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Gamma Gage II
Portable Germanium (HPGe) Gamma Ray Spectrometer
- Portable Germanium (HPGe) Gamma-Ray Spectrometer with Integral
LN2 Dewar
- Standard holding times in the range 1–5 days*
- Available in all-attitude and compact multi-orientation dewar
types
- Lightweight: <11 lbs for 24-hour holding time version
- Available for all GEM, GMX, SLP or GLP detectors
- Automatic high-voltage shutdown and high count-rate indicator
- SMART-1 detector option provides temperature monitoring when
used in conjunction with DigiDART†
- PopTop and non-PopTop versions
- 16 engineering design improvements over previous models.§
 Gamma
Gage II represents a series of engineering improvements over the highly
successful Gamma Gage of which many thousands are deployed daily in
portable high resolution spectroscopy applications. These improvements
have been implemented specifically in response to requests from users
of the original Gamma Gage.
Gamma Gage II is intended for most any situation in which it is necessary
to "take the instrument to the sample."
Examples of such measurements are found in many waste assay and site
characterization measurements, as well in nuclear materials holdup,
and portable safeguards isotopic ratio measurements. In some cases,
a Gamma Gage dewar is an excellent solution when space/weight is at
a premium, for example, in Whole Body Counting applications or in some
multi-detector research applications, although increasingly, electrical
cooling is a viable alternative in these.The integral LN2 dewar is
available in a variety of hold times to suit the measurement constraints
on size/weight and holding time.
The Tale of Two Dewars
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All-Attitude
Gamma Gage II
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Multi-Orientation
(MOD) Gamma Gage II
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Two dewar type options on Gamma Gage II allow a choice between complete
all-attitude no-spill operation and no-spill operation in a slightly
restricted range of attitudes from a more compact dewar, the MOD dewar.
The definition of an all attitude dewar is that, apart from the inevitable
venting of boil-off liquid nitrogen during use, the liquid refrigerant
cannot escape from the dewar while the detector is in use, regardless
of the orientation ("attitude") of the dewar. This is achieved by the
relatively simple expedient of making the single fill-vent tube extend
the geometrical middle of the LN2 reservoir and no further. Thus whatever
the orientation of the dewar, the fill/vent tubes are above the level
of the liquid. The dewar is never more than 50% full.
In some situations, the constraint on size is more important, and a
dewar which may be filled completely is required, even at the expense
of having to restrict the range of movement allowed without some venting
of refrigerant. The MOD (multi-orientation dewar) option allows this.
It may be operated pointing vertically upward, downward or horizontally.
* Hold times are approximate for standard non-PopTop cryostats
in 2.75" diameter size endcap. Hold time for larger sizes, PopTop cryostats
and special cryostats may vary.
† At time of printing, only DigiDart portable MCA supports SMART-1 detector
option. This will be extended to other ORTEC MCA types in the near future,
ask factory for latest information.
§ Improved balance, operation stood vertically "on end" for in-field
grab sample counting, improved cabling, "on-board" storage of fill adapter,
SMART-1 intelligent detector option, etc
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Holding Times for Various Sizes
of Gamma Gage Detectors
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Dewar Type
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All Attitude
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Multi-Orientation (MOD)
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LN2 Volume
Hold Time1
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1.2 L
1 day |
3 L
2 days |
5 L
4 days |
3L
2 days |
7 L
5 days |
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Unit |
Tolerance |
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|
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Q |
mm |
±13 |
229 |
302 |
302 |
229 |
302 |
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(in.) |
±0.5 |
(9.0) |
(11.9) |
(11.9) |
(9.0) |
(11.9) |
|
Y |
mm |
±5 |
157 |
229 |
229 |
157 |
229 |
|
(in.) |
±0.2 |
(6.2) |
(9.0) |
(9.0) |
(6.2) |
(9.0) |
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Z |
mm |
±5 |
229 |
267 |
419 |
292 |
320 |
|
(in.) |
±0.2 |
(9.0) |
(10.5) |
(16.5) |
(11.5) |
(12.6) |
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1Holding times are
approximate for standard non-PopTop cryostats in 2.75 in, diameter
size endcap only. Hold time for PopTop cryostats and special
cryostats may vary. Actual hold times may vary depending on
specific dewar, cryostat and detector. |
The SMART-1 Detector Option
ORTEC’s new SMART-1 detector technology is a great advance in HPGe detectors
and their operation. (Currently the SMART-1 option is only available
in conjunction with the DigiDart portable MCA.) SMART-1 technology is
a major enhancement to data and chain of custody integrity. It is a
dramatic improvement in detector management practice and data control.
A SMART-1 detector is intelligent. The built-in controller monitors
and reports on all vital system functions. The individual vital signs
are available as well as the overall "state of health." The controller,
which includes the high voltage supply, is built into a module which
is firmly attached to the detector itself. Used in conjunction with
the DigiDART, the following attributes may be monitored to ensure correct
operation:
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This is NOT appropriate for
the MOD dewar.
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Preamplifier ±12, ±24 Volt values (read only)
Detector element temperature (read only)
Detector high voltage value (read only)
Detector high voltage state (on/off) (read/write)
Detector overload state
Detector high voltage shutdown state
Detector serial number (read only)
Detector authentication code (read/write) Gamma Gage II Fill
Options
Both the all-attitude and MOD versions of the Gamma Gage II include
fill funnels, to allow manual filling in a HORIZONTAL orientation. (Vertical
filling of the MOD dewar is NOT recommended.) Both dewar types are compatible
with the ORTEC manual and Automatic LN2 fill systems. The all-attitude
version may be filled or kept "at the ready" by attachment to the DWR
S/F "mother cow" long term storage dewar.
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Table 1. Multi-Orientation Dewar
vs. All-Attitude Dewar
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MOD |
All-Attitude |
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Ease of filling with a funnel |
More difficult and slower than
all-attitude |
Fills Easily |
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Ease of filling with a pressurized
source |
Equal |
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Storage/Fill Dewar |
Not compatible |
Easily used with S/F dewar |
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Size |
Smaller (all of the volume is utilized
for LN) |
Larger (only half the dewar volume
is utilized for LN) |
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Dry Weight (Same LN2 Capacity) |
Smaller dewar equals lighter weight |
Larger dewar equals heavier weight
(~4 lbs.) |
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Spill Possibilities |
LN is Easily Spilled by moving
dewar |
Very Difficult to make LN spill
out of ports |
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Rotation About Center Axis |
Causes pressurization of dewar
and consequent leakage of refrigerant |
No LN is spilled |
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Rotation on Longitudinal Axis (Tilting
Up or Down) |
Only 180°operation in one plane |
No LN is spilled |
Ordering Information
PopTop Types: To ORDER, specify:
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Model |
Description |
CFG-PG4-x
or
CFG-PG-x |
Gamma Gage II with x liter All
Attitude Dewar for use with PopTop Capsule x = 1.2, 3 or 5 (liter
dewar) |
CFG-PMOD4-3
or
CFG-PMOD-3 |
Gamma Gage II with 3L MOD Dewar
for use with PopTop Capsule |
CFG-PMOD4-7
or
CFG-PMOD-7 |
Gamma Gage II with 7L MOD Dewar
for use with PopTop Capsule |
NON-PopTop Types:
To ORDER, specify:
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Model |
Description |
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CFG-GG, DWR-1.2G |
non-PopTop Gamma Gage II with 1.2L
All-Attitude Dewar |
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CFG-GG, DWR-3.0G |
non-PopTop Gamma Gage II with 3.0L
All-Attitude Dewar |
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CFG-GG, DWR-5.0G |
non-PopTop Gamma Gage II with 5.0L
All-Attitude Dewar |
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CFG-GG, DWR-MOD-3L |
non-PopTop Gamma Gage II with 3.0L
MOD Dewar |
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CFG-GG, DWR-MOD-7L |
non-PopTop Gamma Gage II with 7.0L
MOD Dewar |
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