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GWL
Series Germanium (HPGe) Well Detectors
For analysis of small, low-activity samples
- Ultimate absolute counting efficiency for small samples
- Active Volumes to 400 cc
- Unique ion-implanted blind well
- Resolution specified with source inside the well
- Spectroscopy from 10 keV to 10 MeV
- Near 4 ∏ geometry
- Extra-large well (1.55 X 4.0 cm) standard
Figure 29. Simplified Isometric View of
HPGe Well Detector Cryostat. |
Figure 30. Absolute Detection Efficiency in the
Well vs.
Photon Energy. [If a well detector is used
as a general-purpose coaxial detector (a
use not
recommended by ORTEC), its relative efficiency at
25 cm can be determined from the
equation.] |
ORTEC’s High-Purity Germanium (HPGe) Well Detectors offer the
ultimate absolute counting efficiency for radiochemical analysis and low-level gamma-ray
spectroscopy. The unique ion-implanted detector well has an ultra-thin dead layer (only
0.3 µm thick), and therefore provides the most extensive useful energy range (10 keV to
10 MeV). Unlike other Well detectors that have a hole all the way through the germanium
crystal, ORTEC’s Well Detectors have a "blind hole" with at least 5 mm of
active germanium at the bottom of the hole (Fig. 29). This near 4-∏
geometry provides the maximum absolute counting efficiency available. The large well
(1.55-cm-diam and 4.0-cm-long) accommodates an extensive range of sample sizes. Like all
of ORTEC’s HPGe photon detectors, the HPGe Well detector may be stored or cycled
repeatedly to room temperature without performance degradation. Well detectors, not
available in PopTop capsule, can be supplied in these "streamline" cryostats:Vertical or horizontal dipstick and side-looking or J "bucket."
As specified in ANSI/IEEE Std. 325-1996, the resolution is measured with
a point source inside the well, 1 cm from the bottom. Measurements of resolution outside
the well can be deceiving.
A typical curve of absolute efficiency in the well vs. photon energy is
shown in Fig. 30.For large, dilute samples (such as water, soil, grass, etc.), the GAMMA-X
detector, used with a Marinelli beaker, is the optimal choice.
Ordering Information
GWL Series Germanium (HPGe) Well Detector — NOT Available in PopTop Capsules.
|
Model No. |
Active
Volume
(cc) |
Well
Diameter*
(mm) |
Well
Depth*
(mm) |
Energy Resolution FWHM |
End Cap
Diameter
(mm) |
|
at 1.33 MeV
(keV) |
at 122 keV
(keV) |
|
GWL-90-10 |
90 |
10 |
40 |
2.10 |
1.2 |
70 |
|
GWL-90-15 |
90 |
15.5 |
40 |
2.30 |
1.4 |
70 |
|
GWL-110-10 |
110 |
10 |
40 |
2.10 |
1.2 |
70 |
|
GWL-110-15 |
110 |
15.5 |
40 |
2.30 |
1.4 |
70 |
|
GWL-120-10 ** |
120 |
10 |
40 |
2.10 |
1.2 |
70 |
|
GWL-120-15 ** |
120 |
15.5 |
40 |
2.30 |
1.4 |
70 |
|
GWL-130-10 |
130 |
10 |
40 |
2.10 |
1.2 |
70 |
|
GWL-130-15 |
130 |
15.5 |
40 |
2.30 |
1.4 |
70 |
|
GWL-150-10 |
150 |
10 |
40 |
2.10 |
1.2 |
83 |
|
GWL-150-15 |
150 |
15.5 |
40 |
2.30 |
1.4 |
83 |
|
GWL-170-10 |
170 |
10 |
40 |
2.10 |
1.2 |
83 |
|
GWL-170-15 |
170 |
15.5 |
40 |
2.30 |
1.4 |
83 |
|
GWL-190-10 |
190 |
10 |
40 |
2.10 |
1.2 |
83 |
|
GWL-190-15 |
190 |
15.5 |
40 |
2.30 |
1.4 |
83 |
|
GWL-220-10 |
220 |
10 |
40 |
2.10 |
1.2 |
95 |
|
GWL-220-15 |
220 |
15.5 |
40 |
2.30 |
1.4 |
95 |
|
GWL-250-10 |
250 |
10 |
40 |
2.10 |
1.2 |
95 |
|
GWL-250-15 |
250 |
15.5 |
40 |
2.30 |
1.4 |
95 |
|
GWL-280-10 |
280 |
10 |
40 |
2.15 |
1.2 |
95 |
|
GWL-280-15 |
280 |
15.5 |
40 |
2.30 |
1.4 |
95 |
|
GWL-300-10 |
300 |
10 |
40 |
2.15 |
1.2 |
95 |
|
GWL-300-15 |
300 |
15.5 |
40 |
2.30 |
1.4 |
95 |
|
GWL-350-10 |
350 |
10 |
40 |
2.15 |
1.2 |
95 |
|
GWL-350-15 |
350 |
15.5 |
40 |
2.30 |
1.4 |
95 |
|
GWL-400-10 |
400 |
10 |
40 |
2.15 |
1.2 |
108 |
|
GWL-400-15 |
400 |
15.5 |
40 |
2.30 |
1.4 |
108 |
|
GWL-450-10 |
450 |
10 |
40 |
2.15 |
1.2 |
108 |
|
GWL-450-15 |
450 |
15.5 |
40 |
2.30 |
1.4 |
108 |
|
*Larger detectors (up to 450 cc) and other well dimensions
are available on special order.
**Note GWL-120 is standard order and delivery, all others are special order
only. |
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