Neutral Current Detector Background Calibrator -- CHIME

The background level of the Neutral Current Detectors will be measured by deploying a septet of counters, which are close resemblance of the real NCD counters, prior to the deployment of the full NCD array. The septet of counters used in this measurement -- Construction Hardware In-situ Monitoring Experiment (CHIME) -- consists of five regions:

• Region ICALI_CHIME_OVL, a cylinder representing the outer nickel volume.
• Region ICALI_CHIME_IVL, a cylinder representing the inner fill gas.
• Region ICALI_CHIME_D2O, a cylinder representing the inner D$_{2}$O volume of the counter.
• Region ICALI_CHIME_QTZ, a cylinder representing the quartz tubes in the inner volume.
• Region ICALI_CHIME_EC, a cylinder representing the endcaps installed in the counters

In SNOMAN, each counter in the septet is assigned a counter serial number ($S_{c}$) between 1 and 7. The serial number for the ICALI_CHIME_OVL, ICALI_CHIME_IVL, ICALI_CHIME_D2O, and ICALI_CHIME_QTZ regions in each counter is the same as the serial number of the corresponding counter. Because there are four endcaps (ICALI_CHIME_EC) inside each counter, the $I^{th}$ endcap in a counter of serial number $S_{c}$ is assigned a serial number of $(10\times S_{c} + I)$.

User Control

The septet of counters can be turned on in SNOMAN using the command file GEOM_CHIME.CMD. This command file will position the centre of the CHIME septet at the centre of the SNO detector. One can translate the centre of the CHIME septet to the position (x,y,z) by:

	$translate_chime x y z