# Gamma Guru — Gamma-ray Energy Reference

> Radioisotope gamma-ray reference and decay calculator. (iPhone/iPad app by Matthew Kiser.)

- Source: https://appshunter.io/ios/app/gamma-guru/id1610890905 (this page in markdown: same URL + `.md`)
- Developer: [Matthew Kiser](https://appshunter.io/developer/1610890907)
- Category: Reference, Education
- Price: $3.99
- Rating: 5.00/5 from 2 App Store ratings
- Age rating: 4+
- Requires: iOS 15.2 · 2 MB
- Languages: American English
- Released: 2022-02-20
- Data updated: 2026-06-01
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/gamma-guru/id1610890905/reviews.md

## What is Gamma Guru?

Gamma Guru provides fast, convenient access to a library of over 400 radioisotopes. Simply select an isotope of interest from the Isotope Library to view the associated gamma-rays and branching ratios and other information. Alternatively, enter up to three gamma-ray energies to see a list of isotopes that emit those gammas. Gamma Guru also includes radioactive decay and dose rate calculators.

## Key features

- Extensive radioisotope library
- Gamma-ray and branching ratio data
- Isotope identification by gamma energy
- Radioactive decay calculator
- Dose rate calculator


## Frequently asked questions about Gamma Guru

### What is Gamma Guru?

Gamma Guru is a reference application that provides access to a library of over 400 radioisotopes, their gamma-ray data, and includes radioactive decay and dose rate calculators.

### How many radioisotopes are in Gamma Guru?

Gamma Guru features a library of over 400 radioisotopes, offering extensive data for each.

### Can Gamma Guru identify isotopes?

Yes, you can enter up to three gamma-ray energies into Gamma Guru, and it will provide a list of isotopes that emit those specific gammas.

### What calculators are included in Gamma Guru?

Gamma Guru includes both a radioactive decay calculator and a dose rate calculator to assist with nuclear physics calculations.

### What devices does Gamma Guru support?

Gamma Guru is available for iPhone, iPad, and iPod devices, ensuring broad compatibility for Apple users.

### How much does Gamma Guru cost?

Gamma Guru is a paid application, priced at $3.99, offering a one-time purchase for full access to its features.

### Is Gamma Guru updated frequently?

The latest version of Gamma Guru is 1.5, and it was last updated on February 10, 2026, indicating ongoing development and support.

### What is the age rating for Gamma Guru?

Gamma Guru has an age rating of 4+, making it suitable for a wide range of users interested in nuclear science.

## Version history (last 5 releases)

### 1.5 — 2026-02-10

Updated for latest iOS requirements. Improved isotope search and list navigation.

### 1.4 — 2022-03-04

New features added in Version 1.4:
- Isotope selection now tracks across Isotope Library, Decay, and Dose Rate views.
- Isotope Search research are now clickable - tapping on a particular isotope automatically navigates to the corresponding entry in the Isotope Library.

### 1.3 — 2022-02-28

Improvements in this version:
- smashed bug related to user defaults not initializing correctly

### 1.2 — 2022-02-27

Improvements in this version include:
 - isotope selection is now a wheel picker on all screens
 - columns are now sortable in Isotope Library
 - updated Isotope Search window
 - added user Settings for default isotope, energy threshold, half-life threshold, and search energy window
 - smashed bug when viewing last isotope in library
 - added useful References (more to come)

### 1.1 — 2022-02-21

Keypad entry boxes now support decimal values;
Clear button now included for all entry boxes to reset values

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-01.*