally all (n, t)

• 4x107 histories for all energies

• Backscatter by energy deposited & “flux”


P4: 41QUADOSQUADOS

Normalized response: P4-B

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101


0.8

1.0

2

3

5

7

10

15

20

25

No

rmalize

d r

esp

on

se

E1: 6LiF, direct

E3: 6LiF, albedo

E4: 7LiF, albedo

E2: 7LiF, direct


P4: 42QUADOSQUADOS

Backscatter from F6: P4-B

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

101


0.01

0.1

1

10

No

rmalize

d b

ack

scatt

er

E1: 6LiF, direct

E3: 6LiF, albedo

E4: 7LiF, albedo

E2: 7LiF, direct


P4: 43QUADOSQUADOS

Backscatter from F4: P4-B

0.10

1.00

10.00

2.53E-08 1.00E-06 1.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+00 1.00E+01 2.00E+01


Bac

ksca

tter f

ract

ion

E1: 6Li, directE3: 6Li, albedoE2: 7Li, directE4: 7Li, lbedo


P4: 44QUADOSQUADOS

P4-C

• No report

• Problem with 7Li chips: results ~ factor of 104 too low

• 6Li results ~ 0.4 but energy dependent difference

• Backscatter by phantom voiding, but not presented here because of problems with total response


P4: 45QUADOSQUADOS

Normalized n response: P4-C

0.0000

0.0500

0.1000

0.1500

0.2000

0.2500

0.3000

0.3500

0.4000

0.4500

0.5000

2.53E-08 1.00E-06 1.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+00 1.00E+01 2.00E+01


Neu

tron

resp

onse

E1: 6Li, direct

E3: 6li albedo

0.0000

0.0001

0.0010

0.0100

0.1000

1.0000


Neut

ron

resp

onse

E1: 6Li, direct

E2: 7Li direct

E3: 6li albedo

E4: 7Li albedo


P4: 46QUADOSQUADOS

P4-D

• No report - late submission

• Problem with all data ~ factor 100-1000 low

• Energy dependent difference

• Backscatter not calculated


P4: 47QUADOSQUADOS

Normalized n response: P4-D

0.00E+00

1.00E-03

2.00E-03

3.00E-03

4.00E-03

5.00E-03

6.00E-03

7.00E-03

8.00E-03

2.53E-08 1.00E-06 1.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+00 1.00E+01 2.00E+01

Neutron Energy (MeV)

Neut

ron

resp

onse

E 1: 6Li, directE 2: 7Li, DirectE 3: 6Li, AlbedoE 4: 7Li, Albedo


P4: 48QUADOSQUADOS

P4-E

• No report, but input files and comprehensive data supplied

• Calculation analogue in provided input file

• Calculated induced photon signal in the chips (would be important in the real dosemeter)

• Backscatter by phantom voiding


P4: 49QUADOSQUADOS

Normalized n results: P4-E

-0.50

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

2.53E

-081.0

0E-06

1.00E

-051.0

0E-04

1.00E

-031.0

0E-02

1.00E

-011.0

0E+0

01.0

0E+0

12.0

0E+0

1


Bac

ksca

tter

frac

tion

E 1: 6Li, direct

E 2: 7Li, Direct

E 3: 6Li, Albedo

E 4: 7Li, Albedo

0.800

0.850

0.900

0.950

1.000

1.050

1.100

1.150

1.200


Neut

ron

Resp

onse

E 1: 6Li, direct

E 2: 7Li, Direct

E 3: 6Li, Albedo

E 4: 7Li, Albedo


P4: 50QUADOSQUADOS

P4-F

• No report

• Large energy dependent errors


P4: 51QUADOSQUADOS

Results: P4-F

0.01

0.10

1.00

10.00

100.00

2.53E

-081.0

0E-06

1.00E

-051.0

0E-04

1.00E

-031.0

0E-02

1.00E

-011.0

0E+0

01.0

0E+0

12.0

0E+0

1


Bac

ksca

tter f

ract

ion


0.100

1.000

10.000

100.000

1000.000

2.53E

-081.0

0E-06

1.00E

-051.0

0E-04

1.00E

-031.0

0E-02

1.00E

-011.0

0E+0

01.0

0E+0

12.0

0E+0

1


Neu

tron

resp

onse



P4: 52QUADOSQUADOS

P4-G

• No report

• Very small statistical uncertainties: 0.3-2.7%

• Tripoli solution but very close agreement with normalization solution

• Did not calculate backscatter

• Only participant to request experimental data


P4: 53QUADOSQUADOS

Normalized n response: P4-G

0.900

0.920

0.940

0.960

0.980

1.000

1.020

1.040

1.060

1.080

2.53E

-08

1.00E

-06

1.00E

-05

1.00E

-04

1.00E

-03

1.00E

-02

1.00E

-011.0

0E+00

1.00E

+012.0

0E+01


Nor

mal

ized

neu

tron

resp

onse



P4: 54QUADOSQUADOS

P4-H

• Brief report - paper submitted with updated data

• Generally small statistical uncertainties: 1-3%, but larger for some results

• Close agreement with normalization solution

• Backscatter by voiding phantom


P4: 55QUADOSQUADOS

Normalized n response: P4-H

0.80

0.85

0.90

0.95

1.00

1.05

1.10

2.53E

-081.0

0E-06

1.00E

-051.0

0E-04

1.00E

-031.0

0E-02

1.00E

-011.0

0E+0

01.0

0E+0

12.0

0E+0

1


Nor

mal

ized

neu

tron

resp

onse


0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

2.53E

-081.0

0E-06

1.00E

-051.0

0E-04

1.00E

-031.0

0E-02

1.00E

-011.0

0E+0

01.0

0E+0

12.0

0E+0

1


Nor

mal

ized

bac

ksca

tter

frac

tion E 1: 6Li, direct

E 2: 7Li, DirectE 3: 6Li, AlbedoE 4: 7Li, Albedo


P4: 56QUADOSQUADOS

P4-J

• Provided report & input files

• Some significant statistical uncertainties

• Generally close agreement with normalization solution

• Backscatter by cell flagging

• S(α, β) for water only

• 15 million histories

• Analogue

• Pure 6Li for tallies


P4: 57QUADOSQUADOS

Normalized n results: P4-J

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.53E

-081.0

0E-06

1.00E

-051.0

0E-04

1.00E

-031.0

0E-02

1.00E

-011.0

0E+0

01.0

0E+0

12.0

0E+0

1


Bac

ksca

tter

frac

tion

E 1: 6Li, direct

E 2: 7Li, Direct

E 3: 6Li, Albedo

E 4: 7Li, Albedo

0.600

0.800

1.000

1.200

1.400

1.600

1.800

2.53E

-081.0

0E-06

1.00E

-051.0

0E-04

1.00E

-031.0

0E-02

1.00E

-011.0

0E+0

01.0

0E+0

12.0

0E+0

1Neutron energy (MeV)

Neu

tron

resp

onse

E 1: 6Li, direct

E 2: 7Li, Direct

E 3: 6Li, Albedo

E 4: 7Li, Albedo


P4: 58QUADOSQUADOS

P4-K

• Provided short report & input files


• S(α, β) not used

• 15 million histories

• Used cell importances for variance reduction

• Pure 6Li for tallies

• Used 6000.24y ENDF/B-V dosimetry cross-section


P4: 59QUADOSQUADOS

Normalized n results: P4-K

0.800

0.900

1.000

1.100

1.200

1.300

1.400

1.500

1.600

2.53E

-081.0

0E-06

1.00E

-051.0

0E-04

1.00E

-031.0

0E-02

1.00E

-011.0

0E+0

01.0

0E+0

12.0

0E+0

1


Neu

tron

resp

onse

E 1: 6Li, direct

E 2: 7Li, Direct

E 3: 6Li, Albedo

E 4: 7Li, Albedo

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

2.53E

-081.0

0E-06

1.00E

-051.0

0E-04

1.00E

-031.0

0E-02

1.00E

-011.0

0E+0

01.0

0E+0

12.0

0E+0

1


Bac

ksca

tter

frac

tion

E 1: 6Li, direct

E 2: 7Li, Direct

E 3: 6Li, Albedo

E 4: 7Li, Albedo


P4: 60QUADOSQUADOS

P4-N

• Deterministic

• Backscatter not possible with deterministic method

• Provided short report

• Direct and adjoint

• Results for group energies

• Takes seconds to run

• Simplified geometry


P4: 61QUADOSQUADOS

Normalized n results: P4-N

0.600

0.800

1.000

1.200

2.53E-08 1.00E-06 1.00E-05 1.00E-04Neutron energy (MeV)

Neut

ron

resp

onse

E 1: 6Li, direct

E 2: 7Li, Direct

E 3: 6Li, Albedo

E 4: 7Li, Albedo

0.70

0.80

0.90

1.00

1.10

1.20

1.30

2.53E-08 1.00E-06 1.00E-05 1.00E-04 1.00E-03 1.00E-02 1.00E-01 1.00E+00 1.00E+01 2.00E+01


Neu

tron

Res

pons

e

E 1: 6Li, directE 2: 7Li, Direct

E 3: 6Li, AlbedoE 4: 7Li, Albedo

Direct Adjoint


P4: 62QUADOSQUADOS

P4-P



• Very small statistical uncertainties


P4: 63QUADOSQUADOS

Normalized n results: P4-P

0.100

1.000

10.000

100.000

2.53E

-081.0

0E-06

1.00E

-051.0

0E-04

1.00E

-031.0

0E-02

1.00E

-011.0

0E+0

01.0

0E+0

12.0

0E+0

1


Neu

tron

resp

onse

E 1: 6Li, direct

E 2: 7Li, Direct

E 3: 6Li, Albedo

E 4: 7Li, Albedo

-0.50

0.00

0.50

1.00

1.50

2.00

2.53E

-081.0

0E-06

1.00E

-051.0

0E-04

1.00E

-031.0

0E-02

1.00E

-011.0

0E+0

01.0

0E+0

12.0

0E+0

1


Bac

ksca

tter

frac

tion

E 1: 6Li, direct

E 2: 7Li, Direct

E 3: 6Li, Albedo

E 4: 7Li, Albedo


P4: 64QUADOSQUADOS

P4-R

• Provided short report - subject to thorough approval process

• Backscatter not calculated• Beta-version of MCNP5 (no Doppler broadening)• Used source biasing to improve statistics• Mesh based weight windows for neutrons and

photons• Generally small statistical uncertainties• Checked for convergence of results• Energy dependent systematic difference

compared to author


P4: 65QUADOSQUADOS

Normalized neutron results: P4-R

0.000

20.000

40.000

60.000

80.000

100.000

120.000

140.000

160.000

180.000

2.53E

-08

1.00E

-06

1.00E

-05

1.00E

-04

1.00E

-03

1.00E

-02

1.00E

-01

1.00E

+00

1.00E

+01

2.00E

+01


Neu

tron

resp

onse

E 1: 6Li, direct

E 2: 7Li, Direct

E 3: 6Li, Albedo

E 4: 7Li, Albedo


P4: 66QUADOSQUADOS

P4-S


• Backscatter by flagging

• Very small statistical uncertainties


P4: 67QUADOSQUADOS

Normalized neutron results: P4-S

0.850

0.900

0.950

1.000

1.050

1.100

1.150

2.53E

-081.0

0E-06

1.00E

-051.0

0E-04

1.00E

-031.0

0E-02

1.00E

-011.0

0E+0

01.0

0E+0

12.0

0E+0

1


Neu

tron

resp

onse


0.60

0.70

0.80

0.90

1.00

1.10

1.20

1.30

1.40

2.53E

-081.0

0E-06

1.00E

-051.0

0E-04

1.00E

-031.0

0E-02

1.00E

-011.0

0E+0

01.0

0E+0

12.0

0E+0

1


Bac

ksca

tter

fract

ion

E 1: 6Li, direct

E 2: 7Li, Direct

E 3: 6Li, Albedo

E 4: 7Li, Albedo


P4: 68QUADOSQUADOS

Conclusions - neutrons I

• Several participants noted that they are not familiar with this type of dosemeter (nor is the author!)– 1 participant comes from a laboratory that runs a TLD-

albedo service– others (including the author) come from laboratories that

run β/γ TLD services

• Impressed by the quality of some of the reports

• Some late entries were clearly not given as much time as they otherwise would have received

• I have not interacted with the participants to give them a chance to submit revised data, although some authors did revise their data spontaneously


P4: 69QUADOSQUADOS

Conclusions - neutrons II

• Some problems with tallying/scoring

– Some FM card values not calculated correctly

– Some participants tallied over LiF

– Others have errors that have not been explained

– Correct cross-section: 3006.60c or 3006.24y?

• Not very much use of variance reduction

• Statistical errors reported in almost all cases

• Some very large, energy dependent errors

• Deterministic calculation quickest and better than badly applied Monte Carlo

neutron and/or photon response of a tld-albedo personal...

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