Additional Mechanical Information

B1. Materials

Material	Pros	Cons
PEEK	Very available Light compared to metals at 1.32g/cm^3 (Curbell plastics, n.d.) Radiation Resistant (Ensinger, n.d.)	Does not have strong shielding properties without high Z materials added as composite. (Khozemy et al., 2022)
PEEK infused with heavy atoms	Strong shielding properties. (Khozemy et al., 2022)	Unavailable and expensive. (Khozemy et al., 2022)
Aluminium 6061	Very available	Only shields alpha and beta particles. (IMS Team, n.d.)
Concrete	Strong shielding properties. (IMS Team, n.d.) (Onaizi et al, 2024)	Heavy and brittle (Onaizi et al, 2024)
Lead	Strong shielding properties. (IMS Team, n.d.)	Environmental unfriendly (Sampson, n.d.) Heavy

Table B-1. Materials comparison.

B2. GM Counter

fig b-1

Figure B-1. GM Counters.

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Figure B-2. GM Counter Specs.

Background radiation can fluctuate from 20 to 100 CPM. Product Link

B3. Radiation Experiment Data

Each reading is 30 minutes.

We first check whether the two counters are calibrated. A total of 7 readings are taken, with both GM Counters left outside.

No.	Counter A	Counter B
1	2598	2613
2	2612	2542
3	2586	2576
4	2624	2710
5	2655	2453
6	2587	2573
7	2534	2474
Avg	2599.43	2563.00
CPM	86.64761905	85.43333333

Table B-2. Counter Data.

The counters are calibrated and have very close values.

fig b-3

Figure B-3. GM Counters and aluminium boxes.

Next we put Counter A inside the box and Counter B outside the box and take the reading. We swap the two counters and take the readings again to average out any errors from their differences. Then we repeat for different thicknesses.

Raw Data	Counter A	Counter B		Counter A	Counter B
Thickness	Inside Box (1)	Inside Box (2)	Inside Box (Average)	Outside Box (1)	Outside Box (2)	Outside Box (Average)
0mm	2598	2576	2587	2613	2586	2599.5
2mm	2480	2428	2454	2496	2613	2554.5
4mm	2247	2448	2347.5	2526	2579	2552.5
6mm	2294	2262	2278	2596	2635	2615.5
8mm	2258	2247	2252.5	2600	2548	2574
10mm	2093	2079	2086	2557	2629	2593

Table B-3. Counter Data in aluminium boxes.

We tabulate the data below.

Thickness (mm)	Inside Box CPM	Outside Box CPM	Absolute Difference (CPM)	Percentage Drop
0	2587	2599.5	0.42	0.48%
2	2454	2554.5	3.35	3.93%
4	2347.5	2552.5	6.83	8.03%
6	2278	2615.5	11.25	12.90%
8	2252.5	2574	10.72	12.49%
10	2086	2593	16.90	19.55%

Table B-4. Counter Data Analysis.

Graph is plotted with an error bar. More data has to be collected.

fig b-4

Figure B-4. Counter Data Analysis.

B4. CAD Models

fig b-5

Figure B-5. Top view.

fig b-6

Figure B-6. Bottom view.

fig b-7

Figure B-7. Side view.

fig b-8

Figure B-8. Isometric view.

fig b-9

Figure B-9. Isometric (Without Central Shielding).

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Figure B-10. Inner Side of High Voltage PCB.

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Figure B-11. Inner Side of Low Voltage PCB.

B5. Dimensions and Specifications

Item	Dimensions (mm by mm)	Area (mm^2)	Thickness (mm)
PCB Plate	94.39 x 90.33	8526.25	2.00 (estimated)
PCB Plate (Usable)	70.75 x 57.79	4088.64	2.00 (estimated)
Z-SOM	68.00 x 45.00	3060.00	2.00 (estimated)
AT-Mega	10.00 x 10.00	100.00	2.00 (estimated)
GM Tube	49.20 x 15.10	742.92	15.10
HV Converter	28.00 x 15.00	420.00	8.000
Side Shielding	90.33 x 79.26	7159.56	4.00
Central Shielding	90.31 x 79.29	7160.68	4mm thickness, 24mm height

Table B-5. Dimensions and Specifications.

B6. Bill of Materials and Mass Budget

Item	Material	Manufacturing Method	Estimated Mass (g)	Number of Counts	Total Mass (g)
PCB Plate	PCB Plastic	Bought	30	2	60
Z-SOM	PCB Plastic	Bought	20	1	20
AT-Mega	PCB Plastic	Bought	5	2	10
GM Tube	446 Stainless Steel	Bought	8.0	1	8.0
HV Converter	Steel with Zinc Plating	Bought	50	1	50
Top/Bottom Shielding	Aluminum 6061	Laser Cut/CNC	31.40	2	62.80
Centre Shielding	Aluminium 6061	CNC	89.12	1	89.12

Table B-6. Bill of Materials and Mass Budget.

Total Mass: 299.92 grams