BATTELLE-TBD-6000 Appendix BB General Steel Industries 

DOSE ESTIMATES FOR BETATRON OPERATIONS 

Prepared by Dave Allen, DCAS 

January 2012 

Background 

Numerous documents and information from former workers at General Steel Industries 

(GSI) have come to light since the original exposure estimate for GSI was written and 

approved (DCAS 2007). The information contained in these documents, as well as the 

input from former workers, has proven to be useful in refining the estimates of potential 

radiation dose to employees of GSI. This white paper is intended to incorporate all 

information into a model for exposures at GSI that are consistent with all the data. The 

scenarios developed are intended to represent either realistic or worst case exposure 

conditions when information is lacking. 

This paper starts by adjusting the previous exposure model for the new betatron building 

to incorporate the newly collected information. The exposure conditions developed in the 

new model are compared to the survey results obtained when a Co-60 source was 

exposed. Next the dose rates from various routes of exposure are developed. Lastly, the 

information is assembled in a manner that is consistent with film badge records. In this 

paper, the process of exposing x-ray film to radiation in an attempt to produce a 

radiograph of a piece of equipment is referred to as a “shot”. An attempt was made not to 

refer to the process as “an exposure” to avoid confusion with radiation exposure to a 

person. 

New Betatron Building 

Previous exposure models for GSI’s new betatron utilized building drawings from a 

January 1992 report (ORNL 1990) that described an August 1991 FUSRAP survey (see 

Figure 1). After these models were developed, new information and drawings were 

obtained that provided additional details of the building. The additional drawings are 

provided in Figures 2 through 4 (ML093480290). Some of the additional building details 

included: 

 The existence of a concrete shield wall extending beyond the 10 foot thick 

walls of the equipment tunnel; 

 The existence of lead inside the double leaf door at the end of the equipment 

tunnel; and, 

 Various dimensions of the building and its relationship to adjacent buildings. 

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. 

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Figure 1 – New Betatron Building from 1992 FUSRAP report 

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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 

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

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Figure 2 – New Betatron Building from AEC License Application 

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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 

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Figure 3 – New Betatron Building with Nearby Buildings 

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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 

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Figure 4 – New Betatron Building Elevations 

A survey of the new betatron building with an 80 curie cobalt-60 source exposed was 

conducted on January 29, 1971 (ML093480290). The survey, which included 

measurements taken at various points around the building, is reproduced in Table 1. The 

letters in parentheses correspond to the locations identified in Figures 2 through 4. 

Table 1 – 1971 Survey of New Betatron Building with 80 Curie Co-60 Source Exposed 

Location Radiation Level Remarks 

Control Room 3.0 mr/hr Meter held against door joint (B) 

Control Room 0.6 mr/hr 2’ from door 

Control Room 0.1 mr/hr At control desk 

Processing Room 0.05 mr/hr Highest reading in the area against 

wall 

Concrete Exterior Wall 0.05 mr/hr Highest level, survey meter against 

wall at 5’ height, entire exterior wall 

surveyed 

Transformer Room 1.5 mr/hr At meter door (I) 

Transformer Room 2.0 mr/hr At open area in ceiling – wall 

junction near door (C) 

Outside Surface of Double 

Leaf Door (C) 

0.3 mr/hr Left side 5’ high 

1.8 mr/hr Left side at horizontal door joint 10’ 

high 

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2.5 mr/hr Left side 2’ above horizontal joint at 

12’ height 

0.2 mr/hr Left side 10’ from door 12’ high 

0.4 mr/hr Right side 5’ high 

3.4 mr/hr Right side at horizontal door joint 10’ 

high 

4.4 mr/hr Right side 2’ above horizontal joint at 

12’ height 

1.8 mr/hr Right side 10’ from door 12’ high 

Corner at Door E 0.4 mr/hr Taken against exterior surface of wall 

Corner at Door F 0.2 mr/hr Taken against exterior surface of wall 

The new information was used to modify the previous model of the new betatron 

building. An 80 curie Co-60 source was then added to the model at the position labeled as 

an X within a circle in Figure 2. Radiation levels were determined, using MCNPX, at 

many of the same locations surveyed by GSI in 1971. Table 2 provides a comparison 

between the actual survey results and the modeled results. 

Table 2 – Comparison of Modeled Radiation Levels to 1971 Survey 

Location 1971 Radiation 

Level (mr/hr) 

Modeled 

Radiation Levels 

(mr/hr) 

Control Room 3.0 2.5 Meter held against door 

joint (B) 

Control Room 0.6 1.1 2’ from door 

Control Room 0.1 0.2 At control desk 

Outside Surface of 

Double Leaf Door 

(C) 

0.3 0.4 Left side 5’ high 

1.8 2.4 Left side at horizontal 

door joint 10’ high 

2.5 2.2 

Left side 2’ above 

horizontal joint at 12’ 

height 

0.2 2.0 Left side 10’ from door 

12’ high 

0.4 0.6 Right side 5’ high 

3.4 4.2 Right side at horizontal 

door joint 10’ high 

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

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4.4 4.0 

Right side 2’ above 

horizontal joint at 12’ 

height 

1.8 2.4 Right side 10’ from door 

12’ high 

Corner at Door E 0.4 0.6 Taken against exterior 

surface of wall 

Corner at Door F 0.2 0.6 Taken against exterior 

surface of wall 

With one exception, the modeled value was either higher or within 20% of the measured 

value. The exception was for the location 10 feet from the double leaf door, 12 feet high. 

Inspection of the other survey results near that door revealed that all other measured 

results, 10 feet or more above the floor, are at least 1.8 mr/hr. The survey measurement at 

that point, however, is 0.2 mr/hr. The difference between the model and the measured 

results could be a typographical error or an error in reading the instrument (such as the 

wrong scale). Since the scaled on instruments are typically factors of 10, it is very 

possible the actual reading was 2.0 mr/hr. The other possibility is that there could be 

some piece of equipment mounted there (such as a door motor) creating additional 

shielding that is not depicted in the model. Either way, the values 5 feet above the floor 

are more representative of the location of workers and those values differ by no more 

than 0.2 mr/hr. 

The reasonable agreement between the modeled and measured exposure values indicates 

that the building model provides a realistic representation of the shielding presented by 

the new betatron building. This model was used later to estimate dose rates from various 

shooting scenarios in the new betatron building. 

Shot scenarios 

The betatron could be positioned and aimed in various directions in the shooting area. 

Limit switches prevented it from being pointed in the direction of the control room, but 

reports from operators indicated a procedure was sometimes used to defeat these limits. 

The procedure, referred to as “flipping the head”, was used starting no earlier than 1965. 

To explore the effect of various positions of the betatron on exposure conditions, three 

equipment positions were modeled. In this context, “equipment position” refers to the 

position in which the equipment being x-rayed was located. The first position is referred 

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final NIOSH or ABRWH (or their technical support and review contractors) positions unless specifically 

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to as the “railroad” position. In this position, the equipment is assumed to be on a railroad 

type cart located in the shooting room. For this configuration, the betatron is assumed to 

be pointed directly at the equipment, perpendicular to the railroad tracks. Additional 

scenarios could involve aiming the betatron head 45 degrees to the right and to the left of 

that position. It should be noted that aiming 45 degrees to the right would be a “flipped 

head” position. For all three scenarios, the shots were aimed parallel to the floor. For the 

straight and right scenarios, the shot was also aimed up and down 45 degrees. 

The second equipment position is referred to as the “center shot” position. For this, 

configuration, the equipment is centered in the shooting room near the wall opposite of 

the control room. The betatron head was aimed directly away from the control room as 

well as 45 degrees to the right and to the left and was aimed parallel with the floor for all 

three shots. 

The third equipment position is referred to as the “back shot” position. For this position, 

the equipment is located near the wall in the shooting room opposite the rail road tracks. 

The aiming scenarios including pointing the betatron head directly away from the rail 

road tracks, as well as 45 degrees to the right and to the left of that position. In this 

configuration, 45 degrees to the left would be a “flipped head” position. For all three 

shots, the head was aimed parallel to the floor. For the 45 degree to the left position, the 

head was also tilted 45 degrees up and 45 degrees down. 

Ten tally locations, listed in Tables 3 and 4, were explored for dose rate modeling. Three 

locations were in the control room. The first being 2 feet inside the control room door, the 

second being the approximate center of the control room and the third at the control room 

desk shown in Figure 4. Location 4 was just behind the double leaf door. Location 5 was 

just inside #10 building centered with the equipment tunnel. Location 6 was located in 

the restroom near the new betatron building. 

In determining the location of the restroom, it was noted that Figure 3 appears to be a 

scale drawing for the betatron building and equipment tunnel, but not for the adjacent 

buildings. This can be seen easily by comparing the 21 feet across the equipment tunnel 

to the 30 feet from the wire mesh fence to the adjacent building. Therefore, the drawing 

in Figure 5 was utilized in combination with Figure 3 to estimate the location of the 

restroom. The restroom was identified on Figure 5 by former workers, so this drawing 

was considered to be a good representation of the scale (SCA 2008). Dimensions from 

Figure 3 were then used to scale the drawing and determine the location of the restroom. 

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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 

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Figure 5 – Location of Restroom 

Tally locations 7, 8, and 9 are the three vents on the roof of the new betatron building. 

Their locations were approximated from Figure 6. Location 10 was outside the betatron 

building. This location was chosen to be in the area of low shielding and at a close 

distance to the building. The distance to the building was limited due to the wire mesh 

fence shown in Figure 3. 

Tables 3 and 4 provide the modeled photon exposure rates and neutron dose rates 

respectively for each of the ten locations and for each of the shot scenarios. In Tables 3 

and 4, the positions of the betatron orientation are labeled with the abbreviation for the 

orientation of railroad, center shot or back shot (RR, CS or BS) followed by an 

abbreviation of whether it is aimed straight, turned to the right or turned to the left (ST, 

RT or LT) followed by an abbreviation whether is it not tilted (parallel to the floor), tilted 

up or tilted down (No, Up, or Dn). 

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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 

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Figure 6 – New Betatron Building Vents 

Table 3 – Beam-On Photon Exposure Rates from New Betatron 

CR door CR desk CR center Leaf door #10 Bldg 

RR_ST_No 1.42 0.41 0.65 1.48 1.26

RR_ST_Up 1.15 0.38 0.61 1.52 1.93

RR_ST_Dn 1.28 0.29 0.52 1.98 1.38

RR_LT_No 0.55 0.13 0.27 0.38 0.75

RR_RT_No 8.58 2.21 4.38 29.84 17.13

RR_RT_Up 4.13 1.30 2.83 20.95 8.43

RR_RT_Dn 4.96 1.24 2.81 17.49 7.16

CS_ST_No 0.38 0.06 0.08 0.12 0.29

CS_LT_No 0.25 0.06 0.08 0.19 0.32

CS_RT_No 0.37 0.09 0.12 0.22 0.49

BS_ST_No 0.04 0.03 0.06 0.05 0.17

BS_LT_No 0.08 0.01 0.02 0.06 0.22

BS_RT_No 0.04 0.01 0.01 0.09 0.19

BS_LT_Up 0.10 0.07 0.10 0.23 0.85

BS_LT_Dn 0.06 0.02 0.02 0.07 0.20

Values are in mr/hr 

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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 

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Table 3 – Beam-On Photon Exposure Rates from New Betatron (continued) 

Restroom Roof 1 Roof 2 Roof 3 Outside 

RR_ST_No 0.47 43.14 105.68 208.85 1.64

RR_ST_Up 1.16 54.59 151.75 2349.32 2.34

RR_ST_Dn 0.40 43.52 98.07 135.65 1.35

RR_LT_No 0.33 50.87 122.55 236.28 0.58

RR_RT_No 2.89 49.93 113.35 191.59 28.50

RR_RT_Up 2.67 53.69 170.76 1004.45 10.38

RR_RT_Dn 1.20 46.79 103.71 139.95 9.35

CS_ST_No 0.28 100.13 119.08 90.73 0.32

CS_LT_No 0.30 159.14 139.47 66.53 0.35

CS_RT_No 0.41 67.21 178.41 157.50 0.45

BS_ST_No 0.17 177.39 79.83 34.27 0.13

BS_LT_No 0.24 193.18 85.11 38.89 0.17

BS_RT_No 0.19 228.50 100.57 46.17 0.16

BS_LT_Up 0.44 538.93 116.72 44.81 0.47

BS_LT_Dn 0.17 140.15 78.42 35.43 0.15

Values are in mr/hr 

Table 4 – Beam-On Neutron Exposure Rates from New Betatron 

CR door CR desk CR center Leaf door #10 Bldg 

RR_ST_No 0.30 0.03 0.08 0.23 0.63

RR_ST_Up 0.03 0.02 0.02 0.43 0.36

RR_ST_Dn 0.27 0.41 0.45 1.38 0.35

RR_LT_No 0.10 0.27 0.17 16.68 0.33

RR_RT_No 1.21 0.98 0.86 0.37 0.37

RR_RT_Up 0.15 0.04 0.05 0.66 0.43

RR_RT_Dn 0.01 0.01 0.01 0.15 0.14

CS_ST_No 0.01 0.17 0.20 0.20 0.15

CS_LT_No 0.13 0.00 0.01 0.08 0.10

CS_RT_No 0.07 0.01 0.02 0.16 0.28

BS_ST_No 0.02 0.10 0.06 0.09 0.19

BS_LT_No 0.24 0.09 0.13 0.12 0.09

BS_RT_No 0.53 0.06 0.13 0.06 0.12

BS_LT_Up 0.20 0.03 0.10 0.03 0.05

BS_LT_Dn 0.02 0.00 0.00 0.03 0.06

Values are in mrem/hr 

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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 

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Table 4 – Beam-On Neutron Exposure Rates from New Betatron (continued) 

Restroom Roof 1 Roof 2 Roof 3 Outside 

RR_ST_No 0.06 9.15 18.81 17.63 0.17

RR_ST_Up 0.32 8.69 13.13 12.25 0.65

RR_ST_Dn 0.14 8.95 26.06 19.20 0.56

RR_LT_No 0.15 9.44 18.32 15.19 0.51

RR_RT_No 0.11 9.33 18.80 15.63 0.21

RR_RT_Up 0.13 7.23 11.27 9.49 0.36

RR_RT_Dn 0.05 6.53 14.28 13.80 0.16

CS_ST_No 0.15 12.02 17.30 11.40 0.23

CS_LT_No 0.08 9.00 17.36 12.32 0.10

CS_RT_No 0.15 13.15 19.95 12.63 0.24

BS_ST_No 0.08 20.44 17.21 8.64 0.12

BS_LT_No 0.05 20.54 17.90 11.62 0.10

BS_RT_No 0.10 18.54 14.71 8.20 0.09

BS_LT_Up 0.03 11.86 12.98 6.21 0.05

BS_LT_Dn 0.04 19.53 11.08 5.35 0.05

Values are in mrem/hr 

Residual radiation from uranium 

As part of their AEC contract work, GSI x-rayed slices of uranium ingots from 

Mallinckrodt Chemical Works (SCA 2008). The slices were larger than the largest film 

GSI used, so up to four shots had to be made on each slice to cover 100% of the object. 

Each shot was reported to take 60 minutes with 15 minutes between them to remove the 

film and setup the next shot. 

The dose at 1 foot and 1 meter from the uranium object was modeled using MCNPX. The 

dose was estimated in one minute increments following an irradiation of the uranium 

object with the betatron. The incremental doses were summed to determine the dose 

between zero to 15 minutes following a 1 minute irradiation. The doses were then 

summed to determine the dose between 1 minute and 16 minutes after an irradiation. The 

process was continued until the full 60 minute irradiation was accounted for. It should be 

noted that the first 5 seconds after irradiation were eliminated because at least 5 seconds 

would be necessary for operators to reach the uranium object following an irradiation. 

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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 

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Next, the same process was done for the time frame 75 to 90 minutes following 

irradiation. This was done to account dose from the previous shot. The process was 

repeated for time frames 150 to 165 minutes and 225 to 240 minutes after irradiation. 

When processing a uranium object using 4 shots, the dose from zero to 15 minutes after 

the shot would be received four times while the dose 75 to 90 minutes after the shot 

would only be received three times. This is due to the fact that that dose would not exist 

following the first shot. Likewise, the dose 150 to 165 minute following irradiation would 

only be received twice and the 225 minute to 240 minute dose once. Summing these 

doses produces the dose received from the entire 4 shot series. 

Approximately 90% of the neutron dose is received in the first minute following 

irradiation and the dose rate reduces to zero within a few minutes. Therefore the neutron 

dose received from 4 shots of the uranium object is simply 4 times the dose received from 

a single shot. The photon and neutron doses for 4 x-rays of the uranium object are shown 

in Table 5. 

Table 5 – Dose from Residual Activity in Uranium 

1 foot from uranium object 1 meter from uranium object 

Photon (mr) 4.11 0.49 

Neutron (mrem) 1.04 0.13 

Doses are for a 4 shot series lasting 300 minutes 

The uranium also emits radiation naturally. The dose rate was determined at 1 foot and 1 

meter and is provided in Table 6. One hundred day aged uranium was assumed to insure 

the in-growth of short lived decay products. The photon dose includes both gamma and 

x-rays from decay and from Bremsstrahlung radiation. These dose rates will be added to 

the dose rates from residual activity. 

The operators would also receive a skin dose from beta radiation when working with 

uranium. The beta dose comes primarily from the short lived decay products Th-234 and 

Pa-234m. These isotopes can concentrate near the surface of the uranium ingot when it is 

cast. The assumptions used in an earlier analysis (SCA 2008) are again used here, 

resulting in the skin dose rates shown in Table 6. 

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Table 6 – Dose Rates from Natural Uranium Metal 

Contact with the 1 foot from uranium 1 meter from 

uranium object object uranium object 

Photon (mr/hr) N/A 1.25 0.16 

Beta (mrad/hr) 721.3 37.5 5.3 

The effect of the short lived decay products concentrating on the surface of freshly cast 

uranium has been evaluated previously (Allen 2010). As part of that evaluation, actual 

film badge data from a facility that cast a large quantity of uranium was examined and 

found that a 10 to 1 ratio of beta to photon dose would be favorable. The ratio used here 

is approximately 30 to 1. However, the facility from which the measured ratio was 

obtained worked with considerably more uranium at any time than GSI. It is possible that 

for a given worker, nearby uranium metal contributed to photon dose while not 

contributing to beta dose due to the short range nature of beta radiation. The 10 to 1 ratio 

therefore may not be representative of GSI since only small amount of uranium was 

handled at any one time. A more representative ratio would be higher. This lends 

credibility to the 30 to 1 ratio derived. 

Residual radiation from steel 

The duration of the x-ray exposures for steel castings vary with the thickness of the steel 

being examined. Discussions with operators indicated approximately 90% of the 

examinations were “short shots” and the other 10% were “long shots”. The short shots 

were approximated as being 3 minutes in duration, with the betatron head being 9 feet 

from the target, and 12 minutes needed between shots to setup the next shot. The long 

shots are approximated as being 60 minutes in duration at a distance of 6 feet with 15 

minutes necessary between shots. 

Some radioactive isotopes created during the irradiation have a long half-life, while 

others have a short half life. The time necessary to reach equilibrium is governed by the 

half-life of the isotope being created. For example, if an isotope had a 2 minute half-life, 

half of the activity initially created would decay 2 minutes into a shot. Seven half-lives 

into the shot, the isotope would reach approximately 99% of its equilibrium activity. 

Because of this effect, some of isotopes created would reach equilibrium during a 60 

minute shot and the activity would not increase after that. Others with a longer half-life 

would continue to increase while the shot proceeded. This will affect the ratio of short 

lived isotopes and long lived isotopes depending the duration of the shot. 

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To address this, MCNPX was used to determine the production rate of radioactive 

isotopes in HY-80 steel. HY-80 steel was chosen based on the analysis performed in SCA 

2008. That production rate was then used to determine the buildup of each isotope based 

on the length of a shot. This was then used to correct the modeled doses to account for 

the decay of isotopes during the shot. 

There were two primary reasons for performing x-ray examinations. The first consisted 

of 100% coverage of the casting to check for voids or other flaws. The second was to 

recheck locations repaired after flaws had been discovered. The 100% coverage 

examination would result in exposure not only from the location being shot but from any 

nearby locations previously shot. The nearby locations would contribute less exposure 

than the current shot due to geometry and decay time. Repairs would normally result in a 

follow-up shot to verify the repair. This in turn could result in subsequent repairs and 

additional verification shots. For these shots, the exact same location would be x-rayed 

repeatedly, building up radioactive isotopes in that area. However, since the repair would 

take some period of time, the frequency of the shooting would be less than that of the 

coverage shots. 

To account for both types of shots, the dose was modeled assuming repeated shots on the 

same location. The frequency of the repeated shots is that of the 100% coverage scenario. 

For the long shots, it is assumed 400 previous shots were accomplished in the same 

location while for the short shots it is assumed there were 500 previous shots (SCA 

2008). 

The dose rates at 1 foot and 1 meter at various times following irradiation of the steel 

were determined. The dose rates were determined in line with the betatron beam. The 

times following a shot applicable to the operator exposure for a given exposure scenario 

were added and used to determine a dose to the operator. The decay correction was then 

applied to account for the decay of the isotopes during the shot. In this fashion, the decay 

of isotopes during the shot are accounted for with the decay correction, and the decay of 

isotopes after the shot are accounted for by MCNPX. The modeled results are shown in 

Table 7. 

Table 7 – Photon Dose from Residual Activity in HY-80 Steel 

1 foot (mr/shot) 1 meter (mr/shot) 

Short shot 0.017 0.0033 

Long shot 0.20 0.038 

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15 
For this estimate, the operators are assumed to be directly in front of the location just xrayed. They are further assumed to be at a distance of 1 foot 50% of the time and a 

distance of 1 meter the remaining 50% of the time. The exposure time is assumed to be 

from 5 seconds to 12 minutes following the last shot for the short shots and 5 seconds to 

15 minutes following the last shot for the long shot scenario. The 5 second time period 

represents the minimum amount of time necessary to travel between the control room and 

the casting following a shot. Based on the assumption of 90% of the shots being short 

shots and 10% being long shots, the weekly exposure to the operators was determined to 

be 3.94 mr per week assuming a 65 hour work week. 

Beta Dose 

Beta dose from residual activity in steel was determined using the same techniques 

described in SCA 2008. The technique involved determining the specific activity of beta 

emitting isotopes created in HY-80 steel. The specific activity was determined from a 

relatively small disc of steel (6.5 inch diameter) to insure only the most intense part of the 

betatron beam was used. The activity was allowed to build up for 30 hours. Next the 

specific activity on the surface was calculated and applied to a larger relatively thin steel 

disc (100 cm radius, 0.4 cm thick). From this disc, the dose rate at various distances was 

determined. The dose from each isotope was then integrated over the appropriate time 

and summed. The appropriate time is the time after each shot that the individual is 

working with the casting. The betatron operator time for short or long shots was 

discussed previously. The appropriate time for the layout worker is discussed later. 

Table 8 – Skin Dose from Residual Activity in HY-80 Steel 

Whole Body Skin 

(mrad/week) 

Skin of the hand and forearms 

(mrad/week) 

Betatron Operator 18.4 30.0 

Layout Worker 10.8 20.4 

Film badges 

GSI film badge records covering the period of 1964 through 1973 were obtained from 

Landauer. The records indicate that these badges were exchanged on a weekly basis 

starting in November of 1963. From the beginning of this service through February 6, 

1966, one badge was designated each week for the betatron control room. This results in 

114 badge readings from the control room, all of which indicated exposures of less than 

10 mrem/week. While no film badge was designated for the control room after February 

of 1966, the operators from GSI have repeatedly indicated that film badges were stored in 

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16 
the betatron building whenever they were not working in the betatron building. This 

would indicate the film badges were always in the betatron building either stored when 

not in use or on the radiographer. There is some indication the film badges were actually 

worn outside the betatron building when radiographers were working with isotopic 

sources, but this was generally done by only a few people at a time. The effect of this on 

the dose estimate will be discussed later. More than 99.8% of the badge readings 

indicated exposure of 10 mrem or less. With the badges always in the control room 

during shots (either stored there or worn by the radiographers) the dose rate in the control 

room can be determined to be less than 10 mrem per 168 hour week, even after February 

of 1966. 

The dose in the control room can be affected by the dose rate during various types of 

shots as well as the duration of those shots. For example, if a particular type of shot 

produces a dose rate of 1 mrem/hr in the control room, that type of shot could not 

normally be performed for more than 10 hours in a week. Also, assuming that shot 

occurred for the full 10 hours each week prevents other shots from occurring in the 

betatron building since they would add to the badge reading and cause the total dose on 

the badge to exceed 10 mrem in a week. This fact will be used to determine the maximum 

number of hours each week for each type of shot. That will in turn be used to determine 

weekly dose rates outside the betatron building. 

Residual radiation from the Betatron 

It was reported by a former Allis-Chalmers employee that the betatron apparatus itself 

exhibited residual radiation (Schuetz 2007). He reported: 

“The donut platinum target becomes radioactive generating on average, around 

15 milliroetgens/hour measured at beam centerline 6 ft. from target. This activity 

will diminish to near zero within 15 minutes. Identical measurements made to 

rear show approximately 1% of forward readings. Effective beam readings follow 

the same natural beam shape as 25 Mv x-rays. Instrumentation used was an 

ionization gamma survey meter, model 247A.” 

Attempts to explain this phenomenon have not definitively determined the source of this 

radiation. Some of the possibilities explored include: 

 activation of the platinum target as reported 

 activation of the aluminum ion chamber and beam compensator 

 activation of some other part of the betatron 

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 activation of air in the betatron beam 

 activation of a beam dump (or part being x-rayed) 

 residual current in the betatron continuing to produce x-rays at a lower 

intensity 

 Magnetic interference with the detector 

The first three possibilities involve activation of various parts of the betatron. Figure 7 

provides a drawing of a betatron tube with the ion chamber and beam compensator in 

place (Schuetz 2007). The platinum target is the point inside the doughnut shaped tube 

where the x-ray beam originates. The tube is sandwiched between two large 

electromagnets that control the betatron. The beam compensator is essentially a radiation 

shield that is cone shaped to provide the most shielding at the beam centerline and 

progressively less shielding away from the centerline. This has the affect of flattening the 

intensity of the x-rays to provide a more even useful beam. Without it, the film would be 

highly exposed at the centerline of the beam and much less exposed at the edges. 

Radiation originating from activation products would be isotropic in nature. That is, the 

radiation would be emitted in all directions equally. Radiation originating from inside the 

betatron tube should therefore be as high in to the rear of the head as it is in front. The 

exception to this is that the radiation intensity should be lowest in front of the 

compensator since that would provide some shielding. This is in contrast with the 

description that indicates the readings to the rear were 1% of the readings in the beam 

centerline and that the readings showed the same shape as the 25 MeV x-rays. Therefore, 

this phenomenon does not appear to be consistent with any parts of the betatron being 

activated with the possible exception of the aluminum compensator. 

It may be possible for activation of the compensator to give these indications. Activation 

products produced in the middle of the compensator could be equally shielded in the 

forward and reverse directions. With a longer distance from the compensator to the rear 

of the machine, the readings in the rear would be lower. Also, the compensator is thickest 

in the centerline of the beam and exposed to the most intense radiation at that point, so 

there is more material that can be activated resulting in a more intense activation field. 

However, attempts to demonstrate this effect using the known physical constants of 

aluminum and the betatron field indicates the activation of the aluminum would not 

produce a radiation field of this magnitude. Also, the entrance of the compensator is 

closest to the x-ray beam and should be most highly activated. This implies the most 

intense radiation would be emitted from the rear of the compensator and that would 

reduce the difference between the forward and reverse radiation fields. Therefore, it was 

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18 
not possible to recreate induced activity in the aluminum ionization chamber and beam 

compensator that would produce the described exposure conditions. 

Figure 7 – Drawing of Betatron Doughnut and Beam 

The betatron is also capable of activating air in the x-ray beam. If the air was stagnant, 

and the beam on long enough, it could be possible for the activated air to produce a 

measureable amount of radiation. This source of radiation would produce a more intense 

radiation field in front of the machine than behind because only the air in front of the 

machine would be activated. The intensity of the radiation would, however, not follow 

the shape of the very directional 25 MeV x-ray profile as was reported. The air would 

provide very little shielding so the activated air in the beam centerline would produce a 

radiation field for several feet to the sides. The profile would be more like a point source 

in front of the betatron and it could not be described as following the shape of the 25 

MeV x-ray profile. Furthermore, air in an operational radiography room would not be so 

stagnant as to allow a small volume of air to become activated to a high degree. Instead 

the air movement would create a much larger source of lower activity and the profile of 

the radiation when measured with an instrument would be much more consistent 

throughout the area rather than directional as was reported. 

The report of this phenomenon did not discuss what was in front of the beam. Even if the 

purpose was calibration and testing, rather than x-raying equipment, it is possible the 

experimental setup used some type of beam dump to shield nearby areas from the beam. 

If this beam dump became activated, it could produce a radiation field with the highest 

intensity in the beam centerline and decreasing quickly as the instrument was moved to 

the side. That could give the illusion of an intensity profile similar to the betatron x-ray 

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profile. Depending on the material used to construct the dump, the half-life of the 

activation product could be short enough to result in the reduction in dose rate reported. If 

this was the cause of the phenomenon, this would not have to be accounted for separately 

at GSI since the activation of the steel being x-rayed is already accounted for separately. 

Another possibility explored was the idea that the betatron could exhibit some residual 

current creating residual radiation in the form of x-rays. This possibility was explored by 

SC&A and no method of producing residual x-rays near this intensity could be found. 

(SCA 2010) 

The last possibility explored is the effect of magnetic interference on the survey 

instrument used to measure this dose rate. The instrument was reported to be an 

ionization gamma survey meter, model 247A. This was likely to be a model 247A 

portable gamma survey meter manufactured by Victoreen. It is a well know fact that 

survey meters can be affected by magnetic fields. Figure 8 has been reproduced from a 

paper that explored the effect of static magnetic fields on survey instruments (Liu 1993). 

The Figure shows the effect of moving a Victoreen model 450 instrument parallel with 

the magnetic field. With a field strength of 10 milliTesla, the instrument over responded 

by a factor of 70 when moved in one direction while in the other direction, it under 

responded, showing only 20% of the actual radiation intensity. A magnetic field of this 

strength can be created by a betatron. Kerst constructed a 315 MeV betatron in 1949 that 

had a magnetic field of 9200 Gauss or 920 milliTelsa (Lee 2004). While that would be 

the operating strength of the magnetic field, it is credible that a small amount of residual 

magnetism would exist in the magnet core for a period of time following operation and 

that the residual magnetism would decay gradually. The strength explored in the paper by 

Lee is only about 1% of that reported to have been used by Kerst. Furthermore, this paper 

explored the affect of a static field but clearly it was relative motion in the field that 

caused the effect (movement of the instrument). A similar effect can be caused by a 

changing magnetic field which is what would be expected as any residual magnetism or 

residual current in the magnet coils decay. 

It is impossible to predict the indication the instrument would give in this situation. 

However, it is credible that the survey instrument would be moved towards the front of 

the machine in one direction and towards the rear of the machine in the opposite 

direction. Measurements around the machine would likely move perpendicular to that 

motion and thus be much less affected. So as the instrument is moved around the 

magnetic field, it would greatly over respond as it was moved in one direction (say near 

the area of the compensator), have little effect as it was oriented away from this direction 

and under respond when oriented in the opposite direction as the original measurement 

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20 
(the rear of the machine). This could cause the readings to the rear to be 1% of the 

readings in the front and produce a profile roughly similar to the 25 MeV x-ray of the 

betatron. 

Figure 8 – Ion Chamber Response to Magnetic Field 

One last issue to explore is to consider the exposure scenarios. A reasonable scenario of 

“short shots” and “long shots” was described by SC&A and will be used again in this 

paper (SCA 2008). This scenario results in approximately 185 shots in a 65 hour work 

week. Since 99.8% of the film badges recorded a value of 10 mrem or less in a week, it is 

reasonable to believe the maximum dose that could be achieved per shot is 0.054 mrem 

(10 mrem/ 185 shots). If a person exposed to a 15 mrem/hr field only receives 0.054 

mrem, the half-life associated with the decay would have to be 0.15 seconds. This 

eliminates virtually any possible activation product of the materials in the betatron, 

including those in air. 

Of the possibilities explored, the idea that a magnetic interference affected the instrument 

appears to be the most likely. At the least, instruments of this type are known to be 

unreliable in magnetic fields that are easily produced by a betatron. This fact alone brings 

into question the reliability of the measurements. 

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21 
Even if one of the other possibilities occurred, the aluminum, iron, and other materials 

common to the machine typically produce activation products that emit a 511 keV 

photon. Photons of this energy would be easily detected by the film badges which means; 

1) the half life would have to be so short that no significant dose is received; and, 2) 

ignoring the effect means in order to receive a dose equal to the sensitivity of the badges, 

other mechanisms would have to be assumed. Those mechanisms tend to also produce 

neutron or electron dose which would result in a more claimant favorable dose estimate. 

Betatron operator dose estimate 

The operators of the betatron can receive radiation dose while in the control room during 

a shot, as well as from residual activity in the material being x-rayed. Since 99.8% of the 

film badge readings indicated exposures of 10 mrem/week or less, any scenario of typical 

exposures must stay within this value. It should be noted that dose received by workers 

outside of the betatron building laying out shots on recently exposed steel is dealt with 

separately in the next section. Dose to these workers was dealt with separately because 

operators reported they did not wear their film badges in the 10 building while 

performing this task. As such, the operators were either performing radiography or laying 

out shots in another building, but not both at the same time. 

Communications with operators indicated approximately 10% of the shots lasted 60 

minutes while the other 90% lasted 3 minutes. The assumptions used in this analysis are 

that it took 12 minutes between short shots. This would include time for traveling to and 

from the control room and the casting, setting up and taking down film, orienting the 

betatron head, and setting controls to initiate the next shot. The assumption for long shots 

is that it took 15 minutes between shots. Therefore, the total time per shot is 15 minutes 

per short shot and 75 minutes for long shots. Based on this, an 8 hour shift would be 

sufficient time to accomplish 32 short shots or 6.4 long shots. If 90% of the shots are 

short shots, then these values would indicate 64% of the time the betatron was involved 

in taking short shots and 36% of the time involved long shots. Therefore, the weekly dose 

in the control room will be based on 430.1 short shots and 48.4 long shots per week. 

Obviously, a fraction of a shot would not occur but the values are intended to be an 

average. 

These assumptions also indicate that for 69.89 hours of a 168 hour week the beam of the 

betatron is on. Since the operators were reported to work an average of 65 hours per 

week, they were not present during all of this time. Prorating the utilization of the 

betatron to a 65 hour work week, would result in the operators being present for 27.04 

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22 
hours per week with the betatron on and for the remaining 37.96 hours per week they are 

exposed to residual radioactivity from the steel. Additionally, the badges are exposed in 

the control room when the operators are not there and the betatron is on for an additional 

42.85 hours per week. 

The 114 weekly film badges assigned to the betatron control room all indicated exposures 

of less than 10 mrem/week. With the betraton assumed to be on 69.89 hours per week, 

the average dose rate in the betatron control room, while the betatron is on, would be no 

greater than 0.143 mrem/hr. Assuming the film badges are exposed to 10 mrem/week 

from the operating betatron does not allow for the accrual of any dose received from 

exposure to residual activity in the steel castings. This is because the vast majority of the 

film badges (approx. 99.8%), indicated total exposures of 10 mrem/week or less. Because 

the dose from residual activity in the steel is based on bounding assumptions which likely 

over predict that dose, subtracting that dose from the dose received in the control room 

would possibly under predict the true dose in the control room. This would in turn under 

predict the doses received by others outside the betatron building. Therefore, this dose 

estimate will assume the badges receive 10 mrem per week in the control room. 

Operators, however, are not exposed to the entire 10 mrem each week. Much of that 

exposure occurs while the operators are not at work and their badges are stored in the 

betatron building. The operator exposure is assumed to be 3.87 mrem per week from the 

operating betatron. This value comes from considering the fact that the operators are 

present for only 27.04 hours of the 69.89 hours per week the betatron is operating. 

Combining this 3.87 mrem per week with the 3.94 mrem per week from residual activity 

in the steel results in a total dose to the operators of 7.81 mrem/week. 

This dose assumes the operator is working 65 hours per week, performing radiography on 

steel. Adjustments to this estimate must be made to account for radiography operations 

with uranium. Sixty five work hours per week for 50 weeks per year results in an average 

work year of 3250 hours. The amount of uranium work performed at GSI has been 

derived from work orders and is described in Appendix BB to TBD 6000 (OCAS 2007). 

Table 9 shows the assumed number of hours per year of uranium work, along with the 

fraction of time the work involved uranium (based on 3250 work hours per year). 

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Table 9 – Hours per Year of Uranium Work at GSI 

Years Hours per year working 

with uranium 

Fraction of work year 

working with uranium 

1953-1960 337.5 0.104 

1961 387.5 0.119 

1962 281.25 0.087 

1963 76.5 0.024 

1964 28 0.009 

1965 20.5 0.006 

1966 13 0.004 

The weekly dose from exposure to the uranium metal (intrinsic radiation as well as 

residual activity) was estimated to be 39.06 mr, based on continuously working with 

uranium. Since the amount of uranium work was limited, it is possible that any one 

operator worked with all the uranium. Also, the amount of uranium handled varied from 

year to year. Therefore, the dose estimate will vary from year to year. The assumption is 

that any particular operator worked with all the uranium and worked with HY-80 steel the 

remainder of the time. The fractions of time spent on uranium work are listed in Table 9. 

Also, the dose estimate while the betatron is on assumes 64% of the shots are short shots, 

which is not the case for uranium work. Therefore, the dose to the operator while in the 

control room is adjusted to account for the higher fraction of the time the betatron is on. 

The weekly dose rate while continuously x-raying uranium is then 39.06 mr/week from 

the uranium metal plus 7.44 mr/week in the control room for a total of 46.5 mr per week. 

This weekly dose is assumed for the fraction of time listed in Table 9 with the remaining 

fraction of the work year assumed to be at the rate of 7.81 mr per week from x-raying 

steel. The overall annual estimate year by year is listed in Table 11. 

The same assumptions are combined with the applicable neutron and skin dose rates to 

arrive at the annual dose estimates in Table 11. 

Workers outside the betatron building 

Workers not working in the betatron building may also have been exposed to radiation 

resulting from betatron operations. This would be caused by scattered radiation 

(including skyshine) while the betatron is in operation, as well as from residual activity 

when repairing a recently x-rayed casting. 

Dose from scattered radiation depends on the location of the worker. A number of 

locations outside the betatron building were explored, with several locations of interest 

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24 
discussed below. Dose rates in those locations vary depending on the location and 

orientation of the betatron head. In general, however, those betatron orientations that 

resulted in higher dose rates outside the betatron building also resulted in higher dose 

rates inside the betatron control room. As described earlier, dose received inside the 

betatron control room would be detected on the film badges. 

Dose rates from these locations and shot orientations were described earlier. In order to 

estimate the weekly dose locations outside the betatron building, Excel’s “Solver” 

function was utilized. Solver allows the user to find the optimal value for a formula. The 

function was used to find the maximum weekly dose at the number 10 building location. 

The criteria for Solver were: 

 weekly dose at the control room desk equal to 10 mr 

 hours per week (of betatron operation) equal to 69.89 

The results of the Solver calculation was an assumed 67.46 hrs per week oriented in the 

back shot, left, up position and 2.42 hours per week oriented in the railroad, right, level 

position (see discussion on orientations in a previous section). With these assumed hours, 

the dose rate in the number 10 building is estimated to be 99.2 mr/week from photon and 

4.04 mrem/week from neutrons. However, this is based on a 168 hour week. Prorating 

exposures for a 65 hour work week resulted in an estimated dose of 38.4 mr from photons 

and 1.56 mrem from neutrons. 

With these assumptions in place for the shooting orientation, weekly photon doses at 

other locations were estimated. Weekly doses for a 65 hour week were estimated to be 

14.3 mr in the restroom and 38.9 mr in the outdoor area. However, it is not realistic to 

believe workers spent 3,250 hours per year in either of these locations. Since the number 

10 building dose rate is nearly the same as the dose in the outdoor area (and higher than 

the restroom) workers will be assumed to be working continuously in the number 10 

building. 

An additional point of interest is the examination of potential exposures on the roof of the 

betatron building. One report indicated that a maintenance worker performed periodic 

work on the fans above the shooting room. The frequency of this operation was reported 

as being 20 minutes per fan twice per year (Meeting Minutes 2007). There were three 

fans on the roof of the shooting room. To estimate this dose, the weekly dose at all three 

fans was determined and averaged. Next this was multiplied by the fraction of a week the 

person would be at work assuming a 65 hour per week work week. Lastly, this was 

multiplied by the fraction of the work week the person would be on the roof. This was 

estimated by assuming 2 hour of maintenance per 3,250 hour year (20 minutes per fan 

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times 3 fans twice per year). This results in an estimated weekly dose of 3.82 mr. The 

maintenance person could have worked in the number 10 building near the betatron 

building equipment door, but it is unlikely any maintenance activity would require full 

time work at one location. More likely the maintenance worker worked all over the plant 

at various times. Even assuming the maintenance worker worked elsewhere (such as the 

betatron building roof) 10% of the time would result in a lower dose estimate than if the 

worker is assumed to work 100% of the time in the number 10 building. Since placing 

workers in an exact location is usually difficult, no special treatment will be considered 

for this worker. As with other workers, the maintenance worker will be considered to 

spend 100% of his work day in the number 10 building. 

One additional exposure potential for workers outside the betatron building is the dose to 

workers from residual activity in steel castings. This is addressed in the next section. The 

section is based on a radiographer laying out shots on the casting but will also serve as a 

bounding estimate for anyone working on the freshly x-rayed casting. 

Layout Worker 

Castings were often prepared for an x-ray by laying out the shots prior to moving them 

into the betatron building. This minimized the time necessary to set up a shot in the 

betatron building and allowed the betatron to be operated more efficiently. If the casting 

had been previously x-rayed, residual activity could cause a dose to be received while 

laying out another shot. Furthermore, radiographers reported that the company policy was 

to not wear film badges in this location because hot sparks could burn through them. 

Residual activity from steel decreases fairly quickly. Therefore, the highest dose rate to 

which these workers would be exposed was from a freshly x-rayed casting. The bounding 

estimate will be based on the same shot scenario used elsewhere. For short shots, the 

assumption is the shot lasted 3 minutes with an additional 12 minutes to take down the 

shot and move the casting out of the betatron building. Based on this, the layout worker is 

exposed to the casting starting 12 minutes after the shot. It is further assumed that this 

cycle repeats every 15 minutes. Therefore, the layout worker is exposed to a casting from 

12 minutes to 27 minutes after a 3 minute shot. It is also possible that the casting was 

cycled into and out of the betatron repeatedly. While most of the dose would be caused 

by the latest shot, some additional radiation would be created from the previous shots. 

Also, if two castings were alternated, it would be possible for the layout worker to always 

be exposed to a freshly x-rayed casting that had been shot numerous times previously. 

This scenario was explored by assuming two castings alternated in the short shots. It was 

further assumed that this continued until the castings had each been shot 250 times. 

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The layout worker could also be exposed to residual radiation from long shots. In this 

case, the shot lasts 60 minutes with 15 minutes between shots. So the assumption is that 

the layout worker is exposed from 15 to 90 minutes following a 60 minute shot. This 

cycle is repeated every 75 minutes. Again, the scenario was explored in which two 

castings were alternated until each had been shot 200 times. 

When the layout worker is working with the casting, it is assumed he is within one foot of 

the exposed location of the casting 50% of the time and 1 meter the other 50% of the 

time. Again, it is assumed 90% of the shots are short shots and the other 10% are long 

shots. Using these assumptions, the weekly photon dose from a single shot would be 2.05 

mr while the multiple shot scenario yields a 2.21 mr/week dose. The reason the difference 

in the two scenarios is small is because the dose rate from residual activity decreases 

relatively quickly and the castings can only be x-rayed half as frequently due to the two 

castings being alternated. Even though the scenario chosen for the multiple shot scenario 

may be unrealistic, it is only marginally higher than the single shot scenario and the 

single shot scenario could under estimate the dose in some situations. Therefore, the 

multiple shot scenario will be used in the dose estimate. 

If we assume this work always occurred in the number 10 building near the betatron 

building, an additional 38.4 mr per week from scattered radiation must be added to that 

estimate for a total of 40.6 mr/week. 

For skin dose, the same technique was used that was used for the betatron operator. The 

technique included assuming a single 30 hour shot on the casting just prior to the operator 

being exposed. Therefore this is essentially a multiple shot scenario. The time the layout 

worker was assumed to be exposed was from 15 minutes to 90 minutes following the xray for the long shots and 12 to 27 minutes following the short shots. The short shot 

exposure was repeated every 15 minutes and the long shot cycled every 75 minutes. 90% 

of the shots were assumed to be short shots. The resulting weekly skin dose to the layout 

worker was 20.4 mrad/week to the hands and forearms and 10.8 mrad/week to the skin of 

the whole body. 

The annual doses to the layout worker are shown in Table 10. These doses are to be used 

for all employees. 

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. 

27 
Table 10 – Annual Dose to Layout Worker 

Year Photon 

(mr/yr) 

Neutron 

(mrem/yr) 

Skin-WB a 

(rad/yr) 

Skin-HF b 

(rad/yr) 

1953-1965 2030 78 0.540 1.020

1966 c 1015 39 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
 

Summary 

The annual doses to the betatron operators derived in this white paper are summarized in 

Table 11. 

Table 11 – Annual Dose to Betatron Operator 

Year Photon 

(mr/yr) 

Neutron 

(mrem/yr) 

Skin-WB a 

(rad/yr) 

Skin-HF b 

(rad/yr) 

1953-1960 590 125 2.269 25.867

1961 620 132 2.469 29.477

1962 557 117 2.044 21.806

1963 435 89 1.226 7.023

1964 406 82 1.032 3.522

1965 401 81 1.002 2.980

1966 c 199 40 0.972 2.439

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
 

Betatron operator dose is intended to apply to anyone working in the betatron building. 

Because little information is available for the location of most workers, these doses will 

apply to all workers at GSI. For the same reason, the layout worker dose is intended to 

apply to all workers. These doses are not intended to be additive. Dose reconstructors will 

chose the most favorable set of doses for the given case. 

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. 

28 
In order to reconcile all the available data, the film badge data was used in estimating this 

dose. Film badge data, however, are only available starting in 1964. The estimate is 

considered reasonable for years prior to 1964 for two reasons. 

First, the time period from approximately 1963 on has been referred to as the busiest time 

for the betatron. This was stated by betatron operators as well a former supervisor. It is 

also consistent with a large increase in the number of radiographers. Furthermore, prior to 

1963, only one betatron was in operation at this facility. In 1963, an additional betatron 

from the Eddystone plant was moved to the Granite City plant and upgraded. The original 

betatron was reported to have a maximum intensity of approximately 100 R/minute while 

the new betatron (moved from the Eddystone plant) was reported to have a maximum 

intensity of 250 R/minute (Transcript 2006). Therefore, the years in which film badge 

data are available are the years for which: 

 The maximum betatron throughput was occurring 

 Two betatrons were in operation instead of one; and. 

 Betatron intensity was increased (100 R/min max prior to 1963) 

Lastly, the effect of the lower intensity of the old betatron would be lower doses, even if 

all other parameters were equal. If it is assumed that similar castings were being x-rayed, 

it would take longer to expose the film using the old betatron. Indeed, this was reported 

by operators. That would result in the operators being exposed to scatter radiation for 

longer durations and thus exposed to residual activity less frequently. The dose rate of the 

scatter radiation can be approximated as proportionally lower but for a longer duration 

resulting in the same exposure delivered to the casting and to the operators. Therefore, 

the overall result would be to reduce the dose estimate slightly, based on workers being 

exposed to residual activity less frequently. Since all the shot scenarios used in this 

whitepaper come from workers that were not employed prior to 1963, no detailed 

estimate was performed. The post 1963 (adjusted for uranium work) is considered 

bounding on the old betatron and the time period prior to 1964. 

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. 

29 
References 

Allen 2010, White Paper, TBD-6000 Working Group – Putzier Effect, September 2010. 

Lee 2004, S. Y. Lee, Accelerator Physics, Second Edition, World Scientific, 2004. 

Liu 1993, Liu, Mao, McCall, Donahue, The Effect of the Static Magnetic Field on the 

Response of Radiation Survey Instruments, Health Physics, 64(1):59-63; 1993 

Meeting Minutes 2007, SC&A Interviewing Former Employees of General Steel 

Industries, meeting minutes; October 9, 2007 meeting in Collinsville, Illinois; SRDB Ref 

ID: 47970 

ML093480290, U.S. Atomic Energy Commission Byproduct Material License, No. 12-

08271-01 Amendment No. 08, July 28, 1972 

OCAS 2007, Site Profiles for Atomic Weapons Employers that Worked with Uranium 

and Thorium Metal - Appendix BB: General Steel Industries, Battelle-TBD-6000, 

Appendix BB, Rev. 0, June 25, 2007. 

ORNL 1990, Oak Ridge National Laboratory, Results of the Radiological Survey at the 

Granite City Steel Facility, Granite City, Illinois. ORNL/RASA-89/10, July 1990 

SCA 2008, Review of “Site Profiles for Atomic Weapons Employers That Worked 

Uranium and Thorium Metals – Appendix BB: General Steel Industries,” Battelle-TBD6000, Appendix BB, Rev. 0., S. Cohen and Associates, March 2008. 

SCA 2010, Response to Action Items Related to GSI SEC Issues Matrix, S. Cohen and 

Associates, May 9, 2010. 

Schuetz 2007, Schuetz, J. G., Personal communication with Samuel Glover, NIOSH, May 

1, 2007 

Transcript 2006, General Steel Industries Worker Outreach Meeting, transcript; August 

21, 2006; SRDB Ref ID: 47927 

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. 

30