🧪 Vintage U.S. Nuclear Corp. SP-200 Spectrometer + RM-420 Ratemeter |

Original Or Reproduction

Vintage original

Asking Price: $200 OBO Location: Cerritos, CA (Local pickup preferred — unit weighs approx. 60+ lbs) Dimensions: 14.5" W × 22" D × 28.5" H Condition: Untested. Vintage, complete, unrestored. Sold as-is. 📦 What’s Included This is a complete mid-century integrated nuclear spectroscopy system from U.S. Nuclear Corporation of Burbank, California — a rare survivor of Cold War-era radiation research instrumentation. This rack contains two fully-labeled original modules: 1️⃣ Model SP-200 – Transistorized Automatic Recording Spectrometer Serial No. 6005 Front panel includes: Energy Scale (MeV) dial Sweep Time Set options Auto Sweep, Reset, Start functions Analog gain & window controls Built-in chart recorder by Westronics, a leading industrial recording brand of the 1960s Used for analyzing gamma radiation energy levels over time and recording spectra in analog form 2️⃣ Model RM-420 – Precision Ratemeter Serial No. 6048 Dual analog meters labeled: Count/Time Constant Kilovolts (HV Output) Background Suppress, Calibrate, Zero, High Voltage controls Used for displaying count rates in real-time from paired detectors (GM tubes or scintillation probes) 🔌 Rear Panel Highlights Fully populated with: PRE-AMP, HV, G.M., Input/Output, and ACCESSORY jacks Original vacuum tubes, transformers, and cooling fan Octal-style and mil-spec circular connectors (1 cable included) Standard 117V/115V power input (typical of 1960s lab equipment) 🧠 Historical Context Manufactured by U.S. Nuclear Corporation, Burbank, CA, a licensed Atomic Energy Commission (AEC) contractor active in the 1950s–70s. This exact style of equipment was used in: University nuclear physics labs Government facilities for radiation testing DOE/AEC experiments involving gamma spectroscopy and uranium/thorium analysis The term “Transistorized” and hybrid vacuum tube design place this model in the early-to-mid 1960s — a transitional era for lab equipment moving from vacuum tubes to solid-state tech. This is not a replica, toy, or art piece — it’s an authentic piece of Cold War scientific hardware from a real AEC-approved instrumentation manufacturer. 🧠 What it did (plain English) The RM-420 ratemeter converted detector pulses into a continuous reading of count rate (counts per second/minute) and fed the display/recording. It would be used with Geiger-Müller probes or, more likely here, a scintillation detector + photomultiplier (PMT) for gamma spectroscopy. The SP-200 spectrometer swept/selected energy windows (note the MeV scale) and recorded the output on paper via the Westronics chart recorder—standard practice in that era’s spectrometers (spectrometer + HV supply + ratemeter + recorder). (Representative 1950s–60s instrument descriptions show this exact combination.) ⚠️ Condition & Notes Untested. This system has been stored in a dry garage for over 15 years. Original condition — dust, oxidation, and age-related wear visible. Power-up has not been attempted; this should be treated as non-functional unless inspected/restored by a qualified vintage electronics hobbyist or lab equipment restorer. No radioactive sources included or present. Sold as-is — no guarantees, returns, or warranties. ✅ Why This Matters to Collectors Two fully-labeled, serial-tagged modules from a known AEC-licensed U.S. manufacturer Includes original meters, dials, tubes, chart recorder, and connectors An unusually complete example of a 1960s-era gamma spectroscopy system Ideal for: Historical display Electronics restoration Museum piece Industrial/steampunk art Cold War science collectors 🔍 Provenance Highlights SP-200 (S/N 6005) and RM-420 (S/N 6048) built by U.S. Nuclear Corp., Burbank, CA Integrated Westronics chart recorder Original mil-spec connectors, octal sockets, and vacuum tube modules Design consistent with instrumentation referenced in DOE/AEC documents, physics journals, and university procurement records from the early 1960s 🚚 Shipping / Pickup Info Local pickup strongly preferred (Cerritos, CA – 90703). Approximate weight: 60 lbs If shipping is required, buyer must arrange packing/shipping — due to fragility (glass tubes, analog meters, etc.) this unit will require special care. 📸 Photos Available Front & rear views Internal electronics (tubes, transformers, fan) Nameplates, connectors, original cable Message me for close-ups or additional shots 💬 Questions Welcome I'm happy to answer questions or provide specific photos for serious buyers. If you're a collector, lab restorer, or just a vintage tech nerd — this is a rare, intact piece of U.S. nuclear history. Asking $200 OBO – open to reasonable offers. Thanks for looking!