Difference between revisions of "CH HPGe Log"

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! Date of pump down !! Components !! Reason
 
! Date of pump down !! Components !! Reason
 
|-
 
|-
−
| 05/2021 || Cold head and poptop || Detector had not been used in years
+
| 05/2021 || X-Cooler 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)
+
| 07/20/2022 || Poptop || Detector temp increased (~5 degree increase in ~14 days, according to thermistor).
 +
|-
 +
| 11/09/2022 || Poptop || Detector resolution changed dramatically from 1.4KeV to 2.1KeV then to 5KeV with what looks to be double humped peaks.
 +
|}
 +
 
 +
='''Maintenance'''=
 +
 
 +
{| class="wikitable mw-collapsible" border="2" style="text-align:center;" |cellpadding="20" cellspacing="1
 +
|-
 +
! Date !! Components !! Reason !! Outcome
 +
|-
 +
| 11/09/2022 || X-Cooler II || Ortec sent new o-ring, sieve pill, and high vacuum grease to help try and remedy issues listed above under pumpdown for 11/09/2022. ||
 +
|-
 +
| 11/10/2022 || Poptop ||  Detector thermal contacts were cleaned using small amount of acetone and q-tips. Left to air dry before reassembly. Old sieve pill looks discolored but will be saved and stored as they can be refurbished via baking at IAC. ||
 
|}
 
|}
  
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  Make sure detector high voltage is turned off
 
  Make sure detector high voltage is turned off
  
−
  Unplug pre-amp power
+
  Unplug (or turn off) pre-amp power
  
 
  Unscrew detector electronics housing (8 screws total)
 
  Unscrew detector electronics housing (8 screws total)
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='''Thermistor Reading Log'''=
 
='''Thermistor Reading Log'''=
  
−
{| class="wikitable mw-collapsible" border="2" style="text-align:center;" |cellpadding="20" cellspacing="1
+
{| class="wikitable mw-collapsible mw-collapsed" border="2" style="text-align:center;" |cellpadding="20" cellspacing="1
 
|-
 
|-
 
! Date !! Time !! Thermistor Measurement (Ω) !! Detector Thermal Cycled Between Previous Measurement !! Notes
 
! Date !! Time !! Thermistor Measurement (Ω) !! Detector Thermal Cycled Between Previous Measurement !! Notes
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|-
 
|-
 
| 07/25/22 || 10:10am|| 169.5 || No || Detector continued to cool over a weekend, shutdown cable = -11.99V
 
| 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.
 +
|-
 +
| 11/07/22 || 7:45am|| 192.6 || No || Detector cooling for >36hrs.
 +
|-
 +
| 11/10/22 || 3:55pm|| ---- || Yes || Began cooling detector at 3:55pm.
 +
|-
 +
| 11/11/22 || 10:15am|| 168.6 || Yes || Maintenance on X-Cooler and pumpdown seems to have been successful.
 
|-
 
|-
 
|}
 
|}

Latest revision as of 17:18, 11 November 2022

Pump downs

Date of pump down Components Reason
05/2021 X-Cooler and Poptop Detector had not been used in years.
07/20/2022 Poptop Detector temp increased (~5 degree increase in ~14 days, according to thermistor).
11/09/2022 Poptop Detector resolution changed dramatically from 1.4KeV to 2.1KeV then to 5KeV with what looks to be double humped peaks.

Maintenance

Date Components Reason Outcome
11/09/2022 X-Cooler II Ortec sent new o-ring, sieve pill, and high vacuum grease to help try and remedy issues listed above under pumpdown for 11/09/2022.
11/10/2022 Poptop Detector thermal contacts were cleaned using small amount of acetone and q-tips. Left to air dry before reassembly. Old sieve pill looks discolored but will be saved and stored as they can be refurbished via baking at IAC.

How to Read HPGe Thermistor

Make sure detector high voltage is turned off

Unplug (or turn off) 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.
11/07/22 7:45am 192.6 No Detector cooling for >36hrs.
11/10/22 3:55pm ---- Yes Began cooling detector at 3:55pm.
11/11/22 10:15am 168.6 Yes Maintenance on X-Cooler and pumpdown seems to have been successful.

PAS HPGe Detector

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