How to Read HPGe Thermistor
Make sure detector high voltage is turned off
Unplug pre-amp power
Unscrew detector electronics housing (8 screws total)
Arrows pointing to screws on detector electronics housing
Slide electronics housing towards the crystal end of the detector
Slide the sectioned area in the direction of the arrow to expose the thermistor terminals
Turn multimeter to resistance (Ω) setting
Measure resistance across the white/black wires the exit the white nylon 4 pinned terminal
Check resistance in tables below for corresponding detector temperature
Resistance and Corresponding Temperatures
100-109Ω
| Thermistor Resistance (Ω) |
Detector Temperature (Κ)
|
| 100 |
76.5780
|
| 101 |
77.0421
|
| 102 |
77.5063
|
| 103 |
77.9706
|
| 104 |
78.4352
|
| 105 |
78.9000
|
| 106 |
79.3649
|
| 107 |
79.8300
|
| 108 |
80.2952
|
| 109 |
80.7607
|
110-119Ω
| Thermistor Resistance (Ω) |
Detector Temperature (Κ)
|
| 110 |
81.2263
|
| 111 |
81.6921
|
| 112 |
82.1581
|
| 113 |
82.6242
|
| 114 |
83.0906
|
| 115 |
83.5571
|
| 116 |
84.0238
|
| 117 |
84.4906
|
| 118 |
84.9576
|
| 119 |
85.4248
|
120-129Ω
| Thermistor Resistance (Ω) |
Detector Temperature (Κ)
|
| 120 |
85.8922
|
| 121 |
86.3597
|
| 122 |
86.8275
|
| 123 |
87.2954
|
| 124 |
87.7634
|
| 125 |
88.2317
|
| 126 |
88.7001
|
| 127 |
89.1686
|
| 128 |
89.6374
|
| 129 |
90.1063
|
130-139Ω
| Thermistor Resistance (Ω) |
Detector Temperature (Κ)
|
| 130 |
90.5754
|
| 131 |
91.0446
|
| 132 |
91.5141
|
| 133 |
91.9837
|
| 134 |
92.4524
|
| 135 |
92.9234
|
| 136 |
93.3935
|
| 137 |
93.8637
|
| 138 |
94.3342
|
| 139 |
94.8048
|
140-149Ω
| Thermistor Resistance (Ω) |
Detector Temperature (Κ)
|
| 140 |
95.2755
|
| 141 |
95.7465
|
| 142 |
96.2176
|
| 143 |
96.6888
|
| 144 |
97.1603
|
| 145 |
97.6319
|
| 146 |
98.1036
|
| 147 |
98.5756
|
| 148 |
99.0477
|
| 149 |
99.5199
|
150-159Ω
| Thermistor Resistance (Ω) |
Detector Temperature (Κ)
|
| 150 |
99.9923
|
| 151 |
100.4649
|
| 152 |
100.9377
|
| 153 |
101.4106
|
| 154 |
101.8836
|
| 155 |
102.3569
|
| 156 |
102.8303
|
| 157 |
103.3038
|
| 158 |
103.7775
|
| 159 |
104.2514
|
160-169Ω
| Thermistor Resistance (Ω) |
Detector Temperature (Κ)
|
| 160 |
104.7254
|
| 161 |
105.1996
|
| 162 |
105.6740
|
| 163 |
106.1485
|
| 164 |
106.6232
|
| 165 |
107.0980
|
| 166 |
107.5730
|
| 167 |
108.0482
|
| 168 |
108.5235
|
| 169 |
108.9989
|
170-179Ω
| Thermistor Resistance (Ω) |
Detector Temperature (Κ)
|
| 170 |
109.4746
|
| 171 |
109.9503
|
| 172 |
110.4263
|
| 173 |
110.9024
|
| 174 |
111.3786
|
| 175 |
111.8550
|
| 176 |
112.3316
|
| 177 |
112.8083
|
| 178 |
113.2851
|
| 179 |
113.7622
|
180-189Ω
| Thermistor Resistance (Ω) |
Detector Temperature (Κ)
|
| 180 |
114.2393
|
| 181 |
114.7167
|
| 182 |
115.1941
|
| 183 |
115.6718
|
| 184 |
116.1496
|
| 185 |
116.6275
|
| 186 |
117.1056
|
| 187 |
117.5838
|
| 188 |
118.0622
|
| 189 |
118.5408
|
190-199Ω
| Thermistor Resistance (Ω) |
Detector Temperature (Κ)
|
| 190 |
119.0194
|
| 191 |
119.4983
|
| 192 |
119.9773
|
| 193 |
120.4564
|
| 194 |
120.9357
|
| 195 |
121.4152
|
| 196 |
121.8947
|
| 197 |
122.3745
|
| 198 |
122.8544
|
| 199 |
123.3344
|
Thermistor Reading Log
| Date & Time |
Thermistor Measurement (Ω) |
Detector Thermal Cycled Between Previous Measurement |
Notes
|
| 4/13/22 11:45am |
241.2 |
Yes |
Detector casing cold to touch, has been cooling down >72hrs
|
| 4/13/22 1:50pm |
229.3 |
No |
|
| 4/14/22 11:26am |
176.0 |
No |
|
| 6/2/22 11:46am |
185.0 |
No |
Cooler was off for a few minutes prior due to detector being moved to other side of room
|
| 6/16/22 10:00am |
176.8 |
No |
Measured before use of high voltage
|
| 6/30/22 11:00am |
184.1 |
No |
Preliminary shutdown cable measurement of -11.97, .1V away from normal of -11.87V
|
| 7/3/22 12:45m |
182.2 |
No |
|
PAS HPGe Detector
