Instrumented Ball Source

The instrumented ball source geometry is at present a simplified version of the geometry of the existing $^{8}$Li source.

Each region consists of the following:

Region	Priority	Description	No. of	Media
			Primitives
261	561	$^{8}$Li Head	2	Stainless steel
262	562	$^{8}$Li carrier gas	1	Air
263	563	Dummy overwritting vol	1	Stainless steel
271	571	Bottom flange	1	Stainless steel
281	581	Instrumented top portion	1	Stainless steel

The geometry of the instrumented ball source is displayed in Figure 12.4.

Figure 12.4: The $^{8}$Li source chamber geometry. Each point represents an intersection of a neutrino propagation path and the boundary of a detector element.

User Control

The orientation of the primitives relative to each other has been set in the respective GEDS banks. Therefore, it is not necessary for the user to change the rotational matrix and the translational vector in the GEDS banks. In fact, the users are urged not to change any of the entries in any of the GEDS banks for this source.

To enable this source, the enable flag in each of the GEDS banks must be turned on. There is a command file calibration_8li_inst_ball.cmd to perform this task.

It is possible to move the source inside the D$_2$O volume. To accomplish this task, one needs at the moment to set the translational vector and rotational matrix for ALL the source regions. The default for the rotational matrix is the 3$\times$3 unit matrix and the default setting for the translational vector in the GEDP banks is a null vector. The user can make the necessary transformations in the calibration_8li_inst_ball.cmd command file.

The source may be operated into the D$_{2}$O, the H$_{2}$O, the chimney inner region (ACRC_IVL), the PMT panel zone (PAN_ZONE), the PMT empty hex cells (HEX) and between PMT panels (ABS_SKIRT).

The umbilical and manipulator weight code have not been altered yet to deal with the instrumented ball source geometry.