This is a working document prepared by NIOSH or its contractor for use in discussions with the ABRWH or its 

Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper documents are not final NIOSH or 

ABRWH (or their technical support and review contractors) positions unless specifically marked as such. This 

document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor. 

NOTICE: This report has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution.

1

BATTELLE-TBD-6000 Appendix BB General Steel Industries 

ADDENDUM TO 

DOSE ESTIMATES FOR BETATRON OPERATIONS WHITE PAPER

Prepared by Dave Allen, DCAS

March 2012

Background

At a meeting of the TBD-6000 working group held on March 15, 2012, the NIOSH white paper 

on Betatron Operations submitted in January was discussed. Some issues were raised that affect 

the calculated values in the white paper. This addendum presents recalculated values based on 

those issues as well as a discussion on some of the other issues raised.

Issues Affecting Estimate

Lead shielding

The white paper included lead shielding in the double leaf door as described in GSI NRC license 

applications. The new betatron building was first included in license applications in 1968 thus 

there is no mention of the lead prior to that. The issue was raised that the lead could have been 

added in 1968 to accommodate a large Co-60 source purchased at that time. With no 

information about the existence of the lead prior to that, this addendum recalculates the 

applicable values without the lead present. It should be noted that the lead remains in the 

building model for the calculations used to verify the building model using the 1971 Co-60 

survey data. 

Location of Badge Rack

In the original white paper, the film badges were assumed to be stored in the betatron control 

room. Since a large majority of badges indicated less than 10 mr each week, the dose rate in the 

control room was assumed to be no more than 10 mr/week. After the white paper was submitted, 

former workers pointed out that the badges were kept on a badge rack in a hall way outside the 

betatron control room. This addendum uses the same techniques as discussed in the white paper

but assumes the 10 mr/week limit is at the badge rack instead of in the control room. The 

location of the badge rack was estimated using a drawing from the SC&A review of the white 

paper. The drawing is included here as Figure 1.
This is a working document prepared by NIOSH or its contractor for use in discussions with the ABRWH or its 

Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper documents are not final NIOSH or 

ABRWH (or their technical support and review contractors) positions unless specifically marked as such. This 

document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor. 

NOTICE: This report has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution.

2

Figure 1 – Drawing of New Betatron Building from FUSRAP documentation with location of 

badge rack superimposed by SC&A.
This is a working document prepared by NIOSH or its contractor for use in discussions with the ABRWH or its 

Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper documents are not final NIOSH or 

ABRWH (or their technical support and review contractors) positions unless specifically marked as such. This 

document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor. 

NOTICE: This report has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution.

3

Issues Not Affecting Estimate

Some addition issues were discussed that did not require recalculating doses in the white paper. 

Some of these issues are discussed below.

Betatron Control Room Badges

Dosimetry reports from Landauer through February 6, 1966 included a reading for a badge 

labeled “Betatron CTL”. The white paper interpreted that as betatron control room. Operators 

indicated they knew of no such badge located in the betatron control room. This addendum to 

the white paper removes that assumption but that does not affect the calculations. For most 

operators, the operator badges were either in the badge rack or on their person while they were 

working in the betatron building. A large majority of the operator badges indicated a reading of 

less than 10 mr per week. Therefore, the 10 mr/week limit is applied to the badge rack 

regardless of the location of the Betatron CTL badge.

Control Badges

Normal Landauer practice was to keep a control badge (not to be confused with the Betatron 

CTL badge) with each batch of film. One of the purposes of the badge is to determine the 

background radiation levels in the location the personnel badges were kept. That control badge 

can be used to subtract the background radiation from the other badges and thus determine the 

actual occupational radiation dose. The control badge dose is included in each weekly dosimeter 

report from Landauer. For each week of the covered period, the control badges indicated “M” 

which is recorded for all badges reading less than 10 mrem. It is not clear if Landauer subtracted 

dose directly in the 1960s or if they subtracted some other value derived from the optical density 

reading of the film badge. Either way, the value subtracted would have to be directly 

proportional to the control badge dose. Since the control badges results were reported as “M” 

each week of the covered period, there would have been no background subtraction performed.

Residual Radiation from Betatron 

The white paper explored several possibilities for conflicting information about the magnitude of 

residual radiation from the Betatron apparatus itself. The white paper concluded the most likely 

source of reported readings was magnetic interference with the survey instrument. However, the 

white paper also pointed out that assuming this affect is real would not necessarily increase the 
This is a working document prepared by NIOSH or its contractor for use in discussions with the ABRWH or its 

Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper documents are not final NIOSH or 

ABRWH (or their technical support and review contractors) positions unless specifically marked as such. This 

document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor. 

NOTICE: This report has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution.

4

estimated dose. An example calculation to demonstrate this is included at the end of this 

addendum.

Adjusted Values

Adjustments were made to the white paper calculations as described in the first two issues. In 

the white paper, dose rates while the betatron is operating were determined in various locations 

for a variety of shot scenarios. For this addendum, these calculations were redone after 

eliminating the lead from the double leaf door. An additional dose point at the badge rack was 

included. 

The photon dose estimate for the betatron operators was not based on this analysis so it is 

unaffected by the recalculated dose rates. The neutron dose however is affected due to a change 

in the hours for each orientation of the betatron. The dose to the Layout man is also affected. As 

in the white paper, the Solver add-on in Excel was used to find the maximum weekly dose at the 

number 10 building within the following constraints:

- Maximum weekly reading at #10 building centerline with equipment tunnel

- Weekly dose at the badge rack equal to 10 mr

- Hours per week (of betatron operation) equal to 69.888 hours

- Hours per week for each orientation greater than or equal to zero

The results of solver calculation was 59.858 hrs per week oriented in the back shot, left, down 

position and 10.030 hours per week oriented in the railroad, right, up position. Additionally, 

Solver assigned small amounts of time (less than 0.002 hours) to each of the other orientations.

This resulted in a weekly dose rate in the number 10 building of 226 mr/week from photons. 

However, this is based on a 168 hour week. Prorating exposures to a 65 hour work week results 

in an estimated dose of 87.4 mr/week from photons. No significant change of neutron dose rates 

is expected from the removal of the lead in the double leaf door. However, the hours and 

orientation of the betatron shots was changed by Solver so the neutron dose to both the betatron 

operator and the layout man changed.

Table 1 below shows the annual neutron doses to the betatron operator both from the white paper 

and from this addendum. Table 2 shows the annual doses to the layout man from both the white 

paper and this addendum.
This is a working document prepared by NIOSH or its contractor for use in discussions with the ABRWH or its 

Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper documents are not final NIOSH or 

ABRWH (or their technical support and review contractors) positions unless specifically marked as such. This 

document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor. 

NOTICE: This report has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution.

5

Table 1 – Betatron Operator Annual Neutron Dose

January 2012 White Paper Revised value

Year Neutron (mrem/yr) Neutron (mrem/yr)

1953-1960 125 50

1961 132 56

1962 117 43

1963 89 19

1964 82 13

1965 81 12

1966 40 6

Table 2 – Annual Dose to Layout Worker

Year Photon 

(mr/yr)

Neutron 

(mrem/yr)

Skin-WB a

(rad/yr)

Skin-HF b

(rad/yr)

January 2010 White Paper

1953-1965 2030 78 0.540 1.020

1966 c 1015 39 0.270 0.510

Revised Values

1953-1965 4483 148 0.540 1.020

1966 c 2241 74 0.270 0.510

a Skin-WB represents the skin of the whole body

b Skin-HF represents the skin of the hands and forearms

c 1966 represents 6 months

Residual Radiation from Betatron 

As mentioned earlier, an example calculation is included here to demonstrate the effect of 

including dose from residual radiation from the betatron apparatus. For this example, it is 

arbitrarily assumed that 5 mr per week of the badge reading is attributable to this residual 

radiation. 
This is a working document prepared by NIOSH or its contractor for use in discussions with the ABRWH or its 

Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper documents are not final NIOSH or 

ABRWH (or their technical support and review contractors) positions unless specifically marked as such. This 

document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor. 

NOTICE: This report has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution.

6

For the betatron operators, the assumption is then that the film badges are exposed to 5 mr per 

week from this residual radiation while the operator is wearing the badge. In keeping with that 

assumption, the dose to the badge from scattered radiation is reduced from 10 mr per week to 5 

mr per week to be consistent with actual badge readings. Overall, that results in a higher photon 

dose but lower neutron dose to the operators as can be seen in Table 3.

Table 3 – Annual Dose to Betatron Operator

Year Photon 

(mr/yr)

Neutron 

(mrem/yr)

Photon 

(mr/yr)

Neutron 

(mrem/yr)

Revised Values in this 

Addendum

Accounting for betatron 

residual radiation

1953-1960 590 50 734 45

1961 620 56 763 51

1962 557 43 702 39

1963 435 19 586 14

1964 406 13 558 9

1965 401 12 554 8

1966 a 199 6 275 3

a 1966 represents 6 months

The layout man dose estimate is also affected by this example. This is due to the fact that the 

hours associated with each betatron shot scenarios had to change to avoid estimating that the 

badges would always show a dose greater than 10 mr per week. To estimate this dose, Solver 

was used as before but the weekly dose rate at the badge rack was changed from 10 mr to 5 mr. 

This resulted in betatron being oriented in the back shot, left, down position for 65.963 hours per 

week and the railroad, right up position for 3.925 hours per week. That results in 97.4 mr per 

week at the equipment door in #10 building which is prorated to 37.7 mr per week to the layout 

man. Neutron dose was 5.34 mrem per week prorated to 2.07 mrem per week. Table 4 shows

the layout man annual doses revised in this addendum compared to that obtained in this example.
This is a working document prepared by NIOSH or its contractor for use in discussions with the ABRWH or its 

Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper documents are not final NIOSH or 

ABRWH (or their technical support and review contractors) positions unless specifically marked as such. This 

document represents preliminary positions taken on technical issues prepared by NIOSH or its contractor. 

NOTICE: This report has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution.

7

Table 4 – Annual Dose to Layout Worker

Year Photon 

(mr/yr)

Neutron 

(mrem/yr)

Skin-WB a

(rad/yr)

Skin-HF b

(rad/yr)

Revised values in this Addendum

1953-1965 4483 148 0.540 1.020

1966 c 2241 74 0.270 0.510

Results of example calculation

1953-1965 1995 103 0.540 1.020

1966 c 997 52 0.270 0.510

a Skin-WB represents the skin of the whole body

b Skin-HF represents the skin of the hands and forearms

c 1966 represents 6 months

The white paper indicated that both the layout man and the betatron operator dose can be used 

for employees of GSI and that the most favorable estimate for the case should be used. While 

accounting for the betatron residual radiation caused higher photon dose for the betatron operator 

estimate, it caused lower photon doses for the layout man estimate. Since the layout man 

estimate is the larger of the two, it is the one that would be used in most dose estimates. Thus, it 

is favorable and more realistic to assume the residual dose rate readings of the betatron are due to 

magnetic interference.