Dosimeter Information

Dosimetry Information

Obtaining Dosimetry

Who needs a dosimeter? Anyone on the University of Maryland, College Park Campus, or Satellite Facilities who works with radioactive materials (RAM) or radiation producing equipment may need to be assigned dosimetry. This includes faculty, staff, students, and visiting faculty. People who work with particle accelerators, neutron sources or the nuclear reactor need neutron dosimetry. Dosimeters can also be used as stationary monitors and are attached to walls, ceilings, etc., in facilities such as particle accelerators and the nuclear reactor. In this instance, the dosimeter is read for non-personnel dosimetry. *Some RAM work does not require a dosimeter as the energy is so low that the dosimeter cannot detect it. (The RSO will determine who falls within this category).

How do I apply for dosimetry? A short form requesting dosimeter service must be filled out before dosimeter can be issued. Forms are available at the Radiation Safety Office. A dosimeter will be issued immediately upon receipt of a completed Request for Dosimeter Service Form. The whole process is short.

Regular Service

How will I get new dosimetry? Dosimeters are in general issued for a two month wearing period. The first day of the wearing period is printed on the dosimeter. Once you have filled out the dosimeter request form, you should automatically get a new dosimeter at the beginning of each new wearing period. The new dosimeters are sent through the campus mail from the RSO to one person in your department or group. It is important that you know where your new dosimeter will be sent and that you pick them up promptly.

How do I return old dosimeters? Do not return your old dosimeter until you receive a new one, unless you are departing before the end of the wear period. In this case, send the dosimeter to the RSO when you leave. You may continue wearing the old dosimeter for a short time before the end of the one month wearing period until your new dosimeter arrives.

If you do not receive a new dosimeter within two weeks, call the RSO immediately. Once the new dosimeter comes, the old one is returned to the RSO. One person in your department or group should be designated to handle this, however, you may return the old dosimeter yourself through the campus mail if this person is not available.

Where should I store my dosimeter while it is not being used? In no case should dosimeter be left in an area of where it will be exposed to radiation, or in an area where temperature extremes will be present. The dosimeter should be stored in a convenient place so that it is always handy for you to put on and it must be kept in an area of background radiation levels only. Do not take dosimeters home or off campus without consulting the RSO. Remember that dosimeters are for occupational exposure on the College Park Campus or Satellite facilities only.

How should I wear my dosimeter?

Dosimeters should be placed in the holders so that the printed side is away from the wearer (i.e., so that the printed side can be read). Neutron films have a special additional detection packet incorporated in the holder (always). All dosimeters should be attached to the holder. Filters incorporated in the holder provide information for determining the radiation energy and type of radiation that the wearer is exposed to. Dosimeters are issued to individuals and are not transferable. Never wear another person's dosimeter.
Dosimeters are normally issued for whole body dosimetry. It is important that the dosimeter be worn in the front of the body, on the trunk, somewhere between the waist and shoulders, and in an area of the highest expected radiation exposure. The dosimeter should be upright, with the clip toward the body. Do not put your dosimeter inside a pocket, and never wear a dosimeter inside clothes unless you consult the RSO. Under certain circumstances, this may be necessary to prevent contamination of the dosimeter, but again, this should only be done upon consultation with the RSO.
When working in a non-uniform field of radiation or working with highly radioactive sources, additional dosimeters may be necessary because different parts of your body may receive significantly different doses. In these cases, dosimeters for extremities or for other parts of the body as well as a whole body dosimeter may more accurately indicate your dose. A dosimeter holder for the wrist is available, or dosimeter placed on other parts of the body can be used to monitor the areas of highest exposure concern. The RSO can supply you with additional dosimeters when the need arises.

Does a dosimeter need special care? Yes. Radiation dosimetry is sensitive to heat, moisture, pressure, light, and time. Protect your dosimeter from physical damage.

What is the "Control" badge for? Each batch will receive a "control" dosimeter which accompanies the dosimeter during transit, and while the dosimeters are in use for determining any exposures to the lot not associated with the primary purpose of dose determination. When you receive a control dosimeter, store the dosimeter where you keep your dosimeter when not in use. Return the control dosimeter when you return your regular dosimeter, even if you do not receive another control dosimeter.

How do I cancel dosimetry service? When radioactive work terminates permanently, or when you are transferred or leave the University, include a note to the RSO with your last dosimeter, requesting cancellation. Be sure that the complete dosimeter number, name and a forwarding address is given. If you transfer from one department to another, notify the RSO so that a new group identifying code can be given to your dosimeter and it will be sent to where you are moving to.

Problems -

What do I do if I lose my dosimeter? Call or visit the RSO to get a replacement dosimeter. Do not go without the required form of dosimetry for radioactive material or equipment work. If you find the lost dosimeter, return it to the RSO for processing.

What should I do if I find someone's dosimeter? Return it to the RSO. We can tell by the dosimeter number to whom it belongs.

What should I do if my dosimeter is damaged? If your dosimeter seems damaged from heat or if it is torn or broken, in most cases it cannot be processed accurately. Come to the RSO and you will be issued a new replacement dosimeter for the remainder of the wearing period. Bring your damaged dosimeter with you, in case we feel it can be processed.

What if I need additional dosimeters? The RSO will issue you any additional dosimeters that we consider necessary. If you have questions about this, a health physicist will be happy to observe your procedures and recommend the dosimetry needed.

What should I do if I think I may have received a high dose of radiation? Report to the RSO immediately. Remember to bring your dosimeter or dosimeters with you and we will provide immediate processing.

Question -

Should I receive a report of my radiation exposure? Yes. An annual report covering a calendar year is provided to you automatically. These reports are usually received in the Spring and will be sent to you to the permanent address you indicated on the Dosimeter Request Form.

I would like to know my radiation exposures more frequently than once a year. How can I do this? A visit to the RSO is all that is necessary to see your latest exposure records. You may also request your exposure history through the campus mail. Please include or bring your dosimeter number with you to facilitate finding your records.

How long must my records be kept by the RSO after I leave the University? The RSO is required to keep personnel exposure records indefinitely as the law now stands.

What happens if I go to another facility where I use radioactive materials? Your new place of employment (as authorized in writing by you) will request your exposure history from the RSO. In this way, a lifetime whole body dose will be maintained throughout your occupational exposure time.

Reports -

As required by federal and state law, records of personnel exposure to ionizing radiation must be maintained in perpetuity. Exposure records on the College Park Campus are maintained by regulation by the RSO.

Comments -

The RSO strongly recommends that for your own personal information you keep track of your own radiation exposures and maintain a copy of your yearly reports in your files. This is beneficial if you seek employment where you will be using or exposed to radiation.

If you have any questions concerning your dosimeters, records or other aspects of radiation protection, please call on us.

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