Pump downs
| Date of pump down |
Components |
Reason
|
| 05/2021 |
Cold head and poptop |
Detector had not been used in years
|
| 07/20/2021 |
Poptop |
Detector temp increased (~5 degree increase in ~14 days, according to thermistor)
|
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 that 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
|
| 04/13/22 |
11:45am |
241.2 |
Yes |
Detector casing cold to touch, has been cooling down >72hrs
|
| 04/13/22 |
1:50pm |
229.3 |
No |
|
| 04/14/22 |
11:26am |
176.0 |
No |
|
| 06/02/22 |
11:46am |
185.0 |
No |
Cooler was off for a few minutes prior due to detector being moved to other side of room
|
| 06/16/22 |
10:00am |
176.8 |
No |
Measured before use of high voltage
|
| 06/30/22 |
11:00am |
184.1 |
No |
Shutdown cable measurement of -11.97, change from normal of -11.87V
|
| 07/03/22 |
12:45pm |
182.2 |
No |
|
| 07/06/22 |
11:40am |
181.7 |
No |
Detector warmed after this measurement in prep for pumpdown
|
| 07/21/22 |
10:50am |
177.2 |
Yes |
Poptop pumped down by IAC, chiller turned on 3:50pm 07/20/22
|
| 07/21/22 |
11:00am |
176.2 |
No |
Repeat of above
|
| 07/21/22 |
11:30am |
174.7 |
No |
Repeat of above
|
| 07/21/22 |
12:30pm |
173.4 |
No |
Repeat of above
|
| 07/21/22 |
1:22pm |
172.0 |
No |
Repeat of above
|
| 07/21/22 |
2:11pm |
171.2 |
No |
Repeat of above
|
| 07/21/22 |
3:30pm |
170.3 |
No |
Repeat of above
|
| 07/25/22 |
10:10am |
169.5 |
No |
Detector continued to cool over a weekend, shutdown cable = -11.99V
|
| 10/27/22 |
10:55am |
181.2 |
No |
Resolution of detector changed from ~1.4KeV FWHM to ~2.1KeV FWHM
|
| 11/01/22 |
10:48am |
171.8 |
Yes |
Thermal cycle of detector in attempt to bring temp back down, attempt was successful.
|
| 11/03/22 |
12:16pm |
175.1 |
No |
Cs137 peak was wide, poor energy resolution. HV/Preamp turned off, detector beginning to cool again.
|
| 11/03/22 |
1:00pm |
170.8 |
No |
Preamp & HV off for 45 mins, detector cooled again.
|
| 11/06/22 |
12:58pm |
184.2 |
Yes |
Thermal cycled detector due to >5KeV sigma in energy peaks.
|
PAS HPGe Detector
