Patent Number: 048333352
Section: description

DETAILED DESRIPTION OF THE PREFERRED EMBODIMENTS Referring in detail to the drawings and with particular reference to FIG. 1, a neutron shielded door 2 is disclosed for a radiation treatment room housing an accelerator (not shown). While it is contemplated that the particular accelerator will be a medical accelerator which may be used for instance in cancer therapy, other types of accelerators which are known in the art are equally applicable for use with the neutron shielded door of the instant invention. These accelerators will produce x-ray beams which are contaminated with low levels of neutrons. In order to protect the personnel operating the equipment, it is necessary to provide a neutron shielding door leading to the treatment room. The neutron shielded door 2 of the instant invention is formed having a front face 4, a rear face 6, a top face 8, two side faces 10, 12 and a bottom face 14. This door may be manufactured from stainless steel or other suitable materials. The door has a hollow interior defined by the various faces. Within this interior, a neutron retarding fluid is held. Two fluid inlets, 18 are provided on the top face 8 of door 2. Fluid inlet plugs 20 are also provided for closing inlets 18. While two inlets are shown, it is contemplated that any configuration of suitable inlets may be used. These inlets 18 permit the neutron retarding fluid to be introduced into the interior of the door. This fluid may be removed from the interior of the door through drain 22 which is normally sealed by drain plug 24. Again, while this drain is shown as being on the bottom portion of side 10, any suitable placement for this plug may be used. Within door 2, internal baffles 26 are provided which prevent surging of the neutron retarding fluid. Thus, sudden shifting in the center of gravity of the door is prevented when this door is opened or closed. Ease of use of the door is therefore enhanced. The neutron retarding fluid which is held within the door may be any suitable hydrogen rich compound. For instance, it is contemplated that water will be loaded into the door which contains a dissolved boron compound. Thus, the door will satisfactorily operate to provide a neutron capturing arrangement and will protect workers from the low levels of neutrons emitted by the accelerator. A handle 16 is provided for opening and closing the door. Furthermore, it is contemplated that a latch mechanism (not shown) may be used for assuring that the door remains in a closed, locked position. In order to open and close the door, various arrangements are contemplated. In particular, in FIG. 1, a sliding door arrangement is used. Tracks 30 are provided on a door frame associated with the door whereby door 2 may be slid between an open and closed position. Track followers 32 are indicated for door 2 for permitting this door to slide along track 30. These track followers may be no more than the edge of the door 2 or they may consist of a wheel-type of other bearing arrangement. As seen in FIG. 2, an alternate arrangement for opening and closing the door is contemplated. In this arrangement, door 2 pivots about pivot point 34. A hinge (not shown) is provided for permitting this pivoting of the door. Other arrangements for permitting ready opening and closing of the door are also contemplated as being within the spirit and scope of the instant invention. On door 2, a fluid indicater 28 is provided. This indicator enables an operator to readily determine the amount of neutron retarding fluid contained in the hollow interior portion of door 2. This fluid indicator may consist of a small water level view port provided near the top of the door. This indicator 28 permits detection of any loss of water by leakage. Other types of indicators such as electronic metering indicators or mechanical fluid level indicators are also contemplated for use with the neutron shielded door of the instant invention. The neutron shielded door of the instant invention is simple and inexpensive to manufacture yet produces a highly effective neutron shield for a radiation therapy room with an accelerator. This door may be easily maintained and may be incorporated into existing rooms housing accelerators or may be a part of newly constructed rooms for housing accelerators. This door is simple to operate and does not require extensive maintenance. The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.