NIMROD
Multipurpose charged particle array at Texas A&M University
The Neutron Ion Multi-detector for Reaction Oriented Dynamics (NIMROD) is a 4π array of detectors build at Texas A&M to study reactions mechanisms in heavy ion reactions. The charged particle detectors are composed of Silicon (Si) telescopes and CsI(Tl) scintillators covering angles between 3.6° and 167.0°. Capabilities also exist to add ionization chambers, which were utilized in previous campaigns.
The back half of NIMROD (90.0-167.0°) consists of half of the Indiana Silicon Sphere. These charged particle detectors are placed in a cavity inside the TAMU neutron ball. The combination of the charged particle detector and the powerful detector array allows for identification of both heavy ions as well as neutrons.
NIMROD Schematic
Fig. 1. Angular configuration of the NIMROD detectors.
The charged particle detector setup consists of the following:
| Ring |
ΔΘ |
Δφ |
Telescopes Si
mm (thick) |
Super
telescopes |
CsI (Ring 2-11)
PD (Ring 12-15) |
CsI length
(cm) |
| 2
| 3.6-5.0°
| 30°
| 6 (300μm)
| 6
| 12
| 10.0
|
| 3
| 5.0-7.6°
| 30°
| 6 (300μm)
| 6
| 12
| 10.0
|
| 4
| 8.0-10.8°
| 30°
| 8 (300μm)
| 4
| 12
| 10.0
|
| 5
| 10.8-14.7°
| 30°
| 8 (300μm)
| 4
| 12
| 10.0
|
| 6
| 15.3-20.9°
| 30°
| 8 (300μm)
| 4
| 12
| 6.5
|
| 7
| 20.9-27.6°
| 15°
| 8 (300μm)
| 4
| 18
| 6.5
|
| 8
| 28.6-35.8°
| 30°
| 10 (300μm)
| 2
| 12
| 6.0
|
| 9
| 35.8-45.0°
| 15°
| 10 (300μm)
| 2
| 18
| 6.0
|
| 10
| 52.7-69.2°
| 20°
| 18 (300μm)
| -
| 18
| 4.0
|
| 11
| 70.1-86.3°
| 20°
| 18 (300μm)
| -
| 18
| 3.0
|
| 12
| 93.5-110.8°
| 20°
| 18 (500μm)
| -
| 18
| 2.8
|
| 13
| 110.8-128.4°
| 20°
| 18 (500μm)
| -
| 18
| 2.8
|
| 14
| 128.4-147.4°
| 20°
| 18 (500μm)
| -
| 18
| 2.8
|
| 15
| 147.4-167.0°
| 20°
| 18 (500μm)
| -
| 18
| 2.8
|
Table 1. Angular layout of NIMROD. The telescope and super-telescope silicon configurations at each angle are given with the CsI crystal lengths.
To minimize cost of the detector, the INDRA geometry was adopted in the forward direction. This reduced significantly the cost of the silicon detectors since no mask had to be fabricated. The forward rings of detectors thus covers polar angles from 3.6 to 45° in 8 concentric rings of 12 CsI(Tl) detector each.
This work is supported by the Welch Foundation and the Department of Energy.
Last modified: